Svoboda | Graniru | BBC Russia | Golosameriki | Facebook
Next Article in Journal
Sedimentary Characteristics and Evolution of the Late Miocene to Quaternary Tributary Channels in the Head of Bounty Channel, New Zealand
Next Article in Special Issue
Optimizing the Influence of Fly Ash as an Anti-Sagging Additive in Highly Deviated Geothermal Well Drilling Fluids Using Surface Response Method
Previous Article in Journal
Entity-Alignment Interaction Model Based on Chinese RoBERTa
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Applied Sciences
Volume 14
Issue 14
10.3390/app14146161
applsci-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Reducing Torque and Drag in Extended-Reach Wells Using Thermoplastic Polymers for Protective Sliding Rings

by
Karim El Sabeh
,
Borivoje Pašić
*,
Petar Mijić
and
Igor Medved
Faculty of Mining, Geology and Petroleum Engineering, University of Zagreb, 10000 Zagreb, Croatia
*
Author to whom correspondence should be addressed.
Appl. Sci. 2024, 14(14), 6161; https://doi.org/10.3390/app14146161
Submission received: 4 May 2024 / Revised: 5 July 2024 / Accepted: 11 July 2024 / Published: 15 July 2024
(This article belongs to the Special Issue Recent Advances in Drilling Fluid Technologies)
Browse Figures
Versions Notes

Abstract

:
Extended-reach drilling represents an advanced way of drilling and accessing reservoirs that were previously economically not feasible to drain, impossible to reach or in an environmentally sensitive area. One of the main issues that appears while drilling such wells is caused by the high values of friction factor which cause high values of torque and drag. One of the suggested solutions is to use a protective sliding ring made from materials such as POM, Teflon and PA6 in combination with lubricants added to a polymer mud system. First, measurements were conducted on a lubricity tester to choose the best material and, after finishing, a mechanical wear test was conducted on a specially designed device to measure mechanical wear. Results showed that Teflon showed lower values of friction factor in comparison to steel and the mechanical wear was minimal. The lowest value of friction force was recorded for blocks made from Teflon in tested mud systems. It is also noticeable that, in polymer mud with weighting additives and lubricant, the value of the friction force is higher than in polymer mud with lubricant only.

1. Introduction

Successful wellbore construction is an exceptionally challenging process and, because a large number of potential problems can occur, drilling processes can be slowed down and in extreme cases the well may be even abandoned [1,2,3,4,5]. Further, the mentioned problems result in non-productive time, and cause additional cost for companies involved in the drilling process as well. According to some sources, wellbore instability alone causes more than a billion unplanned costs for the oil and gas industry and makes up approximately one-third of all unplanned costs during drilling operations [6,7,8,9].
With the increased depth of drilled wellbores and the increasing number of inclined and horizontal wells, the oil and gas industry faces issues which were not encountered during the drilling of vertical wells [10]. On the other hand, horizontal wells have become a common method that enable economical access to oil or gas reservoirs from existing vertical wellbores, enable access to reserves that were previously out of reach, and reduce the negative impact on environment [11].The main purpose of drilling horizontal wells, i.e., wells whose production section occupies a horizontal position in space, is increasing the contact area of the wellbore with the oil or gas reservoirs [12], thus increasing the productivity/injectivity of these wells. Therefore, despite all the risks arising from this type of wellbore trajectory, in certain cases this is either a better or the only option for the economical production of hydrocarbons from certain underground formations [13,14]. Also, the capacity of fluid injection is better compared to vertical wells under equivalent differential pressures [15]; therefore, horizontal wells are used for EOR projects, and are widely used in offshore projects [15,16]. The productivity of horizontal wells largely depends on the length of the horizontal section of the wellbore through the production formation [17]. If it is determined that it is cost effective, extended-reach drilling (ERD) is the best variant for the maximum exploitation of the underground formation potential compared to a development of the same reservoir with a few vertical wells. Horizontal wells with an extended reach can have a very long wellbore and a relatively small true vertical depth, so the kick off point can be located shallowly, as shown in Figure 1(5). Also, an extended-reach well can be used as the best option for the development of the offshore field, ensuring distant parts of the reservoirs are reached from one fixed location above the sea.
Extended-reach drilling uses directional and horizontal drilling techniques and represents an advanced form of directional and horizontal drilling technology. An extended-reach well can be defined as a well where the ratio between the horizontal reach and true vertical depth is larger than 2, or where the horizontal displacement is greater than 6096 m (20,000 ft) [18,19,20]. With the development of the industry, the technical limits that once existed in the construction of this type of well are becoming less of a problem nowadays, and the longest extended-reach well today has a measured depth of 15,240 m (50,000 ft) [18]. Although these records are broken primarily due to the development of the equipment needed to drill such demanding wells, special attention should be placed on the drilling fluid design, as this is probably the most important and most expensive component of the drilling process [21]. Drilling fluid selection for extended-reach drilling must fulfill all the functions needed for a successful drilling process, such as removing drill cuttings from the well to the surface (hole cleaning), this the primary barrier to formation pressure, providing lubrication for the drill string and drill bit, stabilizing the wellbore and ensuring filtration through its walls, and many others [22,23,24,25]. Also, there is a more pronounced problem related to possible reservoir damage, especially in the large open-hole section, which is often the case in extended-reach drilling. With all the above, extended-reach drilling requires excellent control of other extremely important factors, such as torque and drag, equivalent circulating density (ECD) and lost circulation [18,22,26,27], to avoid non-productive time and the possible above-mentioned problems.
As mentioned earlier, during drilling conventional and especially for a horizontal well, various technical problems can occur, and most of them are due to high values of torque and drag forces which are caused by high friction. High torque and drag values represent a big problem while drilling deviated wells, especially in the deviated and horizontal part of the well and, basically, they affect the possibility of drilling wells, that is, they affect the possibility of drilling wells with a designed path. The important thing for successfully drilling this type of well is using the drill string to put weight on the bit through the deviated and horizontal section of the well. This means placing the drill collars as well as heavy-weight drill pipe in the vertical section of the wellbore, while the rest of the drill string through the deviated and horizontal section is composed of drill pipe. Another thing that should be paid attention to is to not allow the bending of the drill string if it is under a lot of compression load, which is often the case during the drilling of the large horizontal section in extended-reach drilling. This significant increase in compressive load is directly a consequence of the position of the drilling string within the wellbore. Unlike the drilling of the vertical well, where the used drill string is positioned theoretically in the center of the wellbore with minimum contact with the wellbore wall, in directional, horizontal, and extended-reach drilling the used drill string lies on the lower wall of the wellbore. This situation entails increased contact between the used drill string and wellbore wall as well, significantly increasing torque and drag forces during drilling and casing installation operations. Except for drilling operations, all the above-mentioned problems make well completion and workover operations difficult to perform as well.
Despite increased torque and drag forces, there are extensive problems related to the drill pipe joint wearing, since the joints are the most exposed part of the drill pipe and in direct contact with the wellbore wall (steel casing or rock in the open-hole section). This problem can be solved by adding pipe protectors/nonrotating rings on the pipe body or by the hardbanding of the pipe joint with wolfram carbide or some other materials (Figure 2). In the first case, adding the pipe protectors/nonrotating rings on the pipe body inevitably increases the contact point between the drill string and wellbore wall, and in the second case, the hardening of the pipe joint can cause excessive wear of the installed casing string.
Decreasing the torque and drag values can be achieved using different methods because usually using only one method does not solve the issue related to increased values of torque and drag. Most research conducted by different groups of researchers is directed at reducing the friction factor by changing the mud fluid composition (using lubricants or oil-based muds, as well as protecting the drill string/casing from mechanical wear) [28,29].
Geng et al. (2023) have introduced a new lubricant derived from triolein. After the preparation of graphene and triolein, they were incorporated in the mud system. After aging for 16 h at a temperature of 240 °C, an examination of the rheological and filtration properties was conducted to test the impact of the lubricant on the mud system as well as the lubricating performance of the drilling fluid. They concluded that adding lubricant at a temperature of 240 °C has successfully controlled the adhesion coefficient of the drilling fluid to below 0.2, reaching a minimum of 0.055, resulting in a reduction rate of over 70% [30]. Ji et al. (2023) studied the effect of two kinds of synthesized microcapsules filled with ionic liquids (e.g., [OMIM]Br and [OMIM]BF4), acting as smart tribological additives for water-based drilling mud. The results showed a successful reduction in friction, with the coefficient of friction decreased by 25.7% (from 0.35 to 0.26) for [OMIM]Br and 22.9% (from 0.35 to 0.27) for [OMIM]BF4 when compared with the basic mud [31].
To reduce torque and drag while drilling, it is desirable to use some of the below-mentioned procedures and techniques, such as [32]:
  • Optimization of a well trajectory plan;
  • Proper selection of the drilling bit;
  • Proper drill string design;
  • Use of a rotary steerable system;
  • Use of a modular motor;
  • Use of non-rotating drill pipe protectors;
  • Use of lubricants;
  • Optimization of hole cleaning.
The main goal of this research is to find a technical solution for reducing the friction factor and protect the dill pipe from extensive wear during the drilling of extended-reach wells. One of the considered technical solutions is to use a sliding protective ring made from different materials that will be installed on the tool joint. It will have the role of protecting the tool joint from material wear and tear and to reduce friction factor appearing from contact between the drill string and the casing/open hole at the same time.
The starting point in this research, and hypothesis at the same time, was the assumption that different materials in contact with the steel casing achieve a smaller friction coefficient regarding the usual contact between the steel drill string and steel casing. With this examination, different materials were evaluated in order to evaluate their applicability as materials for sliding protective rings. After initial analysis, certain materials such as PA6 (polyamide), POM (polyoxymethylene) and Teflon were chosen for laboratory testing. These materials were chosen due to their temperature- and pressure-related ability to withstand similar conditions to those in the well, as well as their known durability. Also, we decided to use a combination of lubricants and to use different materials, which the sliding protective ring will be made from, to simulate the real downhole condition in the wellbore during extended-reach drilling.

2. Laboratory Testing

Over the years, significant advances have been made in the development of lubricants aimed at reducing friction, and thus the torque that will occur during drilling. Due to the difficult working conditions in the field and the impossibility of the continuous monitoring of the changes occurring in the well, it is necessary to carry out detailed laboratory tests aimed at selecting the appropriate lubricant and material to produce the protective sliding rings.
All laboratory tests, whose results are shown in this paper, have been conducted in the laboratory for drilling fluids at the Faculty of Mining Geology and Petroleum Engineering, University of Zagreb, and in the laboratory for machine elements at the Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb.
In the laboratory for drilling fluids, according to API standards (API RP 13B-1 [33] and 13B-2 [34]), the physical parameters of the used drilling fluid have been tested. The OFITE lubricity tester shown in Figure 3 was used for the assessment of the lubricating potential of drilling fluids, providing data to evaluate the type and quantity of lubricating additives that may be required in known fluid systems.

Materials Used for Measuring

On the lubricity tester, a test was carried out on different materials such as steel (regularly used), Teflon, PA6 and POM, which could potentially be used for the manufacturing of protective sliding rings. To ensure the uniformity of the laboratory test, the blocks made from PA6, Teflon and POM are produced in the same dimensions as the steel block as it is described in the manual of the OFITE lubricity tester. The blocks made from steel, PA6, Teflon and POM are shown in Figure 4.
Polyamide 6 (PA6)
Polyamides are a group of mostly crystalline plastomers which, according to their use, belong to the group of structural plastomers and are a common material used to produce polymer gears and other structural elements [35].
Polyoxymethylene (POM)
Polyoxymethylene (POM) is one of the polymers with excellent mechanical properties developed in recent years. Polyoxymethylene (POM) belongs to the type of crystalline polymer material with a degree of crystallinity over 70%. Thanks to the strong –C–O– structure in its main chain, POM maintains the characteristics of stable chemical compositions and excellent mechanical properties, such as high strength/stiffness, favorable impact/creep resistance, and prominent long-term durability [36].
Teflon
Teflon is a synthetic fluoropolymer made up of a tetrafluoroethylene monomer. The chemical name of Teflon is poly (1,1,2,2 tetrafluoroethylene). It is a thermoplastic polymer. Teflon’s chemical formula is (C2F4)n. The Teflon formula shows repetitive or n numbers of C2F4 units. It has an ability to maintain high strength, toughness, and self-lubrication at low temperatures (around −268.15 °C (5 K)), and good flexibility at temperatures above −79.15 °C (194 K) [37].
When testing the drilling fluid lubricity, two steel surfaces are brought into contact and in between them a friction force occurs, i.e., a rotating ring is placed on a rotating shaft and during the measurement it is brought into contact with a steel block. In this way, the friction force that occurs is simulated between the drill string and the casing string both made from steel material.
The lubricity Test should only be performed when the unit has been successfully calibrated with deionized water and gives a coefficient of friction reading of 34 ± 2 (that is, the friction force value). After the device is calibrated, mud lubricity testing is carried out for 5 min, after which the torque value is read and recorded. The measurement was performed for 15 min, and the reading was recorded after 5, 10 and 15 min. After the device is brought to the speed of rotation of the shaft, and therefore the ring, of 60 rpm, the torque arm is positioned so it is inside the torque arm clamp and then, turning the torque adjust handle, so the gauge reads 17 Nm (150 lb-in), is applied to the block, and then contact between the two surfaces is achieved.
In the laboratory for machine elements, mechanical wear was measured on a Teflon block in polymer mud with and without weighting agents, in which lubricants were added in specific concentrations. For this test, a device was designed and manufactured at the Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, and its function was measuring the mechanical wear of machine parts that are in direct contact. In Figure 5, a schematic representation of the device for measuring the mechanical wear of machine parts that are in direct contact is given, and in Figure 6, the manufactured device is shown (Timken).
The device consists of a frequency regulator (1) that displays data on the rotation speed of the shaft for measuring the torsional moment; (2) that is integrated into the rotational part, a force converter; (3) that is built into the part that serves to generate the load, a non-contact temperature indicator; (4) that has a measuring amplifier; (5) that has a computer program for data collection and (6) that is installed on a personal computer [38].
Figure 7 shows the test block made from Teflon.
In Table 1, the composition of drilling fluid used in these laboratory tests is shown. The selected polymer drilling fluid was chosen based on similar drilling fluid that is used to drill deviated and extended-reach wells within a reservoir (drill-in fluid) in the Republic of Croatia. The laboratory test was conducted on simple drill-in polymer fluid with and without different-sized marble particles of weighting/plugging materials as well as with and without commercial lubricant in a concentration of 2% vol. This variation in composition is very important, because solid particles as well as lubricant directly influence the friction coefficient and consequently the torque and drag force.
After researching the literature, we decided to use lubricant in the drilling fluid at a concentration of 2%. In this experiment, two commercial lubricants intended for use for extended-reach drilling were tested at a concentration of 2% vol. in polymer fluid with and without weighting additives (in the following text for PLX2 or PWLX2: P—polymer mud, W—weighting additive, L—lubricant, X—type of lubricant, 2—concentration in %).

3. Results and Discussion of Conducted Laboratory Research

According to the lubricity tester manual, the test is performed for 5 min and then the friction force value is recorded; so, for the steel block, the test was performed for both polymer fluids with and without weighting additives in which one of three lubricants, X, Y and Z, was added at a concentration of 2% vol. The results of friction force for the steel block after 5 min of testing are given in Table 2, and they will be used for comparing the results obtained with test blocks made from thermoplastic polymers. From the results shown in Table 2, it is shown that the recorded results of friction force depend on the solid particles as well as the type of lubricant used in the mud system.
In order to have a better understanding of the materials that were being tested, the way they would react with lubricants and whether there would be a significant wearing of the test blocks or not, it was decided to prolong the test time to 15 min, with recordings every 5 min. The first drilling fluid to be tested was a polymer fluid without weighting additives and without lubricants. The value of the friction force for each block was recorded after 5, 10 and 15 min and Figure 8 shows a diagram of the measured friction force for the tested blocks in polymer fluid without weighting additives and without lubricants.
From the measurement data shown in Figure 8, the value of the friction force for the steel block increases as the test time progresses, for the test blocks made of PA6 it decreases as the test time progresses, while for the test blocks made of POM and Teflon the value of the friction force does not significantly change. After 15 min of testing, the highest value of friction force was recorded for the steel block, followed by the test blocks made of PA6 and POM, while the lowest value was recorded for the test block made of Teflon.
The second drilling fluid to be tested was a polymer fluid without weighting additives in which lubricant X was added at a concentration of 2% vol. (PLX2%). Figure 8 shows a diagram of the measured friction force for the tested blocks in polymer fluid without weighting additives in which lubricant X is added at a concentration of 2% vol.
From the measurement data shown in Figure 8, the value of the friction force for the blocks made of PA6 and POM decreases as the test time progresses, while for the test block made of Teflon, the value of the friction force changed slightly. After 15 min of testing, the highest value of the friction force was recorded for the block made from PA6, followed by the test blocks made from POM, while the lowest value was recorded for the test block made from Teflon.
The next drilling fluid to test was the polymer fluid with weighting additives in which lubricant X was added at a concentration of 2% vol. (PWLX2%). Figure 9 shows a diagram of the measured friction force for the tested blocks in polymer fluid with weighting additives in which lubricant X is added at a concentration of 2% vol.
From the measured values of the friction force shown in Figure 9, the value of the friction force for the blocks made of PA6 and Teflon decreases as the test time progresses, while for the block made of POM the value of the friction force changed slightly. After 15 min of testing, the highest value of the friction force was recorded for the block made from PA6, followed by the test blocks made from POM, while the lowest value was recorded for the test block made from Teflon.
Comparing both polymer fluids without and with weighting additives in which lubricant X was added at a concentration of 2%, the value of the friction force for all blocks (PA6, Teflon and POM) in polymer mud with weighting additives in which lubricant X was added at a concentration of 2% is higher than that of the polymer fluid without weighting additives in which lubricant X.
The next drilling fluid to test was the polymer fluid without weighting additives in which lubricant Y was added at a concentration of 2% vol. (PLY2%). Figure 10 shows a diagram of the measured friction force for the tested blocks in polymer fluid without weighting additives in which lubricant Y is added at a concentration of 2% vol.
From the measured data shown in Figure 10, the value of the friction force of the test blocks made of PA6, Teflon and POM showed a slight decrease as the test time progressed. Again, after 15 min of testing, the highest value of the friction force was recorded with the block made from PA6, followed by the test blocks made POM, while the value was the lowest with the test block made of Teflon.
The next drilling fluid to test was the polymer fluid with weighting additives in which lubricant Y was added at a concentration of 2% (PWLY2%). Figure 11 shows a diagram of the measured friction force for the tested blocks in polymer fluid with weighting additives in which lubricant Y is added at a concentration of 2% vol.
From the measured values of the friction force shown in Figure 11, the value of the friction force in the test blocks made from PA6, Teflon and POM decreases as the test time progresses. After 15 min of testing, the highest value of the friction force was recorded with the blocks made from PA6 and POM, while the lowest value was recorded with the test block made from Teflon.
Comparing the values of the friction force for each block tested in both polymer fluids with and without weighting additives in which lubricant Y is added at a concentration of 2%, it can be seen that, for blocks made from PA6, Teflon and POM, the friction force is higher in polymer fluid with weighting additives and lubricant Y at a concentration of 2% vol.
The next drilling fluid to test was the polymer fluid with weighting additives in which lubricant Z was added at a concentration of 2% vol. (PLZ2%). Figure 12 shows a diagram of the measured friction force for the tested blocks in polymer fluid with weighting additives in which lubricant Z is added at a concentration of 2% vol.
From the measured data shown in Figure 12, the value of the friction force of the test blocks made from PA6, Teflon and POM decreased as the test time progressed. Again, after 15 min of testing, the highest value of the friction force was recorded with the block made from PA6, followed by the test blocks made POM, while the value was the lowest with the test block made of Teflon.
The last drilling fluid to test was the polymer fluid with weighting additives in which lubricant Z was added at a concentration of 2% vol. (PWLZ2%). Figure 13 shows a diagram of the measured friction force for the tested blocks in polymer fluid with weighting additives in which lubricant Y is added at a concentration of 2% vol.
From the measured data shown in Figure 13, the value of the friction force of the test blocks made from PA6 showed a slight increase as the test time progressed. For the test block made from POM, the value of the friction force slightly decreased, while for the test block made from Teflon, the friction value did not change. After 15 min of testing, the highest value of the friction force was recorded with the block made from PA6, followed by the test blocks made of POM, while the value was the lowest with the test block made of Teflon.
Comparing the values of the friction force for each block tested in both polymer fluids with and without weighting additives in which lubricant Z is added at a concentration of 2% vol., for test blocks made from PA6, Teflon and POM the friction force is higher in polymer fluid with weighting additives and lubricant Y at a concentration of 2% vol.
After analyzing all the friction forces measured on the block made from different materials in tested polymer drilling fluid with and without weighting additive and with two different lubricants of X, Y and Z, at a concentration of 2% vol., using Equation (1) the friction factor was calculated for each block made from different materials. Table 3 shows the friction factor for each block made from different materials in polymer mud with and without weighting additive in which one of two lubricants of X, Y and Z is added at a concentration of 2% vol.
Coefficient   of   friction = Torque   reading   100
From Table 2 it can be seen that the value of the friction factor for each block in the polymer mud with weighting additive in which one of three lubricants, X, Y and Z, was added at a concentration of 2% vol. is higher than for those in polymer mud without weighting additives and with the same concentration of lubricant. The increase in the friction factor value in polymer mud with weighting additives and lubricant at a concentration of 2% is the result of the addition of solid particles of different size to the mud system.
After analyzing all the measured values of friction force for each block in all four drilling fluids, it was concluded that after 15 min of testing the lowest value of friction force was registered for the Teflon block compared to the blocks made of steel (Table 1), PA6 and POM in each polymer fluid with lubricant at a concentration of 2% with and without weighting additives. Figure 14 shows the comparison of three lubricants, X, Y and Z, added at a concentration of 2% vol. to polymer fluid without weighting additives (PL2) for the Teflon block.
From Figure 14 it can be seen that, after 15 min of testing, for the Teflon block in polymer fluid without weighting additives but with lubricant X and Z at a concentration of 2% vol., the friction force was higher than for the one with lubricant Y at the same concentration of 2% vol., and for all three lubricants, X, Y and Z, it can be seen from the first 5 min to 15 min of testing that the friction force value has slightly changed.
Figure 15 shows the comparison of three lubricants, X, Y and Z, added at a concentration of 2% vol. to polymer fluid with weighting additives (PWL2).
From Figure 15 it can be seen that, after 15 min of testing, for the Teflon block in polymer fluid with weighting additives with lubricant Z at a concentration of 2% vol., the recorded friction force was the highest, followed by lubricant X, while lowest value was recorded with lubricant Y. For both lubricants X and Y, it can be seen from the first 5 min to 15 min of testing that the friction force value has slightly decreased, while for lubricant Z the value did not change for all the period of testing.
After finishing the measurements of the friction force of the test block made from Teflon in polymer mud with and without weighting agents in which one of two lubricants X and Y were added at a concentration of 2% vol., the next step was to measure the mechanical wear on the previously mentioned device in the Faculty of Mechanical Engineering and Naval Architecture. The test was performed at room temperature with a rotation speed of 60 rpm and the generated load on the test block made from Teflon was 670 N. The weights of the test blocks made from Teflon were measured before the beginning of the test and after the test had finished, i.e., after 24 h. Also, the measurement was conducted using the same mud system that was previously mentioned but KCl was removed from the mud due to the appearance of corrosion in the initial tests that were performed. Figure 13 shows the block made from Teflon before the test (A) and measurement after 24 h (B). In Figure 16A, the surface of the test block made from Teflon is flat, while in Figure 16B, it can be seen that a dent has been formed after 24 h under constant rotation and generated load. Figure 17 shows the mechanical wear of the Teflon blocks after 24 h of testing in polymer mud with and without weighting additive in which one of two lubricants X and Y are added at a concentration of 2% vol.
From the calculated data that are graphically presented in Figure 17, the mechanical wear of the blocks made from Teflon is higher in polymer mud with weighting additive in which one of two lubricants X and Y were added at a concentration of 2% vol. compared with polymer mud without weighting additive in which lubricant was added at a concentration of 2% vol. For lubricant Z, the mechanical wear is higher in polymer mud without weighting additive and with the same concentration of 2% vol.
The highest mechanical wear of the Teflon block in polymer mud with and without weighting additives in which one of three lubricants was added at a concentration of 2% vol. was recorded for lubricant Z, followed by lubricant X, while the lowest value of mechanical wear was recorded for lubricant Y in both polymer fluids.
In addition to the measurements of mechanical wear, the device can measure the friction factor, so Figure 18 shows the values of friction factor before and after 24 h of testing in both mud systems.
Observing the obtained data of the friction factor value of Teflon blocks that are graphically presented in Figure 15, the friction factor values for blocks in polymer mud without weighting additives in which one of three lubricants, X, Y and Z, are added at a concentration of 2% vol. is lower compared with polymer mud with weighting additive in which one of three lubricants, X, Y and Z, are added at a concentration of 2% vol. After 24 h of testing, the value of the friction factor decreases in polymer mud without weighting additives in which one of three lubricants, X, Y and Z, are added at a concentration of 2% vol. In polymer mud with weighting additives in which one of two lubricants X and Y are added at a concentration of 2% vol., it increases, while for lubricant Z the value of the friction factor decreases. However, comparing all three lubricants used in this test, it is noticeable that the lowest recorded friction factor value in polymer mud with and without weighting additives in which one of three lubricants was added at a concentration of 2% vol. was for lubricant Y followed by lubricant X, while the highest value was recorded using lubricant Z.

4. Discussion

To reduce the high values of torque and drag in extended-reach wells, usually one method does not solve the issue. One of the most common ways to reduce high values of friction and thus high values of torque and drag is to use lubricants in mud systems at certain concentrations. After conducting research, it has been shown that using only one method does not solve the problem by itself, so a combination of different methods should be used to reduce the high values of friction force. The method proposed in this paper to reduce the high values of friction is using lubricants in a polymer mud system in combination with protective sliding rings that would be put on the drill pipe joint. This idea is thought to reduce the friction that appears between two surfaces in contact and also reduce the wear of tool pipe joints.
After conducting thorough research, thermoplastic polymers were found to be the most suitable choice to make the protective sliding rings, so three materials were chosen: PA6, Teflon and POM. The first step in testing these materials was to choose a polymer mud system with and without weighting additives in which lubricant was added at a concentration of 2% vol.
The first part was to test the test blocks in polymer mud with and without weighting additives in which one of three lubricants, X, Y and Z, was added at a concentration of 2% vol. The results showed that, compared to the steel block, the blocks made from PA6, Teflon and POM showed significantly lower values of friction force in both polymer muds with and without weighting additives in which one of three lubricants, X, Y and Z, was added at a concentration of 2% vol.
Comparing all three tested materials, PA6, Teflon and POM, the results presented in this paper show that the lowest value of friction force was registered for Teflon in all polymer muds with and without weighting additives in which one of three lubricants, X, Y and Z, was added at a concentration of 2% vol. After analyzing all the results obtained from these tests it was obvious that the next step in measuring the mechanical wear of one of these three materials (PA6, Teflon and POM) would be using the test block made from Teflon.
The mechanical wear of the Teflon block was tested in both polymer muds with and without weighting additives in which one of three lubricants, X, Y and Z, was added at a concentration of 2% vol.
From the presented figure above, small changes in the friction force value during testing time can be seen. It is very difficult to pick a special reason for this change, but it can be assumed that this change is due to a combination of factors such as the presence of the fine solid particles of weighting additives in a polymer mud system, chemical interaction between drilling fluid and material, and slightly increasing the temperature of the two surfaces in direct contact. Also, one of the reasons could be about the way the testing block was prepared (mechanically milling the curved contact surface) where it is noticeable that the rough surface has been smoothed with time. It would be beneficial to test the effect itself in future research.
The protective sliding ring would be installed on the drill pipe joint, and it would have the role of reducing torque and at the same time protecting the drill pipe joint from excessive mechanical wear. In Figure 19, there is an example of installing the protective sliding ring on the drill pipe joint. The design shown in Figure 19 assumes that welding metal rings act as a border on both drill pipe joints (on the third of the length of each drill pipe joint from the end) and they will act as a barrier to hold the protective sliding ring in the same position, considering both drill pipe joints.

5. Conclusions

One of the suggested ways to reduce torque and drag in this paper is using lubricants in a polymer mud system and combining it with a material that would be used to manufacture protective sliding rings to put on drill pipes. These rings would have the role of decreasing mechanical wear and at the same time have a lower value of friction factor than steel. For all three tested materials (PA6, Teflon and POM), the results showed a significant decrease in friction force value, thus also in friction factor. The measured friction force for the Teflon block was far lower than for other materials as well as steel. The lowest value of friction force was recorded for blocks made from Teflon and for this reason it was selected as a material to be tested for mechanical wear.
From the obtained results for mechanical wear, the Teflon block showed minimum wear (after 24 h) mostly as a result of the testing procedure and lubricity effect. In polymer mud with lubricant, mechanical wear ranged from 0.28% to 2.05%, while in polymer mud with weighting additives and lubricant, mechanical wear ranged from 0.39% to 1.11% after 24 h of testing. From this point of research, we can conclude that Teflon is probably the best material for further research. Certainly, before designing sliding protective rings, more thorough research should be conducted on the chemical effect of lubricants and the chemical composition of a used drilling mud system on Teflon. The results showed that the lowest value of mechanical wear for the test block made from Teflon used lubricant Y in both polymer fluids with and without weighting additives in which one of three lubricants, X, Y and Z, was added at a concentration of 2% vol.

Author Contributions

Conceptualization, K.E.S. and B.P.; methodology, K.E.S. and B.P.; validation, B.P. and P.M.; formal analysis, I.M.; investigation, K.E.S.; data curation, B.P.; writing—original draft preparation, K.E.S., B.P., P.M. and I.M.; writing—review and editing, P.M. and I.M.; supervision, B.P. All authors have read and agreed to the published version of the manuscript.

Funding

Investigation of the influence of different lubricants on the properties of water-based drilling fluids-PODUIS; Ground water protection during well drilling-GWProtect, and Friction reduction during extended reach well drilling-FRERD, Faculty of Mining, Geology and Petroleum Engineering, University of Zagreb, Croatia.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.

Acknowledgments

I would like to extend my sincere thanks to Halliburton for providing lubricants for conducting tests.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Chenevert, M.E.; Osisanya, S.O. Shale/Mud Inhibition Defined with Rig-Site Methods. SPE Drill. Eng. 1989, 4, 261–268. [Google Scholar] [CrossRef]
  2. Simpson, J.P.; Dearing, H.L. Diffusion Osmosis-An Unrecognized Cause of Shale Instability. In Proceedings of the IADC/SPE Drilling Conference (Paper IADC/SPE 59190), New Orleans, LA, USA, 23–25 February 2000; pp. 1–14. [Google Scholar] [CrossRef]
  3. Labenski, F.; Reid, P.; Santos, H. Drilling Fluids Approaches for Control of Wellbore Instability in Fractured Formations. In Proceedings of the SPE/IADC Middle East Drilling Technology Conference & Exhibition (Paper SPE/IADC 85304), Abu Dhabi, United Arab Emirates, 20–22 October 2003; pp. 1–8. [Google Scholar] [CrossRef]
  4. Osuji, C.E.; Chenevert, M.E.; Sharma, M.M. Effect of Porosity and Permeability on the Membrane Efficiency of Shales. In Proceedings of the SPE Annual Technical Conference and Exhibition (Paper SPE 116306), Denver, CO, USA, 21–24 September 2008; pp. 1–12. [Google Scholar] [CrossRef]
  5. Qu, Y.; Lai, X.; Zou, L.; Su, Y. Polyoxyalkyleneamine as Shale Inhibitor in Water-Based Drilling Fluids. Appl. Clay Sci. 2009, 44, 265–268. [Google Scholar] [CrossRef]
  6. Muniz, E.S.; da Fontoura, S.A.B.; Lomba, R.F.T. Rock-Drilling Fluid Interaction Studies on the Diffusion Cell. In Proceedings of the SPE Latin American and Caribbean Petroleum Engineering Conference (Paper SPE 94768), Rio de Janeiro, Brazil, 20–23 June 2005; pp. 1–5. [Google Scholar] [CrossRef]
  7. Tare, U.A.; Mody, F.K.; Tan, C.P. New Generation of Membrane Efficient Water-Based Drilling Fluids: Pragmatic and Cost-Effective Solutions to Borehole Stability Problems. In Proceedings of the Petroleum Society’s Canadian International Petroleum Conference (Paper 2002-166), Calgary, AB, Canada, 11–13 June 2002; pp. 1–11. [Google Scholar]
  8. Zhang, J.; Chenevert, M.E.; Al-Bazali, T.; Sharma, M.M. A New Gravimetric-Swelling Test for Evaluating Water and Ion Uptake in Shales. In Proceedings of the SPE Annual Technical Conference and Exhibition (Paper SPE 89831), Houston, TX, USA, 26–29 September 2004; pp. 1–9. [Google Scholar] [CrossRef]
  9. Khodja, M.; Canselier, J.P.; Bergaya, F.; Fourar, K.; Khodja, M.; Cohaut, N.; Benmounah, A. Shale Problems and Water-Based Drilling Fluid Optimisation in the Hassi Messaoud Algerian Oil Field. Appl. Clay Sci. 2010, 49, 383–393. [Google Scholar] [CrossRef]
  10. Medved, I.; Gaurina-Međimurec, N.; Pašić, B.; Mijić, P. Green Approach in Water-Based Drilling Mud Design to Increase Wellbore Stability. Appl. Sci. 2022, 12, 5348. [Google Scholar] [CrossRef]
  11. Walker, M.W. Pushing the extended reach envelope at Sakhalin: An operator’s experience drilling a record reach well. In Proceedings of the IADC/SPE Drilling Conference and Exhibition, OnePetro, San Diego, CA, USA, 6 March 2012; pp. 1–11. [Google Scholar] [CrossRef]
  12. Wang, W.; Shahvali, M.; Su, Y. A semi-analytical fractal model for production from tight oil reservoirs with hydraulically fractured horizontal wells. Fuel 2015, 158, 612–618. [Google Scholar] [CrossRef]
  13. Lacy, S.; Ding, W.; Joshi, S.D. Horizontal Well Applications and Parameters for Economic Success. In Proceedings of the SPE Latin America Petroleum Engineering Conference, Caracas, Venezuela, 8 March 1992. [Google Scholar] [CrossRef]
  14. Joshi, S.D. Cost/Benefits of Horizontal Wells. In Proceedings of the SPE Western Regional/AAPG Pacific Section Joint Meeting, Long Beach, CA, USA, 19 May 2003. [Google Scholar] [CrossRef]
  15. Liang, S.; Hu, S.; Li, J.; Xu, G.; Zhang, B.; Zhao, Y.; Yan, H.; Li, J. Study on EOR method in offshore oilfield: Combination of polymer microspheres flooding and nitrogen foam flooding. J. Pet. Sci. Eng. 2019, 178, 629–639. [Google Scholar] [CrossRef]
  16. Kumar, R.; Ramanan, S.; Narasimham, J.L. Redevelopment of a Matured Multilayered Carbonate Offshore Field Through High-Technology Horizontal and Multilateral Wells. SPE Reserv. Eval. Eng. 2007, 10, 453–457. [Google Scholar] [CrossRef]
  17. Zhu, J.; He, S.; Lin, L. Optimization of the Lateral Length of Shale-Gas Horizontal Wells Based on Geology–Engineering–Economy Integration. Processes 2023, 11, 249. [Google Scholar] [CrossRef]
  18. El Sabeh, K.; Gaurina-Međimurec, N.; Mijić, P.; Medved, I.; Pašić, B. Extended-Reach Drilling (ERD)—The Main Problems and Current Achievements. Appl. Sci. 2023, 13, 4112. [Google Scholar] [CrossRef]
  19. Chen, X.; Gao, D. The Maximum-Allowable Well Depth While Performing Ultra-Extended-Reach Drilling from Shallow Water to Deepwater Target. SPE J. 2018, 23, 224–236. [Google Scholar] [CrossRef]
  20. Bennetzen, B.; Fuller, J.; Isevcon, E.; Krepp, T.; Meehan, R.; Mohammed, N.; Poupeau, J.-F.; Sonowal, K. Oil Filed Review Autumn 2010; Schlumburger: Paris, France, 2010; Volume 22, pp. 4–15. [Google Scholar]
  21. Medved, I.; Pašić, B.; Mijić, P. The influence of mandarin peel powder on filtration properties and temperature stability of water-based drilling mud. Rud.-Geol.-Naft. Zb. 2023, 38, 53–64. [Google Scholar] [CrossRef]
  22. Medved, I.; Gaurina-Međimurec, N.; Novak Mavar, K.; Mijić, P. Waste mandarin peel as an eco-friendly water-based drilling fluid additive. Energies 2022, 15, 2591. [Google Scholar] [CrossRef]
  23. Li, X.; Jiang, G.; He, Y.; Chen, G. Novel starch composite fluid loss additives and their applications in environmentally friendly water-based drilling fluids. Energy Fuels 2021, 35, 2506–2513. [Google Scholar] [CrossRef]
  24. Medhi, S.; Chowdhury, S.; Gupta, D.K.; Mazumdar, A. An investigation on the effects of silica and copper oxide nanoparticles on rheological and fluid loss property of drilling fluids. J. Pet. Explor. Prod. Technol. 2020, 10, 91–101. [Google Scholar] [CrossRef]
  25. Pašić, B.; Gaurina-Medimurec, N.; Matanović, D. Wellbore Instability: Causes and Consequences. Rud.-Geol.-Naft. Zb. 2007, 19, 87–98. [Google Scholar]
  26. Morrison, A.; Serov, N.; Ahmed, F. Completing Ultra Extended-Reach Wells: Overcoming the Torque and Drag Constraints of Brine. In Proceedings of the Abu Dhabi International Petroleum Exhibition & Conference, Abu Dhabi, United Arab Emirates, 11–14 November 2019. [Google Scholar] [CrossRef]
  27. Costa, S.S.; Stuckenbruck, S.; Fontoura, S.A.B.; Martins, A.L. Simulation of Transient Cuttings Transportation and ECD in Wellbore Drilling. In Proceedings of the 2008 SPE Europec/EAGE Conference and Exhibition, Rome, Italy, 9–12 June 2008. [Google Scholar] [CrossRef]
  28. Ref, D.; Yakhimovich, V.A.; Kolotiy, A. Testing of a Polymer Drill String Protector under Conditions close to Borehole. Key Eng. Mater. 2023, 941, 335–340. [Google Scholar] [CrossRef]
  29. Huang, W.; Gao, D.; Liu, Y. Mechanical model and optimal design method of tubular strings with connectors constrained in extended-reach and horizontal wells. J. Pet. Sci. Eng. 2018, 166, 948–961. [Google Scholar] [CrossRef]
  30. Geng, Y.; Zhang, Z.; Yan, Z.; Yuan, Y.; Zhou, X.; Yue, W.; An, Y. A novel graphene/triolein complex-based lubricant for improving high temperature water-based drilling fluid. RSC Adv. 2023, 13, 34772–34781. [Google Scholar] [CrossRef] [PubMed]
  31. Ji, M.; Liu, S.; Xiao, H.; Li, H. Investigation on tribological performance of Ionic liquid filled microcapsules as additives under water-based drilling mud conditions. Tribol. Int. 2023, 184, 108439. [Google Scholar] [CrossRef]
  32. Çağlayan, B.K. Torque and Drag Applications for Deviated and Horizontal Wells: A Case Study. Master’s Thesis, Middle East Technical University, Ankara, Turkey, 2014. [Google Scholar]
  33. API RP 13B-1; Recommended Practice for Field Testing of Water-Based Drilling Fluids. American Petroleum Institute: Washington, DC, USA, 2019.
  34. API RP 13B-2; Recommended Practice for Field Testing of Oil Based Drilling Fluids. American Petroleum Institute: Washington, DC, USA, 2014.
  35. Domitran, Z. Investigation of Dimensional Tolerances on the Polymer Gear Life. Ph.D. Thesis, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Zagreb, Croatia, 2013. [Google Scholar]
  36. He, J.; Wang, Q.; Yao, B.; Ho, J. Mechanical properties of high strength POM-FRCC and its performance under elevated temperatures. Constr. Build. Mater. 2021, 290, 123177. [Google Scholar] [CrossRef]
  37. Teflon. Available online: https://www.vedantu.com/chemistry/teflon (accessed on 22 April 2024).
  38. Domitran, Z.; Žeželj, D.; Katana, B. Influence of Contact Pressure and Sliding Speed on the Temperature and Coefficient of Friction in Sliding Contact Between Two Pet Samples. Teh. Vjesn. Znan. Stručni Časopis Teh. Fak. Sveučilišta Osijeku 2016, 23, 389–396. [Google Scholar] [CrossRef]
Applsci 14 06161 g001
Figure 1. Different well types [18].
Figure 1. Different well types [18].
Applsci 14 06161 g001
Applsci 14 06161 g002
Figure 2. Non-rotating drill pipe protector with pipe joint hardbanding.
Figure 2. Non-rotating drill pipe protector with pipe joint hardbanding.
Applsci 14 06161 g002
Applsci 14 06161 g003
Figure 3. OFITE lubricity tester used for measuring coefficient of lubricity.
Figure 3. OFITE lubricity tester used for measuring coefficient of lubricity.
Applsci 14 06161 g003
Applsci 14 06161 g004
Figure 4. Blocks made from Teflon, PA6, POM and steel used for research on lubricity tester.
Figure 4. Blocks made from Teflon, PA6, POM and steel used for research on lubricity tester.
Applsci 14 06161 g004
Applsci 14 06161 g005
Figure 5. Schematic representation of a device for measuring the mechanical wear of machine parts that are in direct contact [37].
Figure 5. Schematic representation of a device for measuring the mechanical wear of machine parts that are in direct contact [37].
Applsci 14 06161 g005
Applsci 14 06161 g006
Figure 6. Device for measuring the mechanical wear of machine parts that are in direct contact.
Figure 6. Device for measuring the mechanical wear of machine parts that are in direct contact.
Applsci 14 06161 g006
Applsci 14 06161 g007
Figure 7. Test block made from Teflon.
Figure 7. Test block made from Teflon.
Applsci 14 06161 g007
Applsci 14 06161 g008
Figure 8. The friction forces measured on the block made from different materials in tested polymer drilling fluid without weighting additives and with lubricant X at a concentration of 2% vol. (PLX2%).
Figure 8. The friction forces measured on the block made from different materials in tested polymer drilling fluid without weighting additives and with lubricant X at a concentration of 2% vol. (PLX2%).
Applsci 14 06161 g008
Applsci 14 06161 g009
Figure 9. The friction forces measured on the block made from different materials in tested polymer drilling fluid with weighting additive and with lubricant X at a concentration of 2% vol. (PWLX2%).
Figure 9. The friction forces measured on the block made from different materials in tested polymer drilling fluid with weighting additive and with lubricant X at a concentration of 2% vol. (PWLX2%).
Applsci 14 06161 g009
Applsci 14 06161 g010
Figure 10. The friction forces measured on the block made from different materials in tested polymer drilling fluid without weighting additive and with lubricant Y at a concentration of 2% vol. (PLY2%).
Figure 10. The friction forces measured on the block made from different materials in tested polymer drilling fluid without weighting additive and with lubricant Y at a concentration of 2% vol. (PLY2%).
Applsci 14 06161 g010
Applsci 14 06161 g011
Figure 11. The friction forces measured on the block made from different materials in tested polymer drilling fluid with weighting additive and with lubricant Y at a concentration of 2% vol. (PWLY2%).
Figure 11. The friction forces measured on the block made from different materials in tested polymer drilling fluid with weighting additive and with lubricant Y at a concentration of 2% vol. (PWLY2%).
Applsci 14 06161 g011
Applsci 14 06161 g012
Figure 12. The friction forces measured on the block made from different materials in tested polymer drilling fluid without weighting additive and with lubricant Z at a concentration of 2% vol. (PLZ2%).
Figure 12. The friction forces measured on the block made from different materials in tested polymer drilling fluid without weighting additive and with lubricant Z at a concentration of 2% vol. (PLZ2%).
Applsci 14 06161 g012
Applsci 14 06161 g013
Figure 13. The friction forces measured on the block made from different materials in tested polymer drilling fluid with weighting additive and with lubricant Z at a concentration of 2% vol. (PWLZ2%).
Figure 13. The friction forces measured on the block made from different materials in tested polymer drilling fluid with weighting additive and with lubricant Z at a concentration of 2% vol. (PWLZ2%).
Applsci 14 06161 g013
Applsci 14 06161 g014
Figure 14. Comparison of friction forces measured on the block made from Teflon in polymer drilling fluid without weighting additive (PL2) and with one of three lubricants, X, Y and Z, at a concentration of 2% vol.
Figure 14. Comparison of friction forces measured on the block made from Teflon in polymer drilling fluid without weighting additive (PL2) and with one of three lubricants, X, Y and Z, at a concentration of 2% vol.
Applsci 14 06161 g014
Applsci 14 06161 g015
Figure 15. Comparison of friction forces measured on the block made from Teflon in polymer drilling fluid with weighting additive and with one of three lubricants, X, Y and Z, at a concentration of 2% vol. (PWL2).
Figure 15. Comparison of friction forces measured on the block made from Teflon in polymer drilling fluid with weighting additive and with one of three lubricants, X, Y and Z, at a concentration of 2% vol. (PWL2).
Applsci 14 06161 g015
Applsci 14 06161 g016
Figure 16. Test block made from Teflon before (A) and measurement after (B) 24 h.
Figure 16. Test block made from Teflon before (A) and measurement after (B) 24 h.
Applsci 14 06161 g016
Applsci 14 06161 g017
Figure 17. Mechanical wear of Teflon blocks after 24 h of testing in polymer mud with and without weighting additive in which one of three lubricants, X, Y and Z, was added at a concentration of 2% vol.
Figure 17. Mechanical wear of Teflon blocks after 24 h of testing in polymer mud with and without weighting additive in which one of three lubricants, X, Y and Z, was added at a concentration of 2% vol.
Applsci 14 06161 g017
Applsci 14 06161 g018
Figure 18. Values of friction factor before and after 24 h of testing in polymer mud with and without weighting additives in which one of three lubricants, X, Y and Z, are added at a concentration of 2% vol.
Figure 18. Values of friction factor before and after 24 h of testing in polymer mud with and without weighting additives in which one of three lubricants, X, Y and Z, are added at a concentration of 2% vol.
Applsci 14 06161 g018
Applsci 14 06161 g019
Figure 19. Example of installing a protective sliding ring on the drill pipe joint.
Figure 19. Example of installing a protective sliding ring on the drill pipe joint.
Applsci 14 06161 g019
Table 1. Composition of mud fluid used in laboratory tests.
Table 1. Composition of mud fluid used in laboratory tests.
ComponentFunctionPolymer Mud with Lubricant (PL)Polymer Mud with Weighting Additives and Lubricant (PWL)
WaterBase fluid++
KClInhibit clay muds++
Sodium carbonate (Na2CO3)Increase the yield of clay and the deposition of calcium++
Potassium hydroxide (KOH)Maintain and control pH in inhibited muds++
PAC RFiltration control++
PAC L++
Filter checkReduce mud filtration++
Barazan DIncrease viscosity++
Baracarb-5Plugging material, weighting additive +
Baracarb-25 +
Baracarb-50 +
Avacarb-ME +
Lubricant at concentration of 2% ++
Table 2. Friction force value for steel block after 5 min of testing.
Table 2. Friction force value for steel block after 5 min of testing.
XYZ
Friction force (N)PL2192.16160.1465.83
PWL2176.15136.12148.13
Table 3. Friction factor for each block made from different material in polymer mud with and without weighting additive in which one of two lubricants X and Y is added at a concentration of 2% vol.
Table 3. Friction factor for each block made from different material in polymer mud with and without weighting additive in which one of two lubricants X and Y is added at a concentration of 2% vol.
PL2 PWL2
XYZXYZ
Friction factorSteel block0.2920.4820.1340.3440.3360.29
PA60.110.10.0740.1450.1640.105
Teflon0.0390.0310.0320.0540.0460.08
POM0.0890.0730.0660.1260.1580.116
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

El Sabeh, K.; Pašić, B.; Mijić, P.; Medved, I. Reducing Torque and Drag in Extended-Reach Wells Using Thermoplastic Polymers for Protective Sliding Rings. Appl. Sci. 2024, 14, 6161. https://doi.org/10.3390/app14146161

AMA Style

El Sabeh K, Pašić B, Mijić P, Medved I. Reducing Torque and Drag in Extended-Reach Wells Using Thermoplastic Polymers for Protective Sliding Rings. Applied Sciences. 2024; 14(14):6161. https://doi.org/10.3390/app14146161

Chicago/Turabian Style

El Sabeh, Karim, Borivoje Pašić, Petar Mijić, and Igor Medved. 2024. "Reducing Torque and Drag in Extended-Reach Wells Using Thermoplastic Polymers for Protective Sliding Rings" Applied Sciences 14, no. 14: 6161. https://doi.org/10.3390/app14146161

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop