Lubrication is a must to minimize friction and wear on the drill string. No reference table for selecting the best composition of drilling mud has been made in recent years to study these frictional and wear activities on the wellbore and tool assemblies. From the results, calcium chloride is the best additive to reduce the friction and wear activities of WBM and VG Plus is the best additive for OBM.
Synthetic and polymer-based muds should be included in the future to complete the COF and wear ranking of drilling fluids. M Nur Fitri bin Ismail who always helped and assisted me in topic selection, suggestions and guided me in friction and wear studies in industry.
INTRODUCTION
- Background of Study
- Problem Statement
- Objectives
- Scope of Study
Dressing will reduce the thickness of the drill string and changing drill strings will increase the cost of drilling. Appropriate evaluation should be done to study the effects of water-based mud (WBM) and oil-based mud (OBM) on the drill string and well formation. To prepare a tabulation reference of the coefficient of friction (COF) and wear ranking of WBM and OBM in order to predict the effect of friction and wear between the drill string and the well formation.
To observe the topography of friction and wear effects of WBM and OBM to the drill string and wellbore formation. This study puts more emphasis on different compositions of WBM and OBM to be used in mud circulation systems and the effect of these drilling muds on the friction and wear activities imposed on the drill string and well formation.
LITERATURE REVIEW
Drilling mud
- Drilling Mud Selection
- Water-based Mud (WBM)
- Advantages and Disadvantages of WBM and OBM
- Drill String
- Friction Factor
The availability and source of the make-up water must be considered so that the costs of mud treatment can be minimized. This force is proportional to Fn, but does not depend on the surface area. The maximum rotational speed and energy is limited by the disc's burst strength.
They are determined by equating the maximum stress in the disc with the strength of the material. The friction factor can be given in terms of the coefficient of friction between the materials, the mud lubricity coefficient (L), the pipe sticking coefficient (S), the pipe rotation speed (N), the temperature (t), the well path profile, which includes the curvature and torsion of the well (τ ) [14]. Axial is the axial stress at the lower end of the member, which is the weight of the member lifted.
To reduce resistance and torque, it is mandatory to eliminate or reduce any of the components in the equation.
![TABLE 2.1: Advantages and disadvantages of WBM and OBM [8]](https://thumb-ap.123doks.com/thumbv2/azpdforg/10260194.0/19.918.185.782.191.831/table-advantages-and-disadvantages-of-wbm-and-obm.webp)
METHODOLOGY
- Laboratory Experiments
- Materials Preparation
- Mud Samples Preparation and Testing
- Multispecimen Wear Tester (MWT) Experiment
- Friction and Wear Topograhy Experiment
- Research Plan .1 Gantt Chart
- Project Activities
- Flowchart/Workflow Process
The drilling fluid container is the component that will be used to hold the disc and the drilling fluid. The tools that will be used in this experiment are a mud balance and a FANN viscometer. All mud samples will be prepared in accordance with the American Petroleum Institute API Series 13 standard.
Mud samples will be prepared in the drilling laboratory of the Universiti Teknologi PETRONAS in block 16. The composition of the drilling fluids and additives will be different for each experiment to find the difference in wear effect on the pin and disc plate. The prepared mud samples are poured into the space between the pin and the disc.
First, the disk plate will be weighed to get the initial weight before the experiment. On the other side, the disc plate will be placed in the drilling fluid cup as shown in Figure 3.13. After fastening, drilling fluid will be filled into the cup until the disc is submerged in the fluid.
After all the components are set up inside the rig, the setup will be done in the software. Since it is only used to make contact between the pin and disc, only a small load will be placed on the lever. At the same time, the applied load will be set to zero in the software.
The pin and disc will be polished and used in the third and final work process, which is the study of materials topography. The disk plate after the friction and wear test will be observed and a magnified image of the wear activity on the disk plate will be shown, such as Figure 3.17.
RESULTS AND DISCUSSION
Results
- Mud Rheology
Based on the observation of the trend of the chart and the MWT lever which has fluctuated a lot during the experiment, it shows that the disk surface is not flat, irregular and rough. The result is imperfect because of this error, since the same applied load (10N) must be applied to all surface points of the granite disc plate. Observation of the plate after the experiment shows that mud residues, especially oil-based mud, increase the back weight of the disc plate.
The result of the pin, during its rotational movement towards the disc plate, has resulted in a weight reduction. The wear classification shown in Figures 4.3 and 4.4 does not apply because MWT only detects the wear activity between two identical minerals. Because the project involves two different minerals, namely ground steel (drill string) and granite (drill bore), the wear rating values cannot be trusted.
Sample #1
Sample #2
Sample #3
Sample #4
Sample #5
Sample #6
Sample #7
Sample #8
Based on this observation, HYDRO-PAC LV additive can reduce the effect of wear on the well formation. Based on Figure 4.22, the wear effect on the disk plate is visible to the naked eye. Based on this observation, the HYDRO-PAC R additive wears the well formation more than the other three WBMs.
Based on Figure 4.23, the wear effect on the disc plate is the least visible compared to others. Based on this observation, a calcium chloride additive can reduce the wear effect on the well formation the most compared to the other three samples (WBM). Based on Figure 4.24, the wear effect on the disc plate is not so visible compared to others.
Based on this observation, HYDRO-PAC UL additive can also reduce the wear effect to the wellbore formation. For OBM, based on Figure 4.25, the wear effect on the disk plate is visible to the naked eye. Based on Figure 4.26, the wear effect on the disk plate is visible to the naked eye.
Based on Figure 4.27, the wear effect on the disc plate is the least visible compared to other OBM. Based on this observation, VG Plus addition can reduce the wear effect to the wellbore formation the most compared to the other three samples (OBM). Based on this observation, ECOTROL RD additive can reduce the wear effect to the wellbore formation.
Wear (pin & disc plate)
Based on Figure 4.31, sample #3 has the lowest COF value for WBM, while sample #7 has the lowest COF value for OBM. VG Plus, often used as a filtration control, is proven to have the lowest COF value. For wear testing, MWT cannot measure the wear effect between two different minerals (mill steel and granite).
The effect of wear is checked by the difference in the weight of the pin before and after the experiments. There is a big difference between WBM and OBM in reducing the weight of the granite slab. An increased amount of weight on the disc plate indicates that the mud is plugged on the disc plate (well formation) and a decrease in the amount of weight on the pin indicates that the pin (drill string) is eroded.
From Figure 4.32, for WBM, sample #3 shows the smaller weight change for both pin and disc plate. Although the smallest weight change is sample #1, but the weight difference between sample #3 and sample #1 is only 0.001 g, which is not significant. Sample #6 is the smallest weight change for OBM, but the difference in weight change between sample #6 and sample #7 is not too significant (0.001 g).
In OBM, the wear effect on the disk plate due to mud viscosity is visible. Sample no. 3 and sample no. The 7 disc plates show the least visible effect of wear compared to the other samples. These indicate that calcium chloride and VG Plus are the best additives used to reduce the wear effect between the drill string and the well formation.
CONCLUSION AND RECOMMENDATION
Conclusion
Instead of water and oil based mud, this project can be extended to include synthetic based mud (SBM) and its friction and wear ranking. Different types of additives can also be included in WBM and OBM types to study the friction and wear activities as well as to calculate the friction and wear values as future reference. MWT can only be tested under room temperature and atmospheric pressure, which is quite unreliable.
A test simulation must include variation of temperature and pressure values because drilling operations occur at high temperature and pressure. Drilling operations require different types, sizes and shapes of drill bits for different well formations. Instead of using mill steel for cylindrical pin and granite for round disc plate, other shapes and types of ingredient should be used to get a variety of results.
2nd run will be used as trial result as the disc plate is positioned correctly. Although only eight (8) samples have been tested, this paper should be a kick-start to the other projects to study COF and abrasion values in other types of drilling fluids, as friction and abrasion play a major effect in drilling operations, especially in horizontal drilling.
Retrieved May 2, 2013, from http://www.slb.com/services/miswaco/services/drilling_fluid.aspx. Retrieved May 2, 2013, from http://www.scomi.com.my/GUI/pdf/drilling_fluid.pdf.
APPENDIX
![TABLE 2.2: Range of friction factors by using Mud Lubricity Tester [17]](https://thumb-ap.123doks.com/thumbv2/azpdforg/10260194.0/26.918.198.785.713.975/table-range-friction-factors-using-mud-lubricity-tester.webp)
![FIGURE 2.9: Effect of drill string rotation on axial friction [22]](https://thumb-ap.123doks.com/thumbv2/azpdforg/10260194.0/30.918.284.699.237.564/figure-effect-drill-string-rotation-axial-friction-22.webp)
