E-ISSN : 2541-5794 P-ISSN : 2503-216X Journal of Geoscience, Engineering, Environment, and Technology Vol 02 No 02 2017 Novriyanti et al./ JGEET Vol 02 No 02/2017 133 Kick-Off Point (KOP) and End of Buildup (EOB) Data Analysis in Trajectory Design Novrianti 1 , Rycha Melisa 1 , Rafhie Adrian 1 1 Department of Petroleum Engineering, Universitas Islam Riau, Jln. Kaharuddin Nasution No. 113, Pekanbaru, Riau Abstract Well X is a development well which is directionally drilled. Directional drilling is choosen because the coordinate target of Well X is above the buffer zone. The directional track plan needs accurate survey calculation in order to make the righ track for directional drilling. There are many survey calculation in directional drilling such as tangential, underbalance, average angle, radius of curvature, and mercury method. Minimum curvature method is used in this directional track plan calculation. This method is used because it gives less error than other method. Kick-Off Point (KOP) and End of Buildup (EOB) analysis is done at 200 ft, 400 ft, and 600 ft depth to determine the trajectory design and optimal inclination. The hole problem is also determined in this trajectory track design. Optimal trajectory design determined at 200 ft depth because the inclination below 35º and also already reach the target quite well at 1632.28 ft TVD and 408.16 AHD. The optimal inclination at 200 ft KOP depth because the maximum inclination is 18.87º which is below 35º. Hole problem will occur if the trajectory designed at 600 ft. The problems are stuck pipe and the casing or tubing will not able to bend. Keywords: Directional Drilling, Trajectory, Kick of Point, End of Buildup, Minimum of Curvature 1. Introduction Directional drilling is a technique to deflect the wellbore and then directed to desired target in the formation also not located vertically below the well. In the beginning, directional drilling is used to correct the turn that occured at the vertical hole. (Grace BS, Widrajat, AK, 2015) (Adams, 1985) (Rubiandini, 2012). Actually in drilling always desirable a vertical hole because of The operation cost is cheaper and easier to implement. But not all Drilling can be done vertically certain reasons, so it should be directional drilling.(Grace BS, Widrajat, AK, 2015) There are causative factors in directional drilling: (Bourgoyne, AT, 1991)(Inglis, 2005) 1. Topograph Factor a. Productive formation is located below the lake or river. b. Productive formation is located below the buildings. 2. Geological Factor a. Salt dome b. Faults 3. Economic Factor a. Land acquisition fee b. Equipment removal c. Waste treatment 4. Multi-lateral cluster system 5. Cluster System 6. Blowout prevention by relief well. 7. Sidetracking There are 3 common types of track in directional drilling: (Rabia, 2002),(Adila, Maruti Tiffani, 2015) (Mitchell, 1995)(Omar Farah, 2013)(Mitchell and Miska, 2011). a. Build Hold The turning point depth in Kick-Off Point located not to far from the surface (shallow). The deflection of hole is done by increasing the slope and corresponded to Buildup Rate (BUR) that has been planned. Kick of Point (KOP) is the point or depth where the well track will be distorted until it reaches the specified inclination angle. (Hamid and Setiawan, 2015) b. Build Hold and Drop This type is used in certain condition, for example at salt dome or while sidtracking. The deflection of hole is done far from the surface casing, and the the slope is mainatained until reach the target. The well with the deep turning point or Kick-Off Point (KOP) have certain deficiency, there are: 1. The formation may be harder and is hard to deflect. 2. Tripping will be more often to replace Bottom Hole Assembly (BHA) while turning. 3. Buildup Rate will be uncontrolable. c. Build Hold Partial Drop and Hold First, it will be same with the deflection in the shallow depth but then it will be deflected * Corresponding author : novrianti@eng.uir.ac.id Tel.:+81-22-2000489 Received: May 2, 2017. Revised : May 25, 2017, Accepted: May 31, 2017, Published: 1 June 2017 DOI: 10.24273/jgeet.2017.2.2.302 mailto:novrianti@eng.uir.ac.id 134 Novriyanti et al./ JGEET Vol 02 No 02/2017              2 tan 2 DL DL RF again into vertical. As for the selection for the type of drilling based on coordinate between sufrace location and the target location or the desired formation. After the plan and the drilling operation is done, the measurement of slope for each depth and the direction of borehole (survey) are executed. If the points are deviated, borehole will be directed to the point that already set before. There are many methods that can be used to determine suface point coordinates, tangential, balance tangential, average angle, radius of curvature, minimum of curvature, and mercury method (Inglis, 2005)(Zaremba, 1973) (Wilson, 1968)(Sawaryn and Thorogood, 2005). The calculation of each methods based on measurement of 3 kinds of parameter. There are, depth of well (MD), the alteration of slope (I), and the direction angle (A) which are written on the survey equipment. The first reference to the minimum curvature directional survey calculation method is credited to Mason and Taylor in 1972.(Sawaryn and Thorogood, 2005)(Taylor and Mason, 2013) Minimum of curvature method seperate 2 intervals where the upper interval and lower interval. For the upper interval, inclination angle and azimuth is being used at the initial point. For the lower interval, inclination angle and azimuth is being used at the end of point. Minimum of curvature method can be seen in the fig. 1 below: Fig 1. Minimum of Curvature Method In this study, minimum of curvature method is used in the calculation of well track plan in well X. This method is used because it will gives the lower error than other method. Besides that, to determine the trajectoory design and optimal inclination analysis for the Kick-Off Point (KOP) and End of Buildup (EOB) is done by using 3 type of sesitivities based on depth, there are 200 ft, 400 ft, and 600 ft depth. 2. Material and Methods In well trajectory design, the maximum inclination angle, target distance, BUR, and azimuth must be determined in the first place. The formulas used are : a. Target Direction c b d 1 tan   (1) b. Target Distance (D2) 22 222 cba cba   (2) c. Build Radius BUR R R BUR 58,5729 58,5729   (3) d. Maximum Inclination         DO DC DOC 1 tan (4) DOC DO OC   cos (5) OC R BOC 1 cos   (6) DOCBOCBOD  (7) BOD 90 (8) e. EOB MD EOB MD =        1001 x BUR V  (9) Trajectory design parameters are calculated by using minimum of curvature method. The formulas are : (10) a.      122112 cos1sinsincos AAIIIIDL  (11) b.  RFII MD TVD 21 coscos 2    (12) c . Measured Depth (ft) BUR nAInklinationBInklinatio  (13) d. Closure distance = 2 2 EN  (14)  RFAIAI MD N 2211 cossincossin 2    (15)  RFAIAI MD E 2211 sinsinsinsin 2    (16) Novriyanti et al./ JGEET Vol 02 No 02/2017 135 Trajectory design and optimal inclination is done by analyze the Kick-Off Point (KOP) and End of Buildup (EOB) at 200 ft, 400 ft, and 600 ft depth. The profile data of well X that being used in trajectory and incliatnin design can be seen in the table 1. Table 1. Well Profile 3. Results and Discussion The coordination of target, target distance, and azimuth that used in drilling track design in well X can be seen in fig. 2. below : Fig 2. Plan View Fig 3. Target Coordinate azimuth which is the direction of drilling it self. a is the horizontal displacement, b and c is the drilling target coordination and d is the azimuth value and drilling direction. Trajectory design of well X at 200 ft KOP Fig 4. Trajectory Design at 200 ft KOP Fig 5. Vertically Track Direction In the drilling track design catogory, the good track with 200 ft KOP already assumed as good criteria because the inclination is 18.87º , which is the suitable value when the inclination in drilling opration si less than 35º because in other well data if the inclination is more than 35º will caused the casing is unable to bend or the it will caused casing failure because the casing will break. The result in the 200 ft KOP are 1632.28 ft TVD and 408.16 ft AHD, when with the 200 ft KOP it will reach the.target well because the desired target is 1632.3 ft and 408.75 ft AHD. Fig 6. Trajectory design at 400 ft KOP Location Name Sumur RA Classification Development Tipe Well Directional Total Depth 2000 ft MD Coordinate Target Target Formation Coordinate Surface 136 Novriyanti et al./ JGEET Vol 02 No 02/2017 Fig 7. Direction of Vertical Track Kick-Off Point determinated at 400 ft depth in well X has 23.62º inclination, the target depth reached at 1632.41 ft TVD and 407.92 ft AHD. The good criteria is at 400 ft KOP because the inclination is below 35º Fig 8. Trajectory Design at 600 ft KOP Fig 9. Direction of Vertical Track At 600 ft KOP the maxumum inclination angle is 35.26º, the target depth at 1632,43 ft TVD and 407.99 ft AHD. This depth has large the maximum incliation angle and its capability to reach the target will not be at maximum effort and if the KOP is too deep it will be reach the hard formation so the track will be hard to deflect, then it will be caused stuck pupe when tripping out because the inclination is too large. When the maxumum inclination angle is too large it also cause casing failure or tubing failure when installation, and the inability to maintain when bent. Because when a drillstring need to be bent or deflected at 600 ft sharply to reach desired target. Because in drilling track design must consider the probability of the drillstring to be bent. If the drillstring passed its limit to be bent, the drillstring will be break. 4. Conclusion Acccording to the drilling track design to the effect of KOP and EOB depth selecton in well X, the conclusion are: 1. Optimal trajectory design at 200 ft KOP because it gives the inclination below 35º and it will reach the target very well at 1632.28 ft TVD and 408.16 ft AHD. 2. Optimal inclination at 200 ft KOP because the maximum inclination angle is 18.87º, which is good. 3. Hole problem that will occured if the trajectory design at 600 ft are stuck pipe and inability of drillstring to be bent. References Adams, N.J., 1985. Drilling Engineering. Tulsa. Adila, Maruti Tiffani, W.A., 2015. Perencanaan Lintasan dan Analisis Pembebanan pada lubang 81/2 sumur FA - 12 Lapangan A. Semin. Nas. Cendikiawan 267 275. Bourgoyne, AT, K.M.M., 1991. Drilling Engineering. Grace BS, Widrajat, AK, H., 2015. Perbandingan Lintasan Pemboran Berarah dengan Berbagai Metode Perhitungan Pada Sumur G- 12 Lapangan G I, 446 454. Hamid, A., Setiawan, A., 2015. Evaluasi Lintasan Pemboran Berarah dengan metode Minimum of Curvature pada sumur X Lapangan Y Petrochina Internasional 58 64. Inglis, T., 2005. Directional Drilling, Encyclopedia of Hydrocarbons - Volume I. doi:10.2118/7835- MS Mitchell, R.F., Miska, S.Z., 2011a. Fundamentals of Drilling Engineering. Mitchell, R.F., Miska, S.Z., 2011b. Fundamentals of Drilling Engineering, Society of Petroleum Engineers Journal February. Mitchell, Wi., 1995. Oil well drilling engineering handbook, 10 th Edit. ed. USA. Omar Farah, F., 2013. Directional Well Design , Trajectory and Survey Calculations , With a Case Study in Fiale, Asal Rift, Djibouti. Rabia, H., 2010. Well Engineering & Construction 248. Rubiandini, R., 2012. Teknik Operasi Pemboran I.pdf. Bandung. Sawaryn, S.J., Thorogood, J.L., 2005. A Compendium of Directional Calculations Based on the Minimum Curvature Method. SPE Drill. Complet. 20, 24 36. doi:10.2118/84246-PA Taylor, H.L., Mason, M.C., 2013. A Systematic Approach to Well Surveying Calculations. Soc. Pet. Eng. J. 12, 474 488. doi:10.2118/3362-PA Wilson, G.J., 1968. An Improved Method for Computing Directional Surveys. J. Pet. Technol. 20. doi:10.2118/1992-PA