SONATRACH DIVISION PRODUCTION HASSI R MEL

Transcription

1 SONATRACH DIVISION PRODUCTION HASSI R MELR Optimization of Perforated Completions for Horizontal Wells in High-Permeability, Thin Oil Zone Hassi R mel Oil Rim, Algeria By MAHDI BOURENANE JANUARY 2003

2 OUTLINE Introduction Statement of the problem Objectives of the Study Methodology Geological and Reservoir Characterization Sensitivity Analysis on Perforated Completions Performance of Inverted High Angle Completion Case Study : HRZ-09 Conclusions and Recommendations

3 INTRODUCTION The success of Horizontal well technology is mainly due to the advantages a that horizontal wells offer such as : productivity improvement, coning g reduction and sand problems attenuation. Very often, either for geological reasons or for production purposes, poses, the wells need to be cased and perforated. It is important in this case to know how much of the horizontal length should be perforated and where to locate e the perforations. In this respect, minimizing the horizontal section to be perforated for an optimization purpose is justified.

4 INTRODUCTION (Continued) A considerable number of studies have been done on how to optimize the perforated completions for horizontal wells; but very few of them took into consideration the reservoir heterogeneity as well as coning problems. Probably one the most important work directly related to this topic is the one developed by Goods and Wilkinson. They have presented an analytical solution for the performance of partially completed horizontal well.

5 INTRODUCTION (Continued) According to their model, the inflow performance of a well is related to the long-time behavior of constant rate pressure. So, they derived a formula that expresses the inflow performance of a partially open horizontal well as follows : Where : P ID J : Dimensionless Inflow Pressure. S* m : Skin Factor. h = 7.08 µ o β o 10 ( P ID k + S 3 h h ) m* ( STB/D PSI )

6 INTRODUCTION (Continued) Goods and Wilkinson s s model limitations : It considers the reservoir as Homogeneous. It does not consider the gas and water coning effects. So in this study, a numerical solution was developed to optimize the perforated completions in a heterogeneous reservoir laying between a large gas cup and active aquifer (Double coning problem).

7 STATEMENT OF THE PROBLEM In thin oil zones with high permeability, horizontal wells are used u to minimize water and or gas coning; so that, an inappropriate perforated completion on scheme may actually exacerbate the problem at the downstream end of the well. l. In addition, the productivity of horizontal wells producing from m such reservoir may be severely restricted by frictional pressure losses within the perforation section of the well. Hence, in thin oil zones, optimizing the perforated completion n in horizontal wells will substantially improve the oil recovery, alleviate gas and water w coning, and so that minimize the investment cost.

8 OBJECTIVES OF THE STUDY Investigate the effect of the most relevant reservoir parameters on horizontal well performance for different perforation alternatives. es. Generate correlation curves that can be used to optimize the perforated completions for Horizontal wells. Find out the optimum perforation scheme for horizontal wells in Hassi R mel Oil Rim. Study the performance of the Inverted High Angle completion in Hassi R mel Oil Rim (Case study : HRZ-09).

9 METHODOLOGY Reservoir Characterization of the A-Sand A reservoir of Hassi R mel Oil Rim using the sedimentary subdivision and the best approaches to estimate the petrophysical properties. Hence, the most accurate geological model to be introduced in the simulator. A single well simulation model was built to investigate the effect ect of perforation length and its distribution, reservoir permeability, vertical anisotropy and areal anisotropy on horizontal well performance.

10 METHODOLOGY (Continued) A second single well model was involved in a real case where the performance of the well HRZ09, for different perforation schemes, was a concern. To cover this part, three points have to be developed : History matching Comparative study based on well performance Comparative study based on Economic Analysis

11 RESERVOIR CHARACTERIZATION Introduction Statement of the problem Objectives of the Study Methodology Geological and Reservoir Characterization Sensitivity Analysis on Perforated Completions Performance of Inverted High Angle Completion Case Study : HRZ-09 Conclusions and Recommendations

12 RESERVOIR CHARACTERIZATION PETROPHYSICAL (RESERVOIR) CHARACTERIZATION Cases where core and log analysis data were available, the priority ity for porosity and permeability determination was given to core analysis. The permeability for the non-cored sections were estimated from the curve fitting of the permeability-porosity porosity relationship. Effective Formation : Cut-off porosity = 4% Cut-off Shale content = 35% Cut-off Water Saturation = 55% Cut-off Permeability = 1md

13 RESERVOIR CHARACTERIZATION PETROPHYSICAL (RESERVOIR) CHARACTERIZATION Shale Content, Vsh : ( 2 2 1) I = Sh VSh I Sh ( Older Rock ) Effective Porosity : φ = + φ e = φ(1-vsh) φ 2 2 NC φ Dc Water Saturation : S W = + ( V ) Sh 2 4 m ar W V φ Sh + 2 φ m R Sh R Sh ar W R t 0.5 ( Vsh>10% )

14 RESERVOIR CHARACTERIZATION PETROPHYSICAL (RESERVOIR) CHARACTERIZATION Porosity-Permeability Correlation Lnk Lnk = 0.401(Ph) LnK = 0.401(Ph) R 2 = R 2 2 = Permeability, md Porosity, %

15 RESERVOIR SUBDIVISION HR-198 HRE-203 HR-210 HRZ-09 HRE-402 Top A U3 HR-208 HR-189 HRE-202 HRE-201 U2 U1 M3 M2 M1 L3 L2 Bottom A L1 RESERVOIR CHARACTERIZATION

16 GEOLOGICAL MODEL REFINEMENT HR-198 HRE-203 HR-210 HRZ-09 HRE-402 Top A Layer 1 HR-208 HR-189 HRE-202 HRE-201 Layer 2 Layer 3 Layer 4 Layer 5 Layer 6 Layer 7 Layer 8 Layer 9 Layer 10 Layer 11 Layer 12 Layer 13 Bottom A Layer 14 RESERVOIR CHARACTERIZATION

17 RESULTS OF THE PETROPHYSICAL CHARACTERIZATION HR-189 Geological layer Layer N Gross thickness (m) Net thickness (m) Porosity (fraction) Water Saturation (%) Permeability (md) U U U M M M L L L RESERVOIR CHARACTERIZATION

18 SENSITIVITY ANALYSIS ON PERFORATED COMPLETIONS Introduction Statement of the problem Objectives of the Study Methodology Geological and Reservoir Characterization Sensitivity Analysis on Perforated Completions Performance of Inverted High Angle Completion Case Study : HRZ-09 Conclusions and Recommendations

19 SENSITIVITY ANALYSIS ON PERFORATED COMPLETIONS A parametric study is conducted to analyze the effect of the e most relevant reservoir parameters on horizontal well performance for different Perforation Schemes. This in High-permeability thin Oil zone.these parameters are : Perforation length and its Distribution Reservoir Permeability Vertical anisotropy Ratio Horiziontal anisotropy Ratio

20 RESERVOIR GEOMETRY FOR HORIZONTAL WELL MODEL To perform this study, a single-horizontal well model is needed. For this simulation model, a 3-D 3 D regular Cartesian grid was built. Number of blocks in X-directionX 15 Number of blocks in Y-directionY 15 Number of blocks in Z-directionZ 14 Total number of blocks 15x15x14=3150 SENSITIVITY ANALYSIS

21 The Proposed Perforation schemes Once the single well simulation model was built, the sensitivity analysis can be performed for different perforation alternatives.. All the simulation runs were done for 12 years forecast. Assuming that the well is completed with a fully cemented and perforated liner, and the horizontal wellbore has 500m long, seven (07) perforation schemes were proposed for this study. These are : SENSITIVITY ANALYSIS

22 The Proposed Perforation schemes Case 1 : Lp = 500m (100%) Lp = 500m Heel Toe L = 500m SENSITIVITY ANALYSIS

23 The Proposed Perforation schemes Case 2 : Lp = 400m (80%) Lp = 400m Heel Toe L = 500m SENSITIVITY ANALYSIS

24 The Proposed Perforation schemes Case 3 : Lp = 300m (60%) Lp = 300m Heel Toe L = 500m SENSITIVITY ANALYSIS

25 The Proposed Perforation schemes Case 4 : Lp = 200m (40%) Lp = 200m Heel Toe L = 500m SENSITIVITY ANALYSIS

26 The Proposed Perforation schemes Case 5 : Lp = 100m (20%) Lp = 100m Heel Toe L = 500m SENSITIVITY ANALYSIS

27 The Proposed Perforation schemes Case 6 : Lp = 300m UD (60%) Lp = 100m Lp = 100m Lp = 100m Heel Toe L = 500m SENSITIVITY ANALYSIS

28 The Proposed Perforation schemes Case 7 : Lp = 200m TE (40%) Lp = 200m Heel Toe L = 500m SENSITIVITY ANALYSIS

29 Base Case Perforation Length and its Distribution Effect 1. Base Case ( Perforation Length and Distribution Effect) ) : All the reservoir parameters are kept unchanged; and they took t values that match those of Hassi R mel Oil rim. These are : K = 500md Kv/Kh Kh = 0.01 Ky/Kx Kx = 1 Qo = 100 SM 3 /D SENSITIVITY ANALYSIS

30 Base Case Perforation Length and its Distribution Effect Plot of Oil Recovery Versus Time For different perforation scenarios Oil Recovery, % Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE Time, Year SENSITIVITY ANALYSIS

31 Base Case Perforation Length and its Distribution Effect Plot of Gas-Oil Ratio Versus Time For different perforation scenarios GOR, NM3/SM Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE Time, Year SENSITIVITY ANALYSIS

32 Base Case Perforation Length and its Distribution Effect Perforation Distribution Effect Oil Recovery, % Plot of Oil Recovery versus time for the comparison between case 3 and case Time, Year Lp=60% CP Lp=60% UD GOR, NM3/SM Plot of Gas-Oil Ratio versus time for the comparison between case 3 and case Time, Year Lp=60% CP Lp=60% UD SENSITIVITY ANALYSIS

33 Base Case Perforation Length and its Distribution Effect Perforation Distribution Effect Plot of Oil Recovery versus Time for the comparison between case 4 and case 7 Plot of Gas-Oil Ratio versus Time for the comparison between case 4 and case 7 Oil Recovery,% Lp=40% HE 2 Lp=40% TE Time, Year GOR, NM3/SM Lp=40% HE Lp=40% TE Time, Year SENSITIVITY ANALYSIS

34 Base Case Perforation Length and its Distribution Effect Oil Recovery for the different perforation schemes proposed after 12 years production - Base Case - 14 Best Case 12 Oil Recovery, % Lp=100% LP=80%CP LP=60%CP LP=40%HE LP=20%CP LP=60%UD LP=40%TE Perforation Schemes SENSITIVITY ANALYSIS

35 Base Case Perforation Length and its Distribution Effect Gas-Oil Ratio for the different perforation schemes proposed after 12 years production - Base Case Best Case Gas-Oil Ratio, NM3/SM Lp=100% LP=80%CP LP=60%CP LP=40%HE LP=20%CP LP=60%UD LP=40%TE Perforation Schemes SENSITIVITY ANALYSIS

36 SENSITIVITY ANALYSIS Base Case Perforation Length and its Distribution Effect In case of continuous perforation, The higher the perforation length, the higher the oil recovery, and the higher the Gas-Oil ratio. The perforation length can be reduced, and in many cases, without a substantial decrease in oil recovery. Moreover, lower values of perforation length lead to lower gas-oil ratios produced. Hence, the perforation length has to be optimized with respect not only to oil recovery, but also to gas-oil ratio in order to guarantee the lowest investment cost in gas facilities.

37 Base Case Perforation Length and its Distribution Effect The reservoir produces more efficiently when the perforation intervals are uniformly distributed along the wellbore rather than being continuously placed. Case 6 (60% Uniformly Distributed Perforation) is the most favorable able case of all the proposed perforation schemes since it guaranties: High Oil recovery and low Gas-oil ratio. Pressure and production rate stabilization. Coning reduction. Lowest investment cost (Maximum net Present Value). SENSITIVITY ANALYSIS

38 RESERVOIR PERMEABILITY EFFECT 2. Reservoir Permeability Effect To investigate the effect of reservoir permeability on horizontal ontal well performance for various completion alternatives, we considered five f values of reservoir permeability : K 1 = 1000 md K 2 = 500 md K 3 = 100 md K 4 = 50 md K 5 = 10 md SENSITIVITY ANALYSIS

39 RESERVOIR PERMEABILITY EFFECT K 1 = 1000 md Plot of Oil Recovery Versus Time For different perforation scenarios Plot of Gas-Oil Ratio Versus Time For different perforation scenarios Oil Recovery,% Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE GOR, NM3/SM Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE Time, Year Time, Year Horizontal well performance for the different perforation schemes SENSITIVITY ANALYSIS

40 RESERVOIR PERMEABILITY EFFECT 16 K1=1000md K2=500md K3=100md K4=50md Reservoir Permeability values K5=10md K1=1000md K2=500md K3=100md K4=50md K5=10md Oil Recovery, % Perforation length,% GOR,NM3/SM Perforation Length,% Effect of Perforation Length on well performance for different Reservoir Permeability values after 12 years SENSITIVITY ANALYSIS

41 RESERVOIR PERMEABILITY EFFECT Oil Recovery, % Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE GOR, NM3/SM Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE Permeabilty, md Permeabilty, md Effect of Reservoir Permeability on well performance for different perforation scenarios after 12 years SENSITIVITY ANALYSIS

42 RESERVOIR PERMEABILITY EFFECT The higher the reservoir permeability, the higher the oil recovery for any perforated completion alternative. In case of a thin oil rim sandwiched between a large gas-cap and an active aquifer, lower values of reservoir permeability yield higher gas-oil ratio in comparison to the case of higher permeability values. Hence, high reservoir permeability values (K>50md) are more favorable in such case ( thin oil rim). SENSITIVITY ANALYSIS

43 VERTICAL ANISOTROPY EFFECT 3. Vertical Anisotropy Effect Four (04) vertical anisotropy ratios were examined : (Kv/Kh) 1 = 1 (Kv/Kh) 2 = 0.1 (Kv/Kh) 3 = 0.01 (Kv/Kh) 4 = SENSITIVITY ANALYSIS

44 VERTICAL ANISOTROPY EFFECT (Kv/Kh) 1 = 1 Plot of Oil Recovery Versus Time For different perforation scenarios Plot of Gas-Oil Ratio Versus Time For different perforation scenarios Oil Recovery,% Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE GOR, NM3/SM Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE Time, Year Time, Year Horizontal well performance for the different perforation schemes SENSITIVITY ANALYSIS

45 VERTICAL ANISOTROPY EFFECT Oil Recovery, % (Kv/Kh)1=1 (Kv/Kh)3=0.01 (Kv/Kh)4= Perforation length, % (Kv/Kh)2=0.1 GOR, NM3/SM (Kv/Kh)1=1 (Kv/Kh)3=0.01 (Kv/Kh)2=0.1 (Kv/Kh)4= Perforation length,% Effect of Perforation Length on well performance for different Vertical Anisotropy values after 12 years SENSITIVITY ANALYSIS

46 VERTICAL ANISOTROPY EFFECT Oil Recovery,% Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE Kv/Kh c GOR, NM3/SM3 Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE Kv/Kh Effect of Vertical Anisotropy on well performance for different perforation scenarios after 12 years SENSITIVITY ANALYSIS

47 VERTICAL ANISOTROPY EFFECT In case of a thin oil rim trapped between a large gas-cap and an active aquifer, the higher the vertical anisotropy ratio, the lower the oil recovery for any perforation scenario. Hence, in this case, low anisotropy ratios are preferable not only to get higher oil recovery but also to come out with the least amount of gas produced. SENSITIVITY ANALYSIS

48 HORIZONTAL ANISOTROPY EFFECT 4. Horizontal Anisotropy Effect Four (04) values of horizontal anisotropy were considered to t investigate its effect on horizontal well performance for different ent perforation alternatives. These are : (Ky/Kx) 1 = 10 (Ky/Kx) 2 = 5 (Ky/Kx) 3 = 1 (Ky/Kx) 4 = 0.1 SENSITIVITY ANALYSIS

49 HORIZONTAL ANISOTROPY EFFECT (Ky/Kx) 1 = 10 Plot of Oil Recovery Versus Time For different perforation scenarios Plot of Gas-Oil Ratio Versus Time For different perforation scenarios Oil Recovery, % Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE GOR,NM3/SM Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE Time, Year Time, Year Horizontal well performance for the different perforation schemes SENSITIVITY ANALYSIS

50 HORIZONTAL ANISOTROPY EFFECT (Ky/Kx)1=10 (Ky/Kx)2=5 (Ky/Kx)1=10 (Ky/Kx)2=5 16 (Ky/Kx)3=1 (Ky/Kx)4= (Ky/Kx)3=1 (Ky/Kx)4= Oil Recovery,% GOR, NM3/SM Perforation Length,% Perforation Length,% Effect of Perforation Length on well performance for different Horizontal Anisotropy values after 12 years SENSITIVITY ANALYSIS

51 HORIZONTAL ANISOTROPY EFFECT Oil Recovery, % Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE Ky/Kx GOR, NM3/SM3 Lp=100% Lp=80% Lp=60% Lp=40% Lp=20% Lp=60% UD Lp=40% TE Ky/Kx Effect of Horizontal Anisotropy on well performance for different perforation scenarios after 12 years SENSITIVITY ANALYSIS

52 HORIZONTAL ANISOTROPY EFFECT For all the perforated completion schemes, the higher the horizontal anisotropy (Ky/Kx), the higher the oil recovery. This is because the well is drilled in X-direction. X However, if the well was drilled in Y-direction, Y the opposite trend would be got. SENSITIVITY ANALYSIS

53 Conclusion of The Sensitivity Analysis All the plots generated in this parametric study are very useful to optimize perforated completions for horizontal wells in Hassi R melr Oil Rim, and to predict their performance within a wide range of reservoir permeability, vertical anisotropy and Horizontal anisotropy. SENSITIVITY ANALYSIS

54 Performance of Inverted High Angle Completion «Case Study : HRZ-09» Introduction Statement of the problem Objectives of the Study Methodology Geological and Reservoir Characterization Sensitivity Analysis on Perforated Completions Performance of Inverted High Angle Completion Case Study : HRZ-09 Conclusions and Recommendations

55 «Case Study : HRZ-09» Total Oil Recovery = 7.4% GAS 8-13 m Oil Rim K avg = 500md WATER CASE STUDY

56 CASE STUDY «Case Study : HRZ-09» All those factors made the necessity to develop this oil rim m by implementing horizontal wells, in addition to vertical wells (Mixed Development Strategy), to improve the oil recovery in one hand, and to alleviate the water and gas coning problems in the other hand. Among the areas where most horizontal wells have been drilled is the CTH2 area. This area will be our zone of interest in this study since the well HRZ-09 belongs to it.

57 HRZ-09 HISTORY HRE-203 HRE-402 HR-189 HRZ-09 ( January 2002 ) HRE m GAS Oil Oil Rim Rim 2214m WATER 500m 2208m CASE STUDY

58 HRZ-09 HISTORY HRZ-09 GAS Oil Oil Rimim m, WATER HRZ-09 Planned Path HRZ-09 Actual Path Planned GOC (2202m) Planned WOC (2214m) CASE STUDY

59 HRZ-09 HISTORY HRZ-09 GAS Oil Oil Rimim WATER HRZ-09 Planned Path HRZ-09 Actual Path Planned GOC (2202m) Planned WOC (2214m) CASE STUDY

60 HRZ-09 ACTUAL PATH 2175 HRZ09 Path TopA TVD,m GOC WOC Distance to the East from the Well head, m CASE STUDY

61 CASE STUDY OBJECTIVE OF THE STUDY Because of the difficulty in locating the GOC and WOC contacts in the CTH2 area, there will probably be other horizontal wells that will take the same profile as that of HRZ-09. So, it is important to study the performance of this well and to investigate various perforation scenarios in case of inverted high angle profile. Hence, to come up with the best perforation scheme that guarantees the maximum oil recovery, the minimum gas-oil ratio, and consequently, the lowest investment cost.

62 CASE STUDY HRZ-09 SIMULATION MODELING To study the performance of the well HRZ-09 for different perforation schemes, a simulation modeling of this well is needed. d. The model Grid, in this case, has to be refined in the vicinity of the well. A history match is needed for wells that are inside the Model grid. g

63 CASE STUDY RESERVOIR GEOMETRY FOR HORIZONTAL WELL MODEL For this well model, an irregular Cartesian grid was built, and a the Cartesian (X-Y-Z) coordinate are as follow : Number of blocks in X-directionX 31 Number of blocks in Y-directionY 17 Number of blocks in Z-directionZ 14 Total number of blocks 31x17x14 = 7378

64

65 THE PROPOSED PERFORATION SCHEMES 1. Horizontal Section Perforation (Actual( Case) Layer 1 Gas im Oil R Layer 4 Layer 5 296m Water Layer 14 CASE STUDY

66 THE PROPOSED PERFORATION SCHEMES 2. Slanted Section Perforation Layer 1 Layer 4 Layer 5 Gas Oil Rim Water Layer 14 CASE STUDY

67 THE PROPOSED PERFORATION SCHEMES 3. Horizontal& Slanted Section Perforation (Double Perforation Scheme) Layer 1 Gas Oil Rim Layer 4 Layer 5 296m Water Layer 14 CASE STUDY

68 CASE STUDY Comparative Study of The three Perforation schemes In this section, the focus will be on selecting the best perforation scheme of the three proposed. The selection will be based on well performance, especially oil recovery and gas-oil ratio, as well as economic analysis of the three perforation alternatives.

69 Comparative Study Based on well Performance 14 Comparative Plot of Oil Recovery versus Time for the Three Perforation Schemes Oil Recovery,% Slanted Section Horizontal Section (Actual Case) Slanted & Horizontal Sections (Double Perforation Case) Time, Years CASE STUDY

70 Comparative Study Based on well Performance GOR, NM3/SM Comparative Plot of Gas-Oil ratio versus Time for the Three perforation Schemes Slanted portion Horizontal Section (Actual Case) Slanted & Horizontal Sections (Double Perforation Case) Time, Years CASE STUDY

71 CASE STUDY Comparative Study Based on well Performance Hence, the actual case (base case) is the most favorable case according to well performance analysis. This result has to be confirmed by an economic analysis on the three perforation schemes.

72 CASE STUDY Comparative Study Based On Economic Analysis The economic analysis in this study is based on the calculation of the Net Present Value (NPV( NPV) ) for each perforation scenario. This parameter, NPV,, provides a convenient measure to select the best perforation alternative The optimum case is the one that corresponds to the maximum NPV.

73 CASE STUDY Comparative Study Based On Economic Analysis NPV : NPV = n i= 1 ( CF ) i Ri Where : (CF) i : Cash Flow in the Year i R i : Discount Rate in the Year i Ri 1 = i ( 1 + τ ) 1 τ : Rate of Interest

74 CASE STUDY Comparative Study Based On Economic Analysis Knowing that in Hassi R mel Oil Rim : Perforation Cost, Cp = 1,300 $/meter Cost of Fluid Transport, T = 1.2 $/bbl Drilling Cost, C = 5 MM$ D And assuming that : Oil Price = 25 $/bbl Rate of Interest, τ = 12%

75 CASE STUDY Comparative Study Based On Economic Analysis 1. Horizontal Section perforation (Actual( Case) NPV = 21.05MM$ Year Year Npi Income Ii Drilling Transport Cash Flow Discount (NPV)i Number (i) M.Barrels (MM$) Cost Cost (MM$) Rate Ri (MM$) Cumulative

76 Comparative Study Based On Economic Analysis 2. Slanted Section perforation NPV = 14.61MM$ Year Number, i Year NPi M.Barrels Income Ii (MM$) Drilling Cost Transport Cost Cash Flow (MM$) Discount Rate, Ri (NPV)i (MM$) Cumulative CASE STUDY

77 Comparative Study Based On Economic Analysis 3. Horizontal & Slanted Sections perforation NPV = 21.37MM$ Year Number, i Year NPi M.Barrels Income, Ii (MM$) Drilling Cost Transport Cost Cash Flow (MM$) Discount Rate, Ri (NPV)i (MM$) Cumulative CASE STUDY

78 Comparative Study Based On Economic Analysis Comparative Histogram of the Three Perforation Schemes Oil Price = 25 $/bbl NPV, MM$ Horizontal Section Slanted Scetion Slanted & Horizontal Sections CASE STUDY

79 CASE STUDY CONCLUSIONS (CASE STUDY) The simulation results indicate that there is no extra-recovery recovery to be expected from the double perforation scheme. Besides, such perforation scheme leads to higher Gas-Oil Ratio to be produced in comparison to the Horizontal section perforation (actual case). Thus, the best perforation scheme is the one that corresponds to the actual case.

80 CASE STUDY CONCLUSIONS (CASE STUDY) The Economic analysis performed on the three perforation scenarios has confirmed the above conclusion, which means that the maximum net present value (NPV) will correspond to the actual case if we take into account the investment cost in gas facilities. Although the well HRZ-09 took an inverted high angle profile accidentally, this profile has brought several advantages, such as :

81 CONCLUSIONS (CASE STUDY) Allow the exact location of Gas-Oil and Water-Oil contacts, so that, the horizontal drain can be placed at a desired depth. Explore the entire oil column and find out the high quality sand d of this column prior to placing the horizontal drain. Thus, it serves es as a Pilot Hole. Alleviate the water and gas coning problems. CASE STUDY

82 CONCLUSIONS AND RECOMMENDATIONS Introduction Statement of the problem Objectives of the Study Methodology Geological and Reservoir Characterization Sensitivity Analysis on Perforated Completions Performance of Inverted High Angle Completion Case Study : HRZ-09 Conclusions and Recommendations

83 CONCLUSIONS Based on the entire study, the following conclusions can be drawn : 1. The perforation length can be reduced, and in many cases, without a substantial decrease in oil recovery. Moreover, lower values of perforation length lead to lower gas-oil ratios produced. 2. Hence, the perforation length has to be optimized with respect not only to oil recovery, but also to gas-oil ratio. This to guarantee the lowest investment cost in gas facilities. CONCLUSIONS

84 CONCLUSIONS (Continued) 3. The reservoir produces more efficiently when the perforation intervals are uniformly distributed along the wellbore rather than being continuously placed. 4. The correlation curves developed in the parametric study can be used to optimize the perforation scheme for horizontal wells in Hassi R mel R Oil Rim, especially CTH2 area. CONCLUSIONS

85 CONCLUSIONS (Continued) 5. In Hassi R mel R Oil Rim, the optimum perforation scheme for horizontal well is the case that corresponds to 60% uniformly distributed perforation. 6. Although the well HRZ-09 took an inverted high angle profile accidentally, this profile has brought several advantages. CONCLUSIONS