Comparative  Analysis of Performance of Horizontal and Hydraulically Fractured Wells in a Tight Gas Reservoir using Numeri...
Project Team<br /><ul><li>  External Advisor: </li></ul>Dr. SuhailQadeer(Senior Manager Production Engineering, Pakistan P...
Haris Ali Soomro (PE-027)
M. OwaisNaseem (PE-025)
Muneeb Ahmad (PE-006)
Zeeshan-ul-Haq (PE-015)</li></ul>02<br />
Contents<br />
Objective<br />To compare the Performance of Horizontal and Vertical Hydraulically Fractured Wells in a Tight Gas Reservoi...
Scope<br /><ul><li>In years to come, when conventional resources of Oil and Gas will be depleted, the world will have to l...
The question arises “Which is the suitable method to  develop a particular Tight Gas Reservoir?”
Our project can serve as a prototype which can be scaled up for the real  data.</li></ul>05<br />
TIGHT GAS RESERVOIRS<br />A Brief Introduction<br />AsifAzhar (PE-033)<br />
Introduction to Tight Gas Reservoirs<br />Tight gas is the term commonly used to refer low permeability reservoirs that pr...
Definition of Tight Gas Reservoir<br />“ . . . The best definition of tight gas reservoir is a reservoir that cannot be pr...
What Makes a Reservoir Tight?<br /><ul><li> The original depositional fabric itself was tight.
The original sedimentary fabric have been subsequently reduced in porosity by post depositional diagenesis to unacceptably...
Possible Candidates for TGR in Pakistan<br /><ul><li>  Lower Goru Tight Sands
Sembar Sands and Siltstones
  Sui Upper Limestone
HabibRahi Limestone
Pirkoh Limestone</li></ul>‘Untapping Tight Gas Reservoirs’ by Muhammad AjazSarwar & AbdurRaufMirza, OGDCL<br />10<br />
Possible Candidates for TGR in Pakistan<br />‘Scope of Tight Gas Reservoir in Pakistan’ by SalahHaikal, Eni Pakistan Ltd<b...
                  TGR Completion Techniques<br />Fractured Vertical Wells<br />Multi-lateral Wells<br />Horizontal Wells<b...
Fractured Vertical Wells<br />Important Issues<br /><ul><li>No significant control over Fracture Height
  Obtaining Infinite Conductivity Fractures
  More effective in reservoirs having permeability less than 10md</li></ul>‘Horizontal Well Technology’ by  Sada D. Joshi ...
                          Horizontal Wells<br />Important Issues<br /><ul><li>  Large Reservoir Contact Area
  Only one pay zone can be drained per horizontal well
  Costs 1.3-4 times more than a Vertical well
  In TGR, Horizontal wells can improve drainage area per well and reduce the number of wells
  In some cases of TGR horizontal fractured wells may work better.</li></ul>‘Horizontal Well Technology’ by  Sada D. Joshi...
RESERVOIR SIMULATION<br />A Brief Introduction<br />Haris Ali Soomro (PE-027)<br />
Reservoir Simulation<br /><ul><li>  Reservoir simulation is an area of reservoir engineering in which computer models are ...
  Gordon Adamson in his article “Simulation Throughout the Life of a Reservoir” writes:</li></ul>“Simulation is one of the...
Simulation Approaches<br /><ul><li>Single Well Simulation
Field Scale Simulation
Window Study</li></ul>17<br />
Simulation Approaches<br />Single Well Simulation<br />Field Scale Simulation<br />18<br />
Flow Geometries<br /><ul><li>Rectangular Geometry
Radial or Cylindrical Geometry
Elliptical Geometry
Spherical Geometry</li></ul>19<br />
Flow Geometries and Dimensions<br />One-Dimensional Flow<br /><ul><li>  A long skinny reservoir </li></ul>Two-Dimensional ...
  Thin blanket sands</li></ul>Three-Dimensional Flow<br /><ul><li>  Layered reservoirs
  Multi layered production schemes
  Thick reservoirs </li></ul>z<br />y<br />x<br />Rectangular Geometry<br />20<br />
Flow Geometries and Dimensions (contd.)<br />One-Dimensional Flow <br /><ul><li>  Well test analysis
  Flow is constrained to the r-direction     </li></ul>Two-Dimensional Flow<br /><ul><li>  Single well problems where grav...
Flow Geometries and Dimensions (contd.)<br />Ф<br />θ<br />r<br />Elliptical Geometry<br />Spherical Geometry<br />22<br />
Construction of models<br />Data Preparation<br />M. OwaisNaseem (PE-025)<br />
Data Preparation<br /><ul><li>Reservoir Geometry
Reservoir Rock Properties
PVT Data
Capillary Pressure Data
  Relative Permeability Data
  Well Data</li></ul>24<br />
Reservoir Geometry<br /><ul><li>Horizontal Well Model
Fractured Vertical Well Model</li></ul>Radial  Co-ordinate System<br /><ul><li>Eclipse Limitation
Reason for the substitution of Horizontal Well with Vertical Well</li></ul>Rectangular Co-ordinate System<br />25<br />
Reservoir Properties<br /><ul><li>Homogenous
Isotropic
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Comparative Analysis of Performance of Horizontal and Hydraulically Fractured Wells in a Tight Gas Reservoir using Numerical Simulations

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Transcript of "Comparative Analysis of Performance of Horizontal and Hydraulically Fractured Wells in a Tight Gas Reservoir using Numerical Simulations"

  1. 1. Comparative Analysis of Performance of Horizontal and Hydraulically Fractured Wells in a Tight Gas Reservoir using Numerical Simulations<br />1<br />December 9, 2009<br />
  2. 2. Project Team<br /><ul><li> External Advisor: </li></ul>Dr. SuhailQadeer(Senior Manager Production Engineering, Pakistan Petroleum Limited)<br /><ul><li>Internal Advisor: </li></ul>Mr. Adnan-ul-Haq(Lecturer, NED University of Engineering and Technology)<br />Group Members<br /><ul><li>AsifAzhar (PE-033)
  3. 3. Haris Ali Soomro (PE-027)
  4. 4. M. OwaisNaseem (PE-025)
  5. 5. Muneeb Ahmad (PE-006)
  6. 6. Zeeshan-ul-Haq (PE-015)</li></ul>02<br />
  7. 7. Contents<br />
  8. 8. Objective<br />To compare the Performance of Horizontal and Vertical Hydraulically Fractured Wells in a Tight Gas Reservoir<br />04<br />
  9. 9. Scope<br /><ul><li>In years to come, when conventional resources of Oil and Gas will be depleted, the world will have to look towards Unconventional Resources among which Tight Gas Reservoirs are one of the options.
  10. 10. The question arises “Which is the suitable method to develop a particular Tight Gas Reservoir?”
  11. 11. Our project can serve as a prototype which can be scaled up for the real data.</li></ul>05<br />
  12. 12. TIGHT GAS RESERVOIRS<br />A Brief Introduction<br />AsifAzhar (PE-033)<br />
  13. 13. Introduction to Tight Gas Reservoirs<br />Tight gas is the term commonly used to refer low permeability reservoirs that produce mainly dry natural gas.<br />‘Tight Gas Sands’ by Stephen A. Holditch, SPE Texas A &M U<br />07<br />
  14. 14. Definition of Tight Gas Reservoir<br />“ . . . The best definition of tight gas reservoir is a reservoir that cannot be produced at economic flow rates nor recover economic volumes of natural gas unless the well is stimulated by a large hydraulic fracture treatment or produced by the use of a horizontal wellbore or multilateral wellbores . . . ”<br />‘Tight Gas Sands’ by Stephen A. Holditch, SPE Texas A &M U<br />08<br />
  15. 15. What Makes a Reservoir Tight?<br /><ul><li> The original depositional fabric itself was tight.
  16. 16. The original sedimentary fabric have been subsequently reduced in porosity by post depositional diagenesis to unacceptably low amounts.</li></ul>‘What is considered a Tight Gas Reservoir’ by Ravi Mishra<br />09<br />
  17. 17. Possible Candidates for TGR in Pakistan<br /><ul><li> Lower Goru Tight Sands
  18. 18. Sembar Sands and Siltstones
  19. 19. Sui Upper Limestone
  20. 20. HabibRahi Limestone
  21. 21. Pirkoh Limestone</li></ul>‘Untapping Tight Gas Reservoirs’ by Muhammad AjazSarwar & AbdurRaufMirza, OGDCL<br />10<br />
  22. 22. Possible Candidates for TGR in Pakistan<br />‘Scope of Tight Gas Reservoir in Pakistan’ by SalahHaikal, Eni Pakistan Ltd<br />11<br />
  23. 23. TGR Completion Techniques<br />Fractured Vertical Wells<br />Multi-lateral Wells<br />Horizontal Wells<br />12<br />
  24. 24. Fractured Vertical Wells<br />Important Issues<br /><ul><li>No significant control over Fracture Height
  25. 25. Obtaining Infinite Conductivity Fractures
  26. 26. More effective in reservoirs having permeability less than 10md</li></ul>‘Horizontal Well Technology’ by Sada D. Joshi <br />13<br />
  27. 27. Horizontal Wells<br />Important Issues<br /><ul><li> Large Reservoir Contact Area
  28. 28. Only one pay zone can be drained per horizontal well
  29. 29. Costs 1.3-4 times more than a Vertical well
  30. 30. In TGR, Horizontal wells can improve drainage area per well and reduce the number of wells
  31. 31. In some cases of TGR horizontal fractured wells may work better.</li></ul>‘Horizontal Well Technology’ by Sada D. Joshi <br />14<br />
  32. 32. RESERVOIR SIMULATION<br />A Brief Introduction<br />Haris Ali Soomro (PE-027)<br />
  33. 33. Reservoir Simulation<br /><ul><li> Reservoir simulation is an area of reservoir engineering in which computer models are used to predict the flow of fluids (typically, oil, water, and gas) through porous media.
  34. 34. Gordon Adamson in his article “Simulation Throughout the Life of a Reservoir” writes:</li></ul>“Simulation is one of the most powerful tools for guiding reservoir management decisions. From planning early production wells and designing surface facilities to diagnosing problems with enhanced recovery techniques, reservoir simulator allow engineers to predict and visualize fluid flow more efficiently than ever before.”<br />www.wikipedia.org <br />16<br />
  35. 35. Simulation Approaches<br /><ul><li>Single Well Simulation
  36. 36. Field Scale Simulation
  37. 37. Window Study</li></ul>17<br />
  38. 38. Simulation Approaches<br />Single Well Simulation<br />Field Scale Simulation<br />18<br />
  39. 39. Flow Geometries<br /><ul><li>Rectangular Geometry
  40. 40. Radial or Cylindrical Geometry
  41. 41. Elliptical Geometry
  42. 42. Spherical Geometry</li></ul>19<br />
  43. 43. Flow Geometries and Dimensions<br />One-Dimensional Flow<br /><ul><li> A long skinny reservoir </li></ul>Two-Dimensional Flow<br /><ul><li> Variety of completion strategies
  44. 44. Thin blanket sands</li></ul>Three-Dimensional Flow<br /><ul><li> Layered reservoirs
  45. 45. Multi layered production schemes
  46. 46. Thick reservoirs </li></ul>z<br />y<br />x<br />Rectangular Geometry<br />20<br />
  47. 47. Flow Geometries and Dimensions (contd.)<br />One-Dimensional Flow <br /><ul><li> Well test analysis
  48. 48. Flow is constrained to the r-direction </li></ul>Two-Dimensional Flow<br /><ul><li> Single well problems where gravity and/ or layering effects are significant. </li></ul>Three-Dimensional Flow<br /><ul><li> Property variation in all three directions.</li></ul>z<br />z<br />r<br />r<br />θ<br />Radial or Cylindrical Geometry<br />21<br />
  49. 49. Flow Geometries and Dimensions (contd.)<br />Ф<br />θ<br />r<br />Elliptical Geometry<br />Spherical Geometry<br />22<br />
  50. 50. Construction of models<br />Data Preparation<br />M. OwaisNaseem (PE-025)<br />
  51. 51. Data Preparation<br /><ul><li>Reservoir Geometry
  52. 52. Reservoir Rock Properties
  53. 53. PVT Data
  54. 54. Capillary Pressure Data
  55. 55. Relative Permeability Data
  56. 56. Well Data</li></ul>24<br />
  57. 57. Reservoir Geometry<br /><ul><li>Horizontal Well Model
  58. 58. Fractured Vertical Well Model</li></ul>Radial Co-ordinate System<br /><ul><li>Eclipse Limitation
  59. 59. Reason for the substitution of Horizontal Well with Vertical Well</li></ul>Rectangular Co-ordinate System<br />25<br />
  60. 60. Reservoir Properties<br /><ul><li>Homogenous
  61. 61. Isotropic
  62. 62. Porosity = 0.02
  63. 63. Permeability = 0.1 millidarcy
  64. 64. Reservoir Temperature = 300˚F
  65. 65. Reservoir Pressure = 5000 psia</li></ul>26<br />
  66. 66. PVT Data<br /><ul><li>Specific Gravity = 0.7
  67. 67. Formation Volume Factor
  68. 68. Viscosity</li></ul>27<br />
  69. 69. Formation Volume Factor<br />‘Reservoir Engineering Handbook’ by Tarek Ahmed <br />28<br />
  70. 70. Viscosity<br />‘Reservoir Engineering Handbook’ by Tarek Ahmed <br />29<br />
  71. 71. Carr’s Viscosity Correlation<br />‘Reservoir Engineering Handbook’ by Tarek Ahmed <br />30<br />
  72. 72. Calculated Formation Volume Factors and Viscosities<br />31<br />
  73. 73. Capillary Pressure Data<br />‘Empirical Capillary Pressure Relative Permeability Correlation’ By James H. Schneider<br />32<br />
  74. 74. Calculated Capillary Pressures<br />33<br />
  75. 75. Relative Permeability Data<br />‘Empirical Capillary Pressure Relative Permeability Correlation’ By James H. Schneider<br />34<br />
  76. 76. Determination of λ<br />Brooks and Corey observed that a log-log plot of Sw* against Pc results in a straight line with a slope of -λ<br />35<br />
  77. 77. Calculated Relative Permeabilities<br />36<br />
  78. 78. Well Data<br /><ul><li>Wellbore diameter = 0.6 ft
  79. 79. Constant Flowing Bottomhole Pressure = 1000 psia</li></ul>37<br />
  80. 80. Construction of models<br />Reservoir Discretization<br />Muneeb Ahmad (PE-006)<br />
  81. 81. Horizontal Well Model<br /><ul><li> Radial Geometry
  82. 82. Cylindrical Reservoir; r = 225ft & h = 2000ft
  83. 83. 12500 Blocks; r:θ:z = 25:25:20
  84. 84. Well in the centre; L = 1000ft
  85. 85. Quarter of the reservoir is modeled.</li></ul>39<br />
  86. 86. Assumed Model<br />1000 ft<br />2000 ft<br />100 ft<br />200 ft<br />40<br />
  87. 87. Eclipse Generated Model<br />3-D View<br />Top View<br />41<br />
  88. 88. Vertical Well Model<br /><ul><li> Rectangular Geometry
  89. 89. Rectangular Reservoir with Well in the centre
  90. 90. Quarter of the Reservoir is modeled
  91. 91. Reservoir dimension (Quarter); 2000 x 200 x 100 ft3.
  92. 92. 1680 blocks; x:y:z = 24:07:10</li></ul>42<br />
  93. 93. 4000 ft<br />Assumed Model<br />Fracture Width<br />100 ft<br />Fracture Height<br />400 ft<br />Fracture Half Length<br />Top view of the quarter of the Reservoir<br />43<br />
  94. 94. Fracture Properties<br /><ul><li> Fracture Width = 0.6 inch
  95. 95. Half Fracture Length = 1000 ft
  96. 96. Fracture Porosity = 35%
  97. 97. Dimensionless Fracture Conductivity = 10
  98. 98. Fracture Permeability = 20000 md
  99. 99. Equivalent Fracture Width = 2 ft
  100. 100. Fracture Porosity = 0.875%
  101. 101. Fracture Permeability = 500 md</li></ul>‘Fracture Face Interference Of Finite Conductivity Fractured Wells Using Numerical Simulation’ By SvjetlanaLale<br />44<br />
  102. 102. Flow Geometries and Dimensions (contd.)<br />Equivalent Fracture Width<br />Original Fracture Width<br />45<br />
  103. 103. Eclipse Generated Models<br />3-D View<br />Top View<br />46<br />
  104. 104. Cases for Comparison<br />Vertical Well<br />Vertical Well<br />Fracture Height<br />Fracture Height<br />Horizontal Well<br />Horizontal Well<br />When the fracture penetrates half of the vertical well length<br />When the fracture penetrates the total vertical well length<br />CASE: 01<br />CASE: 02<br />Vertical Well<br />Fracture Height<br />Horizontal Well<br />When the fracture penetrates quarter of the vertical well length<br />CASE: 03<br />47<br />
  105. 105. Classification of Each Case<br />Each Case<br />L = 1000 ft<br />L = 100 ft<br />L = 200 ft<br />L = 400 ft<br />L = 500 ft<br />48<br />
  106. 106. Results<br />Zeeshan-ul-Haq (PE-015)<br />
  107. 107. Initial Production Rate Plot<br />50<br />
  108. 108. Decline In Production Rate (Horizontal Well)<br />51<br />
  109. 109. Decline In Production Rate (Vertical Well)<br />52<br />
  110. 110. Cumulative Production (Horizontal Well)<br />53<br />
  111. 111. Cumulative Production (Vertical Well)<br />54<br />
  112. 112. Productivity Index Plot<br />55<br />
  113. 113. Area Open to Flow Plot<br />56<br />
  114. 114. conclusions<br />
  115. 115. Conclusions<br /><ul><li>As the length of the fracture or the horizontal well is increased:
  116. 116. The production rate is increased,
  117. 117. The decline in the production rate is faster due to the closed reservoir system,
  118. 118. The cumulative production is more or less same,
  119. 119. Economics will dictate the optimum length of the horizontal well or the fracture half length,
  120. 120. In case of fractured wells same results can be achieved by either increasing the half length or the height of the fracture.
  121. 121. Since the area open to flow for the fractured well is more than that of the horizontal well, its productivity index is also greater. However achieving fracture half lengths similar to the length of the horizontal wells is impossible in practice.
  122. 122. The productivity index increases almost linearly for the horizontal well.
  123. 123. For vertical fractured wells the increase in productivity index becomes less as the length of the fracture increases.
  124. 124. It will therefore be a matter of economics to decide between the fractured wells and the horizontal well.</li></ul>58<br />
  125. 125. Recommendations for future work<br />
  126. 126. Recommendations For Future Work<br /><ul><li> The comparison should be done for the realistic values of Half Fracture Length.
  127. 127. Effect on the performance should also be analyzed by varying other parameters such as Permeability, Location of the Wells, etc.
  128. 128. If possible, then it is highly advisable to include economic analysis.</li></ul>60<br />
  129. 129. QUESTIONS ???<br />61<br />

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