Reservoir Simulation

1.

Reservoir Simulation
Chapter-one
Introduction
Sadam .H
1

2. THE CHALLENGE OF RESERVOIR SIMULATION …

2

3. DYNAMIC RESERVOIR SIMULATION

3

4. Incentives for running a flow simulation

4

5. Computer Modeling

The reservoir model
Fluid flow Equation within the reservoir
The reservoir is modeled by subdividing the reservoir
volume into an array, or grid, of smaller volume
elements, which called: gridblock, cell, or node.
The well model
Fluid flow that represents the extraction of fluids from
the reservoir or the injection of fluids into the reservoir
The well bore mode
Fluid flow from the sand face to the surface
The surface model
constraints associated with surface facilities, such
as platform and separator limitations
5

6. Reservoir simulator

6

7. Reservoir simulation model

7

8. Reservoir simulation model

8

9. Main modeled phenomena

9

10. Definitions

10

11. Types of models

11

12. Types of simulators

12

13. Types of simulators

13

14. Black Oil model

14

15. NUMERICAL MODELS: DISCRETIZATION

15

16. Reservoir Simulation PLANNING

16

17.

A question of Scale
17

18. Prediction Future performance

Reservoir Simulation Model
Geological Model
History Matching
Reduce Operation Expenses
Increase Recovery
Prediction
18

19. Problem definition

19

20. Data review

20

21. Main Types of Data

21

22. Study approach

22

23. Study approach

23

24. GRID TYPES

24

25. GRID TYPES

25

26. Sugar box geometry

26

27. Sugar box geometry

27

28. Corner point geometry

28

29. Reservoir description : PROPERTIES

29

30. Reservoir description : PROPERTIES

30

31. Reservoir Discritization

Defination: the reservoir is described by a set of gridblocks (or
gridpoints) whose properties, dimensions, boundaries, and locations in the
reservoir are well defined.
Block centered grid
Point distributed grid
i-1
i
i+1
ΔY
ΔX
ΔX
31

32. Block Identification and Ordering

32

33. Block Identification and Ordering

• Natural ordering
• Zebra ordering
• Diagonal D2 ordering
• Alternating diagonal
D4 ordering
• Cycle ordering
• Cycle-2 ordering
33

34. GRID SIZE SELECTION

34

35. ACTIVE and DEAD CELLS

35

36. GEOLOGICAL CONSTRAINTS

36

37. CHOICE OF VERTICAL DISCRETIZATION

37

38. Using LGR to model gas coning

38

39. Block-centered grid

39

40. Block-centered grid

40

41. Block-centered grid

41

42. Dip or fault ?

42

43. CPG grid intercell flow

43

44. Fault description in CPG grid

44

45. Example of CPG reservoir model

45

46. Fault description in CPG grid

46

47. Reservoir layering: Use of log Correlation

K.FEKI
47

48. Upscaling

• Optimum level of
and techniques
for upscaling to
minimize errors
Gurpinar, 2001
48

49. Rock properties: Main parameters

49

50. Rock properties: Net thickness and porosity

50

51. Rock properties: Compressibility

51

52. Rock properties: Compressibility

52

53. Horizontal & Vertical Permeability

Horizontal & Vertical Permeability
53

54. Horizontal Permeability

54

55. Vertical Permeability

55

56.

History Matching
56

57.

History Matching
57

58.

History Matching
58

59.

FIRST STEP - GENERAL FIELD MATCH - RUN 1
59

60.

FINAL STEP - GENERAL FIELD MATCH - RUN 3
60

61.

Predictions
61

62.

Predictions
62

63.

Predictions
63

64. Fluid flow equations

Conservation laws
–
Conservation in mass
Assume:
–
–
Isothermal condition
complete and instantaneous phase equilibration in each cell
Conservation in energy
Conservation in momentum
Additional constraints
Wells and facilities
Large number of non-linear equations
64

65. Fluid flow equations

Type of fluid in the reservoir
Flow regimes
Reservoir geometry
Number of flowing fluids in the reservoir
65

66. Type of fluid in the reservoir

Incompressible
Slightly compressible
Compressible
66

67. Flow regimes

Steady State flow
Unsteady State flow
Pseudo Steady State flow
67

68. Reservoir geometry

Radial flow
Linear flow
Spherical and Hemispherical flow
68

69. Number of flowing fluids in the reservoir

Single Phase flow
Two phase flow
Three phase flow
69

70. IN OUT

Reservoir Simulator
Pressure
Saturation
Newton-Raphson (IMPLICIT)
all primary variables are calculated at the same time.
IMplicit Pressure Explicit Saturation (IMPES)
The IMPES procedure solves for pressure at the new time level using
saturations at the old time level, and then uses the pressures at the
new time level to explicitly calculate saturations at the new time level
70

71. Numerical Models

Black oil model
o
o
Depletion
Water Injection
Component: oil water gas
Phase: Oil water gas
71

72.

Compositional model
o
o
Gas injection to increase or maintain reservoir pressure
Miscible flooding as the injection gas goes into solution with oil
Carbon dioxide flooding, with the gas soluble in both oil and water
Thick reservoirs with a compositional gradient caused by gravity
Reservoirs with fluid compositions near the bubblepoint
High-pressure, high temperature reservoirs
Natural-fracture reservoir modeling.
Component: C1,C2, ….So2,H2S,N2,..
Phase: Oil water gas
72

73.

Chemical model
o
o
Polymer and surfactant injection
Component: Water oil surfactant alcohol
Phase: Agues oleic microemulsion
73

74. Reservoir simulators

ECLIPSE
GPRS
SENSOR
NEXUS
UTCHEM
Boast 3
COMET3
…
Objective
Accuracy
Time
Limitations
User friendly
Easy to integrate
…
74

75. Eclipse reservoir simulator

• Commercial reservoir simulator for over 25 years
• Black-oil
• Compositional
• Thermal
• Streamline
75

76. Eclipse reservoir simulator

Local Grid Refinement
Gas Lift Optimization
Gas Field Operations
Gas Calorific Value-Based
Control
Geomechanics
Coalbed Methane
Networks
Reservoir Coupling
Flux Boundary
Environmental Traces
Open-ECLIPSE Developer's Kit
Pseudo-Compositional
EOR Foam
EOR Polymer
EOR Solvent
EOR Surfactant
Wellbore Friction
Multisegmented Wells
Unencoded Gradients
Parallel ECLIPSE
76

77. Grid definition : Example

77

78. Rock properties: Main parameters

78

79. Thank You!

79

80. Quiz

• Look at the following sentences . Establish
for each one if it is a true or false
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Reservoir layering should be defined before XY grid
Reservoir layering is derived from well data
Reservoir layering is derived from fault geometry
Reservoir layering should respect wells correlation
Reservoir layering should respect flow unit
Grid geometry can vary with time
Any grid has locally three main flow directions
Grid axes should be locally orthoganal
One cell can communicate with maximum of 6 neighbours
grid blocks are refered by three indexes (I ,j , k)
K.FEKI
80

81. Reservoir layering: Quiz

81

82. Grid definition: Quiz

82