Course overview

This is a basic reservoir simulation course that is designed for novice engineers in reservoir simulation, or engineers needing a refresher in the basics of reservoir simulation. The course begins with discussion of the fundamentals of reservoir simulation: why, how and under what conditions reservoir simulation is necessary over, for instance, a simple material balance. The course refreshes the student in the basics of the partial differential equation and the diffusivity equation, beginning in 1-D coordinate systems. The analytical solutions to the diffusivity equation are discussed and the assumptions are presented that allow the use of finite differences to be utilized to create a system of algebraic equations that can be solved by iterative procedures. We then discuss the solution methods, implicit, explicit and IMPES methods. We discuss the conditions for stability and convergence and the applicability of each of the methods. We review matrix solvers and establish the fundamental engine in all finite difference simulators.

After this we discuss simple 1-D, single phase applications for simple short term well tests. We cover the basics of time step optimization and move on to the more sophisticated problems like design of a hydraulic fracture, design and simulation of horizontal wells, and eventually multi-well simulation of pattern water injection models that require understanding the basics of two phase flow, gridding a pattern area, optimizing specific patterns based on reservoir properties and analysis of saturation fronts as water injection proceeds. We conclude with the concepts of history matching with field case histories and demonstration of full field modelling. During the course we have modules that allow the attendees to perform practical simulation with the use of RFD’s TNavigator.

The course is designed for

This course is designed for engineers with a good grasp of fundamental reservoir engineering principles. This could be a fresh graduate with limited exposure to simulation principles and applications or more experienced engineers that have had limited exposure to numerical simulation and would like to learn or refresh their knowledge base. The course is designed such that attendees with little or no experience in reservoir simulation can pick up the principles and run a modern reservoir simulator for very simple to more complex small models (i.e. single well to multi-well pattern models).

Course objectives

• Learn or refresh the basic mathematics behind numerical simulation
• Discuss the practical use of reservoir simulation
• Learn the numerical methods to convert partial differential equations into simulation equations using finite differences
• Teach the attendee how to simulate simple single well models like well tests, hydraulic fracturing and horizontal wells with practical modules and direct use of software
• Discuss the concepts of a successful history match in preparation for forecasting infill wells, water injection projects and gas injection EOR
• Fortify the learnings with case history studies of simulation projects
• Demonstrate large projects with multi-million cell models and the current state of the art in speed efficiency for TNavigator

Course outline

Day 1 Morning

• Introduction to reservoir simulation
• Diffusivity equation and partial differential equations
• Analytical and numerical solutions to diffusivity equation
• Application of finite differences for system of algebraic equations
• *Simulation of single well pressure transient test (1-D)

Day 1 Afternoon

• Pressure transient analysis
• Description of damage, geometric and mechanical skin
• Determination of reservoir permeability
• Discussion of boundary conditions
• Discussion of cylindrical and Cartesian coordinate systems
• *Simulation of single well pressure transient test (1-D)

Day 2 Morning

• Numerical solutions to 1-D diffusivity equation
• Implicit, explicit and IMPES solutions to diffusivity equation
• Flow chart for solution of implicit method
• Use of matrix solvers for solution of iterative equations
• Extension of 1-D simulation models to 2-D and 3-D
• Relative permeability, capillary pressure for oil-water and gas-oil systems

Day 2 Afternoon

• Principles of hydraulic fracturing
• Determination of fracture conductivity
• Use of fine grid blocks to simulate hydraulic fracture
• Fracture permeability and half-length
• *Simulation of hydraulic fracture in vertical well (2-D)

Day 3 Morning

• Horizontal well simulation
• Peaceman’s equation and productivity index
• Inflow performance and calculation of well index
• Vertical permeability and determination net pay thickness
• Review of open-hole logging for determination of porosity and net pay

Day 3 Afternoon

• Horizontal wells and sensitivity of EUR to lateral length
• Gridding fundamentals for horizontal wells
• Principles of symmetry
• *Simulation of horizontal well in Cartesian coordinates

Day 4 Morning

• Multi-well principles in reservoir simulation
• Waterflood principles
• Pressure maintenance and secondary to primary ratio
• Patterns for water injection (5-spot, 9-spot...etc)

Day 4 Afternoon

• Gridding principles for injection wells
• Rate and pressure constraints for production and injection wells
• Optimization of patterns for maximum reserves
• *Simulation of water injection in patterns

Day 5 Morning

• Aquifers and water drive (peripheral and bottom water drive)
• Simulation of aquifers
• Initialization of aquifer models with capillary pressure
• History matching principles
• History matching average reservoir pressure and flowing BHP
• History matching GOR, WOR field-wide and for individual wells

Day 5 Afternoon

• Complex large-scale models
• Demonstration of field-wide models
• RFD’s demo of speed of tNav