Well Test Analysis

Well test analysis has been used for many years to assess well condition and obtain reservoir parameters. With the introduction of pressure-derivative analysis and the development of complex interpretation models that are able to account for detailed geological features, well test analysis has become a very powerful tool for reservoir characterization. A new milestone has been reached recently with the introduction of deconvolution, which makes it possible to see boundaries which may not be visible from conventional analysis. This has a significant impact on the ability to certify reserves.

The methodology described in the course, which has become the standard of the industry, presents a systematic way of interpreting well tests and reconciles the various methods that have been developed over the years. The emphasis of the course is on well tests in gas condensate and volatile oil reservoirs, which are the most difficult to interpret as they combine the usual complexities of wells and reservoirs with complexity of the fluids. Practical problem-solving sessions are included in the course.

The use of analysis results to assist in decision making related to reservoir development and well completion will be illustrated through real-life case histories. Attendees are encouraged to bring well tests used in recent projects for discussion.

• UNDERSTANDING the fundamental concepts of well test analysis
• MASTERING state-of-the-art interpretation methodology
• AVOID pitfalls and KNOW limitations of current well test analysis techniques
• ATTAIN the knowledge practical use of well test deconvolution
• DETERMINE and MANAGE characteristics of gas condensate and volatile oil tests below saturation pressure
• LEARNING the use of single phase and two-phase pseudo-pressures
• CHARACTERIZE well test behavior as a function of fluid richness (lean, medium-rich, rich, and volatile)
• INTERPRET Skin effect vs. rate relationship

• Reservoir Engineers
• Reservoir Managers
• Production Engineers
• Production Technologist
• Production Engineering Manager
• Petroleum Engineer

DAY 1

Objectives of Well Testing and Information Obtained from Well Tests

This first day focuses on the well test analysis methodology that has become the industry standard.

• Well testing for Well Performance, Reservoir Characterization and Reservoir Performance
• Well Testing as a Signal Analysis Problem
• Concept of Interpretation Model
• Components of the Interpretation Model (Near-Wellbore Effects, Reservoir Behavior, Boundary Effects)
• Definition of a Methodology (Identification and Verification of the Interpretation Model)
• Analysis Signal and Interpretation Methods

DAY 2

Interpretation Methods

This second day focuses on well test analysis techniques and their evolution during the past half century. Improvements have come in a series of step changes 20 years apart, resulting in increasing ability to discriminate among potential interpretation models and to verify the consistency of the analysis. This has increased drastically the amount of information that one can extract from well test data and, more importantly, the confidence in that information.

• Straight-Line methods
• Pressure Log-Log analysis and Tutorial 1
• Pressure Derivative analysis and Tutorial 2
• Other analysis techniques
• Deconvolution
• The use of simulators in well test analysis

DAY 3

Interpretation models and Practical test considerations

This third day focuses on the most common well test interpretation models, and on practical well test considerations

• Wellbore storage and skin
• Hydraulic fractures and Tutorial 3
• Limited entry
• Inclines and Horizontal wells
• Double porosity behavior
• Double permeability behavior
• Composite behavior
• Single fault and Tutorial 4
• Channel
• Intersecting faults
• Open rectangle
• Closed rectangle
• Test design
• Screening of possible interpretation models
• Summary of the state-of-the-art

DAY 4

Well test analysis of complex fluid systems (gas condensates and volatile oil)

This fourth day focuses on tests in gas condensate reservoirs below the dew point pressure and in volatile oil reservoirs below the bubble point pressure. The combination of complex reservoirs, complex fluids, and complex wells creates well test pressure behaviors that can be very difficult to interpret.

• Gas and multiphase analyses
• Specificity of gas condensate and volatile oil well tests
• Simulated well tests
• Practical analysis considerations
• Data
• Wellbore, reservoir and fluid effects
• Well test analysis tools
• Challenges

DAY 5

Well test analysis of complex fluid systems (gas condensates and volatile oil), cont’d

• Single-phase vs. two-phase pseudo-pressure analysis
• Productivity prediction and Remediation
• Field examples
• Compositional simulation of actual well tests
• Well test interpretation challenges (Lean vs. Medium rich vs. Rich gas vs. Volatile oil behaviors)
• Skin vs. Rate relationship