Well Testing Analysis(Introduction)

Introduction to Well TestingObjectives
• List the more common objectives of well testing.
• Describe the diffusivity equation by explaining
– its purpose and applications
– assumptions made in its derivation and how it is
derived
– its form for one-dimensional radial flow.
• List, define, give the units for, and specify typical sources
for each of the variables that influence responses in a well
test.
• Compute the total compressibility for different reservoir
systems (undersaturated oil, saturated oil, gas).What Is A Well Test?
• A tool for reservoir evaluation and characterization
– Investigates a much larger volume of the reservoir
than cores or logs
– Provides estimates of
– permeability under in-situ conditions
– near-wellbore conditions
– distances to boundaries
– average pressure
How Is A Well Test Conducted?

 

 


Fundamental Concepts
• Applications and objectives of well testing
• Development of the diffusivity equation
• Definitions and sources for data used in
well testingTypes and Purposes of Well
Tests
• Pressure transient tests
– We generate and measure pressure changes with time
• Deliverability tests
– Well controlled production
• (Production Analysis)
– Use of production data for goals usually achieved by
well testingProduction data analysis
• Reservoir properties (permeability, skin
factor, fracture half-length, etc).
• Reservoir pore volume (estimated using
long-term production performance).
• Estimated ultimate recovery (EUR)—
movable fluid volumes.

 Well Testing Objectives

• Define reservoir limits
• Estimate average drainage area pressure
• Diagnose productivity problems
• Characterize reservoir
• Evaluate stimulation treatment effectiveness