Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Error analysis and design considerations for backpressure testing of gas wells

Conference ·
OSTI ID:7074510
;
The theoretical validity of backpressure tests has been analyzed for wells in radial flow and for wells intersected by vertical fractures. It demonstrated that stabilized flow-after-flow and isochronal test are valid test. Unstabilized flow-after-flow and modified isochronal tests result in error in predicted deliverability caused by continued influence of prior flow and shut-in periods (superposition error). It is shown how the superposition error can be minimized by proper selection and design of the backpressure test. Isochronal and modified isochronal tests are unsteady-state methods and provide the transient deliverability of a well. An extended flow period is generally used to determined the stabilized deliverability. In many reservoirs extended flow periods are unreasonably expensive and impractical. Analytical solutions for predicting stabilized deliverability are required. The calculations used in the prediction of stabilized gas deliverability are based on a radial flow geometry. When these calculations are applied to other flow geometries, erroneous conclusions result. In this study a fully-implicit, two-dimensional gas simulator was used to demonstrate the extension of radial flow theory to vertically fractured wells. The effect of fracture length and conductivity was investigated. It was observed that the performance coefficient (C/sub t/) was inversely related to pressure. A proof is presented for the Darcy flow condition. An understanding of how C/sub t/ changes with time will allow a more precise estimate of stabilized deliverability.
Research Organization:
Marathon Oil Co.
OSTI ID:
7074510
Report Number(s):
CONF-861080-
Country of Publication:
United States
Language:
English

Similar Records

Use of simultaneous flow-rate and pressure measurements to replace isochronal gas well tests
Journal Article · Wed Jun 01 00:00:00 EDT 1988 · SPE (Society of Petroleum Engineers) Format. Eval.; (United States) · OSTI ID:6531562
Rapid estimation of stabilized flow behavior of gas wells from short term isochronal test data
Journal Article · Sat Mar 31 23:00:00 EST 1984 · Soc. Pet. Eng. AIME, Pap.; (United States) · OSTI ID:6267218
Non-Darcy compressible flow of real gases in propped fracture
Conference · Wed Sep 01 00:00:00 EDT 1982 · Soc. Pet. Eng. AIME, Pap.; (United States) · OSTI ID:5451936

Related Subjects

03 NATURAL GAS
030900* -- Natural Gas-- Artificial Stimulation
Plowshare-- (-1989)
COMMINUTION
DARCY LAW
ENERGY SOURCES
ENHANCED RECOVERY
ERRORS
EXPERIMENT PLANNING
FLOW MODELS
FLUID FLOW
FLUID MECHANICS
FLUIDS
FORECASTING
FOSSIL FUELS
FRACTURING
FUEL GAS
FUELS
GAS FLOW
GAS FUELS
GASES
HYDRAULIC CONDUCTIVITY
HYDRAULIC FRACTURING
HYDRAULICS
MATHEMATICAL MODELS
MEASURING METHODS
MECHANICS
NATURAL GAS
NATURAL GAS WELLS
PLANNING
PRESSURE MEASUREMENT
PRODUCTION
PRODUCTION LOGGING
RECOVERY
RESERVOIR ROCK
STABILITY
STIMULATION
TIME DEPENDENCE
TWO-DIMENSIONAL CALCULATIONS
WELL LOGGING
WELL STIMULATION
WELLS