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Title: Parameter sensitivity analysis of tailored-pulse loading stimulation of Devonian gas shale

Technical Report ·
OSTI ID:6478840

An evaluation of three tailored-pulse loading parameters has been undertaken to access their importance in gas well stimulation technology. This numerical evaluation was performed using STEALTH finite-difference codes and was intended to provide a measure of the effects of various tailored-pulse load configurations on fracture development in Devonian gas shale. The three parameters considered in the sensitivity analysis were: loading rate; decay rate; and sustained peak pressures. By varying these parameters in six computations and comparing the relative differences in fracture initiation and propagation the following conclusions were drawn: (1) Fracture initiation is directly related to the loading rate aplied to the wellbore wall. Loading rates of 10, 100 and 1000 GPa/sec were modeled. (2) If yielding of the rock can be prevented or minimized, by maintaining low peak pressures in the wellbore, increasing the pulse loading rate, to say 10,000 GPa/sec or more, should initiate additional multiple fractures. (3) Fracture initiation does not appear to be related to the tailored-pulse decay rate. Fracture extension may be influenced by the rate of decay. The slower the decay rate, the longer the crack extension. (4) Fracture initiation does not appear to be improved by a high pressure plateau in the tailored-pulse. Fracture propagation may be enhanced if the maintained wellbore pressure plateau is of sufficient magnitude to extent the range of the tangential tensile stresses to greater radial distances. 26 figures, 2 tables.

Research Organization:
Science Applications, Inc., Golden, CO (USA)
DOE Contract Number:
AM21-78MC08216
OSTI ID:
6478840
Report Number(s):
DOE/MC/08216-1333; ON: DE83006476
Resource Relation:
Other Information: Portions are illegible in microfiche products. Original copy available until stock is exhausted
Country of Publication:
United States
Language:
English