One-Run In Situ Stress Testing by Microfracturing Guides Hydraulic Fracturing, Antelope Shale | Schlumberger
Case Study
Location
United States, North America, Onshore
Details

Challenge: Determine the magnitude of in situ stress for designing hydraulic fracturing of multiple intervals in the Antelope Shale

Solution: Efficiently microfracture test multiple intervals in a single run by deploying the MDT modular formation dynamics tester to isolate the intervals between dual packers and inject fluid to create and propagate small-scale hydraulic fractures

Results: Successfully placed hydraulic fractures in the Antelope Shale on the basis of accurate in situ stress measurements obtained by conducting multiple microfractures with the MDT tester in a single run

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One-Run In Situ Stress Testing by Microfracturing Guides Hydraulic Fracturing, Antelope Shale

MDT tester in dual-packer configuration isolates intervals for measurements to calibrate mechanical properties from sonic logs, San Joaquin Valley

Introducing hydraulic fracturing to the Antelope Shale

An operator in the southern San Joaquin Valley needed in situ stress measurements to design effective completions employing hydraulic fracturing. Whereas the Monterey Formation produces from prolific natural fractures, its equivalent in the southern San Joaquin Valley, the Antelope Shale, is not naturally fractured. For the Antelope Shale to become a major unconventional resource, hydraulic fracturing would be necessary to replace the role that natural fractures playin the Monterey.

Directly measuring minimum stress magnitude in multiple intervals

The MDT modular formation dynamics tester effectively defines intervals for microfracture testing with the high-performance inflatable elements of the Dual-Packer Module. Even thin zones can be isolated between the packers for evaluation with small, controlled injection volumes. In a single trip in the well, multiple intervals can be efficiently individually tested. By measuring the formation's pressure response immediately downhole, the MDT tester avoids the frictional loss and time lag that compromise surface pressure measurement.

Designing effective fracture stimulation

Because fracture height is primarily controlled by the minimum in situ stress, measuring the contrast in the closure pressure during microfacture tests is critical. The operator gained a wealth of useful information in a single trip of the MDT tester by successfully determining the in situ stress for multiple intervals. These discrete measurements were used to calibrate mechanical properties derived from sonic logs for designing efficient, effective fracturing operations for the Antelope Shale.

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Repeated fluid injections create and propagate small-scale fractures in the interval isolated between the MDT tester’s dual packers. The difference in the closure pressures is used to determine the minimum in situ stress that controls the fracture height created during hydraulic fracturing.
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