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Predicting uniaxial compressive strength from empirical relationships between ultrasonic p-wave velocities, porosity, and core measurements in a potential geothermal reservoir, Snake River Plain, Idaho

Conference · · American Rock Mechanics Association, 2017
OSTI ID:1749943
 [1];  [2];  [2];  [3];  [3]
  1. Occidental Petroleum Corp., Houston, TX (United States); Utah State Univ., Logan, UT (United States); Utah State University
  2. Univ. of Alberta, Edmonton, AB (Canada)
  3. Utah State Univ., Logan, UT (United States)
Empirical, core-based, predictive correlations for the calculation of uniaxial compressive strength (UCS) were developed from compressive sonic velocity measurements (55 whole core samples) and porosity, density, and unconfined compressive tests (110 whole core samples). The samples were collected at 55 different depths in a 550 m (1800 ft) interval of core from the MH-2 borehole located in southern Idaho, USA. The western Snake River Plain is a known region of high heat flow and the borehole was drilled into a potential geothermal reservoir characterized by artesian flow of high-temperature (~140°C) fluids from fractured basalt. UCS was measured in unconfined compressive tests, density and porosity were measured using a He-pycnometer, and p-wave velocities were measured in a pressure vessel under variable confining pressures. We use correlations between density and p-wave velocity (R2 = 0.91), UCS and porosity (R2 = 0.78), and UCS and p-wave velocity (R2 = 0.79) in a method to calculate calibrated UCS from wireline logs. Here, the impact of this predictive correlation is that UCS can be calculated from as little as a bulk density log when sonic logs and core are not available, greatly increasing the number of wells in which we can obtain a local UCS estimate.
Research Organization:
Utah State Univ., Logan, UT (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Contributing Organization:
University of Alberta
DOE Contract Number:
EE0006733
OSTI ID:
1749943
Conference Information:
Journal Name: American Rock Mechanics Association, 2017 Journal Volume: ARMA-17
Country of Publication:
United States
Language:
English