Geomechanical Model Calibration Using Field Measurements for a Petroleum Reserve

• Published in: Rock mechanics and rock engineering 2018-03, Vol.51 (3), p.925-943
• Main Authors: Park, Byoung Yoon, Sobolik, Steven R., Herrick, Courtney G.
• Format: Article
• Language: English
• Subjects: 02 PETROLEUM; Bayous; Brines; Calibration; Caverns; Civil Engineering; Closures; Computer simulation; Creep rate; Deformation; Deformation mechanisms; Drawdown; Earth and Environmental Science; Earth Sciences; Finite element method; Geomechanics; Geophysics/Geodesy; GEOSCIENCES; Geotechnical engineering; Mathematical analysis; Mathematical models; Numerical analysis; Original Paper; Petroleum; Saline water; Salts; Skin; Solifluction; Strategic petroleum reserve; Structure factor; Wellheads
• ISSN: 0723-2632; 1434-453X
• DOI: 10.1007/s00603-017-1370-4

A finite element numerical analysis model has been constructed that consists of a mesh that effectively captures the geometries of Bayou Choctaw (BC) Strategic Petroleum Reserve (SPR) site and multimechanism deformation (M-D) salt constitutive model using the daily data of actual wellhead pressure and oil–brine interface location. The salt creep rate is not uniform in the salt dome, and the creep test data for BC salt are limited. Therefore, the model calibration is necessary to simulate the geomechanical behavior of the salt dome. The cavern volumetric closures of SPR caverns calculated from CAVEMAN are used as the field baseline measurement. The structure factor, A 2 , and transient strain limit factor, K 0 , in the M-D constitutive model are used for the calibration. The value of A 2 , obtained experimentally from BC salt, and the value of K 0 , obtained from Waste Isolation Pilot Plant salt, are used for the baseline values. To adjust the magnitude of A 2 and K 0 , multiplication factors A 2 F and K 0 F are defined, respectively. The A 2 F and K 0 F values of the salt dome and salt drawdown skins surrounding each SPR cavern have been determined through a number of back analyses. The cavern volumetric closures calculated from this model correspond to the predictions from CAVEMAN for six SPR caverns. Therefore, this model is able to predict behaviors of the salt dome, caverns, caprock, and interbed layers. The geotechnical concerns associated with the BC site from this analysis will be explained in a follow-up paper.