Laboratory estimates of normal/shear fracture compliance ratio

Journal article

Laboratory estimates of the normal (Bn) and shear (Bt) compliance of an artificial fracture in a sample of Carboniferous limestone under wet and dry conditions are presented. The experiments were performed over a range of confining pressures (from 5 MPa up to 60 MPa), at ultrasonic frequencies (0.6 MHz to 1.0 MHz), in a Triaxial Hoek cell, using the pulse-echo reflection technique. The results of this study are confirmation that the Bn / Bt ratio of a fracture is dependent on the fluid content, A value of Bn / Bt of less than 0.05 was obtained for our honey saturated (wet) sample which is consistent with the prediction that this ratio should be close to zero for fluid saturated fractures. Values of Bn / Bt for the dry sample are significantly higher and increase with confining pressure from 0.2 to 0.5.

Authors: Lubbe, R; Sothcott, J; Worthington, M; McCann, C

• Publisher: Society of Petroleum Engineers
• Journal: 69th European Association of Geoscientists and Engineers Conference and Exhibition 2007: Securing The Future. Incorporating SPE EUROPEC 2007 More from this journal
• Volume: 5
• Pages: 2604-2608
• Publication date: 2007-01-01
• Language: English