Petroleum Related Rock Mechanics

Abstract

Elasticity . Linear elasticity. Non-linear elasticity. Poroelasticity. Time-dependent effects. Failure mechanics. Basic concepts. The failure surface. Shear failure - Mohr's hypothesis. Failure criteria which depend on the intermediate stress. Representation of experimental data. Extension tests. Post-failure behaviour. The theory of plasticity. Soil mechanics. Failure mechanics of saturated rocks. Anisotropy and rock mechanical failure. Some geological aspects of rock mechanics. Underground stresses. Pore pressure. Rock mechanical properties. Stresses around boreholes, and borehole failure criteria. Stresses around boreholes. Borehole failure criteria. Beyond failure initiation. Acoustic wave propagation in rocks. The wave equation. P- and S-waves. Sound velocities in rocks. Acoustic attenuation in rocks. Biot's theory of acoustic wave propagation. Acoustic anisotropy. Rock mechanics and rock acoustics. Micromechanical models. Grain pack models. Effective medium theories of rocks containing cracks. Fractured rocks. Mechanical properties from laboratory analysis. Core samples for rock mechanical laboratory analysis. Laboratory equipment. Rock mechanical test procedures. Index Tests. Acoustic measurements. Mechanical properties from field data. Estimation of elastic parameters. Estimation of in situ stresses. Estimation of strength parameters. Stability during drilling. Unstable boreholes - reasons and consequences. The principle of a stability analysis. Calculation of minimum mudweight required to prevent borehole collapse. Calculation of maximum mudweight before fracturing. Example calculation. Evaluation of the method and the results. Other aspects of practical importance. Sand prediction. What is sand production? How can sand production be controlled? Mechanisms for sand production. What is sand prediction? Examples of problems to be considered. Modelling for sand prediction. Fracturing. Conditions for tensile failure. Orientation and confinement of fractures. Fracturing pressures. Formation break-down pressures. Determination of fracturing pressures from minifrac tests. Pressures during frac jobs. Fracture gradients in drilling. Reservoir compaction. Subsidence and well problems. Elastic modelling of compaction and subsidence. Consolidation theory. A Consolidation type subsidence model. Laboratory testing for compaction predictions. Numerical modelling of compaction and subsidence. Well Problems associated with compaction. Appendix A. Appendix B. Symbols. Index.