Predicting Critical Borehole Pressure And Critical Reservoir Pore Pressure In Pressure Depleted And Repressurized Reservoirs

摘要

Borehole instability, sand production, and completion failuresrnduring production and pore pressure depletion continue to bernsignificant problems confronting the petroleum industry. Thisrnstudy develops quantitative models for predicting boreholernshear failure in pressure-depleted and repressurized reservoirsrnby incorporating stress path into equations for shear ofrnborehole wall rock. Critical reservoir pore pressure (CRPP) isrndefined as the pore pressure below which any drawdown orrnadditional pore pressure depletion will result in the onset ofrnborehole shear failure. Critical reservoir pore pressure andrncritical borehole pressure (CBHP) are defined in terms ofrninitial stress state, initial reservoir pore pressure, the twornhorizontal principal stress paths, and commonly used failurerncriteria. The model includes both overbalanced (drilling) andrnunderbalanced (production) scenarios. The model isrnapplicable to both vertical and horizontal wells.