关键词: 各向异性地层, 重复压裂, 最优压裂时机, 局部应力场, 等应力点, 固-液耦合, 数学模型

Abstract: Based on the mechanical properties and porous flow parameters of low permeability reservoir, an optimal re-fracturing timing model considering solid-fluid coupling in anisotropic formation was established, and the concept of equal stress point was proposed. The small stress difference, large elastic modulus, large length and width of initial fracture, low permeability, and large pressure drawdown are the favorable factors for creation of new fractures in re-fracturing. Those influencing factors are further classified into three groups: ①the factors for deciding whether new fracture be created;②the factors only affecting the optimal re-fracturing timing;③the negligible factors.

Key words: anisotropic formation, repeated fracturing, optimal fracturing timing, local stress field, equal stress point, solid-fluid coupling, mathematic model