关键词: 数学模拟, 裂隙, 有效张应力, 储层

Abstract: Carbonate reservoir fracture prediction is an important and very complicated problem in oil-gas fields of the world. Through mechanical analyses of structural fractures, this paper presents methods to evaluate fracture strength and orientation of reservoir structures. A case of fracture prediction is studied and inspected. The results show that (1) Using effective tensile stress to evaluate tensile and tensile-shear fractures is valid and practical. (2) To a layer of reservoir, the main factors that give effect to the tensile fracture distribution are curvature and torsion coefficient of paleo-structure surface and fault movement (normal, reverse, or translation). From the bottom to top of paleo upheaval, the tectonic fracture is from tensile to tensile-shear and shear. (3) The structure of tensile or tensile-shear fracture lowers down with depth increasing from the paleo-structure surface. (4) Different fracture prediction models have different characteristics and advantages of themselves. It would be more valid and effective to choose proper prediction model by availability of reservoir information and requirement.

Key words: Mathematical modeling, Crack, Effective tensile stress, Reservoir