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

摘要： 根据构造裂缝的力学成因,对储层构造裂缝系发育强度及方向进行了估计,通过实例对该方法进行了检验。结果表明:(1)用有效张应力描述张裂缝和张剪裂缝发育程度是一个切实有效的方法;(2)在储层的同一层位上,影响张裂缝和张剪裂缝的主要因素是古构造面的曲率和扭率及断层运动性质(逆冲、正断或平推),自古隆起顶部向坡底,裂缝由张性向张剪性和剪切性裂缝发展;(3)自储层顶界面(古隆起构造面)往下,随深度增加,张裂缝和张剪裂缝发育程度降低;(4)裂缝预测的不同模型和方法,反映不同方面的特征和优势,根据储层占有资料和目的要求选择合适的裂缝预测模型和方法比较有效。

关键词: 数学模拟, 裂隙, 有效张应力, 储层