长庆气田马五1储层裂缝特征及控制因素探讨

长庆气田主力气层为马五₁,其储层中裂缝类型主要有垂直缝、斜交缝、水平缝及网状缝。虽然马五1储层中裂缝类型多,破裂期次多,但对储层渗流作用有较大影响的裂缝主要有两大类,即构造破裂裂缝和风化破裂裂缝。马五1储层的裂缝形成期主要有三期,第一期为加里东期,形成各类风化缝 ;第二期为燕山中期构造运动,是一次重要的构造破裂期 ;第三期为燕山晚-喜山早期构造运动。通过对裂缝形成的地质因素研究得出:风化缝主要与风化岩溶作用形成地貌条件有关,其次与岩层产状等因素有关 ;构造缝的形成与古应力场条件及岩石本身的力学属性有关

A Discussion on the Fracture Characteristics and Controlling Factors of the Ma51 Reservoir in Changqing Gas Field

The Ma5 1 reservoir is the main gas reservoir in changqing gas field. The main fracture types of reservoir are four types: vertical, oblique, horizontal and braided. Although there are lots of fracture types in Ma5 1 reservoir , the main types that have a great influence on the percolation flow of the reservoir are two types, i.e., structural fracture and weathered fracture. The formation stages of fracture in Ma5 1 reservoir are mainly three, i.e., (1) Caledonian stage, in which all kinds of weathered fractures have been formed; (2) mid stage of Yanshan movement, which is an important structure ruptured stage; (3) Late Yanshan stage to early Himalayan stage. In this paper, geological factors forming fractures are studied and analyzed, it is summarized as that,the formation of the weathered fractures is mainly related to the occurrence of the rock strata, but the formation of structural fracture is related to the condition of palaeo stress field and the mechanics property of rock itself.