大邑地区须家河组储层裂缝特征及主控因素

CONTROLLING FACTORS AND CHARACTERISTIC OF RESERVOIR FRACTURES INXUJIAHE FORMATION OF DAYI AREA

川西大邑地区须家河组属于超致密砂岩储层,储层物性较差,裂缝的存在极大地改善了储层的储渗性能。研究区须家河组储层发育构造缝、成岩缝及异常高压缝,部分井中见钻井诱导缝,其中构造缝最为发育,并以低角度缝和高角度缝为主,为研究区主要裂缝。裂缝发育分布受断层控制,裂缝发育带主要沿北东向断裂带呈条带状分布,断层夹持带及构造高陡部位裂缝较为发育。裂缝发育的主控因素包括构造应力、构造部位、岩石类型及岩层厚度等,其中构造部位及岩石类型为控制裂缝发育分布的关键因素。

The reservoirs of Xujiahe Formation in Dayi area are super tight sandstone reservoir,and the reservoirpetrophysical property is poor. The existence of fractures greatly improves the reservoir permeator. There are tectonicfractures,diagenetic fractures and abnormal high-pressure fractures in this area. There exists drilling inducedfractures in some wells. Tectonic fractures develop well among them,which is the key types of factures. The tectonicfractures of this area mainly take the form of low-angle and high-angle fractures. The distribution of fractures developmentis controlled obviously by faults. Fracture-developed zone presents zebraic distribution along east-northfault belt,where faults clip zone as well as the fracture in high-steep part of structure develop better. The controllingfactors of the fractures development mainly include tectonic stress,tectonic position,rock types,rock stratum,etc.The tectonic position and rock types are the key factors controlling the development and distribution of the fractures.