克拉2气田泥岩隔层封闭性研究

摘要

针对克拉2气田泥岩隔层是否被裂缝穿透的问题,在建立砂泥岩互层三维地质模型的基础上,通过裂缝参数与应力应变的关系模拟出砂泥岩中的裂缝分布情况,研究裂缝在泥岩中的延伸能力,认为裂缝在泥岩中延伸的最大厚度为4 m.据此,结合断层落差与泥岩隔层厚度的比较,将断层分为完全穿透型和部分穿透型两类,并对泥岩隔层的封闭有效性进行了评价。认为克拉2气田南部断层多为完全穿透型断层,北部断层多为部分穿透型断层。巴西盖组顶部泥岩隔层完全穿透型断层分布范围最大,库姆格列木群膏泥岩隔层部分穿透型断层条数最多。%The shale interlayers in Kela-2 gas field are penetrated or not by the fractures？ The sand-shale interbedding 3D geologic model is then developed to simulate the fracture distribution through the relationship between fractural parameter and stress variation as well as extending trend of fractures in the shale.It suggests that the maximum thickness for the fractures extending in the shale is 4 meters.Hence,the faults in this field are classified into partially penetrated faults and totally penetrated faults,and the sealing effectiveness of the shale interlayers is evaluated.It is considered that the totally penetrated faults are mainly found in the southern Kela-2 gas field,particularly at the top of Baxigai formation;the partially penetrated faults mainly found in the northern,most existing in calcium shale interlayer of the Kumugeliemu group.