柳杨堡气田盒1段致密砂岩气藏储层特征研究

鄂尔多斯盆地柳杨堡气田下石盒子组盒1段致密砂岩气藏储层储集及渗流能力差,制约气藏产能的分布,急需对其储层特征进行研究。研究表明:盒1段储层的岩石类型以岩屑石英砂岩为主,石英砂岩、岩屑砂岩和长石石英砂岩次之,储层平均孔隙度为5.8%,平均渗透率为0.42×10-3μm2,孔隙类型以粒间溶孔、粒内溶孔和微裂缝为主,储层岩石孔隙度、渗透率与孔喉结构密切相关。根据毛管压力曲线形态和中值压力、排驱压力、平均孔喉半径等特征参数将毛管压力曲线分为三种类型。综合研究储层岩性、物性、微观孔喉特征参数、测井参数和试气试采特征及其相互关系,把盒1段致密砂岩储层分为三类,分别为较好储层、一般储层及非有效储层,其中前两类是气藏后期开发的重点选层。

Reservoir characteristics of tight sandstone gas reservoir in He 1 member of Iiuyangpu gasfield

The reserving and seepage capability of tight sandstone gas reservoir in He 1 member of lower Shihezi formation,Liuyangpu gasfield of Ordos basin were poor,which restricted the distribution of gas reservoir capacity and therefore,the study on reservoir characteristics was greatly needed.The results indicated the reservoirs in He1 member was mainly of lithic quartz sandstone,followed by quartz sandstone,lithic sandstone and feldspar quartz sand.The average porosity and permeability were 5.8%and 0.42 × 10~(-3)μm~2 respectively.The pores were mainly of intergranular dissolved pores,intragranular dissolved pores and micro cracks.The porosity and permeability were closely related to the pore-throat structure.According to the shape of capillary pressure curve and the characteristics parameters,such as the median pressure,the expulsion pressure and the average radius of pore-throat,the capillary pressure curve was divided into three types.Through comprehensive study of reservoir lithology,physical properties,microscopic pore-throat characteristics,logging parameters,production testing characteristics and their relationship,the reservoirs of tight sandstone gas reservoir in He 1 member were divided into three types,the better ones,the ordinary ones and the ineffective ones,among which the first two types were the target in the late gas reservoir development.