摘要
气-水相渗曲线反映储层综合物性特征,明确致密砂岩气-水相渗行为与气井生产动态的关系,有利于致密气藏高效开发.以鄂尔多斯盆地东缘典型致密砂岩气藏为研究对象,将储层分为3类并开展气-水相渗实验,结合X射线衍射、扫描电镜和核磁共振等岩心分析手段,揭示气-水相渗与气井生产动态曲线的关系.结果表明:①Ⅰ类相渗曲线两相过渡区较宽,孔隙类型以粒间孔为主,Ⅱ类相渗曲线两相过渡区较窄,孔隙类型以粒间孔和晶间孔为主,Ⅲ类储层相渗曲线两相过渡区极窄,孔隙类型以晶间孔为主;②储层黏土矿物含量高,高岭石和绿泥石有利于气水两相流动,伊利石不利于气水两相流动;③孔喉差异大,大致分为3类:中—粗孔喉(大于1.0 μm)、细孔喉(0.1～1.0 μm)和微孔喉(小于0.1 μm),Ⅰ类、Ⅱ类和Ⅲ类储层的中—粗孔喉占比分别约为40％、10％和4％;④根据上述3类储层的气-水相渗特征,可将气井分为3类,其生产动态特征与相渗曲线预测结果均相符,Ⅰ类井主要产层为Ⅰ类储层,有效厚度约为7m,平均 日产气量约为2×104m3,稳产时间长,Ⅱ类井主要产层为Ⅱ类储层,有效厚度约为5m,平均日产气量约为1×104m3,Ⅲ类井主要产层为Ⅲ类储层,有效厚度约为6 m,平均日产气量约为0.5×104 m3,稳产时间极短.通过分析致密砂岩气-水相渗特征预测气井生产动态,揭示了孔隙结构和黏土矿物对气水流动行为的影响,可为制定低压高含水致密气开发过程降阻提效措施提供理论支撑.
Abstract
The gas-water relative permeability curve reflects the comprehensive physical properties of the reservoir.Clarifying the relationship between the gas-water relative permeability behavior of tight sandstone and the production performance of gas wells is conducive to the efficient development of tight gas reservoirs.Taking the typical tight sandstone gas reservoirs in the eastern margin of Ordos Basin as the research object,the reservoirs are divided into three types and gas-water relative permeability experiments are carried out.Combined with core analysis methods such as X-ray diffraction,scanning electron microscopy and nuclear magnetic resonance,the relationship between gas-water relative permeability and gas well production performance curve is revealed.The results show that:① The two-phase transition zone of relative permeability curve Ⅰ is wide,the pore type of which is mainly intergranular pores.The two-phase transition zone of relative permeability curve Ⅱ is narrow,the pore types of which are mainly intergranular pores and intergranular pores.The two-phase transition zone of relative permeability curve Ⅲ is extremely narrow,and the pore type is mainly dominated by intergranular pores;② The clay mineral content is high.kaolinite and chlorite are conducive to gas-water phase flow.Illite is not conducive to gas-water phase flow;③ The pore and throat of in the reservoir have large differences and can be roughly divided into three categories:large pores(greater than 1.0 μm),mesopores(0.1～1.0 μm)and small pores(less than 0.1 µm).The large pores in the reservoir of class Ⅰ,Ⅱ and Ⅲ account for about 40％,10％,and 4％,respectively;④ The gas wells can be divided into three types,the production performance of which are consistent with the predicted results of the relative permeability curves.The main production layer of the well of class Ⅰ responds to the reservoir of class Ⅰ.The effective layer thickness is about 7 m.The average daily production is about 2×104 m3 with a long stable production period.The main production layer of the well of class Ⅱ responds to the reservoir of class Ⅱ.The effective layer thickness is about 5 m.The average daily production is about 1×104 m3.The main production layer of the well of class Ⅲ responds to the reservoir of class Ⅲ.The effective layer thickness is about 6 m.The average daily production is about 0.5X104 m3 with a very short stable production period.By analyzing the gas-water relative permeability characteristics to predict gas well production dynamics,the impact of pore structure and clay minerals on gas-water flow behavior is revealed.This can provide theoretical support for developing measures to reduce resistance and enhance efficiency in the development process of low-pressure,high-water-content tight gas fields.
基金项目
中国石油前瞻性、基础性科研攻关项目(2021DJ2304)
中国石油煤层气有限责任公司工程技术研究院项目(2022-GCYKJ-03)
维普
万方数据