榆林气田山2段气藏描述技术及应用

P_1s^2 GAS RESERVOIR DESCRIPTION TECHNIQUE OF YULIN FIELD AND ITS APPLICATION

在榆林气田的地质研究中,首先提出了山2 段三分的小层划分方案,指出了山23 砂体稳定分布为气井获得高产的物质基础,并以此为主要目的层段分析了砂岩储层孔隙发育的控制因素,指出砂岩中高石英含量是形成榆林气田山2低孔高渗储层关键因素,而以粒间孔、粒间溶孔及高岭石晶间孔为主的特殊的孔隙组合方式是形成高渗储层的主要因素之一。针对榆林气田沙漠和黄土塬的地表条件复杂性,形成了以波形归纳分析、Strata反演等储层厚度预测为主,AVO分析、吸收系数等含气性检测为辅的山2段含气砂岩横向预测技术系列。储层地质建模以GRIDSTAT和GMSS为软件平台,将确定性地质建模和随机建模方法相结合,建立了储层参数和构造三维模型。通过山2段气藏精细描述,先后优选开发目标区块6个,提供开发井位120 余口,已实施井钻井成功率达到了85%以上,应用效果良好。

A plan of dividing P2 s2 (the second member of Shanxi Formation, Lower Permian) into three submembers was firstly put forward in the geologic study of Yulin gas field. It was pointed out that the stable-distribution of P1S23(the third submember of the second member) sandbody was the material basis of getting high productivity gas wells; the control factors affecting pore development in sandstone reservoir was investigated by taking the P1 s2 3 as the main target layer; the high quartz content in sandstone was the key factor of forming P1 s2 low porosity and high permeability reservoirs in Yulin gas field; and the special pore structure, being mainly composed of intergranular pores, intergranular dissolved pores and kaolinite intercrystalline pores; was one of main factors of forming high permeability reservoirs. The P1 s2 gas-bearing sandstone lateral prediction technical series, being mainly composed of the reservoir thickness prediction methods as waveform inductive analysis, Strata inversion and so on while making the gas detection methods as AVO analysis, absorption coefficient and so on subsidiary, was es tablished in consideration of the complicated surface conditions of desert and loess plateaus in the field. The reservoir geological modelling was taking the GRIDSTAT and GMSS as the software platform and the reservoir parameter and structural 3-D models were set up by use of the method of combining the deterministic geological modelling with the random modelling. On the basis of P1 s2 gas reservoir fine description, 6 development target tracts were optimized and more than 120 development well sites were provided early or late. The success ratio of the drilled wells was over 85%, thus achieving a excellent result.