Numerical Simulation of the Influence of Pore Structure on Resistivity, Formation Factor and Cementation Index in Tight Sandstone  

作　　者：WU Feng WEN Zhu YAO Cong WANG Xianhu XI Yanping CONG Linlin 

机构地区：[1]State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China [2]Shandong Provincial Key Laboratory of Depositional Mineralization&Sedimentary Mineral,Shandong University of Science and Technology,Qingdao 266590,China [3]School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China [4]No.1 Mudlogging Company,Bohai Drilling Engineering Company,China National Petroleum Corporation.Tianjing 300280,China [5]Logging Research Institution of Xinjiang Branch,China National Petroleum Corporation,Karamay,Xinjiang 834000,China

出　　处：《Acta Geologica Sinica(English Edition)》2020年第2期290-304,共15页地质学报（英文版）

基　　金：the Open Fund of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University)(Grant No.PLN201719);the Open Fund of Shandong Provincial Key Laboratory of Depositional Mineralization&Sedimentary Mineral(Shandong University of Science and Technology)(Grant No.DMSM2018050);the Scientific Research Starting Project of SWPU(Grant No.2017QHZ004);the Preferential Funded Technological Project for Overseas Talents Returned to Sichuan Province;The supports are gratefully acknowledged.

摘　　要：Tight sandstone,with severe diagenesis and complex pore structure,differs greatly from conventional sandstone in terms of rock electrical parameters.In subsurface rock electrical experiments,various electrical parameters are confounded and can only be analyzed qualitatively.The lack of quantitative analysis for each individual electrical parameter presents a challenge for the evaluation of oil and gas saturation in tight sandstone.Based on the 2D pore-throat model and the features of pore structure in the tight sandstone of the Penglaizhen and Shaximiao Formations in the upper and middle Jurassic of the Western Sichuan Depression,this paper presents 3D micro pore-throat models for three types of tight sandstone.It proposes a finite element-based rock electrical simulation method to analyze the influence of pore structure parameters,such as throat radius and throat tortuosity,on electrical parameters such as resistivity,formation factor,and cementation index quantitatively.The research revealed the following results:(1)Throats of tight sandstone usually have lamellar or curved lamellar shapes that are slender and narrow.The lamellar throat used in the proposed porethroat model is more consistent with the features of tight sandstone than the tubular throat used in the original model.(2)The throat determines the conductivity of tight sandstone.The throat parallel to the electric potential has the greatest influence on conductivity,and the throat perpendicular to the potential has the least influence.(3)In tight sandstone grades I to III,as the porosity decreases,the formation factor increases and the cementation index decreases.(4)The results of the rock electrical simulation are consistent with the results of the rock electrical experiment,which indicates that the proposed rock electrical simulation method of tight sandstone is effective and accurate.

关 键 词：TIGHT SANDSTONE RESISTIVITY formation factor CEMENTATION INDEX numerical simulation western SICHUAN Depression 

分 类 号：P618.13[天文地球—矿床学]