Study On Micro-heterogeneity Of Tight Sandstone Reservoir In Sangonghe Formation Of Mosuowan Area

Unconventional oil and gas has increasingly become a hot spot for exploration and development.Tight sandstone gas,as one of the typical representatives of unconventional oil and gas,has more mature exploration and development experience in China.The tight sandstone gas exploration and development potential in the Mosuowan area of the Junggar Basin is huge.The Sangonghe Formation in Well Mo21 obtained industrial gas flow in 2012,indicating that the Sangonghe Formation has developed effective tight sandstone reservoirs and unconventional tight reservoirs.Micro-heterogeneity controls the accumulation and migration of oil and gas,and is a key factor in the development of tight oil and gas reservoirs.This article takes the Mosuowan area in the Junggar Basin as the research area,based on geological data and previous research results,focuses on selecting characteristic wells and sampling for test analysis,and based on the analysis of test data,the microscopic study of the Sangonghe Formation reservoir in the research area is carried out.Heterogeneity study,and further explore its main controlling factors,the results of the study provide a reference and basis for deepening the exploration and development of the Sangonghe Formation.The main knowledge gained in this article is as follows:(1)The main diagenesis in the study area includes compaction,cementation,dissolution,and metasomatism.The diagenesis is the one that has the greatest impact on porosity.The diagenetic fluid environment in the study area experienced the process of weak acidic to alkaline in the early stage,and then changed to acidic.The diagenetic evolution is in the stage A of intermediate diagenesis.(2)The clastic particles are mainly quartz,feldspar,and tuff.They show regular differences in the plane,and the heterogeneity in the longitudinal direction is not strong.Clay minerals are mainly Yimeng mixed layer,illite,kaolinite,and chlorite,which are regularly distributed in all planes and longitudinal directions except chlorite.(3)Based on the mercury intrusion test,the fractal dimension of the mercury removal curve can represent the complexity of the pore structure and has a good correlation with the permeability porosity.The porosity model is:D=0.1287·log?-0.0286,permeation The rate model is:D=0.0272·logK+0.1046.(4)The main types of pore throats in the study area are sub-micron and nano-scale.Micron-scale occupies a relatively small amount,but micrometer-scale pore-throats contribute greatly to the permeability.The proportion of micron-sized pore throats has a good correlation with reservoir permeability.The relationship is:y=0.2682e^0.1607x,where y is the permeability and x is the proportion of micron-sized pore throats.The proportion of micron-sized pore throats has a good correlation with the contribution of micron-sized pore throats to permeability.The relationship is y=3.0006x+13.29,y is the contribution of permeability and x is the proportion of pore throats.The correlation between the proportion of submicron pore throats and their contribution to permeability is poor,indicating that the contribution of micropore throats to permeability is more complicated.(5)Reservoir evolution is divided into three stages through the configuration of the relationship between tectonic history,burial history,thermal history,hydrocarbon generation history and physical properties.The abnormal high pressure of the reservoir and its formation process have mainly protected the physical properties of the reservoir effect.The sedimentation rate is large,and the accommodating space is reduced.The type of microfacies is the underwater diverted river channel,which is a favorable sedimentary feature for reservoir physical properties.