Geological Characteristics And Numerical Simulation Of Fractured Reservoir In Yanchang Formation In Ordos Basin

Along with the increasing of global demand for oil and gas resources,the exploitation of conventional oil and gas reservoirs can't meet the demand and unconventional reservoirs are considered to be the most promising energy supplement.As the most realistic unconventional oil and gas resources,the exploration and development of tight oil attracted growing attention.The oil and gas reservoirs of yanchang in ordos basin triassic system present reservoir density,difficulty in forecasting,complex reservoiring mechanism,and low yield of single well production,is a typical low permeability reservoir development area in China.On the basis of the research,we analyses and summarizes the the reservoir microscopic features,sensitivity and ground stress character of yanchang in ordos basin triassic system,and provide technical services for further development of subsequent research reservoir through fracturing parameter optimization.After fully digestingprevious research results,we focus on microcosmic features analysis,sensitivity analysis,the parameters of rock and ground stress characteristics analysis and optimization of numerical simulation of the fracturing parameters combining with the core,logging,well logging and production test data.The important advances and new understanding achieved are as follows:(1)According to the X ray diffraction experiment,the casting thin sections,scanning electron microscopy(sem)and so on,we know more about the characteristics of pore,pore throat and in the studied area and have a further understanding of whole rock mineral components.The new study found that the clay content of Chang-6 layer is higher and Chang-6 and Chang-7 layer both have small pore-throat while Chang-7 occasional cracks.(2)Based on the five sensitive experiment study,the anatomy of the reservoir and the statistical analysis,further understanding of the sensitivity of the characteristics in the study area was achieved.Chang-6 layer in Yanchang is weak in the velocity sensitive,water sensitivity and salt sensitive,weak alkali sensitivity,acid sensitivity and stress sensitivity,long 7 layers of weak velocity sensitive,weak water sensitivity,salt sensitivity,alkali sensitivity,acid sensitivity and stress sensitivity.(3)According to the rock uniaxial and triaxial experiments,determined the formation of rock mechanics parameters,to simulate the in-situ stress values,provides the reference for fracturing operation parameters optimization,which extend the leader six floors of the minimum horizontal principal stress and the maximum horizontal principal stress difference at around 2 mpa,a slightly different in different well depth difference;The minimum horizontal principal stress and maximum horizontal principal stress difference of the group leader's 7th floor are about 3MPa,and the difference of the difference of the well is slightly different.(4)According to the experimental data analysis,the optimal fracturing parameter combination is achieved through the software numerical simulation optimization of fracturing construction parameters and fracturing segmentation parameters.