Sensitivity Analysis And Evaluation Of Chang 6 Reservoirs In Southwest Of Ordos Basin

The six reservoirs in the Ordos Basin are located in the southwest,which is a potential resource exploration area.This thesis to mineralogy,reservoir sedimentology,reservoir geology and petroleum geology theory as the instruction,combined with the casting thin sections,scanning electron microscopy,X-ray diffraction analysis of clay minerals content,physical property and mercury injection data,etc.analysis of reservoir characteristics in the study area,reservoir sensitivity analysis and damage mechanism,put forward the reform of the reservoir need to pay attention to prevent reservoir damage reasonable Suggestions.The reservoir property in the study area is very poor,which belongs to ultra-low porosity ultra-low porosity and ultra-low permeability reservoir,Average porosity is 10.52%.The average permeability is 0.75×10-3?m2.The reservoir in the study area of constant velocity pressure mercury is the micropore structure type of the small throat-low pore reservoir.The absolute content of clay minerals in Heshui region is one of the most,Jiyuan region is the second,and Ansai region has the least content.Through sensitivity analysis,experiment and evaluation,reservoir in Chang 6 reservoir Jiyuan region characterized by medium weak water sensitivity,velocity sensitive,weak medium to its sensitivity,its sensitivity and sensitivity characteristics of medium to high salt sensitivity;The Ansai region is characterized by moderate and weak water sensitivity,weak velocity sensitivity,moderate partial strong acid,moderate and moderate alkalinity,and mild salt sensitivity.The Heshui region is characterized by moderate strong water sensitivity,weak velocity sensitivity,moderate partial strong acid sensitivity,moderate weak alkali sensitivity,and moderate strong salt sensitivity.The results showed that the types of sensitive damage in the study area were water sensitivity,acid sensitivity and salt sensitivity,while the remaining sensitivity was relatively weak.Reservoir sensitivity damage mechanism,we can find that these five reservoir sensitivity has cer tain correlation,salt sensitivity also can be thought as the inverse process of water sensitivity,these all of reservoir damage can be thought caused by as the external fluid and clay minerals have some physical and chemical reaction,by these reactions,the clay minerals particles hydrate expand,migrate,react with the fluid to form precipitation,and finally block the pore throat,which leads to the reduction of reservoir permeability and damage the reservoir.