Sensitivity Evaluation And Drilling Fluid Optimization Of Funing Formation In Qintong Sag,Subei Basin

Qintong sag of Subei basin funing group belongs to low permeability to low permeability reservoir.Funing group mainly for sand and mudstone interbedding,tuff,brittle shale containing easily broken,such as drilling,by reason of hole collapse,impellers,spalling,easy to cause the awful a jump,buried drilling downhole accidents.Drilling fluid design pays attention to prevent leakage,inhibition of mud making,reducing,wellbore stability,such as technology,the reservoir damage degree;oil reservoir protection pertinence is not strong.This topic selection in Qintong sag of Subei basin small representative reservoir samples,full of porosity,permeability,full,thin sections,X-ray diffraction,electron microscopy,energy spectrum analysis,summarize the rule of reservoir characteristics,large flow experiment was done at the same time,the current north jiangsu exploration well drilling fluid used for performance analysis,reservoir protection,economic analysis and made an objective evaluation,indoor experiment and field application,the combination of various fields of study suitable drilling fluid formulation.Reservoir lithology is mainly fine sandstone in the study area,a small amount of siltstone,sandstone composition is given priority to with quartz,sorting,cone angles to time,for the low porosity low permeability reservoir,vertical change is bigger,heterogeneity is serious.Completed the 62 sets of indoor drilling fluid damage evaluation experiment,studies the MMH polymer drilling fluid system,and points out that Ye Dian shielding temporary plugging technology is used in the oil and metal zwitterionic polymer drilling fluid to reservoir protection.Cottage oilfield with shielding temporary plugging technology and modified polymer MMH drilling fluid,or the use of potassium base polymer drilling fluid can basically meet the requirements;the permeability recovery value can reach more than 80%.