Research On Drilling Fluid Technology Of Reservoir Protection In Sukri Eastern

In Sukri Eastern,the variation range of reservoir thickness is so large;the gas bearing spacer layer block is poorer;mudstone and sandstone interbed;reservoir drill encounter rate is low,often drilling in large section of the mudstone.Clay minerals content analysis results show that regional mudstone in the quartz content is higher and mudstone is second,and mudstone components in yi/montmorillonite layer between content is higher,especially in the brown mudstone layer between Iraq/montmorillonite content as high as 59%.This kind of mudstone with strong water sensitivity is immersed in the drilling fluid for a long-term caused collapse by hydration expansion of uneven easily.In view of the region of the Sukri Eastern formation characteristics,well bore structure and reservoir protection,separate time optimizing different drilling fluid systems,to ensure the safety of underground,satisfy the needs of drilling construction.The formula of surface drilling fluid is 0.1%CMC+5-6% clay ? 0.2%CMP+0.2% ZNP-1;The formula of the vertical 2nd section drilling fluid is 3% bentonite + 0.3%PAM + 0.3% KPAM + 7%KCl+0.1%NaOH +0.1%Na2CO3 +0.1%PAC-H +0.3% PAC-L;The formula of the inclined 2nd section drilling fluid 3% bentonite +0.3%PAM +0.3%KPAM +0.3%XCD+ 0.1%PAC-H+0.3%PAC-L+7%KCl+0.1% NaOH+ 0.1% Na2CO3 +0.2% DF-A;The formula of the vertical 3nd section drilling fluid is 0.3%PAM +0.3%KPAM +7%KCl+ 0.1%NaOH + 3%CaCO3 +0.1%Na2CO3+ 0.5% HCOONa+0.25%G31O-DQT + 0.25% RT888.Strong inhibition of solid free drilling fluid system,low solid together sulfonated drilling fluid system and soilless phase damage temporary plugging drilling(finish)liquid with temperature resistance,resistance to salt/calcium inhibiting performance,can meet the open table,two opening section,horizontal drilling construction.Soilless phase low damage temporary plugging drilling the well liquid for core total damage rate is 18.1%;Three open temporary plugging of drilling fluid rate of 92.7%,after broken down,broken down rate of 117.6%.Through 15-36 Wells of practical application of the former Soviet union,once again proved that the surface and vertical segments of polymer drilling fluid system,the slope with water use double potassium drilling fluid system and the use of polysulfide drilling fluid collapse prevention along the horizontal section.Three sets of drilling completion fluid system can completely meet or meet the needs of the working condition of horizontal Wells in changqing gas field processing complex.