强力抑制防塌剂QYJ的研究与应用

泥岩水化膨胀、分散造浆是造成井壁失稳、钻井液性能难以维护的主要原因,利用聚合物稳定泥岩的机理,研究出了天然高分子与烯烃类单体合成的高度支链化结构钻井液助剂强力抑制防塌剂QYJ,对强力抑制防塌剂QYJ的室内性能进行了评价。试验表明:1%QYJ膨润土表观黏度上升率仅为25%,优于聚丙烯酸钾、两性离子强力包被剂FA367和10%KC l;页岩回收率明显高于MMH、SJ-1、CAL和KPAM,尤其二次回收率更高;QYJ对淡水浆和4%NaCl盐水浆略有增黏作用,由于其分子量为35万,所以其增黏幅度很小;QYJ在4%NaCl盐水浆中降滤失作用明显,3%QYJ可使4%NaCl基浆API滤失量由98 mL降至17.5 mL;QYJ可抗150℃高温。现场应用表明,该防塌剂具有较好的抑制防塌、润滑防卡及油层保护能力,可满足井下需要。

Development and application of anti-sloughing agent QYJ

The hydrate expansion and mud-making of mudstone is the main reason for borehole wall sloughing.According to the mechanism of polymer on mudstone stabilization,a new type of anti-sloughing agent QYJ was developed,which was a type of branched chain drilling fluid auxiliary synthesized by olefin monomer and natural high polymer.Laboratory experiments were conducted to test its performance.The test result shows that the apparent viscosity of bentonite drilling fluid increases 25% when 1% QYJ is added,which is better than kalium polyacrylate,amphion coater FA367 and 10%KCl.The shale recovery rate of QYJ is apparently higher than MMH,SJ-1,CAL and KPAM.QYJ will increase the viscosity of fresh water drilling fluid and 4% NaCl drilling fluid,but the increasing scope is small because the molecular weight of QYJ is between 30000~50000.The filter loss control of QYJ is apparent while being adding to 4% NaCl drilling fluid,and 3%QYJ could decrease the API filter loss of 4% NaCl drilling fluid from 98 mL to 17.5 mL.QYJ could work well under 150℃ temperature.The field application shows that this new type of anti-sloughing agent could effectively inhibit wellbore sloughing,increase lubrication of drilling fluid and protect the oil reservoir.