花草滩矿区+304孔易降解强抑制防塌聚合物冲洗液体系研究与应用

Study and application of polymer flushing fluid system with easy degradation and strong anti-collapse inhibition for +304 hole in Huacaotan mining area

摘要:

+304孔是在花草滩矿区实施的一口深部煤层钻孔，主煤层埋深普遍超过了800 m，煤质条件以碎粒煤为主，胶结性差，破碎、松散、垮塌风险高，常规钠土聚合物冲洗液体系使用过程中，复杂事故不断。研究了易降解强抑制防塌聚合物冲洗液体系，主要配方：水+4%钠土+0.05%纯碱+0.3%羟乙基纤维素（HEC）+0.5%可降解聚合物（JP）+1%降滤失剂+1%防塌剂+1%可降解封堵剂+0.5%润滑剂+加重剂（碳酸钙）；表观粘度15~20 mPa·s，滤失量<5 mL，动切力8~10 Pa。经过实验，对煤层的膨胀率仅不到0.1%，采用氧化型破胶剂OPJ 1.0%的加量，降解率达93.5%。现场共完成钻孔进尺1077.50 m，未出现坍塌、缩径等复杂情况。

Abstract:

Hole +304 is a deep coal seam borehole drilled in Huacaotan mining area.The buried depth of main coal seam generally exceeds 800m. The coal quality condition is mainly broken coal， poor cementation， high risk of fragmentation， loosening and collapse. During the use of conventional sodium clay polymer flushing fluid system， complex accidents occur continuously. The polymer flushing fluid system with easy degradation and strong inhibition against collapse was studied， main formula： water+4% sodium clay+0.05% soda ash+0.3% hydroxyethyl cellulose （HEC）+0.5% degradable polymer （JP）+1% fluid loss agent +1% anti-collapse agent+1% degradable plugging agent +0.5% lubricant + weighting agent （calcium carbonate）， apparent viscosity 15~20mPa·s， fluid loss <5mL， dynamic shear force 8~10Pa. After experiments， the expansion rate of coal seam is less than 0.1%， using oxidation type gel breaker OPJ 1.0%， The degradation rate reaches 93.5%， the drilling footage is 1077.50m， and there is no collapse， diameter reduction and other complicated situations.