抗高温无固相弱凝胶钻井液体系研究

Study on High Temperature Tolerant and Solids Free Weak Gelling Drilling Fluid

抗高温无固相弱凝胶钻井液配方为:海水+0.5%NaOH+0.5%Na2CO3+1%VIS-H+0.5%抗高温稳定剂SPD+3%KCl+1%聚胺UHIB+3%聚合醇JLX-C+3%降滤失剂RS-1+5%酸溶性储层保护剂JQWY,甲酸钠加重至钻井液密度为1.2 g/cm3。性能评价结果表明,钻井液高温稳定性良好;160℃热滚16 h后的低剪切速率黏度为34095 mPa.s(0.3 r/min),悬浮性优异;90℃黏附系数为0.083,滚动回收率为90.28%,防膨率为90.59%,润滑性和抑制性较好。储层保护剂JQWY可大大减小钻井液对储层的损害,中压滤失量降至2.6 mL。裸眼完井时,通过破胶剂JPC-LV易清除滤饼,岩心渗透率恢复值为97.8%,满足了高温水平井油气层开发的需要。

The formula of high temperature tolerant and solids free weak gelling drilling fluid was： seawater, 0.5% NaOH, 0.5% Na2CO3, 1% VIS-H, 0.5% high temperature stabilizer SPD, 3% KCl, 1% polyamine UHIB, 3% polymerization alcohols JLX-C, 3% fluid loss agent RS-1 and 5% acid-soluble reservoir protection agent JQWY. The density of drilling fluid was aggravated to 1.2 g/cm3 by sodium formate. The results of property evaluation showed that the high temperature stability of drilling fluid was good and the viscosity was of 34095 mPa.s with low rotate speed 0.3 r/min after rolling 16 h at 160℃. The lubricity and inhibitory of drilling fluid wasgood with 0. 083 adhesion coefficient＇at 90℃, 90.28% rolling recovery rate and 90.59% anti-clay-swelling rate. The damage of drilling fluid to reservoir greatly reduced after reservoir protective agent JQWY added and API fotration decreased to 2.6 mL. The filter cake could be easily removed by breaking gel agent JPC-LV on completion and the core recovery of permeability reached 97.8% which met the requirements of hydrocarbon reservoir development in high temperature horizontal well.