抗高温无固相钻井液研究

Asolid free drilling fluid with high temperature resistance

4000m埋深碳酸盐岩储层温度高达150℃以上,普通无固相钻井液无法满足抗温需要。室内通过对比动塑比及抗温极限优选出增黏剂VP和XC,并通过热重分析及滤失实验优选出降失水剂CMJ、SMP-2等处理剂;通过反复对比实验优选出抗高温的无固相钻井液,配方为（1%~饱和）甲酸钠＋3%CMJ＋2%RHJ（润滑剂）＋0.2%XC＋0.3%VP＋3%SMP-2。该体系抗温达200℃,抗钻屑污染20%,抗盐20%,抗钙5%,极压润滑系数0.098,渗透率恢复值90%。实验结果表明该体系不仅能够满足高温深井钻井要求,还能实现对裂缝性碳酸盐岩储层的良好保护。

The formation temperature of carbonate reservoir with the depth of 4000 m may be more than 150 ℃, so the common solid free drilling fluid cannot meet the requirement. By comparing the ratio of yield point to plastic vicosity and temperature resistant limit, viscosifying agents VP and XC are selected. And the fluid loss additives are optimized through the thermal analysis and filtration experiments. Finally, a type of high temperature resistant solid free drilling fluid is formed, with the composition of 3%CMJ＋2%RHJ＋ 0.2%XC＋0.3%VP＋3%SMP-2＋1%~ saturated NaCOOH. The test results show that the system can resist 200 ℃ and 20% drilling cuttings, and the calcium tolerance is 5% and salt tolerance is 20% or more. And the extreme pressure lubrication coefficient is 0.098 and permeability recovery value is above 90%, which can meet the requirements of drilling deep carbonate reservoir and demonstrate good deep fractured carbonate reservoir protection performance.