抗高温饱和盐水无黏土相钻井液室内研究

Labotoray Research on Saturated Salt Water Based Clay-Free Drilling Fluids with High Thermal Stability

为满足高温盐层快速钻进和保护储层的需要,通过对增黏剂、交联剂、降滤失剂、润滑剂和防塌抑制剂优选,得到抗高温饱和盐水无黏土相钻井液配方:饱和盐水+0.2%Na_2CO_3+1.2%增黏剂SSDP+0.4%增黏剂DDL+0.4%增黏剂PAM+0.3%四硼酸钠+3%降滤失剂SL-Ⅱ+3%超细碳酸钙+1%润滑剂HL-8+2%防塌剂AP-1。室内性能评价表明,该钻井液抗温性较好,耐温达170℃;密度为1.22 g/cm^3;抗劣质土污染能力较好,抗污染容量达10%:极压润滑系数为0.0388,与油基钻井液接近,润滑性能较好;钻屑在钻井液中的回收率高达96.84%,黏土在钻井液中的膨胀率远小于清水,防塌抑制性能较好;岩心渗透率恢复率>90%,储层保护效果较好.

In order to meet the requirements of fast drilling and reservoir protection in salt layer at high temperature, the anti-high temperature and saturated salt water based clay-free drilling fluid was developed by selecting and compounding the viscosifiers, cross linkers, filtrate reducers, lubricants and anti-collapse inhibitors. The formula of drilling fluid was： saturated salt water, 0.2% Na2CO3, 1.2% SSDP, 0.4% DDL, 0.4% PAM, 0.3% Na2B407, 3% SL-II,3% ultrafine CaCO3, 1% HL-8 and 2% AP-1. The laboratory evaluation results showed that the temperature resistance of the clay-free drilling fluid reached to 170~C, and the density was 1.22 g/cm3. It had good resistance to unconsolidated rock and the capacity was 10%. The lubrication coefficient was 0.0388, which was close to that of oil-based drilling fluid. The shale recovery was as high as 96.84% in the drilling fluid. The expansion rate of clay in clay-free drilling fluid was lower than that in fresh water, which indicated good anti-collapse performance. The permeability recovery rate of core was more than 90%, which indicated good reservoir protection effect.