温变承压堵漏技术室内试验研究

Research on the Pressure-Bearing Plugging Technology Utilizing Temperature Change Thickening

杨振杰 梅露强 张建卿 吴付频 张 禹

YANG Zhen-Jie MEI Lu-Qiang ZHANG Jian-Qing WU Fu-Pin ZHANG Yu

为提高复杂漏失地层的承压堵漏强度，研究了温变增稠剂对堵漏水泥浆、常规桥堵承压堵漏体系和网状纤维堵漏体系的触变性能与堵漏性能的影响规律。实验结果表明：常温条件下，温变增稠剂对承压堵漏体系的流变性能影响不大，这对堵漏剂的泵送有利；当浆体温度升高到70℃以上，温变增稠剂通过交联反应，产生温变增稠作用，体系的表观黏度>150 mPa·s，提高了承压堵漏剂的凝胶结构强度，触变性增强，使堵漏剂由液态变成半固态塑性浆体结构，从而在漏失地层有效驻留并快速形成封堵屏蔽层，在6 mm滚珠模拟的大孔道漏失层和6 mm模拟裂缝中的承压强度>5 MPa。

In order?to improve the pressure-bearing plugging strength under the complicated geological conditions，the effect of the temperature-change thickener (TCT)on the thixotropic and plugging properties of the cement slurry systems, the conventional pressure-bearing plugging systems and reticular fiber plugging systems. The results showed that, under normal temperature conditions, the TCT has little effect on the rheological properties of the pressure-bearing plugging system, which is favorable to pump the plugging slurry. When the slurry temperature rose to above 70℃, the TET played a thickening role by cross-linking reaction, and the viscosity of the system was above 150 mPa·s, at the same time, the gel strength and thixotropy of the pressure-bearing plugging agent was improved, making the sealing slurry from liquid into a semi-solid plastic paste structure. Thus, the plugging slurry could reside effectively and form plugging layer rapidly in the lost circulation formations. By simulating the large pore path (6 mm) and fracture(6 mm) of thief zones, it was found that the pressure-bearing strength of the plugging slurry exceed 5 MPa. In the plugging system, the optimum dosage of the TCT was 3%.