疏水缔合聚合物在高密度钻井液中的应用研究

Application and research of a novel polymer in high density drilling fluid

钻井液流变性一直是高温深井水基钻井液的主要技术问题之一。研究出了疏水缔合聚合物,用它代替普通高分子量聚合物加入粘土含量低的钻井液中,可以提高钻井液的高温悬浮性。疏水缔合聚合物在钻井液中能和膨润土共同作用形成自身的空间网架结构,在低温、高温及高温老化后能有效地提高钻井液悬浮性;与普通高分子量聚合物相比,疏水缔合聚合物具有明显的抗温抗盐和抗剪切功能。室内试验评价了疏水缔合聚合物含量对低土量钻井液悬浮性的影响及其对不同膨润土含量钻井液流变性的影响、疏水缔合聚合物与其他处理剂的配伍性及疏水缔合聚合物加重钻井液的热稳定性和悬浮性。结果表明,将有双重悬浮功能的疏水缔合水溶性聚合物引入高温深井水基重钻井液(温度为150℃、密度为1.5g/cm3)中,使钻井液在粘土含量为3%,粘度较低的情况下能具有良好的悬浮性;利用疏水缔合聚合物解决目前深井钻井液存在的流变性问题是可行的。

One of the main technical problems of water based drilling fluid for deep wells is the rheological characteristics. In high temperature wells, drilling fluid viscosity is difficult to control, and sometimes gelatification may occur. So hydrophbically associating water-soluble polymer was developed to improve the fluid’s suspension stability at high temperature, which could take the place of conventional high molecule polymers in low-solid drilling fluid. lab tests evaluated the influence of hydrophbically associating water-soluble polymer addition on drilling fluid properties, especially the influence on rheological property of fluids with different bentonite concentration. Results showed that, when hydrophbically associating water-soluble polymer was added into a low-solid drilling fluid, the fluid provides good suspension and stability at high temperature. For example, when it was used in a high density water-base drilling fluid in which the bentonite concentration is 3%,and the viscosity is low, the suspension is still excellent.