钻井液盐度对深水浅层力学性质的影响

Effect of drilling fluid salinity on mechanical properties of deepwater shallow sediments

陈卓 邓金根 蔚宝华 林海2

中国石油大学（北京）石油工程学院，北京 102249 中海石油（中国）有限公司天津分公司，天津 300459）

College of Petroleum Engineering, China University of Petroleum, Beijing 102249, China Tianjin Branch of CNOOC Ltd., Tianjin 300459, China)

深水浅层的压实程度低，结构薄弱，需要对深水浅层力学性质的影响因素进行研究，确保深水浅层的安全钻进。目前国内外关于深水浅层力学性质的研究比较成熟，但是对于深水浅层力学性质的影响因素研究较少。文中通过室内实验，采用单因素分析法，在只改变钻井液盐度的条件下，对深水浅层试样的力学性质进行了测定，从而得到了钻井液盐度对深水浅层力学性质的影响规律。研究结果表明：钻井液的盐度对于深水浅层的内摩擦角基本没影响；深水浅层的黏聚力与钻井液盐度之间为正相关关系；钻井液盐度与深水浅层的流变性能之间关系较复杂，深水浅层的流变性能随着钻井液盐度的增加先增强后减弱。为了抑制因为深水浅层的流动性能而导致的变形破坏，钻井液盐度需控制在50‰以上。

Due to poor compaction and weak structure, it is necessary to study the influencing factors of mechanical properties of deepwater shallow sediments to ensure safe drilling. At present, the research on mechanical properties of deepwater shallow sediments is mature. However, there are little studies on the influencing factors of mechanical properties of deepwater shallow sediments. In this paper, mechanical properties of deepwater shallow sediments were measured with different drilling fluid salinity. The effect of fluid salinity on the mechanical properties of deepwater shallow sediments was obtained. The result shows that the salinity of drilling fluid has no influence on the internal friction angle of deepwater shallow sediments. There is a positive correlation between the cohesive force of deepwater shallow sediments and the salinity of drilling fluid. With the increase of salinity of drilling fluid, the rheological property of shallow sediments increases first and then decreases. In order to prevent deformation damage caused by the rheological property, drilling fluid salinity should be over 50‰.

10.6056/dkyqt201905025