The Study and Application of Intelligent Thixotropic Cement Slurry Based on Nanotechnology

Lu, Haichuan (CNPC Offshore Engineering Company Limited) | Zheng, Huikai (CNPC Offshore Engineering Company Limited) | Li, Zongyao (CNPC Offshore Engineering Company Limited) | Feng, Wangsheng (CNPC Offshore Engineering Company Limited) | Tang, Shaobing (CNPC Offshore Engineering Company Limited) | Zou, Jianlong (CNPC Offshore Engineering Company Limited, Key Laboratory of Drilling Engineering of CNPC) | Li, Lirong (CNPC Offshore Engineering Company Limited, Key Laboratory of Drilling Engineering of CNPC) | Tan, Wenli (CNPC Offshore Engineering Company Limited, Key Laboratory of Drilling Engineering of CNPC)



Lost circulation and fluid channeling in cementing process are common technical problems in domestic and overseas oil-gas field, and making huge damage to oil-gas field development. The cement sheath is easy to be broken because it has only little deformation under force which will affect the cement long-term packing property that could ensure the oil and gas production go smoothly. Aiming at the above problems, to conquer the shortage of traditional materials, a new multi-functional material is developed by combining nanotechnology and polymer synthesis technology according to microstructure design principle. And then an intelligent thixotropic cement slurry system is built. The novel intelligent thixotropic cement slurry is able to rapidly respond to the external stimulus of shear force due to the dynamic net structure between the nanometer material and the polymer. It is thin under shear and become thick rapidly when it is still and become thin again after shear. The process is reversible. The new system which conquers the problems existing in the conventional thixotropic cement slurry could not only make full use of its functions but also reduce the construction risk. The experiments show that the cement slurry has strong thixotropy unaffected by temperature and short transition time and can prevent lost circulation and fluid channeling in cementing process. And the cement stone with the multi-functional material has well tenacity and excellent ability of resisting damage which could keep long-term packing property. Besides, the thixotropic mechanism of nanometer material and its function on mechanical property improvement are studied in the point of microstructure, which will lay a certain foundation for the application of nanotechnology in well cementing. The intelligent thixotropic cement slurry have been used successfully in many oil fields, which prove its function on solving the problems of fluid channeling and lost circulation.