Integration Cementing Technology for Ultra-deep HTHP High Salinity and High Hydrogen Sulfide Well

Abstract

Well-M15 is an ultra-deep exploratory well deployed by CNPC in the Mingebulak project. Its geological conditions are complex, with the characteristics of high temperature, high pressure, high salt, high hydrogen sulfide, and ultra-deep——“four highs and one super”. In the process of cementing, there are problems such as low displacement efficiency, easy mixing of cement slurry, complex formation pressure layers, and high requirements for casing accessories and special well-entry tools, which seriously affect the sealing effect and cementing quality. In view of the above difficulties, the cement slurry design of Well-M15 is based on the optimization of the mature system formula. Choose solid anti-salt fluid loss agent G33S for the second-spud, and choose matrix anti-invasion and anti-channeling agent BCG-200L for the third-spud, which has good salt resistance, temperature resistance and channeling resistance. At the same time, for the purpose of salt resistance, each level of casing cement slurry system is optimized to improve the specific cement slurry formula to meet the cementing needs. Large-size casing floating shoes and floating hoops focus on erosion resistance, while deep well cementing tools focus on high temperature and pressure resistance, which effectively guarantees cementing operations. The successful drilling of Well-M15 has set a series of new records for CNPC’s overseas projects, including the deepest casing of the same size, the largest injection volume, the longest one-time sealing section, the deepest application of graded cementing technology, and the highest density of cement slurry. At the same time, it has also created a new record of quality qualification rate and quality rate of deep well liner cementing in Uzbekistan, providing a reference for the cementing of deep wells and complex wells in similar blocks in the future.