渤中26-6油田发现井钻井设计与施工

Drilling Design and Construction of a Discovery Well in Bozhong 26-6 Oilfield

  • 摘要: 渤海油田渤中26-6构造太古界油气运聚条件优越,且潜山长期遭受剥蚀,具备良好的储层条件,非常有利于成藏。为明确该构造东高点太古界潜山储量,探索潜山成藏模式,在该构造部署了探井26-6-2井,主要目的层为太古界潜山,但该井地质条件复杂,钻井难度大。分析了该井主要钻遇岩性及钻井技术难点,认为该井存在漏失风险高、井壁易失稳、易发生井斜和井控风险高等施工难题。为此,从井身结构、钻头及提速工具、钻具组合、钻井液等方面对渤中26-6-2井进行了一系列优化设计。现场施工中,为了达到风化壳与内幕分隔测试的目的,又创新设计,增加了一开次,顺利在潜山内幕下入尾管并成功封固管鞋。渤中26-6-2井测试获得工业油气流,发现了渤中26-6亿吨级油田。相关钻井技术对渤海油田后续钻井设计及现场施工具有指导意义。

     

    Abstract: The Bozhong 26-6 Structure in Bohai Oilfield has a superior background of oil and gas accumulation in the Archaean group, and the buried hill is subject to long-term erosion, which thus has good reservoir conditions for facilitating reservoir formation. In order to clarify the reserves of the Archean buried hill at the east high point of the structure and explore the buried hill accumulation model, it was decided to drill Well 26-6-2 in this structure, and the main target layer was the Archean buried hill. However, the geological condition of Well Bozhong 26-6-2 is complicated, and drilling is thus difficult. Therefore, the main drilling lithology and drilling technological difficulties of the well were analyzed, and it was considered that the well was faced with some problems such as a high risk of leakage, easy wellbore instability, easy well deviation, and high risk for well control. To this end, a series of optimization designs for the well were carried out from the aspects of the casing program, drill bit, acceleration tool, bottom hole assembly, and drilling fluid. During the on-site construction, in order to separate the weathered crust and the inner cover in tests, the design had been innovatively updated, and a one-section was added. The liner smoothly entered the inner cover of the buried hill and successfully sealed the pipe shoes. Finally, the test of Well Bozhong 26-6-2 obtained industrial oil flow, and a Bozhong 26-6 Oilfield of a hundred million tons was discovered. The relevant drilling technologies can guide the subsequent drilling design and on-site construction of Bohai Oilfield.

     

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