大尺寸井眼钻井工艺在渤海油田某探井中的应用和突破

经过三压力研究和实钻邻区资料证实渤海油田某区块中深部地层存在高温高压。在该区块某探井实际钻探中,地层压力系数1.3,最高达1.65,井底温度高达178℃,根据地层压力及地质特征进行井身结构优化,ф444.5 mm大尺寸井眼钻进至馆陶组顶部垂深2 700 m,才能减轻中深部高温高压地层的钻探风险,在渤海地区,ф444.5 mm大尺寸井眼钻进至2 700 m尚属首次,通过钻具组合优化与轨迹控制、海水/膨润土浆钻进、优化水泥浆体系和浆柱结构等技术,使得该井大尺寸井眼钻探过程中,在防斜打快、钻井液工艺及固井技术等方面均取得了突破,为钻开高温高压井段,进行地质评价提供了有力保障。

Application and breakthrough of large-size hole drilling technology in some exploration well in Bohai Oilfield

3D pressure study and the data of drilled wells in vicinity prove that there is high temperature and high pressure in the middle and deep formations in some block of Bohai Oilfield. While drilling some exploration well in this block, the formation pressure coefficient was 1.3, max. 1.65, and bottom temperature was up to 178 ℃. The wellbore configuration was optimized based on formation pressure and geologic features. When the ?444.5 mm large hole was drilled to the top of Guantao Formation with a vertical depth of2 700 m, the risk in drilling of HTHP formation in the middle and deep formations could be mitigated. In Bohai area, it was the first time that ?444.5 mm hole was drilled to 2 700 m. Through technologies like BHA optimization and trajectory control, drilling with seawater/bentonite fluid, optimized cement slurry system and fluid column structure, etc., breakthroughs were made in deviation control and fast drilling, drilling fluid technology and cementing technology while drilling this large size hole, which provides guarantee for drilling into the HTHP section and for conducting geologic assessment.