随钻地层压力综合评价技术在莺歌海盆地超压井中的应用

Application of Comprehensive Evaluation Technology of Formation Pressure While Drilling in Ultra-high Pressure Wells in Yinggehai Basin

莺歌海盆地中深层异常高压(超压)区域受他源、自源以及地质构造运动影响,地层温度高、压力大,温压分布复杂,常规钻前压力预测技术难以准确预测地层压力系数,预测误差高达0.20~0.40,无法满足作业需求。通过有效整合测井、地震、录井等各类监测方法,并结合区域地质信息对地层压力进行有效评价,建立了一套随钻地层压力综合评价技术。该技术在南海莺歌海盆地超压井压力监测作业中有效规避了意外超压风险,避免了井喷、井漏等井下复杂情况的发生,效果显著,为后续海上超压井随钻压力监测提供了可靠依据。

The high temperature and high pressure area in Yinggehai Basin, South China Sea, is affected by other sources,source and geological tectonic movement, it has high temperature, high pressure and complex temperature and pressure distribution. In complex geological environment, conventional pre-drilling pressure prediction technology is difficult to accurately predict formation pressure coefficient, and often the error of pressure prediction is as high as 0. 20-0. 40, it is hard to meet the requiremens of drilling operation. By integrating the methods of logging, seismic and gological logging, and combined with regional geological information, the formation pressure is effectively evaluated, a set of integrated evluating technology of formation pressure while drilling is established. The technology is used for pressure monitoring in abnormal pressure wells in Yinggehai Basin, by which the risk of accidental overpressure is effectively avoided, blowout and lost circulation are also avoided with obvious effect, it provides reliable basis for pressure monitoring while drilling in consequent offshore overpressure wells.