异常地层压力的预测及其在地质风险评价中的应用

A PREDICTION OF ABNORMALLY HIGH PRESSURE AND ITS APPLICATION IN GEOLOGIC RISK EVALUATION

用地震速度资料进行钻前地层压力预测,大体可分为趋势线法和支撑上覆岩层压力的百分比法。对于常见的趋势线法其预测精度关键在于建立合理的、准确的正常压实趋势线和标定实测地层压力。本文建立了研究区内单组地层的正常压实趋势线,提出了用地层因子法估算地层压力。异常压力的分布直接影响着油气运移的聚集条件,通过分析异常压力区的油气分布特征,在钻前用预测的地层压力进行地质风险评价。

Methods used in the prediction of pore pressure can be classified into two groups-the method of trend line and the method of percentage of overbur- den.The key to the trend line method is to establish a reasonable and accura- te normal compacton trend line.In the studied area,each formation has its own normal compaction trend.In this paper,one of prediction methods-for- mation factor method is presented. The petroleum generation from source rocks moves vertically into the low- er potential sediments and accumulates in the neighbourhood traps.Having analysed the potential of petroleum accumulation in the vertical profile,and the relation of overpressure with distributions of petroleum traps,the author gives a geologic risk evaluation based on the pore pressures estimated from seismic data.