精细压力预测技术研究

Study about the Technology for Fine Prediction of Formation Pressure

异常高压的存在不利于钻井施工安全、人身安全及财产保障,进而关系到油气勘探进程,但同时其存在有可能使得深层储层保持较高孔隙度,有利于油气的运移聚集。因此,准确的钻前压力预测结果对于发现油气藏、保障钻井安全、保护油气层具有十分重要的意义。常规方法预测异常高压多采用地震层速度或已钻井测井曲线进行分析,仅用地震层速度导致纵向分辨率不足,而仅用已钻井测井曲线无法兼顾横向压力预测的要求。此文针对常规压力预测中存在的不足,以已钻井压力测试数据为质量控制条件,以精细构造层位为框架,利用地震数据、层速度和已钻井测井数据进行约束反演,在多参数约束下依据已钻井压力计算参数和地质信息将反演得到的速度体转换为压力体。该方法已成功应用于实际生产。经B1井钻后实测压力数据结果的比较,吻合较好。

The abnormal high pressure might unfavorable for drilling safety, personal safety and property safety, and might influence the process of sequential hydrocarbon exploration. However, the abnormal high pressure might preserve the porosity in deep reservoirs, being favorable for hydrocarbon migration and accumulation. Therefore, it is very significant to forecast accurately the pre-drilling formation pressure for discovery of hydrocarbon reservoir, guarantee of drilling safety and protection of reservoir forma- tion. The forecast of abnormal high pressure is usually conducted with the method of the interval velocity or logging data. If only the interval velocity is used in pressure prediction, the vertical seismic resolution will not be high enough. If only logging data is used in pressure prediction, the requirements for forecast of horizontal pressure could not be reached. To overcome the shortcomings of conventional forecast method, using MDT as quality controlling conditions, with fine structural horizon data as frameworks, restrict- ed inversion has been conducted by using the seismic data, the interval velocity and logging data. Through constrains with multiparameters, based on and pressure parameters from the drilled wells and geological information, the velocity volume finally obtained through inversion is used to calculate pressure volume. The new method has been used to actual production. The final prediction result is matched well with the actually measured pressure data from well B1 after drilling.