Study about the Technology for Fine Prediction of Formation Pressure

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 formation. 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, restricted 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.