Application of formation pressure prediction while drilling technology in HTHP wells

In the Ying-Qiong Basin, HTHP wells are suffered from multiple pressure steps and complex pressure systems, so the field operation cannot be carried out satisfactorily only based on the predrilling seismic data prediction. The formation pressure prediction while drilling technology corrects in real time the predrilling formation pressure prediction model and the prediction results by using the pressure monitoring results while drilling of compound logging, so as to increase the formation pressure prediction accuracy and protect oil and gas layers effectively. In this paper, a case study was carried out on HTHP Well Y1. In this well, internationally advanced Equipoise system is used for formation pressure monitoring while drilling in place. The formation pressure prediction model is corrected according to the actual monitoring results of formation pressure, and then the pressure of undrilled formation in the lower part is re-predicted. The measured pressure after the drilling indicates that the prediction accuracy of formation pore pressure based on this method is up to 94%. The practical application shows that formation pressure monitoring while drilling can be used to correct the formation pressure prediction model and increase the formation pressure prediction accuracy. It provides the technical support for the drilling parameter design of HTHP wells, drilling plan adjustment and safety control.