地层压力随钻预测技术在高温高压井的应用

Application of formation pressure prediction while drilling technology in HTHP wells

莺-琼盆地高温高压井压力台阶多、压力体系复杂,仅靠钻前地震资料预测难以满足现场作业要求。地层压力随钻预测技术是利用综合录井的压力随钻监测结果,实时修正钻前地层压力预测模型和结果,从而提高地层压力预测精度。本文结合高温高压Y1井的实例,应用国际先进的Equi Poise系统进行现场地层压力随钻监测,根据地层压力监测的实际结果来修正地层压力预测模型,进而对下部未钻地层的地层压力进行再预测。钻后实测压力验证表明,该方法的地层孔隙压力预测精度达到94%,说明利用地层压力随钻监测结果实时修正地层压力预测模型,可以实现提高地层压力预测精度目的,为高温高压井钻井参数设计、钻井方案调整和安全控制提供技术保证。

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 byusing 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 partis 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.