高温高压水平井溢流模拟分析

Abstract

水平井溢流后，气体在水平井段膨胀量小，溢流不容易发现，进入垂直井筒后，气体上升膨胀导致井涌快速发展，给井控造成困难。针对海上高温高压水平井的具体工况，考虑井筒温度场、漂移模型的特点以及水平井段与地层的耦合，结合气液两相流基本方程，建立了高温高压水平井井涌理论模型，并对不同时刻、不同地层欠压实、不同裸眼长度的海上高温高压水平井井涌进行了模拟。模拟结果表明：溢流早期，环空压力和截面含气率变化比较快；地层压力系数越高，泥浆池增量、环空压力和截面含气率变化越迅速；裸眼长度较小时，泥浆池增量、环空压力和截面含气率变化不明显，裸眼长度较大时，泥浆池增量、环空压力和截面含气率变化很快。 When well kicking occurs in horizontal section, it will be difficult to discover at early stage of well kick. However, the volume of overflows will suddenly increase, when the overflows passes into vertical section. Considering the characteristic of wellbore temperature field, drift model and the coupling between wellhole and formation, combining basic equation of gas-water two-phase flow, and then build a horizontal well kick theoretical model of high temperature and pressure well. This paper simulates different moment, unbalanced formation and length of barefoot interval of high temperature and pressure of horizontal wells on sea. The simulation results show that annulus pressure and void fraction vary quickly in the early stage of overflow; with the increase of formation pressure coefficient, the pit gain, annulus pressure and void fraction vary more quickly; the pit gain, annulus pressure and void fraction vary slightly in short barefoot interval; while the pit gain, annulus pressure and void fraction vary obviously in short barefoot interval.