Abstract

Pressure control of oil and gas wells in high-sulfur natural gas reservoirs (well control) is critical in oil and gas drilling. Well control accidents have caused great losses of life and property. From 1960 to 1996, more than 1,120 blowout accidents occurred in the Gulf of Mexico and neighboring state capitals. Studying the principles of annulus flow with sour gas can help in early monitoring of overflow and provide theoretical guidance in actual drilling. Research of gas properties and phase behavior can reveal the reasons that sour gas is prone to blowout. The fluid flow principles of the annulus are analyzed with different contents of sour gas. In this study, a multiphase flow model of sour gas in the annulus is established based on sour gas solubility and critical parameters. The model is used to calculate and analyze the changes in sour gas properties and wellbore flow parameters with well depth. It was found that when high-content sour gas overflows, the gas expands violently near the wellhead, and the risk of blowout increases.

摘要

高含硫天然气藏油气井压力控制（井控）是油气钻井的关键。井控事故造成了巨大的生命财产损失。从 1960 年到 1996 年，墨西哥湾和邻近州首府发生了 1120 多起井喷事故。研究酸性气体环空流动原理，有助于早期监测溢流，为实际钻井提供理论指导。气体性质和相行为的研究可以揭示酸性气体易于井喷的原因。分析了不同酸气含量下环空的流体流动原理。本研究基于酸性气体溶解度和临界参数，建立了环空中酸性气体的多相流模型。该模型用于计算分析酸性气体性质和井筒流动参数随井深的变化。结果发现，高含量酸性气体溢出时，在井口附近气体膨胀剧烈，井喷风险增大。