四川油气田气体钻井技术

四川油气田地质情况复杂，长段井漏、恶性井漏时常发生，使得钻井工作的难度大大增加。在四川发展起来的空气泡沫钻井技术和纯空气钻井技术，已成为解决井漏（特别是恶性井漏）最有效的方法之一；四川有很大一部分地区的产层属低渗低压油气藏，采用常规钻井液钻井，容易造成不可逆转的储层伤害，甚至难以发现地下油气资源。为了解决这一难题，在四川研究并发展了欠平衡钻井技术，其中包括天然气钻井、尾气钻井、氮气钻井等技术。特别是近年来，气体钻井的优势在川渝地区的钻井中显现得越来越明显，也越来越受到高度关注。为此，回顾了四川气体钻井技术发展历程，阐述了纯空气钻井、泡沫钻井、氮气和天然气钻井、柴油机尾气钻井、充气钻井和雾化钻井等气体钻井技术在四川的应用现状，分析了四川气体钻井技术发展中遇到的气体钻井井斜、地层出水、钻具失效以及井壁垮塌等问题,以期进一步充分发挥出气体钻井的优势。

DISCUSSION ON SICHUAN GAS DRILLING TECHNOLOGY

The complicated geologic conditions, lost circulation in long wellbore sections, and frequently lost circulations occurred in Sichuan oilfield have all added to the difficulties of drilling operations. The air/foam drilling technology and straight air drilling technology developed in Sichuan has become an effective way to deal with the lost circulation, especially serious loss. In Sichuan, many of the reservoirs are low-permeability and low-pressure reservoirs, the conventional drilling fluid tends to cause irreversible damage to the reservoirs and makes it hard to discover the hydrocarbon resources. To solve these problems, underbalanced drilling, including natural gas drilling, exhaust drilling, nitrogen drilling, are developed here, also attracting more highly attention from other oilfields. Whereby in this paper the evolution of Sichuan gas drilling technology is reviewed, the up to date status of air drilling, foam drilling, nitrogen/natural gas drilling, diesel engine exhaust drilling, aerated drilling, and mist drilling are described, and the bottlenecks of Sichuan gas drilling technology, such as inclination control, drilling through water-producing formations, drilling tool failures and wellbore caving, are analyzed, expecting to take full advantage of gas drilling.