川西地区高压天然气深井钻井完井技术

川西地区天然气储层埋藏深，纵向上普遍存在多个产层和异常高压气层，钻井过程中易出现井喷、井漏、井眼坍塌、卡钻等井下事故和复杂情况。针对复杂的地质条件，开展了技术攻关和现场试验，逐渐形成了包括深井井身结构设计、深井钻井液技术、储层保护技术、高压井控技术、深井长裸眼井段固井技术的深井配套钻井完并技术，并试验应用了包括螺杆钻具＋PDC钻头、深井PDC钻头、旋冲钻井技术、涡轮钻具等提高深井钻井速度的新技术、新工具。近年来，该地区高压天然气深井钻井速度、固井质量不断提高，井下事故及复杂情况不断减少，未出现井喷失控的重大事故，加快了该地区天然气勘探开发速度。

Drilling and Completion Techniques in Deep Gas Wells in Chuanxi Area

Gas reservoirs deposit deep In the Chuanxi area, multiple pay zones and abnormal hign pressures present commonly in vertical direction, downhole troubles of blowing out, lost circulation, wellbore sloughing, and stuck pipe are likely to happen during drilling. In this case, technique researches and field tests are conducted so that a set of supporting drilling and completion techniques are developed which include casing schematics design, drilling fluid suitable for deep wells, reservoir protections, well control under high pressure, cementing techniques for long open holes in deep wells, etc. New tools and techniques to improve deep drilling speed are also tested, including assembly of a mud motor combined with a PDC bit, PDC bits used in deep wells, rotarypounding drilling techniques, turbo drills, etc. In recent years, the ROP and cementing quality in deep gas wells with high pressure have been increasingly improved, and downhole troubles and accidents have been substantially decreased, severe accidents such as well blowout have not taken place any more, which contributes to the enhanced gas producing speed in the area.