川东地区高陡背斜构造地质情况复杂，井下压力异常。川东某井在嘉二2钻遇异常高压气层，通过对钻井液密度与气测全烃值和钻井液静止时间相互关系的研究，利用密度、全烃值、钻井液静止时间的相互控制关系，进行欠平衡钻井和起下钻作业，保证了井下安全，取得了显著效果。 Geological situation of high-steep anticline in eastern Sichuan is complex and underground pressure is abnormal. A well in eastern Sichuan drilled an abnormally high pressure gas reservoir in Jia’er-2. Based on the study on the relationship between the density of drilling fluid and the total hydrocarbon gas and the rest time of drilling fluid, the mutual control of density, total hydrocarbon and drilling fluid quiescence Relations, underbalanced drilling and drilling operations, to ensure the safety of the underground, and achieved remarkable results.