四川天然气深井钻井主要工程地质问题及对策

四川盆地天然气深井钻井地质条件复杂．由于不能预见的工程地质问题造成实钻与设计的差异并导致严重的钻井复杂与事故，不仅危及钻井安全和地质目标的实现，也严重制约钻井速度的提高，显著增加钻井成本．这是四川天然气深井钻井最突出的矛盾?文中分析了四川天然气深井钻井主要工程地质问题(异常地层压力、井壁不稳定、地层自然造斜和储层伤害等)及其特点，提出了预防和处理主要钻井工程地质问题的措施：在钻井设计和施工作业中做好钻井工程地质问题分析和跟踪评价．特别是处理好四个压力(地层压力、坍塌压力、漏失压力和钻井液柱压力)的关系，是提高设计质量，实现安全顺利钻井的根本保证。钻井工程是特殊的地质工程，建立《钻井工程地质学》这一新的专业基础学科对钻井技术发展和钻井效益的提高都有重要的意义。

Engineering Geoiogy Probloms of Deep Drilling and Its Strategy in Sichuan Natural Gas Well

Geologic setting is complicate in Sichuan basin. Due to unforeseeable engineering geology problems that make the discrepancy of real drilling and design, and results in drilling complication and trouble. It not only endangers safety drilling and realization of geologic target, but also restricts seriously the improvement of drilling speed and increases drilling cost. The paper analyses the main engineering geology problems of deep drilling and their features in Sichuan natural gas well, such as abnormal formation pressure,sidewall unstability, and reservoir damage etc., and proposes preventive measures.At the same time, the paper also proposes that treatment the relation of four pressures well (formation pressure, caving pressure, leakage pressure and drilling fluid pressure) and analysis drilling engineering geology problems during drilling design and operation are very important. It is key of improvement design quality and realization safety drilling. Drilling engineering is special geologic engineering. The establishment of Drilling Engineering Geology has important significance for the development of drilling technology and improvement of drilling benefit.