河南中牟页岩气区块地层特征及钻探问题研究

Research on Formation Characteristics and Drilling Problems in Zhongmou Shale Gas Block of Henan Province

摘要:

页岩气主要以吸附和游离状态贮藏在海相、陆相和海陆过渡相泥页岩中，这些岩石的沉积过程、时间和类型不同，表现出了地层或岩石的物理化学性质各向异性的特点。页岩气钻探所遇地层主要是不同时代的泥岩、砂岩、泥质砂岩、砂质泥岩等，这些岩石对钻井液中水分子具有极强的敏感性。所以，在钻探过程中常遇到起下钻遇阻、孔内沉渣多、重复破碎、卡钻等问题，由此花费大量的时间处理，从而减少了纯钻时间。这些问题的根本原因则是由于岩石膨胀缩径、孔壁崩塌超径所造成的。本文首先对河南中牟页岩气区块地层特征进行了描述，并就牟页1井钻探问题从钻孔缩径和超径2个方面进行了理论研究和分析，最后从钻井液和钻探工艺选择方面提出了原则性的建议。

Abstract:

Shale gas mainly deposits in marine, continental and transitional facies in mud shale with adsorption and free state, the different deposition process, time and type of the rocks show the anisotropic of physical and chemical properties of strata or rocks. The formations of shale gas drilling mainly include mudstone, sandstone, argillaceous sandstone, sandy mudstone and so on in different times and these rocks have strong sensitivity to water molecules in drilling fluid, therefore a lot of time was spent to deal with difficult tripping, large amount of sentiments, repeated breaking and pipe sticking during the drilling process, the pure drilling time was reduced. The basic reasons of these problems were the diameter shrinkage and oversize caused by rock expansion and wall collapse respectively. This paper describes the formation characteristics of Zhongmou shale gas block firstly, and then the research and analysis on the drilling problems of Mouye well No.1 are made in borehole diameter shrinkage and oversize, the principled suggestions are put forward for drilling fluid and drilling technology selection.