煤层气钻井中煤储层的保护措施

煤层作为煤层气的生成层和储集层，在储层特征和储存方式等方面与常规油气储层具有不同的特点，决定了煤层气钻井、完井、储层保护及压裂等技术的特殊性。在钻井中，选用欠平衡钻井技术、空气潜孔锤钻井技术；使用低密度、低粘度、低失水量、中性pH值及低（无）固相含量的钻井液；采用低密度、低上返的固井技术。这不仅对煤储层具有一定的适应性，也保护了煤储层的渗透性。

Coal Reservoir Protective Measures During CBM Drilling

Coal seam as the CBM source and reservoir has different features with conventional oil and gas reservoir on reservoir characteristics and storage manners that have determined specialty of CBM well drilling, eompletion, reservoir protection, hydraulic fracturing and other techniques. During drilling, underbalanced drilling, air flush DTH hammer, low density, low viscosity, low water loss, neutral pH value, low solid （or solid free） drilling fluids and low density, low up-return cementing techniques were used, All the measures not only have certain adaptability to the coal reservoir, but also protected permeability of the reservoir.