煤层气井祼眼与套管注入/压降测试渗透率对比分析

我国煤层气井渗透率测试方法目前广泛采用注入/压降试井。通过对试验井的裸眼测试和套管测试发现，套管测试渗透率是裸眼测试的9.82倍，裸眼测试渗透率明显偏低。裸眼测试渗透率低的主要原因是注入和关井时间较短，未出现径向流。由于我国煤层气区块大多处于勘探阶段，且多采用裸眼注入/压降方法，开展区块裸眼和套管注入/压降的对比测试，可以获取区块标准井的注入时间和关井时间，提高渗透率解释结果的准确性。 

Injection/fall off test for comparative analysis of permeability of coalbed methane open and casing wells

At present, the injection/fall off test is widely used for the permeability of coal bed methane wells in China.Through open hole test and casing test of test wells, it is found that the permeability from casing test is 9.82 times of that from open hole test, which shows that the permeability from open hole test is obviously low.The main cause for it is that the injection and shut in time is short, and the radial flow doesn't appear.Because most coal bed methane blocks of China are in exploration phase, and the open hole injection/fall off test is usually adopted, comparison between open hole and casing injection/fall off tests can obtain the injection time and shut in time of the typical well of a block, and improve the accuracy of permeability interpretation.