Time- Control Drilling Technology in Coring and Layer Determination of Coalbed Methane Well

The time- control drilling technology had been used for saving the cost of drilling, shortening the construction period and reducing the risks of drilling in t he process of coring and layer determination of a coalbed methane well in Jixi Basin of Heilongjiang Province. The method identifled the target layerDs which was char acterized by combination of thin seams, controlling the speed of drilling and footage and the application of careful cut logging method, and finally coring successfully. T he results showed that this technology which reduced the workload of coal dilling without coal core, saved the cost of dilling, shortened the period of driling engineeri ng construction and increased the efficiency of drilling, the technology was an effective method for sticking bed in coalbed methane well.