A Study On Drilling Technique Of Cbm Well In Fuxin High Gas Coal Mine Areas

At present, coal resources of our country is third in the world, the resource of CBM which depth low than 2000m is about 31.46×10¹²m³, which mathes in the conventional gas resources. Therefore, the CBM, as a emerging energy, is being taken into consideration. There is a great number of CBM stored in Fuxin high gas coal mine areas, however, with the complex structures and approaching to saturation of coal reservoirs, there are many problems come to being in drilling operation of Fuxin high gas coal mine areas. So it does require to explore a set of new drilling technology applied to these coal mine areas, which depended on the base of analyses to geological characterization of coal reservoir in Fuxin high gas coal mine areas and connected with the construction practice of vertical wells and directional wells.Through studying of drilling technique of CBM well both at home and abroad, this paper analyzes the accommodated conditions of drilling technology of vertical wells, horizontal wells, under-balanced wells and so on. From the analysis of CBM reservoir bed in Fuxin high gas coal mine areas, and studying the geological, adsorption-desorption characteristics and gas-bearing features of coalbeds, we can have a conclusion that vertical well and high-angle well are applied to Fuxin high gas coal mine areas. According to the characters of coal seam, structural properties and pre-production test cases, this paper provides the deployment of development, well structure, well control technique and drilling fluid design of CBM well in Fuxin high gas coal mine areas, which provide a theoretical basis for designing and practicing drilling operation of CBM well in Fuxin high gas coal mine areas. Based on summarizing and analyzing the major problems existing in the drilling operation, application of drilling technology in Fuxin high gas coal mine areas is carried out. As result, WL4 well in mining area, using high-angle well drilling technique, daily mixed-gas production is 3.74×10⁴m³ in production test time; WL3 well in gob area, using vertical well drilling technique, daily mixed-gas production is 0.403×10⁴m³ in production test time, which high-angle well is better than vertical well in Fuxin high gas coal mine areas.