Casing drilling for L-shaped CBM horizontal wells in Hancheng mining area

How geological conditions match engineering technologies determines the coalbed methane (CBM) development. To further explore a development technology applicable to the characteristics of coal reservoirs in the Hancheng mining area and constantly improve the CBM development effect in the area, the development effect of cluster well group perforation and fracturing and multilateral drilling technologies applied in this area was analyzed and then an L-shaped horizontal well casing drilling technology was used according to the low-porosity, low-permeability and low-pressure characteristics of coal reservoirs in this area. With this technology, a third-sized hole of a well can be drilled with casing and no cementing job but only perforation is required after the hole is drilled to total depth (TD). The results show that this type of technology with the advantages of common horizontal well development technologies can maintain borehole wall stability, avoid the unfavorable impact of cementing and fracturing and deliver better gas production than multilateral drilling.