The Design and Analysis of the Scheme for Well Patterns to Produce Coal Bed Methane

Vertical well is the main ways for developing coal bed methane(CBM) in China,multi-lateral horizontal well and U-shaped wells are the subsidiary.But the gas rate per well in China is low constantly.In the view of characteristic of coal geology abroad,there have been developed some new recovery patterns,such as V-shaped wells,multi-lateral herringbone wells,and multi-layer development wells,which can not only increase gas rate but also reduce production cost.Learning from foreign experience,the new CBM patterns of well for produce CBM have been designed in detail,including:two engineering wells are vertical distributed,shared with one vertical well for extracting fluids,two engineering wells are arranged in V shape,shared with one vertical well for extracting fluids,anchored horizontal well and integral anchored wells,etc.According to geologic parameters of Baode district in Erdos Basin,with 16 km2 of CBM resource,single well construction cost and overall economic benefit of each scheme have been analyzed and simulated by using Eclipse software.Through comparison of traditional vertical well and multi-lateral horizontal well,it is found that new pattern of recovery scheme can increase gas rate significantly,reduce gas production cost and boost cumulative economic benefits.Integrated anchor wells have the best gas rate per well and lowest gas production cost,while V-shaped wells have the highest cumulative economic benefits.Finally,the suggestion for producing CBM is presented by considering the present status of well patterns.