Measures and effect analysis for stimulation and rehabilitation of low-production coalbed methane wells in Tunlan Block,Xishan Coalfield
WANG Yu
SONG Xiaoxia
HU Zhazha
LIU Yanfei
DU Liqiang
QI Wei
YAN Jiwei
GUO Hao
CHEN Weidong
Abstract：Coalbed methane(CBM)development in the Tunlan Block of Xishan Coalfield has reached a certain scale,but the gas production of some CBM wells has not met expectations.Therefore,there is an urgent need to carry out targeted stimulation and rehabilitation measures to increase the production of CBM wells.Objectives The objective of this study is to investigate the characteristics of primary fracturing and evaluate the effect of stimulation and rehabilitation on low-production wells in Tunlan Block.Methods Based on the geological engineering data and production data from 102 vertical wells and 7 horizontal wells in Tunlan Block,this study analyzes the characteristics of primary fracturing in CBM wells by considering fracturing curve types,rupture pressure,and production capacity characteristics in the study area.Addi-tionally,a production dynamic analysis method is used to evaluate the stimulation effect of implementing dense well network on low producing CBM wells.Results The study reveals that the fracturing curves of CBM wells in Tunlan Block can be classified into four types:stable,descending,ascending and fluctuat-ing types.Stable and descending fracturing curves are more favorable for efficient CBM extraction.The high proportion of fluctuating and ascending curves in the study area reflects the greater difficulty in fracturing the coal seam and the strong heterogeneity.By implementing a infill CBM well network in the pilot test area,seven horizontal wells were densely deployed between vertical wells,and the average daily gas pro-duction of nine nearby low-producing vertical wells was significantly increased from 150～800 m3/d to 330～6 000 m3/d,demonstrating the effectiveness of the technology.The main reasons for the low gas production of CBM wells in the study area are low original permeability of coal reservoirs and insufficient initial fractur-ing and rehabilitation.The technology of implementing dense CBM well network is a well-established and ef-fective measure to increase gas production of low-production wells.Conclusions This study can provide guidance and reference for the stimulation and rehabilitation of low-production CBM wells in the study area or similar areas.
Keywords：coalbed methaneTunlan Blockfracturing curve typesproduction capacity characteristicsstimulation and rehabilitation measures
Publication Date：2025-05-22
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 101-111 )