CHEN Yue, WANG Liya, LI Guofu, et al. Prediction of favorable areas for low-rank coalbed methane based on Random Forest algorithm[J]. Petroleum Reservoir Evaluation and Development, 2022, (4): 596-603+616. DOI: 10.13809/j.cnki.cn32-1825/te.2022.04.007.
Prediction of favorable areas for low-rank coalbed methane based on Random Forest algorithm
low-rank coal and coalbed methane resources are abundant
meanwhile
as a kind of clean energy
the development and utilization of coalbed methane(CBM) can effectively alleviate the shortage of natural gas resources
but the commercial scale development is slightly insufficient
and systematic research is urgently needed. The premise of efficient CBM development is the selection of favorable areas
but the current CBM development evaluation involves certain subjective human factors
which will indirectly affect or interfere with the prediction effect. Taking the low-rank coal in the Dafosi minefield in the Binchang mining area of Huanglong Coal Field as the research object
based on the actual production data
the random forest algorithm in machine learning is used to predict the favorable area of coalbed methane in the area. The results show that: ① Pearson correlation analysis shows that the gas content
ash content
net thickness of coal seam
structural position
roof thickness
permeability
reservoir pressure and burial depth are eight mutually independent CBM output-related parameters and can be used for model establishment; ② The Random Forest algorithm divides the CBM development area into five types of areas with different degrees
of which type Ⅰ(extremely high) to Ⅱ(highly favorable) areas account for 13.88 % of the entire study area
mainly distributed in the middle of the well field. The southeast is not suitable for subsequent deployment of well locations
and there is a distribution of highly favorable areas in the west
so the well locations for subsequent development and deployment should also be considered. ③ It can be obtained from the receiver operating characteristic(ROC) curve
and the area under the ROC curve (AUC) is 0.961
indicating that the Random Forest model has high prediction accuracy and reliable results. Using machine learning algorithms for comprehensive prediction of CBM favorable areas can avoid human subjective factors in traditional algorithms
and can provide a certain theoretical reference for subsequent unconventional oil and gas development and selection.