Liaohe basin is a special type basin with coal, oil and gas resources. It is important to evaluate reservoir forming conditions of deep coalbed methane for sele

cting favorable exploratory areas and developing unconventional coalbed gas and conventional oil and gas resources together in the eastern sag of the Liaohe basin. The paper analyzes reservoir forming conditions from gas source, reservoir and preservation, and makes a comprehensive evaluation. The result indicates that coal beds in the sag are characterized by wide distribution, big thickness, low metamorphic grade, low coalbed methane contents, high coalbed methane saturation, deep buried depth, coalbed methane of abundant geological reserve and favorable preservation. It also shows that reservoir forming conditions of deep coalbed methane are favorable, deep coalbed methane resources are plenty, unconventional coalbed methane can be developed together with normal oil and gas resources and deep coalbed methane has a good prospect of exploratory development in the sag

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