The Carboniferous-Permian coal measure strata in Dongpu sag is a fair source rock unit of Wenliu gas pool due to its stable distribution and high organic content. There are two hydrocarbon-generating periods in the burial history of coal measures. The first one occurs when the T

1-2

formation is deposited. Vitrinite reflectance

apatite fission track and fluid inclusion analyses indicate that the burial depth of coal measures is about 3500 m

with the palaeotem-perature of 118℃ and R

o

of 0.80%-0.85%.Hydrocarbon generation of coal measures was interrupted in the Meso-zoic uplift and erosion period (about 1.8 million years).During the Paleogene rifting period

the coal measures was entered into its secondary hydrocarbon-generating period as the burial depth increases

reaching its hydrocarbon-generating peak after the deposition of Dongying formation. The gas-prone source rock is mainly distributed in the region of Wendong-Qianliyuan

with the buried depth of 5290-6360m. The discovery maturity (percentage of ultimately proven reserve with respect to total resources) of gas resources in Wenliu area is more than 90%. In the effective gas supply area of Wenliu gas pool

the hydrocarbon-generating volume and hydrocarbon-expelling volume of Carboniferous-Permian coal measures are estimated to be 3253.3 million m

3

and 2657.0 million m

3

respectively

with a gas accumulation coefficient of 5.92%.