Thermal simulation of Silurian bituminous sandstone and its significance of hydrocarbon supply in northern Tarim Basin

To study the hydrocarbon generation potential of the Silurian bituminous sandstone in the northern Tarim Basin,two sets of experiment program were carried out using artificial and geologic samples respectively.According to the yielding rate and product composition under different experiment temperatures,the hydrocarbon generation process of the Silurian bituminous sandstone was divided into 3 stages including evaporative fractionation oil-and-gas expulsion stage(with the simulative temperature of 100-300℃,equivalent to R_o<0.9%),cracking oil-and-gas expulsion stage(with the simulative temperature of 325-400℃,equivalent to 0.9%<R_o<1.8%),and cracking gas expulsion stage(with the simulative temperature over 400℃,equivalent to R_o>2.0%).According to the actual depth and maturity of the Silurian bituminous sandstone in the northern Tarim Basin,those sandstones during the cracking oil-and-gas expulsion stage were buried over 6 000 m deep and mainly located in the western Shaya and Halahatang areas.Through resource estimation,although the bituminous sandstones could not provide enough hydrocarbons for accumulation in large scale,they were the most important auxiliary regenerative hydrocarbon source rocks in the northern Tarim Basin.