The Source Rocks Expulsion Efficiency And Its Influencing Factors Research

Hydrocarbon expulsion is an important prerequisite for hydrocarbon accumulation, the studies of expulsion efficiency about conventional oil and gas exploration and shale oil and gas have important significance. In this passage, we use the hydrocarbon potential method and material balance method to calculate the expulsion efficiency of Qingshankou source rocks in northern Songliao Basin, established the "iron pillars" of the source rocks expulsion efficiency which include basic logging, logging and geochemical data. On this basis, analyzed the the organic matter abundance, type, maturity, source storage configuration relationships, then study their impact on the efficiency of hydrocarbon expulsion. The results showed that: ① When TOC is less than 2% to 3%, the expulsion efficiency increased with the organic matter increasing. When TOC is greater than 2% to 3%, there is no significant change; ② If the type of organic matter is better, the efficiency of hydrocarbon expulsion is higher; ③ If the organic maturity is better,the efficiency of hydrocarbon expulsion is higher; ④ mudstone nested> sand mud interbedded> sandstone nested> thick layer of mudstone; ⑤ If the thick layer of mudstone is closer to the edge, the efficiency of hydrocarbon expulsion is higher; ⑥ Expulsion efficiency increased with clay minerals decreased; ⑦ The source rocks which have been uplifted have lower expulsion efficiency than the source rocks which are sustainable deposited or little uplifted. In the passage we summarized the residual hydrocarbons variation characteristics and mechanisms of Qingshankou in Songliao Basin, and divided the detained hydrocarbon of source rocks into five sections: kerogen swelling hydrocarbons, kerogen absorbing hydrocarbons, kerogen pore shelter hydrocarbon, inorganic minerals absorbing hydrocarbon and inorganic pore shelter hydrocarbon. Then established the kerogen swelling and adsorption models; and evaluated the adsorption and swelling capacity of kerogen to the components in oil and gas quantitatively. When the Ro is under 0.9%, the total swelling capacity and the swelling capacity to the saturated hydrocarbons and lower carbon number hydrocarbons have a such regularity: kerogen Type I > kerogen Type II> kerogen Type III, but when the Ro is higher than 0.9%, because the swelling capacity is decreasing sharply, the swelling capacity reversed, he total swelling capacity and the swelling capacity to the saturated hydrocarbons and lower carbon number hydrocarbons is: kerogen Type I < kerogen Type II< kerogen Type III. In geological conditions, kerogen Type I adsorption capacity < kerogen Type II< kerogen Type III.