影响烃源岩中分散液态烃滞留数量因素研究

SIMULATION OF INFLUENTIAL FACTORS OF DISPERSIVE RESOLUBLE ORGANIC MATERIALS RESIDENT IN SOURCE ROCKS

采用加水热模拟方法,对低丰度海相泥灰岩进行了不同压力条件下的生排烃模拟。结果表明,10MPa压力条件下,烃源岩在310℃左右达到生、排烃高峰,排出油产率和总产油率最大值分别为182.5,193.4mg/g;20MPa压力条件下,烃源岩生、排烃高峰对应的温度为330℃,排出油产率和总产油率峰值分别为92.1,111.4mg/g。对比显示,压力增加抑制了有机质的生烃作用,导致烃源岩的有效排烃期增长,主排烃期延迟,使得更多的液态烃滞留于烃源岩中,为高演化阶段天然气的生成提供了重要母质来源。

The simulations of marine marl with low organic matter abundance under different fluid pre-ssures were carried out. The results indicated that, the peak time of hydrocarbon generation and expulsion was around 310 ℃ under the pressure of 10 MPa, with the expulsive oil rate and the total oil yielding rate of 182.5 and 193.4 mg/g, respectively. Under 20 MPa, the temperature corresponding to the hydrocarbon generation and expulsion peak was about 330 ℃, with the expulsive oil rate and the total oil yielding rate of 92.4 and 111.4 mg/g, respectively. It has been suggested that, the increase of pressure represses the thermal evolution of organic materials. It enlarges the effective hydrocarbon expulsion stage of source rocks in addition to postponing the major expulsion period. As a result, the residence time of resoluble organic materials with large quantity has been enlarged, which provides material basis for the generation of gas during the high evolutionary phase.