不同模拟实验条件下烃源岩生油气能力对比及意义

Hydrocarbon generation potential under different experimental conditions and its petroleum geology significance

张彩明 郑伦举 许锦

Zhang Caiming Zheng Lunju Xu Jin

中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126 2. 中国石化 油气成藏重点实验室, 江苏 无锡 214126

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China 2. SINOPEC Key Laboratory of Petroleum Accumulation Mechanisms, Wuxi, Jiangsu 214126, China

通过对比研究地层孔隙热压生、排烃模拟实验与高压釜生烃模拟实验中油气产率及其演化过程与产物地化参数特征，结果表明由于模拟实验设置的边界条件不同，同样热解温度条件下地层孔隙模拟实验已生成的油气产率是高压釜模拟实验的两倍多，但地层孔隙模拟实验残余固态产物的岩石热解自由烃、生烃潜力、氢指数仍然大于高压釜模拟实验的。分析认为，高压釜模拟实验所设置的热解实验条件加速了干酪根的过度裂解，生成了更多的“焦炭”、二氧化碳和氢气，偏离了烃源岩的自然演化过程；而在地层孔隙模拟实验的实验条件，有效阻止了干酪根的过度裂解，使干酪根向油气的转化率较高，所得油气产率较高压釜大。实验数据表明，地层孔隙模拟的已生成的油气产率不仅大于原始样品的氢指数，且生油后残余固态产物仍具有较高的氢指数。因此，烃源岩的氢指数和模拟实验的油气产率均不能正确评价烃源岩的真正生油气潜量，提出采用油气指数来评价烃源岩的最大生油气潜量。

Hydrocarbon generation rate and process and the geochemical characteristics of experimental products were compared between formation porosity thermocompression simulation and conventional autoclave simulation of hydrocarbon generation and expulsion. Different experimental conditions of the two methods resulted in various discrepancies of pyrolysis analysis data. At the same temperature, the oil and gas production rate of formation porosity thermocompression simulation is twice of that of the conventional autoclave simulation. Free hydrocarbon (S1), hydrocarbon generation potential (S2) and hydrogen index (IH) of solid products of the thermocompression experiment are higher than those of the autoclave experiment. In a conventional autoclave experiment, high temperature not only accelerates C-C bond cleavage to form hydrocarbon, but also generates bitumen, CO2 and H2, which deviates from the natural evolution of source rocks. The experimental conditions (higher fluid pressure, smaller hydrocarbon generation room filled with liquid water) in the formation porosity experiment are more similar to the conditions of real geological evolution. Experimental data show that gas and oil yield is much larger than hydrocarbon potential in the thermocompression experiment, and the solid products after the experiment still have a high hydrogen index. As a result, hydrogen index and hydrocarbon yield in laboratory experiments fail to estimate the real hydrocarbon potential of source rocks. Accordingly, an Oil and Gas Index (OGI) is proposed to estimate the maximum hydrocarbon potential of source rocks.

国家重点基础研究发展计划（973计划）项目（2014CB239102）和中国石化青年科技创新基金（P14132）资助。

https://doi.org/10.11781/sysydz201605665