Evaluation of source rocks and prediction of excellent source rock distribution

Carrying out a study of the elemental geochemistry of source rocks, organic matter abundance, type, maturity, biological sources, and depositional environment of source rocks are analyzed, comprehensively evaluating the hydrocarbon generation potential and development model of source rocks; establishing an effective division method of source rocks, the geochemical characteristics of source rocks and the main controlling factors of their formation are determined, characterizing the hydrocarbon generation evolution law of source rocks, and establishing the hydrocarbon generation model of source rocks. Evaluation of source rock is an essential content and a necessary standard to measure the level of researchers.

Mixed source analysis of complex oil and gas and determination of the main source rocks

Hydrocarbon source correlation refers to establishing the genetic relationship between oil, gas and source rock based on comprehensive geological and geochemical data. Its essence is to use the basic principle of organic geochemistry and reasonably select correlation parameters (indicators) to study the relationship between oil, natural gas and source rock. The fundamental basis is that kerogen and soluble extract bitumen in source rock are related to the oil and gas from that strata, so in some ways, they must have similarities in chemical composition; on the contrary, oil and gas that are not in the same relationship will show significant differences. Oil-source correlation includes the correlation between oil (gas) and source rock and between oil and gas in different reservoirs. The genetic relationship between petroleum, natural gas and source rock in petroliferous basins can be clarified through comparative study.

Hydrocarbon generation kinetics and evaluation of oil and gas resources

The method of hydrocarbon generation kinetics is proposed by Tissot according to the principle that the thermal degradation process of kerogen conforms to the first-order reaction law of chemical kinetics. It introduces the factors of time and temperature into the thermal degradation process of kerogen. Based on thermal simulation data such as the activation energy of each kerogen bonding substance, the potential hydrocarbon generation capacity and the frequency factor of various kerogen corresponding to each activation energy, the change of kerogen concentration was simulated to calculate the hydrocarbon generation rate history. Finally, the hydrocarbon generation history of the source rock was calculated by the volume formula method. The amount of resource in the study area can be calculated using the results of simulation experiment and related software. The research team of the company has calculated and evaluated the resources in Hailar Basin, Bohai Bay Basin and other areas.

Natural gas geochemistry and comprehensive identification system of accumulation

With the expansion of natural gas exploration to deep — ultra-deep and unconventional areas, and the increasing difficulty of exploration, multiple types of complex gas reservoirs such as crude oil cracking gas (including pyrolysis gas generated by the concentrated and dispersed liquid hydrocarbon) and gas reservoirs with high nitrogen content and high carbon dioxide content, the existing natural gas genetic identification methods have been unable to solve the critial technical problems such as degradation gas generated by sapropelic type organic kerogen and crude oil pyrolysis gas, pyrolysis gas generated by the concentrated and dispersed liquid hydrocarbon, organic and inorganic genetic gas identification of high evolution, multiple natural gas genesis and sources. Therefore, it is necessary to conduct a comprehensive identification analysis on the geochemical indexes of natural gas to study the geochemical characteristics, origin, source, and main controlling factors of accumulation and exploration potential of natural gas. In recent years, the team has conducted comprehensive analysis and research on natural gas in Tarim Basin, Xihu sag and Lishui sag of East China Sea Basin, Qiongdongnan Basin and other areas, and established different types of hydrocarbon generation and accumulation models.

Study of accumulation geochemistry

Accumulation geochemistry is a new branch of geochemistry. It mainly adopts modern geochemical analysis and testing technology to explore reservoir fluid’s the heterogeneous distribution law and formation mechanism, and explores the history of oil and gas charging and accumulation and the mechanism of locating accumulation. The mixing effect of reservoir fluid in transverse diffusion is slow. The homogenization time of the heterogeneity of the inherited oil column is about 100Ma and often indicates the direction of regional oil charging.