Method for Determining Lower Limit of Abundance of Dispersed Liquid Hydrocarbons in Source Rocks

Abstract

The invention provides a method for confirming the lower limit of abundance of dispersing liquid hydrocarbon in hydrocarbon source rock. The method comprises the following steps: sampling series of foundational hydrocarbon source rock samples in a to-be-measured area; determining the samples, thereby acquiring a free hydrocarbon volume S1 (determined), a pyrolysis hydrocarbon volume S2 (determined) and a hydrocarbon generating potential volume S1 (determined) + S2 (determined); correcting the S1 (determined), thereby acquiring the S1 (corrected); classifying according to the sedimentary facies, and respectively establishing a relational expression between S1 (corrected) and S1 (determined) + S2 (determined); and by utilizing the relational expressions between the S1 (corrected) and S1 (determined) as well as S1 (determined) + S2 (determined) according to an evaluation criterion for abundance of organic matters established by taking the hydrocarbon generating potential volume S1+S2 as parameters, acquiring the lower limit of abundance of dispersing liquid hydrocarbon in hydrocarbon source rock, which is established by taking the free hydrocarbon volume S1 as the parameter. The acquired result according to the method provided by the invention can be used for accurately judging whether the dispersing liquid hydrocarbon in hydrocarbon source rock can be taken as effective hydrocarbon source rock or effective gas source at any level; the criterion is supplied for evaluation; and the method has important theoretical significance in acknowledging the exploration potential of a deep old petroleum system and also has important reality in expanding the exploration discovery.

Description

technical field [0001] The invention relates to a method for determining the lower limit of the abundance of dispersed liquid hydrocarbons in source rocks, and belongs to the technical field of petroleum exploration. Background technique [0002] Liquid hydrocarbons generated by source rocks have two occurrence states in nature, one is discharged from source rocks, enriched in suitable parts of reservoirs to form accumulation-type oil reservoirs, or distributed in a dispersed state in migration channels and non-circular closed geological body; the other is dispersed in the hydrocarbon source rock body. According to the research work carried out in recent years, in the high-over-mature stage, in addition to the accumulation-type paleo-reservoirs, dispersed liquid hydrocarbons in source rocks can also generate gas on a large scale and make important contributions to the formation of natural gas reservoirs. China's marine strata deposits are thick and widely distributed, and p...

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Problems solved by technology

However, the simulation experiment generally takes a long time, and the experimental results largely depend on the precision of the instrument, the level of personnel operation, and are limited by the experimental equipment (such as the material and size of the sample chamber, etc.) and the experimental conditions such as temperature, pressure, and medium. Experiments are often different from actual geological conditions, and these factors will have adverse effects on the application of experimental results

Therefore, the above two methods not only consume manpower and material resources, but also are not conducive to the popularization and application of a large number of samples.

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