Anisotropism evaluation method for oil and gas generation quantity of shale

Abstract

The invention relates to an anisotropism evaluation method for oil and gas generation quantity of shale. The method includes the following steps that firstly, different depth points on a section of the shale are densely sampled, basic parameter values are obtained through Rock-Eval pyrolysis detection, and organic matter types are determined; secondly, a conceptual model is established, and contents of organic carbon of different types are calculated; thirdly, a simulated experiment is designed, and a heavy hydrocarbon oil yield and natural gas yield evolvement model is established; fourthly, the total quantity of hydrocarbon generated and discharged by the different depth points of the shale and the quantity of heavy oil, light oil and gas generated and discharged by the different depth points of the shale are calculated, and the anisotropism of the oil bearing possibility and gas bearing possibility of the shale is evaluated. The models are established on the basis of a large number of sample data points of the section, anisotropism evaluation can be carried out on oil and gas resources of the shale, under the situation that samples are limited, the method is still suitable in combination with logging information, and therefore the method has a great significance in quantitatively representing the anisotropism of the oil bearing possibility and gas bearing possibility of the shale and accurately evaluating unconventional shale oil and gas resources.

Description

technical field [0001] The invention belongs to the technical field of oil and gas exploration and development, and in particular relates to a method for evaluating the amount of oil and gas generated by mud shale. Background technique [0002] Due to rising energy demand and increasing energy pressure, shale oil and gas, an unconventional energy source, has received more and more attention. The United States is at the forefront of the world in the exploration and development of mud shale, and is currently the only country that has successfully achieved large-scale commercial development of mud shale gas. In 1976, the U.S. Department of Energy began to pay attention to shale gas in the east, and carried out research on shale gas geology, geochemistry and Research in Petroleum Engineering (Curtis, 2002). Canada followed suit, and in recent years has also carried out shale gas exploration and experimental research, evaluating the exploration potential of Devonian, Carbonifer...

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Problems solved by technology

[0007] (1) The existing method mostly calculates the amount of hydrocarbon generation based on the current measured organic carbon content, but the current measured organic carbon content is actually the residual organic carbon content after hydrocarbon generation, and the organic carbon content predicted by well logging information is actually Residual organic carbon content; based on the fact that the generation of oil and gas is determined by the converted organic carbon, the converted organic carbon is converted into hydrocarbons and discharged to form oil and gas resources, so different forms of organic carbon (such as original organic carbon content, discharged organic carbon content, etc.) is also very important for accurate evaluation of shale oil and gas resources, and the existing methods cannot meet the new needs

[0008] (2) The existing evaluation parameters of shale hydrocarbon generation are very limited, usually based on chloroform bitumen “A”, residual hydrocarbon generation potential S1+S2, and residual organic carbon content TOC, because these parameters can be directly detected , it is not necessary to calculate

Moreover, in the existing oil and gas evaluation, heavy oil and light oil (C6-C13 light hydrocarbons) are not separated, because light oil is easy to leak during detection

[0010] (4) Existing research work on hydrocarbon generation evaluation of shale is mostly limited to geochemical testing and analysis of limited sampling points of source rocks

However, due to the serious heterogeneity of continental mud shale and the complexity of hydrocarbon generation and expulsion problems, limited sampling test points cannot objectively reflect the complex geological conditions, and it is even more difficult to effectively analyze the vertically continuous distribution of mud shale. High-resolution evaluation of shale also makes it difficult to identify thin-layer high-quality mud shale with high organic matter content and high hydrocarbon generation and expulsion efficiency in thick source rocks, which affects exploration deployment, such as which resources can be effectively exploited in the near future Which resources can be used as prospective resources to wait for technological progress to be effectively exploited, and which resources have no economic value, thus hindering the progress of oil and gas evaluation and exploration

In addition, the evaluation based on the actual measurement data of the sample has the characteristics of expensive measurement method and high cost

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