An evaluation method based on the effectiveness of shale reservoirs

Abstract

The invention discloses an evaluation method based on effectiveness of a shale reservoir. The method comprises: determining the lithofacies as a basic evaluation unit according to the characteristics of the shale oil reservoir; selecting the oil production property, the storage property, the modifiability and the flowability as evaluation contents; and further performing influence factor analysis by the system, preferably selecting organic carbon content, hydrocarbon generation potential, crack type and development strength, pore type and surface porosity, diagenetic action, relative brittleness coefficient, brittleness index and critical flow aperture as evaluation parameters, and obtaining the shale reservoir type by adopting a gray fuzzy mathematical method.

Description

technical field [0001] The invention relates to the research field of shale reservoirs, and more specifically relates to an evaluation method based on the effectiveness of shale reservoirs. Background technique [0002] At present, the research on shale reservoirs at home and abroad is developing rapidly, the research scale is refined, quantitative and three-dimensional visualization, and the research on unconventional oil and gas accumulation tends to be systematic and theoretical, but for the basis of shale Research is relatively weak. [0003] The three attributes of source, reservoir and cap of shale are integrated, and its oil generation, storage, preservation, reformability and fluidity all have an impact on shale reservoirs. Only those with good oil generation indicators and reservoir Shale reservoirs with good performance, good preservation conditions, and a certain flow capacity or flowable after artificial fracturing are effective. At home and abroad, rock mechan...

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Problems solved by technology

[0006] (2) Mud shale can be deposited in various depositional environments such as semi-deep lake-deep lake, sub-depression, prodelta or gravity flow, but the lithology is similar and lacks practical facies markers, which simplifies the study of depositional environment. It is more difficult to subdivide the sedimentary microenvironment;

[0007] (3) Mud shale has fine grain size, complex composition, and large changes in laminae thickness and continuity, which makes it difficult to classify mud shale lithofacies;

[0009] (5) There are various types of shale reservoir space, with multi-scale features, the naked eye and optical microscope are difficult to meet the observation accuracy, more micro-nano scale features need to be observed with scanning electron microscope;

[0010] (6) Favorable storage space types and occurrence states of mud shale reservoirs are uncertain, and it is difficult to judge whether they can flow or not, and there is a lack of flowability criteria;

[0011] (7) The production practice of continental mud shale reservoirs shows that not all mud shales store or produce oil, and the production varies greatly, and the characteristics of mud shale reservoirs are not deeply understood;

[0012] (8) In the process of comprehensive evaluation of shale reservoirs, there is a lack of in-depth analysis of influencing factors, resulting in unreasonable selection of evaluation units or evaluation indicators

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