Method for predicting plane distribution law of effective natural fissures of oil reservoir

Abstract

The invention discloses a method for predicting the plane distribution law of the effective natural fissures of an oil reservoir and belongs to the field of natural fissure research. The method comprises the following steps: according to the conventional fissure recognition and description technologies, preliminarily determining the characteristic parameters of the natural fissures of the ultra-permeability dense oil reservoir; acquiring the preliminary distribution law of the natural fissures according to the finite element method; according to the characteristic parameters and the preliminary distribution law, building a reservoir-bed fissure geologic model; according to the sequence stratigraphy and the phase-controlled modeling technology, building a reservoir bed matrix geologic model; according to development conditions of the natural fissures in different matrixes, combining the reservoir bed fissure geologic model and the reservoir bed matrix geologic model and building a preliminary reservoir bed geologic model taking the natural fissures into consideration; on the basis of the preliminary reservoir bed geologic model taking the natural fissures into consideration, acquiring the plane distribution law of the effective natural fissures by adjusting the characteristic parameters to be fitted with production data. The method provides a reliable basis for optimizing a development technology policy.

Description

technical field [0001] The invention relates to the field of research on the distribution law of natural fractures in ultra-low-permeability tight oil reservoirs, in particular to a method for predicting the planar distribution law of effective natural fractures in ultra-low-permeability tight oil reservoirs. Background technique [0002] According to the Petroleum and Natural Gas Industry Standard of the People's Republic of China "Evaluation Method for Oil and Gas Reservoirs" (SY / T628521997) implemented in 1998, ultra-low permeability reservoirs refer to reservoirs with air measured permeability less than 1.0mD. There is no classification standard for oil reservoirs, and oil reservoirs with air permeability less than 1.0mD are usually defined as tight oil, so ultra-low permeability oil reservoirs are classified as tight oil. At present, the world petroleum industry has entered the era of equal emphasis on the development of conventional oil and tight oil resources, and the...

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Problems solved by technology

[0006] The finite element method predicts the plane distribution of fractures to fit the fracture density observed by the core, and the description of the fracture density observed by the core is carried out under ground conditions, without considering the influence of reservoir stress release on the fracture density, resulting in the fracture density predicted by this method The density distribution is too large; at the same time, due to the complex stress field distribution of the reservoir and the filling of natural fractures, there are invalid fractures under the reservoir conditions, and the invalid fractures have no practical guiding significance for the development and production of the reservoir. The existing methods The influence of ineffective fractures is not considered, so it is impossible to further understand the distribution of effective natural fractures under reservoir conditions, so that it is impossible to provide a reliable basis for optimizing and adjusting fracturing measures and development technology policies

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