Method for assessing classification standard of tight reservoir pore structure based on nuclear magnetic resonance

Abstract

The invention discloses a method for assessing a classification standard of a tight reservoir pore structure based on nuclear magnetic resonance. The method comprises the following steps of 1, measuring the porosity and permeability of each rock center; 2, measuring the displacement pressure, mid-value pressure, sorting coefficient, pore throat radius and maximum mercury saturability of each rockcenter; 3, analyzing the petrologic feature of each rock center, and the pore throat combination and pore type of the rock center; 4, testing the movable fluid saturation and the movable fluid porosity parameter of each rock center; and 5, based on the abovementioned parameters, dividing the rock centers into I, II and III three types according to the good, middle and bad comprehensive assessmentof reservoirs, and building a classification assessment standard of the three kinds of reservoirs. The invention firstly provides the method for assessing the classification standard of the tight reservoir pore structure based on nuclear magnetic resonance; the reservoir types divided by the method are more accurate and scientific, and the basis is provided for subsequent exploration and development of the tight reservoirs.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field development, in particular to a method for evaluating the pore structure classification standard of tight reservoirs based on nuclear magnetic resonance technology. Background technique [0002] In recent years, with the decrease of conventional oil and gas resources, the exploration and development of unconventional energy, especially tight oil and gas, has been increased worldwide. Tight oil and gas account for a large proportion of my country's oil and gas composition, and improving the development effect of tight oil and gas reservoirs is of great significance to ensure national energy security. [0003] Tight sandstone reservoirs are characterized by small pores, small primary and secondary pores, high proportion of secondary pores, well-developed micro-fractures, and complex pore structures, which make it difficult to develop by water flooding and low recovery by water flooding. A...

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Problems solved by technology

[0003] Tight sandstone reservoirs are characterized by small pores, small primary pores and high proportion of secondary pores, developed micro-fractures, and complex pore structures, which make their waterflooding development difficult and the recovery efficiency of waterflooding is low

At present, the division of tight reservoir microscopic pore structure classification standards is usually only based on reservoir characteristics (including reservoir genesis, petrological characteristics, and sedimentary microequalities), physical properties (porosity, permeability), pore-throat combination, and pore type. However, it is not perfect to evaluate the pore structure of tight reservoirs based on the above methods and related parameters.

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