Ultra-low permeability tight reservoir fracture-pore type core preparation and saturated oil experiment method

Abstract

The invention relates to an ultra-low permeability tight reservoir fracture-pore type core preparation and saturated oil experiment method which sequentially comprises the following steps: (1) selecting a proper ultra-low permeability tight reservoir core, and performing axial and circumferential treatment; (2) cleaning and drying the rock core; (3) placing the rock core in a middle holder for vacuumizing and saturation; (4) wrapping the saturated rock core by using tetrafluoroethylene heated by a high-temperature drying gun, and forming a crack by using crack forming equipment; (5) the finally obtained rock core is saturated again through the rock core holder, and the liquid phase permeability of the rock core is obtained; and (6) obtaining the matrix saturation and the oil saturation according to the provided calculation formula. According to the method, the difficulty that the core matrix part of the fractured ultra-low permeability tight reservoir core cannot obtain sufficient saturated oil after fracture forming is solved, and a more accurate oil saturation mode and an oil saturation calculation formula of the method are provided for oil field development of fractured glutenite.

Description

technical field [0001] The invention belongs to the field of oil and gas field development, and in particular relates to an ultra-low permeability tight reservoir fracture-pore core preparation and saturated oil experimental method. Background technique [0002] Core fractures and saturated oil are one of the important links in the current petroleum development and research laboratory to simulate reservoir displacement experiments. Conventional oilfields have dual media of fractures and pores. It contains a medium characteristic, so it is necessary to carry out a certain treatment of the matrix core to achieve the dual medium characteristics of fractures and pores, so that the treated core has the formation characteristics of simulating oilfield development. Conventional fractured core preparation is divided into mixture preparation and fractured matrix cores with fracture-making tools, through which the cores can reach the target permeability; conventional saturated oil is ...

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Problems solved by technology

In order to better simulate the actual environment of the reservoir, it is necessary to use fracture-making tools to fracture the matrix core. At the same time, it is necessary to fully saturate the oil into the core matrix in the saturation stage. Due to the fragile texture of the ultra-low permeability tight reservoir core, It is difficult to control the fracturing of low-permeability tight reservoir cores and to achieve full oil saturation after fracturing. It is necessary to find a method that can control the fracturing of ultra-low-permeability tight reservoir cores and fully saturate oil.

[0003] The invention patent "a core saturated oil method and device" (CN202010702028.5) mainly provides a core saturated oil method, which does not take into account the influence of fractures on saturation during the core saturation process; the invention patent "a Glutenite tight core saturated oil device and method” (CN201910906032.0), the method of providing saturated oil only considers the saturation of ultra-low permeability core, and does not consider whether the saturated oil can continue to be used after the matrix core is made Way

The saturation methods selected by the above inventions are displacement saturation and intermediate container saturation, but they have not considered whether the saturation method is applicable after the construction, whether it can effectively saturate the ultra-low permeability core matrix under the influence of fractures, and After the investigation, no effective saturation method for ultra-low permeability cores after fracture creation has been found, and it cannot solve the problem of partial saturation of ultra-low permeability core matrix with fractures. The saturation preparation problem of ultra-low permeability core

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