Method and device for determining radius lower limit of reservoir formation pore throat of compact sandstone reservoir

Abstract

The invention discloses a method and a device for determining a radius lower limit of reservoir formation pore throats of a compact sandstone reservoir. The method comprises the steps that: a core sample slice is placed in a working chamber of an all-environment field emission scanning electron microscope to obtain a throat which gradually becomes thin from thick; 1, 2, 3, 4 ellipsis, n, n+1 points are sequentially selected from the thick end of the throat, and energy spectrum determination is conducted point by point to the n+1 points to obtain carbon contents of all points; and if the obtained point n has carbon content, the throat radius corresponding to the point n is measured to be r<n>, if the point n+1 does not have carbon content, the throat radius corresponding to the point n+1 is measured to be r<n+1>, and an interval of the radius lower limit r corresponding the reservoir formation pore throat of the compact sandstone reservoir is more than r<n> and less than r<n+1>; the same core sample slice is measured for many times to obtain intervals of radius lower limit corresponding to a plurality of reservoir formation pore throats of the compact sandstone reservoir; and an intersection set of the obtained intervals of the radius lower limit corresponding to the throats is taken and therefore the final radius lower limit of the reservoir formation pore throats of the compact sandstone reservoir is obtained.

Description

technical field [0001] The invention relates to the testing field of petroleum exploration, in particular to a method and a device for determining the lower limit of the pore throat radius of tight sandstone reservoir accumulation. Background technique [0002] The secondary migration of crude oil in macroscopic reservoirs is shown as the migration of crude oil in pores and channels on the microscopic scale. Under the conditions of accumulation power and resistance in tight sandstone reservoirs, the minimum roar radius that crude oil can pass through is called the lower limit of the pore throat radius for reservoir accumulation. Conventional porosity lower limit calculation methods such as relative permeability method and empirical statistical method used in oilfield reserves calculation cannot represent the minimum pore throat radius that crude oil can really pass through in the process of accumulation. At present, there is no specific method for the determination of the l...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the deficiency in the prior art that the lower limit value of the reservoir-forming pore-throat radius of tight sandstone reservoirs cannot be accurately and quickly measured, and to provide a method for measuring the lower limit of the reservoir-forming pore-throat radius of tight sandstone reservoirs

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