Method and device for determining saturation exponent of tight sandstone

Abstract

The invention discloses a method and a device for determining saturation exponent of tight sandstone. The method comprises: according to nuclear magnetic resonance transverse relaxation time T2 spectrum of a core in a water saturation state and nuclear magnetic resonance transverse relaxation time T2 spectrum of cores in different water saturation states after different centrifugal forces are applied, determining geometric mean value of the nuclear magnetic resonance transverse relaxation time T2, the geometric mean value of the nuclear magnetic resonance transverse relaxation time T2 of the cores in different water saturation states after different centrifugal forces are applied on the cores, and water saturation of the cores after different centrifugal forces are applied; and according to the geometric mean value of the nuclear magnetic resonance transverse relaxation time T2 of the core in a water saturation state, and the geometric mean value of the nuclear magnetic resonance transverse relaxation time T2 of the cores in different water saturation states after different centrifugal forces are applied, and the water saturation of the cores after different centrifugal forces are applied, determining saturation exponent of the cores. The method and the device can accurately and efficiently determine the saturation exponent of tight sandstones.

Description

technical field [0001] The invention relates to the technical field of well logging in petroleum geological exploration, in particular to a method and a device for determining the tight sandstone saturation index. Background technique [0002] In well logging interpretation, the comprehensive analysis of oil, gas and water in the reservoir is usually performed on the basis of Archie's formula. Reasonable selection of interpretation parameters is the core content of the work. Archie's formula contains four important parameters a, b, m, and n. Usually, a and b are very close to 1, so they generally default to 1. Both m and n have their own physical meanings. m is called the pore structure index, which depends on the pore structure of the formation; n is called the saturation index, which mainly reflects the impact of the distribution of oil, gas and water in the rock pores on the rock resistance. The influence of saturation rate, and the distribution of oil, gas, and water in...

AI Technical Summary

Problems solved by technology

However, the porosity and permeability of tight cores will be much lower than those of conventional cores, and rock properties and pore structures will affect the resistivity. In the core resistivity experiment, it is important to use oil or gas to displace water in the core. Very difficult, and the experiment period is very long

Images