Method for evaluating water containing characteristic and occurrence state of compact sandstone storage layer aperture

Abstract

The invention discloses a method for evaluating a water-containing characteristic and an occurrence state of compact sandstone storage layer apertures, comprising: converting a nuclear magnetic T2 spectrum into a false capillary pressure curve by a rock core intrusive mercury experiment and a nuclear magnetic resonance experiment; obtaining a permeability accumulation contribution value by a rock core intrusive mercury experiment, and establishing a storage layer aperture throat space validity division standard based on the permeability accumulation contribution value; and based on the aperture throat space validity division standard, and calculating a clay bound water volume, an immovable capillary bound water volume and a movable fluid volume by the false capillary pressure curve, to implement evaluation of the water-containing characteristic and the occurrence state of the compact sandstone storage layer apertures.

Description

technical field [0001] The invention belongs to the technical field of well logging engineering, in particular to an evaluation method for water-bearing characteristics and occurrence states of pores in tight sandstone reservoirs. Background technique [0002] Tight sandstone reservoirs have poor physical properties, deep burial, and low abundance. They mainly develop microscopic pores, and they are dominated by sheet-shaped pore throats. The pore-throat ratio is similar, and the water saturation is high. The water trapped in the rock pores occurs in various forms. , the Jiamin effect and the surface molecular force act strongly, and have a starting pressure gradient. As the displacement pressure rises, irreducible water may flow, and the impact of water is serious in the process of effective development with stimulation process measures. Conventional logging interpretation and traditional nuclear magnetic resonance logging interpretation methods for such reservoirs can no ...

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Problems solved by technology

As displacement pressure rises, irreducible water may flow, and the impact of water can be severe during effective development with stimulation process measures

Conventional logging interpretation and traditional nuclear magnetic resonance logging interpretation methods for such reservoirs can no longer obtain satisfactory exploration results, and new technical methods must be studied to open up new prospects

[0003] In the prior art, there are many methods for identifying reservoir fluid properties, most of which use the intersection of acoustic waves and neutrons, the intersection of acoustic waves and resistivity, the overlapping method of acoustic waves, neutrons, and density-porosity, array induction logging, and multiple methods based on conventional logging responses. Parameter artificial intelligence and other fluid property identification methods, these methods have certain limitations and adaptability to the identification of reservoir fluid properties

NMR logging uses the relaxation characteristics of pore fluids and the difference in self-diffusion coefficient to develop fluid identification techniques such as difference spectrum method and shift spectrum method. For tight sandstone gas-bearing reservoirs, the rapid self-diffusion of molecules, combined with The gradient magnetic field of the well tool greatly reduces the lateral relaxation time of the gas phase measurement, causing the relaxation time of natural gas to move to the relaxation time spectrum region of the bound fluid, which increases the difficulty of identifying gas signals in NMR logging. Resonance Logging Interpretation Encounters Difficulties in Field Application

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