Device for estimating damage of working fluid to reservoir permeability

Abstract

The invention relates to a device for estimating damage of a working fluid to reservoir permeability. One end of each of a two-axis core holder and a three-axis core holder is separated into two parts; the first parts are sequentially connected with a middle container A, and a pump body; the second parts are sequentially connected with a by-pass valve, a downstream stop valve, a back-pressure device, and a gauge; the other end of each of the two-axis core holder and the three-axis core holder is connected with a supercharger and an ambient pressure valve; each core holder comprises a two-end device and a seal device; the two-end device comprises a choke plug with a central hole and a pressure sensor at one end, and a choke plug with a central hole, a pressure sensor and a contaminating liquid interface at the other end; the seal device comprises a heating system, a pressure sensor, and a temperature sensor; the working fluid contaminating system comprises a middle container B which is connected with a contaminating pump and a vacuum pump; the middle container B is connected with connecting pipes in the two-axis core holder and the three-axis core holder through the contaminating liquid interface; the device simulates underground conditions of different temperatures, pressures and vacuum degrees, so as to provide an estimation method for damage of working fluid of the reservoir with different permeability on the reservoir permeability.

Description

technical field [0001] The invention relates to a device for evaluating the permeability damage of well fluid to reservoir formation. Background technique [0002] Porous media is one of the most important characteristics of rocks. There are holes and cracks inside, that is, pores, which are filled with fluids such as water, oil, and gas. Permeability is a key physical parameter describing the transport ability of water, oil and gas in rock pores. For oil and gas production, permeability is one of the important indicators for the evaluation and prediction of oil and gas reservoirs. At the same time, due to the invasion of well fluid and various physical and chemical reactions with reservoir rocks or fluids, the permeability of the reservoir is damaged, resulting in damage to the reservoir. The misjudgment of permeability affects the evaluation of oil and gas reservoirs; the damage to permeability after well fluid entering the well is also an important method for the researc...

AI Technical Summary

Problems solved by technology

It is difficult to use the same method to evaluate rocks with a wide range of permeability changes. At the same time, different types of rocks have different degrees of physical and chemical reactions after contact with well fluids. Sometimes the permeability changes exceed the boundary conditions of a certain test method, which limits Study on Protecting Reservoir Drilling Fluid

[0004] At present, the permeability test methods are divided into steady-state method and unsteady-state method. The accuracy of the test data of the non-steady-state method needs to be further explored because the test method does not or does not completely pass through the core.

The existing conventional Darcy's law core permeability tester is only suitable for permeability higher than 0.5×10 -3 μm 2 Core test, unable to test low permeability, ultra-low permeability core

The low permeability and ultra-low permeability test methods used in the petroleum field are mainly to increase the pressure of the conventional Darcy's law permeability test (even if the pressure is increased, it is often difficult to obtain results), pressure drop method, pulse method, nuclear magnetic resonance method, etc. Unsteady state method is difficult to accurately describe the real permeability properties

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