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A Method for Judging Viscosity Change of Chemical System in Relative Permeability Curve

A technology of relative permeability and chemistry, applied in the field of judging the viscosity change of the chemical system in the relative permeability curve, can solve the problems such as the difficulty of judging the influence of the change of the viscosity of the chemical system and the difficulty of studying the law of seepage, and achieves the effect of simple method and convenient operation

Active Publication Date: 2022-02-15
SOUTHWEST PETROLEUM UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] However, because the chemical system is affected by shear, adsorption, retention, etc. during the formation flow process, the effective viscosity of the chemical system is not equal to the measured value of the viscometer. Polymer Viscosity Variation Apparatus and Method", using a device that simulates the real conditions of the reservoir to evaluate the polymer viscosity change, and the viscosity value of the chemical system is affected by various factors, which has caused certain problems for the study of the seepage law of the chemical system in the formation. The main difficulty lies in the difficulty of judging the influence of the change of the viscosity of the chemical system on the flow process.

Method used

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  • A Method for Judging Viscosity Change of Chemical System in Relative Permeability Curve
  • A Method for Judging Viscosity Change of Chemical System in Relative Permeability Curve
  • A Method for Judging Viscosity Change of Chemical System in Relative Permeability Curve

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Experimental program
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Effect test

Embodiment 1

[0018] Using 1750-2000 mg / L HPAM with a viscosity-average molecular weight of 25 million in a chemical system with a viscosity of 40 mPa·s, at a flow rate of 1 mL / min, the core (size 4.5 cm×4.5 cm×30 cm) saturated with crude oil with a viscosity of 70 mPa·s ) for displacement, the oil and fluid produced during the displacement process were collected at intervals of 5 minutes, and the oil content fo and outlet water saturation Sw were calculated, as shown in Table 1. Oil cut is equal to the amount of oil produced divided by the amount of liquid produced. The calculation formula of water saturation Sw is as follows: That is, water saturation Sw is equal to irreducible water saturation, plus dimensionless cumulative oil production (cumulative oil production divided by pore volume), minus dimensionless cumulative liquid production (cumulative liquid production divided by pore volume) and oil cut product.

[0019] Table 1. Calculated oil content and water saturation

[0020] ...

Embodiment 2

[0023] The JZ9-3 binary system with a viscosity of 42mPa·s was used, which was composed of HPAM with a concentration of 1750mg / L and HDS with a concentration of 2000mg / L. At a flow rate of 1 mL / min, the cores (dimensions 4.5 cm×4.5 cm×30 cm) saturated with crude oil with a viscosity of 70 mPa s were displaced, and the produced oil volume and produced fluid during the displacement process were collected at intervals of 3 min. Calculate the oil content fo and water saturation Sw at the outlet, as shown in Table 2.

[0024] Table 2 Calculated oil content and water saturation

[0025]

[0026]

[0027] Make a relationship diagram between Sw and ln((fo) / (1-fo)), such as figure 2 shown. It can be seen from the figure that the data of water saturation and oil content do not satisfy the linear relationship, which indicates that the viscosity of the binary chemical system (HPAM+HDS) has a large change during the core seepage process. Viscosity changes need to be considered du...

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Abstract

The invention discloses a method for judging the viscosity change of a chemical system in a relative permeability curve. The steps are as follows: S1. Carry out an oil displacement experiment in a rock core by using a chemical system, collect output fluid at regular intervals, and calculate the oil content of the output fluid rate fo 1 , fo 2 ,..., fo n ; S2. Calculate outlet water saturation Sw according to oil production and irreducible water saturation 1 ,Sw 2 ,···,Sw n ; S3, take the water saturation Sw as the abscissa, and ln ((fo) / (1-fo)) as the ordinate to make a relationship curve; S4, to fit the linear relationship to the relationship curve, if the linear correlation coefficient is greater than 0.98, calculate the relative The constant value calculation is used for the permeability curve; if the linear correlation coefficient is less than 0.98, the influence of the viscosity change of the chemical system needs to be considered in the process of calculating the relative permeability curve. The method provided by the invention provides a reference basis for viscosity value processing for the calculation process of the relative permeability curve of the chemical system, and improves the measurement efficiency of the relative permeability curve of the chemical system.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to a method for judging the viscosity change of a chemical system in a relative permeability curve. Background technique [0002] The relative permeability curve is an important reservoir data in the field of oil and gas field development. For the measurement and research of relative permeability curves, in most cases, the laboratory unsteady method measurement experiment is carried out based on the national standard GB / T 28912-2012 "Measurement method of relative permeability of two-phase fluid in rock". Chemical system flooding is a widely used method of tertiary oil recovery, and the study of its relative permeability curve plays an important role in understanding the seepage law of chemical systems in formations and making efficient use of them. [0003] However, because the chemical system is affected by shear, adsorption, retention, etc. during the forma...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B49/00E21B47/00G01N11/00
CPCE21B49/00E21B47/00G01N11/00
Inventor 施雷庭赵启明汪士凯张恒王晓叶仲斌朱珊珊
Owner SOUTHWEST PETROLEUM UNIV