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A method for evaluating the effect of carbon dioxide flooding salt scale precipitation on oil recovery

A carbon dioxide and recovery factor technology, applied in the fields of fluid production, earthwork drilling, design optimization/simulation, etc., can solve the problems of plugging pore throats, reducing reservoir permeability, affecting the effect of carbon dioxide flooding, etc., to achieve easy prediction. , the effect of improving the accuracy

Active Publication Date: 2022-07-05
PETROCHINA CO LTD
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Problems solved by technology

[0003] If the formation water itself contains high concentrations of calcium ions, magnesium ions and other scaling ions, along with CO 2 The concentration of carbonate and bicarbonate ions in the formation water increases, and the carbonate and bicarbonate ions react with calcium ions and magnesium ions to form calcium carbonate and magnesium carbonate solid phase deposition, which block the pore throats and reduce the reservoir permeability. , which in turn affects the oil displacement effect of carbon dioxide, but there is currently a lack of calculation methods for the impact of salt scale precipitation on oil recovery

Method used

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  • A method for evaluating the effect of carbon dioxide flooding salt scale precipitation on oil recovery
  • A method for evaluating the effect of carbon dioxide flooding salt scale precipitation on oil recovery

Examples

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Embodiment 1

[0045]This embodiment provides a method for evaluating the impact of carbon dioxide flooding salt scale precipitation on oil recovery, including the following steps:

[0046] Step 1) collecting water samples from multiple oil wells in the target reservoir formation, and analyzing and obtaining scale-forming ion species and scale-forming ion content M;

[0047] Step 2) Under different temperatures and different pressure differences, carry out the interaction reaction experiment of carbon dioxide and formation water, obtain the amount of salt scale precipitation generated by carbon dioxide and formation water, and establish the temperature T, pressure difference ΔP and scale-forming ion content M and salt Relational formula of scale precipitation amount;

[0048] Step 3) According to the relationship between the temperature T, the pressure difference ΔP, the scale-forming ion content M and the salt scale precipitation amount, obtain the salt scale precipitation amount correspond...

Embodiment 2

[0059] On the basis of Example 1, this example provides a method for evaluating the influence of carbon dioxide flooding salt scale precipitation on recovery factor. In step 2), the temperature T, the pressure difference ΔP, the scale-forming ion content M and the salt scale precipitation amount The relationship is as follows:

[0060] y=ae (bT+cΔp+dM)

[0061] In the formula, a, b, c and d are constants; T is the temperature, °C; ΔP is the pressure difference, MPa; M is the scale-forming ion content, mg / L.

[0062] In this embodiment, a calculation expression of the precipitation amount of salt scale after the action of carbon dioxide and formation water is established based on the experimental data. The amount of salt scale precipitation has an exponential relationship with temperature, pressure difference, and scale-forming ion content. By substituting four sets of data into the formula, four constant values ​​of a, b, c and d can be obtained.

Embodiment 3

[0064] On the basis of Example 1, this example provides a method for evaluating the effect of carbon dioxide flooding salt scale precipitation on recovery factor. In step 4), Eclipse software is used to establish a one-dimensional numerical model of the physical properties of the target oil reservoir and formation fluid properties The process is as follows:

[0065] The average porosity, permeability, original oil saturation, original pressure, and formation temperature of the target reservoir are input into the Eclipse software to generate a one-dimensional numerical model.

[0066] The parameters are shown in Table 3, and the one-dimensional numerical model is automatically generated after inputting the parameters with the help of Eclipse software.

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Abstract

The invention belongs to the technical field of oil and gas field development, and provides a method for evaluating the influence of carbon dioxide flooding salt scale precipitation on recovery factor. 2 On the basis of theoretical analysis and experimental research of salt scale precipitation caused by flooding, a one-dimensional numerical model was established by numerical simulation software to simulate CO 2 Displacement experiment. Using a chemical reaction model, considering CO 2 The influence of salt scale deposition on the core during flooding. The parameters are continuously adjusted in the numerical model and corrected with the experimental results of the physical model to establish the CO suitable for the research sample 2 The one-dimensional model of salt scale precipitation in the flooding process is used to analyze the influence of salt scale precipitation on the final recovery factor, so as to determine whether the influence of salt scale precipitation needs to be considered in the subsequent prediction of recovery factor, which is convenient for the prediction of recovery factor and improves the Prediction accuracy.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to a method for evaluating the influence of carbon dioxide flooding salt scale precipitation on oil recovery. Background technique [0002] in CO 2 During the displacement process, the injection of CO 2 Meets formation water in the formation, a small fraction of CO 2 Reacts with water to form carbonic acid, but most of the CO 2 in water with CO 2 Exist in molecular form, CO 2 Dissolved in formation water to generate carbonic acid. CO 2 Water dissolves much faster in water than in oil, but CO 2 The solubility in crude oil is 4-10 times that in water, so CO dissolved in water 2 Can be dissolved in oil. CO 2 Solubility in water decreases with increasing temperature and increases with increasing pressure. At the same time, the salinity of water has a significant effect on CO 2 The solubility will also be affected, the higher the salt content...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B43/16E21B49/00G06F30/20
CPCE21B43/164E21B49/00G06F30/20Y02P90/70
Inventor 上官阳南王永宏张永强熊维亮杨金龙郑自刚余光明雷欣慧
Owner PETROCHINA CO LTD
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