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A chemical agent-assisted CO2 huff and puff method to improve the recovery of ordinary heavy oil reservoirs

A technology for heavy oil reservoirs and chemical agents, which is applied in the fields of fluid production, earth-moving drilling, wellbore/well components, etc. It can solve the problems of periodic oil production, decrease in oil-gas ratio, large difference in oil-gas flow rate, and small sweep volume, etc. problems, to achieve the effect of reducing the flow resistance of crude oil, reducing the viscosity of crude oil, and reducing the flow resistance of heavy oil

Active Publication Date: 2019-05-28
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, ordinary heavy oil wells carry out multiple rounds of CO 2 After the huff and puff, due to the large difference in oil and gas velocity, the CO 2 The gas channeling is serious, the affected volume is small, and the periodic oil production and oil-gas ratio will decrease with the increase of throughput rounds

Method used

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  • A chemical agent-assisted CO2 huff and puff method to improve the recovery of ordinary heavy oil reservoirs
  • A chemical agent-assisted CO2 huff and puff method to improve the recovery of ordinary heavy oil reservoirs

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] A chemical agent assists CO 2 The method of huff and puff to improve the recovery of ordinary heavy oil reservoirs, the process is as follows figure 1 As shown, the high pressure CO is passed through the pressure pipeline 2 The outlet of the storage tank 1 is connected to the ground injection device 2, and the ground injection device 2 and the injection well 3 are connected through a pipeline. The foaming agent aqueous solution storage tank 4 is connected to the ground injection device 2 through a pipeline, and the ground injection device 2 and the injection well are connected through a pipeline. 3.

[0034] The specific steps are as follows:

[0035] (1) Foaming agent solution slug injection process: Di-(2-ethylhexyl)-sodium sulfosuccinate foaming agent is formulated into foaming agent aqueous solution, injected into the formation from the wellbore, the mass concentration of foaming agent aqueous solution is 0.5%, the volume injected into the foaming agent aqueous s...

Embodiment 2

[0041] A chemical agent assists CO 2 The method for improving the recovery factor of ordinary heavy oil reservoirs by huffing and puffing includes the following steps:

[0042] (1) The slug injection process of the viscosity reducer solution: the alkyl sulfonate viscosity reducer is prepared into a viscosity reducer aqueous solution, which is injected into the formation from the wellbore. The mass concentration of the viscosity reducer aqueous solution is 1.0%, and the viscosity reducer aqueous solution is injected has a volume of 12m 3 ;

[0043] (2) High pressure CO 2 Slug injection process: the CO 2 The slug is pressurized by ground pressurization equipment, injected into the reservoir from the wellbore, and CO 2 The volume ratio of the volume of the injected chemical agent aqueous solution is 1:1;

[0044] (3) Stew well diffusion: CO 2 After injection into the oil layer, the well was shut down and blotted for 10 days, and the pressure changes during the brine process...

Embodiment 3

[0048] Simulated chemical agent assisted CO 2 The experimental equipment for huff and puff exploitation of ordinary heavy oil reservoirs is mainly composed of double-plunger metering pumps for liquid displacement, double-plunger metering pumps for gas displacement, pressure transmitters, balances, sand filling pipes, temperature and pressure control and recording systems, etc. Composition, the experiment was carried out under constant temperature and pressure to simulate the reservoir environment.

[0049] The specific steps are:

[0050] (1) Fill a rock core with a certain permeability using a sand filling pipe, weigh the dry weight, vacuumize, saturate with water, weigh the wet weight, calculate the porosity, and measure the water phase permeability of the rock core;

[0051] (2) Adjust the core to a formation temperature of 60°C and a formation pressure;

[0052] (3) Saturate the oil at a speed of 0.5ml / min until the output liquid at the outlet end is free of water, close...

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Abstract

The invention relates to a method for improving the recovery rate of ordinary heavy oil reservoirs with the assistance of chemical agent CO2 huff and puff. The method combines chemical agent with CO2 huff and puff, and first injects viscosity reducers into oil wells that have undergone multiple rounds of CO2 huff and puff. A slug of chemical agent or foaming agent chemical agent solution, and then a slug of high-pressure CO2 is injected into the well, and the well is stewed after the injection is completed. When the well is soaked, the viscosity reducer chemical agent and ordinary heavy oil form an oil-in-water emulsion, which can greatly reduce the oil-water interfacial tension and reduce the flow resistance of crude oil during production. The addition of foaming agent chemical agents can control CO2 gas phase mobility, effectively prevent CO2 gas channeling, make CO2 diffuse deep into the formation, and increase CO2 gas sweep volume. The synergistic effect of the chemical agent and CO2 enables the oil well to maintain a high oil production after multiple rounds of huff and puff.

Description

technical field [0001] The invention relates to a chemical agent assisting CO 2 The invention relates to a method for improving the recovery factor of ordinary heavy oil reservoirs by huffing and puffing, which belongs to the technical field of oil and gas field development engineering. Background technique [0002] With the increasing development of the global economy, the world's demand for oil is growing rapidly. After the large-scale development of conventional oil resources in the last century, heavy oil resources have attracted the attention of the world with their rich reserves. Therefore, heavy oil Tibet's development technology has also attracted much attention. Heavy oil is also called heavy crude oil or high-viscosity crude oil. It is classified according to viscosity. The degassed crude oil with a viscosity higher than 100mPa.s at the oil layer temperature is called heavy oil. According to relevant reports, my country's heavy oil reserves rank seventh in the wo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B43/22E21B43/16
CPCE21B43/16E21B43/164
Inventor 李松岩李兆敏张启亮吴明轩李宾飞
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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