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Clean CO2/N2 foam fracturing fluid and preparation method thereof

A foam fracturing fluid and fracturing fluid technology, applied in the direction of chemical instruments and methods, drilling compositions, etc., can solve problems such as impact on fracturing and production process, difficulty in recovery of fracturing fluid, damage to formation permeability, etc. Achieve strong carrying capacity, increase viscosity, and eliminate clay swelling

Inactive Publication Date: 2018-06-15
CHINA NAT OFFSHORE OIL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current common water-based fracturing fluids have their own defects, which affect both fracturing and production processes
The main defects of these fracturing fluids are as follows: (1) After the fracturing is completed, it is difficult to recover the fracturing fluid, which leads to the stagnation of the fracturing fluid in the formation rock, which destroys the formation permeability and seriously affects the production capacity
(2) Due to the compatibility problem of conventional fracturing fluids, sensitive reactions often occur during use, causing clay expansion and migration, formation of corrosive products to corrode formations, etc., damage to production layers that damage natural permeability, and affect productivity
(3) From an economical point of view, conventional fracturing fluids need suction or air pressure equipment to discharge fluids during use, and due to the problem of fluid loss, the amount of fracturing fluids is greatly increased, which increases production costs

Method used

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  • Clean CO2/N2 foam fracturing fluid and preparation method thereof
  • Clean CO2/N2 foam fracturing fluid and preparation method thereof
  • Clean CO2/N2 foam fracturing fluid and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Embodiment 1 - the selection of blowing agent

[0030] blank example

[0031] Add 100ml of liquid carbon dioxide into the autoclave, control the temperature at 2-5°C, and maintain the pressure at 4.5-5.5Mpa; inject 300ml of nitrogen into the autoclave, start stirring at a low speed, and observe the bubbles in the autoclave Condition.

Embodiment 2

[0036] Embodiment 2 - the selection of blowing agent consumption

[0037] Pour 100ml of the solution to be tested into a transparent container with a scale, stir at a high speed (8000r / min) for 60 seconds, and record the foam volume V when the stirring is stopped. o (ml) and the time t to separate 50ml of liquid from the foam 1 / 2 (called the half-life), with V o Indicates the foaming capacity, t 1 / 2 Indicates foam stability. The generated foam volume and half-life are related to the stirring speed. Therefore, when evaluating the performance of the foaming agent, the same rotational speed should be used for comparison. Obviously, V o The larger the value, the stronger the foaming ability; the half-life (t 1 / 2 The longer the value, the slower the liquid in the foam will lose and the better the stability of the foam, which is crucial to the drainage efficiency of deep wells.

[0038] Specifically, in this example, 100ml of liquid carbon dioxide, different contents of fluoro...

Embodiment 3

[0043] Embodiment 3——influencing factors of foam stability

[0044]Add 100ml of liquid carbon dioxide, 2% fluorohexanol polyoxyethylene ether and nitrogen into the reaction kettle to prepare the fracturing fluid. After the fracturing fluid bubbles, change the temperature, pressure, or nitrogen injection amount respectively, and then measure the half-life of the fracturing fluid.

[0045] (1) Influence of temperature

[0046] The control pressure was 3.4MPa, the nitrogen injection rate was 55%, and the influence of temperature on the half-life of fracturing fluid was investigated. The test temperatures were 2°C, 5°C, 10°C, 15°C, and 20°C. The test results are shown in Table 2.

[0047] Table 2

[0048]

[0049] (2) The influence of pressure

[0050] The temperature was controlled at 2°C and the nitrogen injection rate was 55%. The influence of pressure on the half-life of the fracturing fluid was investigated. The test pressure was between 3.4-15.5MPa. The test results ar...

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Abstract

The invention discloses clean CO2 / N2 foam fracturing fluid and a preparation method thereof. The clean CO2 / N2 foam fracturing fluid is an anhydrous fracturing fluid and comprises liquid carbon dioxide, nitrogen and a foaming agent; and the preparation method comprises the following steps: mixing the liquid carbon dioxide with the foaming agent uniformly under conditions of temperature greater thanor equal to 2 DEG C and pressure greater than or equal to 3.4 MPa, and feeding nitrogen to obtain the CO2 / N2 foam fracturing fluid. The clean CO2 / N2 foam fracturing fluid provided by the applicationhas advantages of relatively high viscosity, strong carrying capacity, no damage to formation, easy recovery and simple preparation method.

Description

technical field [0001] This application relates to but not limited to the technical field of oil and gas reservoir fracturing construction, especially to but not limited to a clean CO 2 / N 2 Foam fracturing fluid and method for preparing same. Background technique [0002] Oil and gas resources are stored in the pores, caves and fractures of underground rocks, and flow in these storage spaces. If the storage space and pores of the underground reservoir are large, oil and gas are easy to seep and produce after drilling. At present, high-permeability, high-yield and high-quality oil and gas resources worldwide have entered the middle and late stages of development. A large number of oil and gas resources newly discovered and put into development are low-permeability and ultra-low-permeability reservoirs. Most of these oil and gas resources cannot be produced naturally after drilling. To produce oil and gas, we need to rely on fracturing technology to realize oil and gas pro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/70C09K8/584
CPCC09K8/584C09K8/703C09K2208/12
Inventor 竺彪张劲卢道胜薄海江肖增鹏王洪斌秦绍锋胡秋萍高源薛振乾
Owner CHINA NAT OFFSHORE OIL CORP
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