Phase-change hydraulic fracturing technology

A hydraulic fracturing and process technology, which is applied in wellbore/well components, production fluids, chemical instruments and methods, etc., can solve the problems of shortened construction period, decreased conductivity after fracturing, and increased residue content, so as to reduce the construction period. Risks and potential safety hazards, reduced construction costs, and reduced requirements

Active Publication Date: 2016-09-28
PETROCHINA CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] (1) If the fracturing fluid is not completely broken and flowed back, it will seriously damage the conductivity of the formed artificial fractures and reduce the matrix permeability near the fractures;
[0008] (2) In the face of high-temperature deep wells, in order to maintain the sand-carrying ability of fracturing fluid at high temperature, the concentration of additives such as guar gum and cross-linking agent is increased, resulting in a further increase in residue content and frictional resistance, which further brings about fractures. Glue, flowback and other issues;
[0009] (3) For sand fracturing, in order to pursue high conductivity, high

Method used

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  • Phase-change hydraulic fracturing technology

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Effect test

Embodiment 1

[0037] Taking the ground outcrop as the experimental material, the indoor experiment simulation is carried out by using the core fracture conductivity simulation device.

[0038] First cut the outcrop into rock slabs (8cm×5cm×1.75cm) according to equipment requirements, and put the two rock slabs into the core holder. To simulate the fracturing construction process, at a temperature of 90°C, the injection pressure and confining pressure were changed to carry out the experiment on the conductivity of rock slab fractures. According to "inject fracturing fluid A agent → inject liquid M and liquid N from two acid injection tanks at the same time → inject displacement fluid to displace the phase change fracturing fluid in the pipeline into the slab → hold pressure for 60 minutes → release pressure" , to change the fracture conductivity change data of the closed pressure test. Simulate the flow conductivity of fractures supported by phase change materials in the process of phase ch...

Embodiment 2

[0045] Taking the ground outcrop as the experimental material, the indoor experiment simulation is carried out by using the core fracture conductivity simulation device.

[0046] First cut the outcrop into rock slabs (8cm×5cm×1.75cm) according to equipment requirements, and put the two rock slabs into the core holder. To simulate the fracturing construction process, at a temperature of 80°C, the injection pressure and confining pressure were changed to carry out the experiment on the conductivity of rock slab fractures. According to "Inject fracturing fluid A agent → inject liquid M and liquid N from two acid injection tanks at the same time → inject displacement fluid to displace the phase change fracturing fluid in the pipeline into the slab → hold pressure for 90 minutes → release pressure" , to change the fracture conductivity change data of the closed pressure test. Simulate the flow conductivity of fractures supported by phase change materials in the process of phase ch...

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Abstract

The invention discloses a phase-change hydraulic fracturing technology. The technology includes the steps that firstly, clean water or conventional fracturing fluid is injected to a stratum, so that the stratum cracks; secondly, non-phase-change liquid M and phase-change liquid N are placed in different liquid mixing tanks and injected into a shaft at the same time, wherein the injection volume ratio of the liquid M to the liquid N is (0-0.7):(0.3-1); thirdly, displacement fluid is injected into the shaft, so that the non-phase-change liquid M and the phase-change liquid N in the shaft completely enter a reservoir; fourthly, well shut-in and pressure building are conducted for 30-200 min, so that solid-phase matter generated by the phase-change liquid N is laid in cracks; fifthly, decompression is conducted, and construction is finished. The liquid M is conventional fracturing fluid, seawater, stratum water or ground fresh water, and the liquid N is composed of a super-molecular construction unit, surfactant, inorganic salt, oxidant and the like. Channels and ditches for underground oil gas seepage can be formed without solid supporting agents, flow guide capacity of hydraulic fracturing cracks is greatly improved, and the technology is simple, safe and efficient in construction operation.

Description

technical field [0001] The invention relates to a reservoir hydraulic fracturing stimulation technology in the oil development process, in particular to a phase change hydraulic fracturing technology. Background technique [0002] Hydraulic fracturing technology has been widely used in the development of low-permeability oil and gas fields as the main measure for oil and gas well stimulation and water well injection, and has made important contributions to the stable production of oil and gas fields. The process of hydraulic fracturing is to pump high-viscosity pre-fluid into the target reservoir to form fractures and extend them at high pressure, and then pump sand-carrying fluid mixed with proppant, which can continue to extend the fracture and carry proppant at the same time. Go deep into the fracture, and then degrade the fracturing fluid into a low-viscosity fluid and flow back to the bottom of the well, leaving a flow channel with high conductivity formed by the proppa...

Claims

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Application Information

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IPC IPC(8): E21B43/26E21B43/267C09K8/68
CPCC09K8/68C09K8/885E21B43/26E21B43/267C09K8/602C09K8/80C09K8/88C09K8/90C09K8/70C09K2208/30C09K8/604C09K8/665
Inventor 杨勇赵立强余东合杜娟刘国华罗志峰车航杜光焰裴宇昕李年银刘平礼徐昆刘丙晓
Owner PETROCHINA CO LTD
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