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Carbon dioxide anhydrous sand fracturing method

A carbon dioxide and sand fracturing technology, which is applied in the direction of earthwork drilling, production fluid, wellbore/well components, etc., can solve the problems of unsatisfactory stimulation effect and poor stimulation effect, and achieve good fracture shape and stability, Improve sand carrying performance, easy flowback effect

Active Publication Date: 2018-11-16
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The traditional carbon dioxide fracturing is carbon dioxide foam fracturing and carbon dioxide sand fracturing without sand, the effect of these two processes is not good, the fracture is not supported by proppant, and the stimulation effect is not ideal

Method used

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  • Carbon dioxide anhydrous sand fracturing method
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  • Carbon dioxide anhydrous sand fracturing method

Examples

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Embodiment 1

[0031] This embodiment provides a carbon dioxide anhydrous sand fracturing method, which includes the following steps:

[0032] Step 1) Select gas wells and reservoirs for carbon dioxide waterless sand fracturing: select gas wells with sand body thickness of 10-25 meters and gas layer thickness of 5-15 meters, porosity greater than 8%, permeability greater than 0.8mD, and gas-bearing Reservoirs with saturation greater than 53%;

[0033] Step 2) Fracturing joints: inject carbon dioxide prefluid and viscosity-lifting agent into the annulus of the oil jacket, and at the same time inject carbon dioxide into the tubing, so that the tubing and tubing annulus can be injected simultaneously during fracturing. The injection displacement of the liquid is greater than the injection displacement of the carbon dioxide in the tubing;

[0034] Step 3) Fill the fracture gap: inject carbon dioxide sand carrying liquid and viscosity-lifting agent into the annulus of the oil jacket;

[0035] Step 4) St...

Embodiment 2

[0039] On the basis of Example 1, this example provides a carbon dioxide anhydrous sanding fracturing method. The process of injecting carbon dioxide prefluid and viscosity raising agent into the annulus of the oil jacket in step 2) is: carbon dioxide storage The liquid tank Ⅰ3 is pressurized by the nitrogen pressurization system and connected to the carbon dioxide booster pump truck Ⅰ4 through a high-pressure hose, and then pressurized to deliver the liquid carbon dioxide to the carbon dioxide fracturing pump truck unit Ⅰ6. At the same time, the carbon dioxide viscosity booster tanker 9 The viscosity-lifting agent is injected into the high-pressure pipeline through the carbon dioxide-increasing agent injection pump truck 8, and mixed with the carbon dioxide delivered by the carbon dioxide fracturing pump truck unit I6 in the high-pressure pipeline, and injected from the fractured wellhead 7 to the oil casing annulus of the wellbore.

[0040] Step 2) The process of injecting carbo...

Embodiment 3

[0046] On the basis of Example 1, this example provides a carbon dioxide anhydrous sand fracturing method. The process of injecting carbon dioxide sand-carrying liquid and viscosity-lifting agent into the annulus of the oil jacket described in step 3) is: The carbon dioxide in the carbon dioxide storage tank I3 is pumped into the carbon dioxide booster pump I4 through the liquid nitrogen pressurization system, and the liquid carbon dioxide delivered by the carbon dioxide booster pump I4 enters the closed carbon dioxide sand mixing tank 5 and is mixed with proppant to form carbon dioxide carrying sand The liquid is then transported to the carbon dioxide fracturing pump unit Ⅰ6 through the high-pressure manifold, so that the carbon dioxide-carrying sand liquid is 3.5-4.0m 3 The construction displacement per minute and the 100-150L / min displacement of the viscosity-increasing agent delivered by the pump truck 8 are mixed in the high-pressure pipeline and then pumped into the oil pip...

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Abstract

The invention provides a carbon dioxide anhydrous sand fracturing method. The method comprises the following steps that (1) a gas well and a reservoir which are subjected to carbon dioxide anhydrous sand fracturing are selected; (2) fracturing for fracture forming is carried out, specifically, carbon dioxide is injected into an oil pipe and oil sleeve annulus at the same time, wherein the injection displacement of carbon dioxide prepad is greater than the injection displacement of carbon dioxide in the oil pipe; (3) a gap of a fracturing crack is filled, specifically, a carbon dioxide sand-carrying solution and a viscosity increasing agent are injected into the oil sleeve annulus; and (4) sand stopping and displacing are carried out. Carbon dioxide is simultaneously injected into the oil pipe and the oil sleeve annulus, and pressure balance is achieved; the viscosity increasing agent is added, so that the viscosity and the sand carrying performance of the carbon dioxide are improved, carbon dioxide anhydrous sand fracturing is realized, and the method has the characteristics of small damage to the reservoir, crack filling with a propping agent, and good crack morphology and stability. According to the method, few additives are used, so that the damage and pollution to the environment and the stratum are reduced, and the cost of fracturing fluid is greatly reduced; and carbon dioxide can adsorb and replace natural gas on rock walls, so that the yield of natural gas is improved.

Description

Technical field [0001] The invention belongs to the technical field of oil and gas field fracturing, and specifically relates to a carbon dioxide anhydrous sand adding fracturing method. Background technique [0002] Fracturing is an important way to rebuild low-permeability oil and gas reservoirs and achieve profitable development. Conventional fracturing uses water-based polymer fracturing fluid system for layered fracturing, and fracturing fluid enters the reservoir, especially low-permeability reservoirs. It will cause reservoir damage such as reservoir water sensitivity and water lock, make it difficult for fracturing fluid to flow back, and some fracturing fluid will stay in the formation for a long time, which will reduce the permeability of the reservoir matrix and reduce the effect of fracturing process transformation. [0003] Compared with water-based polymer fracturing fluids, the carbon dioxide waterless sand fracturing process can achieve "waterless fracturing", elimi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26E21B43/22
CPCE21B43/164E21B43/261
Inventor 白建文牟春国李达马得华贾建鹏郑维师兰建平苏伟东衣德强邝聃卢震代东每梁凌云何平张家富薛亚斐
Owner PETROCHINA CO LTD
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