Chemical-heat-generation efficient gel breaking method used in oil-gas well fracturing process

A technology for chemical heat production and oil and gas wells, applied in chemical instruments and methods, earthwork drilling and production, wellbore/well components, etc., can solve the problems of uneven gel breaking dose, strict temperature requirements, limited application range, etc., and achieve the goal of promoting The effect of oxidative chain scission of macromolecules, reduction of labor intensity, and reduction of permeability damage

Inactive Publication Date: 2018-08-07
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, with the volumetric fracturing of oil and gas wells, about 750kg of gel breaker needs to be added for each fracturing (according to the liquid volume of 6000m 3 / section), the amount of workers to carry is large, and the sand mixer has to operate the sand mixer to add sand and manually add the breaker during construction, which is labor-intensive.
Manual dosing will also lead to uneven addition of gel breaking dose, incomplete gel breaking or construction sand blockage
[0004] Chinese patent publication number: CN 105778882A, provides a low-temperature gel breaker, which is polymerized from compounds such as sodium gluconate, potassium iodide, hexamethylenetetramine, triethanolamine, etc. It can only be used for polymer fracturing fluid systems, and expensive
Chinese Patent Publication No.: CN 101781552A, which provides a bio-enzyme gel breaker and a process for using it to break water-based guar gum fracturing fluid. Using biological enzymes to break the guar gum fracturing fluid at low temperature, the effect is good. However, it has strict temperature requirements and can only be used for guar gum fracturing fluids, so its application range is limited

Method used

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  • Chemical-heat-generation efficient gel breaking method used in oil-gas well fracturing process
  • Chemical-heat-generation efficient gel breaking method used in oil-gas well fracturing process
  • Chemical-heat-generation efficient gel breaking method used in oil-gas well fracturing process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] The low-temperature gel breaking test was carried out indoors. The test temperature was 50°C. Add 0.04% ammonium persulfate to 100mL guar gum cross-linked jelly, and place it at a constant temperature of 50°C for 12 hours. The viscosity of the gel breaking solution was 24mPa·s. Add 0.04% ammonium persulfate to the same 100mL jelly, add 5g of maleic acid glycoside, and place it at a constant temperature of 50°C for 30min, and the viscosity of the gel breaking solution is 3mPa·s. Scanning electron microscopy was performed for visual analysis, the results are as follows figure 1 (without addition of thermogenic chemicals) and figure 2 (Adding maleic acid), the results show that the chemical thermogenic gel breaking is obviously more thorough, the molecules are smaller, and the damage is less.

Embodiment 2

[0042] The low-temperature gel breaking test was carried out indoors. The test temperature was 50°C. Add 0.04% ammonium persulfate to 100mL of hydrophobic association jelly, and place it at a constant temperature of 50°C for 720min. The viscosity of the gel breaking solution was 42mPa·s. Add 0.04% ammonium persulfate to the same 100mL jelly, add 5g of polyimide, and place it at a constant temperature of 50°C for 48min, and the viscosity of the gel breaking solution is 4.8mPa·s.

[0043] In order to verify the gel-breaking effect of the present invention, the application of a certain block implementation technology verification is introduced as follows:

[0044] The block is 7 layers long, and the reservoir temperature measured by the downhole pressure thermometer in the early stage is 48.6°C. Two wells (a 45-21 and a 45-23) located in the same well site in this block are undergoing volume fracturing. From August 3, 2016 to August 10, 2016, the well site carried out light casin...

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Abstract

The invention provides a chemical-heat-generation efficient gel breaking method used in an oil-gas well fracturing process and belongs to the field of oil exploitation. The method includes: in a hydrofracturing pumping process, adding a heat-generation chemical agent into a mixture of fracturing fluid and a gel breaking agent which are on the way of being pumped in; when sand adding is completed for replacement, continuing adding the heat-generation chemical agent. Temperature of gel breaking reaction between the gel breaking agent and a thickener can be increased, the fracturing fluid can bepromoted to realize efficient gel breaking, and viscous damage of the fracturing fluid can be reduced.

Description

technical field [0001] The invention belongs to the field of petroleum exploitation, in particular to a method for chemical heat generation and high-efficiency gel breaking in oil and gas well fracturing technology. Background technique [0002] Hydraulic fracturing has become more and more important as a technical measure for oil and gas stimulation. The incomplete gel breaking of fracturing fluid will increase the viscosity of the gel breaking fluid, resulting in a sharp drop in the flowback rate. The gel breaking fluid remaining in the formation will block the rock pores and sand filling fractures, causing formation damage. Therefore, it is necessary to improve the gel-breaking ability of the fracturing fluid as much as possible, increase the flowback rate and increase the oil and gas flow conductivity. [0003] Commonly used oxidative breakers are persulfates (S 2 o 8 - ), which can be thermally decomposed into highly active sulfuric acid groups and destroy the main ...

Claims

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Application Information

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IPC IPC(8): C09K8/66C09K8/68C09K8/84C09K8/86C09K8/88E21B43/24
CPCC09K8/665C09K8/68C09K8/845C09K8/86C09K8/885C09K2208/26E21B43/2405
Inventor 郭钢郑明科赵振峰李宪文薛小佳李楷吴江范华波刘锦周晓群刘怡安杰
Owner PETROCHINA CO LTD
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