Method for slowing dissolving speed of non-crosslinked gel in blockage-adjusting agent for oil field

A dissolution rate, non-crosslinking technology, applied in the field of oil and gas field chemistry, can solve problems affecting pump injection construction, pump blockage, etc., and achieve the effect of improving swelling and sticking time

Inactive Publication Date: 2019-02-22
CHINA NAT OFFSHORE OIL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the above-mentioned non-crosslinked gel of plugging agent for oil field. During the preparation process on site, the viscosity of the high-strength non-crosslinked gel is too fast in the dissolving process, and the viscosity will decrease in a few minutes. A large increase will easily cause pump blockage and affect the technical defects of pump injection construction. It provides a method to delay the dissolution rate of non-crosslinked gel in plugging agent used in oil fields

Method used

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  • Method for slowing dissolving speed of non-crosslinked gel in blockage-adjusting agent for oil field

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] (1) The non-cross-linked gel was added into clear water to prepare a non-cross-linked gel solution with a concentration of 3% by mass, and the swelling and viscous time and viscosity of the solution were measured.

[0031] (2) Sodium chloride is dissolved in clear water to prepare saline solutions with mass percent concentrations of 0.5%, 1%, 1.5%, 2%, 5%, and 10%, respectively, and then add non- The cross-linked gel was prepared into a non-cross-linked gel solution with a concentration of 3% by mass, and the swelling and viscous time and viscosity value of the solution were measured.

[0032] (3) Sodium chloride and calcium chloride are dissolved in clear water at a mass ratio of 9:1, and the total mass percentage concentrations of sodium chloride and calcium chloride are respectively made into 0.5%, 1%, 2%, 5%, 10% salt solution, and then add non-crosslinked gel to each concentration of salt solution to prepare a non-crosslinked gel solution with a mass percent concen...

Embodiment 2

[0040] Wells 40-6-3 and 38-9 in an oilfield belong to typical complex fault-block reservoirs, with many faults, casing leakage, casing damage, casing deformation, and casing damage. Water accidents cause pollution of wetlands, farmland, villages and farms. High formation pressure caused by high injection-production ratio, coupled with the fact that old wells have been abandoned for a long time, the original wellhead cannot be found after the surface is restored, casing damage and leakage, pipe leakage, fault blocks and many other factors are potential factors, making this type of accident There are many difficulties in the processing measures. The use of various plugging agents to control the problem of ground water channeling has ended in failure, such as: cement plugging (near wellbore plugging), chemical cross-linked gel plugging (formation gelation performance and uncontrollable plugging position), Walnut shell rubber powder inorganic material plugging (plugging near the ...

Embodiment 3

[0044] Environmental protection treatment of a certain oilfield: due to poor early cementing quality, insufficient cement return height, poor casing material, and development time of more than 40 years in a certain oilfield, there are many casing corrosion, perforation and fractures, and the formation crude oil has a high gas content pressure coefficient High and high pressure fluids enter the leakage point through the cement annulus, and then enter the under-compacted formation on the surface, causing ground leakage and affecting environmental protection. It is recommended to seal the underground leakage point in the well area to ensure the normal opening of the oil field and environmental protection .

[0045] The construction process is as follows: starting the production string, drilling the well, washing the well, lowering the construction string, pressure testing, construction equipment entering the site, construction materials entering the site, and construction starting...

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Abstract

The invention discloses a method for slowing the dissolving speed of non-crosslinked gel in a blockage-adjusting agent for an oil field. The blockage-adjusting agent is aqueous solutionon-crosslinkedgel solution prepared by adding the non-crosslinked gel into water on a construction site; in the preparation process, the non-crosslinked gel is added into aqueous solution containing soluble inorganic-salt additive to prepare the blockage-adjusting agent; the blockage-adjusting agent is prepared by the following specific steps: (S1) on the construction site, dissolving the soluble inorganic-saltadditive into clean water in advance to obtain salt solution; (S2) dissolving the non-crosslinked gel in the salt solution to obtain the blockage-adjusting agent. The inorganic-salt additive is sodium chloride or calcium chloride or a mixture of the sodium chloride and the calcium chloride. The method for slowing the dissolving speed of the non-crosslinked gel, disclosed by the invention, has thebeneficial effects that the problem that the sticky and rod-climbing phenomenon is serious due to excessively-fast dissolving speed of high-strength non-crosslinked gel and causes difficulty in pumping injection and failure in pumping injection when the non-crosslinked gel is injected into the stratum can be solved and technical support can be provided for operability of on-site construction.

Description

technical field [0001] The invention relates to the technical field of oil and gas field chemistry, in particular to a method for delaying the dissolution rate of non-crosslinked gel in plugging modifiers used in oil fields. Background technique [0002] my country began to study and apply profile control and water shutoff technology in the 1950s. During the "Eighth Five-Year Plan" period, my country's profile control and water shutoff technology has become a conventional production stimulation technology in oilfields. At the same time, most oilfields in my country have entered the late stage of water injection development, and the deep profile control technology of water injection wells and oil well water plugging technology are necessary measures to stabilize production and ensure production in the late stage of water injection development of oilfields, which have good economic benefits. [0003] Most of my country's onshore oilfields are developed by water injection. Spik...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/508
CPCC09K8/5045C09K8/5083
Inventor 张健康晓东郭拥军胡科王姗姗陈文娟华朝李丽霞赵文森冯茹森王捷张新民周明源
Owner CHINA NAT OFFSHORE OIL CORP
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