Gel type annulus protection liquid and preparation method thereof

An annulus protection liquid and gel-type technology, applied in chemical instruments and methods, earthwork drilling and production, special treatment targets, etc., can solve the problems of freshwater layer pollution, long-term safety and environmental protection restrictions on oil fields, and large hidden dangers

Pending Publication Date: 2020-07-07
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Changqing Oilfield has a large number of water injection wells and sewage reinjection wells, and the sewage is highly corrosive. It is located in an ecologically fragile area. Once the oil casing of the water injection well is corroded and damaged, it will cause the following problems: 1. Pollution of surface water and major environmental pollution safety issues , directly affect oilfield environmental governance and safe production; 2. cause invalid water injection, casing damage directly affects oilfield development benefits, and become a prominent hidden danger that restricts long-term oilfield safety and environmental protection
[0003] Especially for sewage reinjection reinjection wells, the oil casing annulus is a relatively immobile dead water area, which is more likely to form bacteria multiplication, corrosion gas accumulation, etc., which will accelerate the corrosion and perforation of the casing, and the channeling sewage after the casing is broken will be Pollution to the freshwater layer, affecting the water quality of drinking water sources, causing shortage of drinking water resources in some areas
At the same time, the dangers caused by it are increasing
At present, the method of filling the annulus with protection fluid is used to protect the oil casing, but in the field application process, it is found that the leakage of the annulus protection fluid is serious due to the failure of the packer or casing damage, and the expected effect is often not achieved

Method used

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  • Gel type annulus protection liquid and preparation method thereof
  • Gel type annulus protection liquid and preparation method thereof
  • Gel type annulus protection liquid and preparation method thereof

Examples

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Effect test

preparation example Construction

[0035] The present invention provides a preparation method of a gel-type annular space protection solution as follows: (Taking Qingshui Well as an example):

[0036] (1) According to the requirements of well conditions on site, according to the weight ratio of the above-mentioned clear water well protection fluid, first add 0.5 to 1 part of oxygen scavenger to the liquid mixing tank, and then add 1 to 5 parts of corrosion inhibitor and 1 to 3 parts of corrosion inhibitor in the state of constant stirring. 1 part of scale inhibitor, 0.5-3 parts of bactericide, 1-5 parts of salt-resistant polymer, 0.5-2.5 parts of cross-linking agent, and the balance is water. Stir continuously for 30-45 minutes to form a gel-type annular space protection solution .

[0037] (2) The annulus protection fluid prepared in step (1) is circulated into the annulus through the tubing and casing. Under the temperature and pressure of the wellbore, the corrosion inhibitor in the protection fluid is adsor...

Embodiment 1

[0040] Embodiment 1 (indoor test of L1-pull clear water well)

[0041] This embodiment provides a gel-type annulus protection solution for injecting clear water wells, the composition of which is as follows: 3 parts of corrosion inhibitor, 1 part of scale inhibitor, 2 parts of fungicide, and oxygen scavenger : 0.7 parts, hydrophobic association and polymer: 3 parts, 1.5 parts of crosslinking agent, and the rest of water.

[0042] Indoor liquid preparation method: first add 0.7 parts of oxygen scavenger in a large beaker, and then add 3 parts of corrosion inhibitor, 1 part of scale inhibitor, 2 parts of bactericide, 3 parts of hydrophobe and polymer in sequence under constant stirring, 1.5 parts of the joint agent, the balance is water, and stir evenly for 45 minutes to form a gel-type annular space protection solution.

[0043] The indoor electrochemical evaluation experiment shows that the corrosion rate of the blank L1-la clear water is 0.722mm / a, and the corrosion rate aft...

Embodiment 2

[0054] Embodiment 2 (L1- pull clear water well field test)

[0055] This embodiment provides a gel-type annulus protection solution for injecting clear water wells, the composition of which is as follows: 3 parts of corrosion inhibitor, 1 part of scale inhibitor, 2 parts of fungicide, and oxygen scavenger : 0.7 parts, hydrophobic association and polymer: 3 parts, 1.5 parts of crosslinking agent, and the rest of water. (The components of the ring protection solution are shown in Table 1).

[0056] On-site liquid preparation method: first add 0.7 parts of oxygen scavenger to the 10L liquid preparation tank, then add 3 parts of corrosion inhibitor, 1 part of scale inhibitor, 2 parts of bactericide, 3 parts of hydrophobic olefin and polymer in sequence under constant stirring, 1.5 parts of cross-linking agent, the balance is water, and stir evenly for 30 minutes to form a gel-type annular space protection solution.

[0057] In August 2018, the annular protection fluid test was c...

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Abstract

The invention provides a gel type annulus protection liquid and a preparation method thereof. The gel type annulus protection liquid is composed of a corrosion inhibitor, an organic phosphonic acid scale inhibitor, a non-oxidizing bactericide, a deoxidant, a hydrophobic association polymer, a cross-linking agent and the like, can be injected into a system at a time according to field requirements,and can also be injected into the system in a slug mode according to concentration decreasing, and the effect of effectively preventing leakage of protection liquid caused by failure of a packer is achieved. In addition, due to the association effect, the hydrophobic association polymer in the system can form an intermolecular association space network structure, gel formed after further crosslinking between molecules has a certain drainage function and can play a certain role in plugging casing breaking formation water immersed into an annulus, and the action period of the annulus protectionliquid is prolonged. The system is simple in on-site injection process, obvious in application effect and free of pollution to the environment.

Description

technical field [0001] The invention provides a gel-type annulus protection fluid, which belongs to the field of oilfield chemistry, and in particular relates to a gel-type annulus protection fluid for water injection wells and sewage wells and a preparation method thereof. Background technique [0002] Changqing Oilfield has a large number of water injection wells and sewage reinjection wells, and the sewage is highly corrosive. It is located in an ecologically fragile area. Once the oil casing of the water injection well is corroded and damaged, it will cause the following problems: 1. Pollution of surface water and major environmental pollution safety issues , directly affect oilfield environmental governance and safe production; secondly, cause invalid water injection, and casing damage directly affects oilfield development benefits, and has become a prominent hidden danger that restricts long-term safety and environmental protection of oilfields. [0003] Especially for...

Claims

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Application Information

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IPC IPC(8): C09K8/54C09K8/52C09K8/44C02F5/08C02F103/10
CPCC09K8/54C09K8/52C09K8/426C09K8/44C02F5/08C02F2303/22C02F2303/08C02F1/50C02F1/20C02F2103/10C09K2208/32Y02P20/141
Inventor 刘宁李琼玮戚建晶王小勇苑慧莹董俊周佩姜毅刘爱华程碧海
Owner PETROCHINA CO LTD
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