Preparation and use method of downhole intelligent plug

A kind of rubber plug, intelligent technology, applied in the field of preparation of underground intelligent rubber plug, can solve the problems of obvious degradation and damage, poor adhesion, low strength, etc., to ensure the safety of operation, prevent upward migration, and ensure the effect of wellbore

Active Publication Date: 2013-06-19
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These conventional gels have low strength, poor adhesion, and cannot automatically break the gel. In addition, the rust on the surface of the steel pipe has a significant effect on its degradation and damage, so it cannot meet the requirements of wellbore isolation

Method used

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  • Preparation and use method of downhole intelligent plug

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The preparation method of downhole intelligent rubber plug of the present invention is as follows:

[0017] 1. Synthetic rubber stopper raw materials: 30% acrylamide and 3% sodium acrylate as raw materials, in deionized water medium, use 20% sodium hydroxide solution to adjust the pH value of the solution to 10-11, and nitrogen to remove oxygen , add 0.1% ammonium persulfate, 0.1% sodium nitrite and 0.2% disodium edetate, react at 30°C for 2 hours, then add 35% soluble starch solution, heat up to 55°C and react for 3h, Cool the discharge.

[0018] 2. Prepare the rubber stopper solution: prepare the synthesized gel into a 5% solution, add 0.5% nano-silica, and stir until completely dissolved. Add 0.3% chromium acetate to the solution, and cross-link at 80°C to form a stable gel for 15 days.

[0019] The added initiator is a mixture of potassium persulfate, sodium sulfite and sodium bisulfite, and the initiation system can generate free radicals at a relatively low temp...

Embodiment 2

[0030] Trial of Downhole Smart Rubber Plug in Ya 940 Well in Yumen Oilfield:

[0031] 1. First use the reaction furnace to synthesize the raw material of rubber stopper: use 12% acrylamide and 3% sodium acrylate as raw materials, in deionized water medium, adjust the pH value of the solution to 10-11 with 15% sodium hydroxide solution, Nitrogen was used to remove oxygen, 0.2% ammonium persulfate, 0.3% sodium nitrite and 0.2% disodium edetate were added, reacted at 30°C for 5 hours, then 16% soluble starch solution was added, and the temperature was raised to 55 °C for 3h, cooled and discharged.

[0032] 2. Prepare the rubber stopper solution: prepare the synthesized gel into a 5% solution, add 0.5% nano-silica, and stir until completely dissolved. Add 0.5% chromium acetate into the solution and inject it into the wellbore at the design position at 80°C. The construction requires a gel with stable cross-linking properties for 5 days.

[0033] Well Ya 940 had obvious oil and g...

Embodiment 3

[0035] Trial of Downhole Smart Rubber Plug in Well Ke 21-2 in Tuha Oilfield:

[0036] 1. First use the reaction furnace to synthesize the raw material of the rubber stopper: use 10% acrylamide and 5% sodium acrylate as raw materials, in deionized water medium, adjust the pH value of the solution to 6-8 with 15% sodium hydroxide solution, Nitrogen was used to remove oxygen, 0.3% ammonium persulfate, 0.4% sodium nitrite and 0.2% disodium edetate were added, reacted at 30°C for 2 hours, then 10% soluble starch solution was added, and the temperature was raised to 80 ℃ reaction 2h, cooling discharge.

[0037] 2. Prepare the rubber stopper solution: prepare the synthesized gel into a 5% solution, add 0.8% nano-silica, and stir until completely dissolved. Add 0.6% chromium acetate into the solution and inject it into the wellbore at the design position at 80°C. The construction requires cross-linking to form a stable gel for 4 days.

[0038] After the downhole smart rubber plug wa...

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Abstract

The invention discloses a preparation and use method of a downhole intelligent plug. The preparation method is as below: using acrylamide and sodium acrylate as raw materials, adding an initiator sodium sulphite to synthesize a jelly, preparing a base fluid, and crosslinking with a cross-linking agent to form a stable plug capable of automatically breaking at a set time. The downhole intelligent plug provided by the invention is in a liquid shape before gelatinization, and is pumped to a preset position of the wellhole by a ground pump; after gelatinization, the rubber plug can seal the wellhole and prevent up transportation of stratum oil gas, so as to ensure wellhole operation safety; meanwhile the rubber plug can avoid entering of killing fluid into the stratum to cause reservoir damage affecting well productivity, and the rubber plug can automatically degrade after operation, thereby ensuring smoothness of the wellhole.

Description

technical field [0001] The invention relates to the preparation and use method of a downhole intelligent rubber plug, which belongs to the technical field of oil and gas well engineering. Background technique [0002] Before oil and gas wells are operated, in order to balance the formation pressure, high-density killing fluid must be used to circulate and kill the wellbore in the wellbore to ensure that the oil and gas in the formation do not enter the wellbore and avoid accidents such as well kicks and blowouts. However, under well killing conditions, the well killing fluid easily enters the formation, causing sensitive damage to the reservoir, blocking oil and gas channels, and affecting oil well productivity. In order to change this situation, snubbing operations can be used instead of killing hydraulic wells, that is, wellbore pressure is controlled through wellhead equipment, which can not only ensure the safety of wellhead operations, but also avoid the damage caused b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/42E21B33/12C08L51/02C08K3/36C08K5/17C08F251/00C08F220/56C08F220/06C08F2/44C08J3/24
Inventor 刘德基尹玉川陈超王涛吴迪李论石峰祝洪爽段志英周小淞
Owner PETROCHINA CO LTD
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