Polymer gel for well killing and preparing method and application of polymer gel

A technology of polymer and well killing, which is applied in drilling compositions, chemical instruments and methods, earthwork drilling and production, etc. It can solve the problems of difficult to meet formation pressure requirements, low compressive strength, and high gel cost. Achieve excellent gel breaking performance, improve compressive strength and compression performance, and good thermal stability

Active Publication Date: 2017-04-19
CHINA UNIV OF PETROLEUM (BEIJING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the prior art, the compressive strength of the polymer gel is low, and it is difficult to meet the re...

Method used

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  • Polymer gel for well killing and preparing method and application of polymer gel
  • Polymer gel for well killing and preparing method and application of polymer gel
  • Polymer gel for well killing and preparing method and application of polymer gel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Use a balance to weigh an appropriate amount of tap water and add it to the beaker. Place the beaker under the stirrer, and the bottom of the stirring rod is about 1 cm from the bottom of the beaker. Turn on the switch of the DW-3 digital display electric agitator, adjust the stirring speed to about 400r / min, make the water form a vortex, then add a certain amount of structural enhancer according to the formula, use an ultrasonic oscillator to disperse for 30min, and a high-speed stirring mixer at 600r / min stirring for 30min. Then use an analytical balance to weigh thiourea and partially hydrolyzed polyacrylamide and add them to the vortex quickly and evenly. Continue to stir until the polymer is completely dispersed (generally take 4h of stirring). Stop stirring, and pour it into a clean reagent bottle after standing for 24 hours. After the polymer base liquid is left for 24 hours, weigh a certain amount of polymer base liquid in a clean beaker, turn on the stirrin...

Embodiment 2

[0044] The preparation method is the same as that in Example 1; the difference is that in the formulation of the well killing polymer gel, the structural enhancer is sodium-based montmorillonite, and its content is respectively 1%, 3%, 5%, and 7%. Table 2 and Table 3 respectively show the compressive strength and compressive performance data of polymer gels for killing wells with different Na-montmorillonite contents.

[0045] Table 2 The compressive strength data of polymer gels with different montmorillonite contents

[0046]

[0047] As can be seen from Table 2, adding Na-montmorillonite can significantly improve the compressive strength of the polymer gel, and the compressive strength increases with the increase of montmorillonite content; when the addition of Na-montmorillonite is 7% , the compressive strength of the composite gel is the highest, up to 0.54MPa m -1 .

[0048] Table 3 The polymer gel compression test data of different montmorillonite content

[0049] ...

Embodiment 3

[0052] The preparation method is the same as that in Example 1; the difference is that in the formulation of the polymer gel for well killing, the structural enhancer is corn starch, and its content is respectively 1%, 3%, 5%, and 7%. Table 4 shows the compressive strength of well kill polymer gels with different cornstarch contents.

[0053] Table 4 Effect of cornstarch dosage on polymer gel compressive strength

[0054]

[0055] It can be seen from Table 4 that when the amount of corn starch is 5%, the compressive strength of the polymer gel is up to 0.40MPa·m -1 .

[0056] The gelation time of the polymer gel of the present invention is about 1.5 hours, and the formed gel has good thermal stability within 30 days at 70°C.

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Abstract

The invention discloses polymer gel for well killing and a preparing method and application of the polymer gel. The polymer gel for well killing is composed of partially hydrolyzed polyacrylamide, chromium acetate, thiourea, a structure reinforcing agent and water, wherein the polymer gel for well killing comprises, by mass, 1%-4% of the partially hydrolyzed polyacrylamide, 0.1%-0.4% of the chromium acetate, 0.05%-0.2% of the thiourea, 1%-7% of the structure reinforcing agent and the balance water. The structure reinforcing agent is Na-montmorillonite or corn starch or organic montmorillonite. The polymer gel for well killing is high in pressure resisting strength, has good adhesion force and a good sealing effect on a casing pipe and can be applied to under-balanced well completion of an oil deposit or a gas deposit.

Description

technical field [0001] The invention relates to the field of well drilling and completion in oil and gas fields, in particular to a polymer gel for well killing and its preparation method and application. Background technique [0002] The development of oil and gas fields requires drilling, well completion, and workover operations. Conventional well killing fluids are prone to leakage and cause great damage to the formation. In order to solve the actual problems on site, in recent years, petroleum workers have conducted research on technologies such as low-damage and anti-leakage killing fluid, gel plugging technology, snubbing operation, and underbalanced drilling and completion. The above technologies have their own advantages. shortcoming. Among them, underbalanced drilling, also known as negative pressure drilling, means that during the drilling process, the drilling fluid acts on the hydrostatic pressure at the bottom of the well, the circulating pressure drop and the ...

Claims

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Application Information

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IPC IPC(8): C09K8/03C09K8/035C09K8/40C09K8/44E21B33/12
CPCC09K8/03C09K8/035C09K8/40C09K8/424C09K8/426C09K8/44C09K8/887C09K2208/12E21B33/12
Inventor 林梅钦陈明晓孙斐斐杨子浩董朝霞
Owner CHINA UNIV OF PETROLEUM (BEIJING)
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