Solid-phase-free well completion fluid as well as preparation method and application thereof

A completion fluid and solution technology, applied in chemical instruments and methods, earthwork drilling, wellbore/well components, etc., can solve problems such as oxidation-reduction reaction, acidification of formate in completion fluid, cracking and failure of tubing and casing, etc. , to achieve the effects of simple preparation method, high specific gravity of reservoir damage, and small reservoir damage

Inactive Publication Date: 2020-04-28
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Phosphate and formate completion fluids have the advantages of high specific gravity and low cost. However, at high temperatures, phosphorus in phosphate is prone to redox reactions due to its unstable valence state, which eventually induces cracking and failure of the tubing and casing.
However, during the development of ultra-high temperature, ultra-high pressure, and ultra-deep wells, the CO in the tubing 2 -H 2 S and other acidic media easily penetrate into the oil casing annulus, resulting in acidification of the completion fluid and pyrolysis of a large amount of formate, which in turn leads to corrosion and cracking of the oil casing

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] 1) 21.0g of sodium chloride and 1024.5g of sodium bromide were dissolved in 1kg of water until completely dissolved to obtain the first solution;

[0028] 2) Add 21.5g of sodium carbonate, 21.5g of sodium bicarbonate and 7.5g of modified imidazoline high-temperature corrosion inhibitor WTH-2600 to the first solution in order until they are completely dissolved respectively to obtain the second solution;

[0029] 3) 1 hour before use, add 0.15 g of sodium sulfite oxygen scavenger to the second solution until completely dissolved to obtain the well completion fluid. Take a certain volume of solution, weigh the mass, and calculate the density as 1.50g / cm 3 .

[0030] The solids-free completion fluid prepared in this example was tested at a high temperature of 210°C and 3MPa CO 2 After the acid gas penetrates into the environment and keeps for 120 hours, its density is the same as before the test, which is 1.50g / cm 3 . The corrosion rate of P110S steel by solid-free com...

Embodiment 2

[0032] 1) 42.8g of sodium chloride and 750g of sodium bromide were dissolved in 1kg of water until completely dissolved to obtain the first solution;

[0033] 2) Add 18.0g of sodium carbonate, 18.0g of sodium bicarbonate and 7.0g of modified imidazoline high-temperature corrosion inhibitor WTH-2600 to the first solution until completely dissolved to obtain a second solution;

[0034] 3) 1 hour before use, add 0.12 g of sodium sulfite oxygen scavenger to the second solution until completely dissolved to obtain the well completion fluid. Take a certain volume of solution, weigh the mass, and calculate the density as 1.41g / cm 3 .

[0035] The solids-free completion fluid prepared in this example was tested at a high temperature of 210°C and 3MPa CO 2 After the acid gas penetrates into the environment and keeps for 120 hours, its density is the same as before the test, both are 1.41g / cm 3 . The corrosion rate of P110S steel by solid-free completion fluid is 0.043mm / a. The res...

Embodiment 3

[0037] 1) Dissolve 251.0g of sodium chloride and 251.0g of sodium bromide in 1kg of water until completely dissolved to obtain the first solution;

[0038] 2) Add 15.0g of sodium carbonate, 15.0g of sodium bicarbonate and 5g of modified imidazoline high-temperature corrosion inhibitor WTH-2600 to the first solution in order until they are completely dissolved respectively to obtain the second solution;

[0039] 3) 1 hour before use, add 0.15 g of sodium sulfite oxygen scavenger to the second solution until completely dissolved to obtain the well completion fluid. Take a certain volume of solution, weigh the mass, and calculate the density as 1.30g / cm 3 .

[0040] The solids-free completion fluid prepared in this example was tested at a high temperature of 210°C and 3MPa CO 2 After the acid gas penetrates into the environment and keeps for 120 hours, its density is the same as before the test, both are 1.30g / cm 3 . The corrosion rate of P110S steel by solid-free completion ...

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Abstract

The invention provides solid-phase-free well completion fluid as well as a preparation method and application thereof. The solid-free well completion fluid comprises a weighting agent, a pH stabilizer, a corrosion inhibitor, a deoxidant and water. The well completion fluid can be applied to development of acidic (such as CO2) gas fields of ultra-high temperature, ultra-high pressure and ultra-deepwells. And in addition, the high-temperature stability, the low corrosivity, the small reservoir damage, the high specific gravity and other characteristics can still be achieved under the environment that a large amount of acid gas permeates.

Description

technical field [0001] The application provides a solid-free completion fluid, a preparation method and its application, especially the application of the solid-free completion fluid in ultra-high temperature and ultra-high pressure sour gas fields. Background technique [0002] Phosphate and formate completion fluids have the advantages of high specific gravity and low cost. However, at high temperature, the phosphorus element in phosphate is prone to oxidation and reduction reactions due to its unstable valence state, which eventually induces cracking and failure of tubing and casing. However, during the development of ultra-high temperature, ultra-high pressure, and ultra-deep wells, the CO in the tubing 2 -H 2 Acidic media such as S can easily penetrate into the annulus of the oil casing, resulting in the acidification of the completion fluid and the pyrolysis of a large amount of formate, which in turn leads to corrosion and cracking of the oil casing. Contents of th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/00C09K8/54
CPCC09K8/00C09K8/54
Inventor 李渭亮杜春朝李冬梅李双贵李林涛万小勇苏鹏黄传艳潘丽娟龙武徐燕东宋海张杰黄知娟许克亮陈东波陶杉邹宁马国锐李丹丹
Owner CHINA PETROLEUM & CHEM CORP
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