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Removing method for gas recovery well shaft aquo-complex blockage

A technology of hydrates and hydrate inhibitors, applied in wellbore/well components, drilling compositions, chemical instruments and methods, etc., can solve the problems of slow unblocking speed, large heat loss, large amount of hot water sources and storage Space and other issues

Active Publication Date: 2015-08-05
SOUTHWEST PETROLEUM UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method is slow in unblocking, especially when the clogging position is located in the upper part of the wellbore. Due to the low surrounding temperature, some unblocking takes as long as several days or is difficult to unblock.
Coiled tubing operation pump hot water circulation operation is an effective method to relieve hydrate blockage. The operation requires the use of coiled tubing operation vehicles, a large amount of hot water source and storage space, and the preparation period for on-site operations is long and expensive. When water is transported by coiled tubing, the heat loss is large and the thermal efficiency is low

Method used

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  • Removing method for gas recovery well shaft aquo-complex blockage

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Experimental program
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Effect test

Embodiment 1

[0025] After natural gas shallow wells (3 Working fluid, its composition ratio by mass fraction is 5% hydrochloric acid; 0.5% corrosion inhibitor; 30% hydrate inhibitor; the rest is water. Then put in a heating unit with an outer diameter less than 10mm of the inner diameter of the wellbore of the gas well through the wax-removing gate of the gas tree, and its length is 500mm. Shut down the well and wait for the reaction. When the wellbore pressure rises and recovers, it can be judged that the wellbore hydrate blockage has been successfully removed.

Embodiment 2

[0027] After deep and shallow wells (3200-4000m) and ultra-deep wells (>4000m) are blocked by hydrate ice, inject 0.3-0.4m through the oil pressure gate of the gas tree. 3 Working liquid, its composition ratio by mass fraction is hydrochloric acid 5%; corrosion inhibitor 1%; hydrate inhibitor 30%; the remaining components are water. Then put in a heating unit with an outer diameter less than 10mm of the inner diameter of the wellbore of the gas well through the wax-removing gate of the gas tree, and its length is 500mm. Shut down the well and wait for the reaction. When the wellbore pressure rises and recovers, it can be judged that the wellbore hydrate blockage has been successfully removed. If the pressure does not recover and rise, it can be judged that the hydrate blockage has not been completely removed, and a new heating unit will be put into the gas tree wax removal gate again. Boil the well behind the body and wait for the hydrate blockage to be removed.

Embodiment 3

[0029] After hydrate ice plugging occurs in a medium gas well containing hydrogen sulfide, inject 0.3~0.4m through the hydraulic gate of the gas tree. 3 The composition of the working fluid is 10% hydrochloric acid by mass fraction; 1%~1.5% corrosion inhibitor; 40%~50% hydrate inhibitor; the rest is water. Then put in a heating unit with an outer diameter less than 10mm of the inner diameter of the wellbore of the gas well through the wax-removing gate of the gas tree, and its length is 500mm. Shut down the well and wait for the reaction. When the wellbore pressure rises and recovers, it can be judged that the wellbore hydrate blockage has been successfully removed. If the pressure does not recover and rise, it can be judged that the hydrate blockage has not been completely removed, and a new heating unit will be put into the gas tree wax removal gate again. Boil the well behind the body and wait for the hydrate blockage to be removed.

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Abstract

The invention discloses a removing method for gas recovery well shaft aquo-complex blockage. After an acidic work solution is pumped into a well shaft subjected to aquo-complex blockage, a heating unit that calcium oxide is coated with materials capable of being dissolved by the acidic work solution is then put in. The acidic work solution is a water solution at least comprising hydrochloric acid, a metal corrosion inhibitor and a hydrate inhibitor. According to the method, calcium hydroxide is generated by the calcium oxide in the work solution and acute heat release is caused in the process that the calcium oxide further reacts with acid, the local part of the well shaft aquo-complex blockage is heated, and thus ice blockage can be removed. No large-sized operation apparatus is needed in the method, and the produced heat can be effectively concentrated the local part of the ice blockage, so the thermal efficiency is greatly improved, and the blockage removal time of aquo-complex is greatly shortened; and the method has the advantages that the used agent dosage is small; the operation time is short; the cost is low; the operation is simple and convenient; no new solid sediment is generated in the processing process; and no new well shaft blockage condition can be caused.

Description

technical field [0001] The invention relates to a method for unblocking wellbore hydrates of gas production wells in oil and gas field development operations. Background technique [0002] In the development of oil and gas fields, the wellbore of gas production wells is blocked by hydrates, which is a common situation in the process of completion testing, commissioning and production of gas wells. When the temperature in the wellbore at a certain depth is lower than the formation temperature of natural gas hydrate, hydrates are easy to form and ice blocks the wellbore, especially at the throttle position in the wellbore. Moreover, with the in-depth development of high-pressure deep formations and sulfur-containing gas reservoirs, the formation temperature of hydrates will be increased due to the high pressure of the wellbore or the presence of hydrogen sulfide components in the fluid, and the formation of hydrates will be easier, so that the wellbore of this type of gas ...

Claims

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Application Information

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IPC IPC(8): E21B37/06C09K8/52
Inventor 雷炜杨洋孙勇赵哲军兰林许剑
Owner SOUTHWEST PETROLEUM UNIV
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