Low-density water bonding well control fluid

A low-density, water pressure technology, applied in drilling compositions, chemical instruments and methods, etc., can solve problems such as corrosion, clogging of formations, water lock damage, etc.

Active Publication Date: 2012-12-12
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The biggest feature of these kill and workover fluids is that they are easy to flow back, but the disadvantages are: large filtration loss, great damage to the formation, especially for wells with relatively high clay content, serious damage to water lock, and at the same time cause clay swelling, corrosion and contact with the formation. When water encounters, it will generate scale and block the formation, etc.

Method used

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  • Low-density water bonding well control fluid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] In 100 kg of water, add 0.02 kg of fluorine-containing surfactant, 1.0 kg of organic cationic surfactant, 0.003 kg of phosphino-maleic acid-acrylic acid copolymer (dissolved in water), and then add 0.5 kg of bound water to polymerize Stir it well and let it sit for 30 minutes to obtain a well-prepared bound hydraulic well fluid. The actual configuration is scaled up according to this ratio.

[0025] Performance of workover fluid: Density: 1.01g / cm 3 , surface tension: 22mN / m, anti-swelling rate: 81.2%, water loss in 30 minutes under 0.7Mpa pressure is less than 9.5% of the kill fluid; stable time at room temperature ≥ 30 days, stable time at 130 ° C ≥ 3 days. Field application was carried out in basin 5 wells.

Embodiment 2

[0027] In 100 kg of water, add 0.05 kg of fluorine-containing surfactant, 1.5 kg of organic cationic surfactant, 0.005 kg of phosphino-maleic acid-acrylic acid copolymer (dissolved in water), and then add 0.666 kg of bound water to polymerize Stir it well and let it sit for 30 minutes to obtain a well-prepared bound hydraulic well fluid. The actual configuration is scaled up according to this ratio.

[0028] Performance of workover fluid: Density: 1.02g / cm 3 , surface tension: 19mN / m, anti-swelling rate: 85.6%, water loss in 30 minutes under 0.7Mpa pressure is less than 6.1% of the kill fluid; stable time at room temperature ≥ 30 days, stable time at 130 ° C ≥ 3 days. Field application in Mazhuang Gas Reservoir Platform 20 Well.

Embodiment 3

[0030] In 100 kg of water, add 0.03 kg of fluorine-containing surfactant, 1.5 kg of organic cationic surfactant, 0.004 kg of phosphino-maleic acid-acrylic acid copolymer (dissolved in water), and then add 0.6 kg of bound water to polymerize Stir it well and let it sit for 30 minutes to obtain a well-prepared bound hydraulic well fluid. The actual configuration is scaled up according to this ratio.

[0031] Performance of workover fluid: Density: 1.02g / cm 3 , surface tension: 21mN / m, anti-swelling rate: 85.1%, water loss in 30 minutes under 0.7Mpa pressure is less than 7.9% of the kill fluid; stable time at room temperature ≥ 30 days, stable time at 130 ℃ ≥ 3 days. Field application in 581 well.

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Abstract

The invention relates to low-density water bonding well control fluid with a density between 1.00g / cm<3> and 1.01g / cm<3>. The well control fluid consists of 150-200 parts by weight of component A and 1 part by weight of component B. The component A consists of the following components in percentages by weight: 0.02-0.05% of fluorinated surfactant, 1.0-1.5% of organic cation surfactant, 0.003-0.005% of copolymer of phosphono-maleic acid and acrylic acid copolymer and the balance of water. The component B is a water absorptive resin polymer. The organic cation surfactant is formed by the reaction of equal molars of benzyl chloride and trimethylamine. The water absorptive resin polymer is a polymer of acrylic acid, acrylamide and 2-acrylamido-2 methylpropane sulfonic acid. The content of thefree water of the low-density water bonding well control fluid is not more than that of 5% of the well control fluid. The viscosity is reduced by not more than 5% after the well control fluid is sheared at the speed of 170S<-1> for 4 hours. The well control fluid can resist 135 DEG C and is suitable for wells with the stratum pressure coefficient which is not more than 0.97MPa / 100m.

Description

technical field [0001] The invention relates to a low-pressure oil and gas well well-killing (workover) operation, which is suitable for protecting reservoirs with a density of 1.00g / cm 3 -1.01g / cm 3 Between low-density bound hydraulic well fluids. Background technique [0002] There are three types of water-based kill and workover fluids widely used in China: mud-improved kill and workover fluids, polymer solid-phase brine kill and workover fluids, and solid-free brine kill and workover fluids. Among them, the mud-improved well killing and workover fluid has a relatively large damage to the formation due to its high solid content, and its use has decreased in recent years. The advantages of polymer solid-phase brine well kill and workover fluid are less fluid loss into the formation and good sand-carrying performance. However, for low-porosity and low-permeability formations with both fractures and pores and heterogeneous structures, the solid phase will cause great damag...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/88
Inventor 唐伏平柳海马喜平李纲要吴丙刚
Owner PETROCHINA CO LTD
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