Clean viscous acid for acid fracturing of carbonate reservoir

A technology of thickening acid in carbonate reservoirs, applied in the direction of chemical instruments and methods, drilling compositions, etc., can solve problems affecting oil and gas well productivity, uneven liquid, clogged formations, etc., and achieve retardation performance Excellent, easy to flow back, prolonging the service life effect
CN102453480BActive Publication Date: 2013-05-01BC P INC CHINA NAT PETROLEUM CORP +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
BC P INC CHINA NAT PETROLEUM CORP
Publication Date
2013-05-01

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Abstract

The invention discloses a clean viscous acid for acid fracturing of a carbonate reservoir, which is applied to the technical fields of acidification and acid fracturing of petroleum carbonate reservoirs. The clean viscous acid consists of the following components in percentage by weight: 3-7 percent of hexadecyl trimethyl ammonium bromide, 0.3-0.7 percent of sodium salicylate, 15-28 percent of hydrochloric acid, 0.125-0.25 percent of citric acid or 0.05-0.1 percent of CX-301 or 0.3-0.5 percent of TW-1 serving as an iron ion stabilizing agent, 0.2-0.25 percent of a diimidazoline quaternary ammonium salt and the balance of water. The clean viscous acid has high retardative property, the retarding rate can reach 42-56 percent, the fresh acid viscosity is 25-40 mPa.S, and the acid liquor viscosity rises during acid fracturing of the carbonate reservoir. When the hydrogen ion concentration falls till the pH is more than or equal to 2, the acid liquor viscosity rises for forming viscoelastic gel, the permeation resistance of an acid liquor in a high permeation layer is increased, and the length of an acid etching crack is prolonged. Reacted residual acid gel can undergo gel breaking automatically, is free from residues, is easy for discharging, and has small damage to stratums.
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Description

technical field

[0001] The invention belongs to the technical field of chemicals used in the petroleum industry, in particular to the technical field of acidification and acid fracturing of carbonate rock reservoirs in the exploitation of petroleum and natural gas. It is a low damage, instant viscosifying, adjustable retarding rate cleaning thickening acid. Background technique

[0002] In oil and gas reservoir formations, carbonate reservoirs occupy a considerable proportion. The oil and gas in this kind of reservoir cannot form high productivity due to low permeability. In the exploitation of oil and natural gas, acid fracturing technology is one of the effective measures to increase the production of oil and gas wells in carbonate reservoirs. The stimulation effect of acid fracturing in low-permeability carbonate reservoirs mainly depends on the length of acid-etched fractures and the conductivity of fractures. However, due to the rapid reaction between hydrochloric ac...

Claims

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