High-viscosity strong-corrosion acid liquid system for low-permeability sandstone oil reservoir

A high-viscosity technology for sandstone reservoirs, applied in the direction of drilling compositions, chemical instruments and methods, etc., can solve the problems of reduced production, increased production and increased injection, unsatisfactory effects of increased production, and increased scaling caused by reservoir blockages. To achieve the effect of increasing the effective distance
CN110791279AInactive Publication Date: 2020-02-14XI'AN PETROLEUM UNIVERSITY
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
XI'AN PETROLEUM UNIVERSITY
Publication Date
2020-02-14
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a high-viscosity strong-corrosion acid liquid system for a low-permeability sandstone oil reservoir. The system comprises the following components in percentage by mass: 6-12%of hydrochloric acid, 1-3% of betaine, 4-8% of a reinforcing agent, 0.05-0.2% of citric acid, 0.5-2% of ammonium chloride, 0.5-2% of a corrosion inhibitor, 0.1-0.4% of a cleanup additive, 0.05-0.2% ofa demulsifier and the balance of water, wherein the sum of the components is 100%. During acidification of the acid liquid system, rise of the viscosity of the acid liquid reduces the filtration lossof the acid liquid, more fresh acid is forced to enter the deep part of a stratum, the effective action distance of the acid liquid is increased, and after acidification is finished, a high-viscosityfluid is automatically broken into a low-viscosity fluid when meeting crude oil in the stratum, so that the stratum is not subjected to secondary damage.
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Description

technical field

[0001] The invention relates to the technical field of oil and gas field development, in particular to a high-viscosity and strong-corrosion acid liquid system for low-permeability sandstone reservoirs. Background technique

[0002] With the increase of oil field development, the increase of water flooding energy, and the fracturing process and the water flooding process may cause some damage to the reservoir, which will bring some new problems in the long-term production of oil wells, such as In the process of water flooding, the migration of fine sand bodies in the formation often blocks the oil outlet channels, and formation fouling pollutes the oil outlet channels, resulting in blockage and pollution of the oil outlet channels. For these reasons, the skin factor of oil wells increases, resulting in a reduction in the production of some oil wells.

[0003] For this reason, it is necessary to acidify oil-bearing reservoirs (fractured sandstone reservoirs),...

Claims

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