Compound acid blockage removing fluid for oil-water wells of ultralow-permeability oil fields

A technology of oil-water wells and compound acid, which is applied in the direction of drilling compositions, chemical instruments and methods, etc., can solve the problems of not being able to simultaneously remove various blockages, backward plugging removal technology, and poor production stimulation measures, etc., to achieve improvement The effect of original permeability, elimination of formation pollution, and improvement of original permeability

CN108822819AInactive Publication Date: 2018-11-16兰州凯宏中原石油科技有限公司
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2018-11-16
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a compound acid blockage removing fluid. The blockage removing fluid is prepared from raw materials in parts by weight as follows: 4-6 parts of a foam flushing fluid, 20-30 parts of a prepad fluid, 70-100 parts of main acid and 10-20 parts of postpad fluid. The acid fluid has higher capacity of removing organic sediment pollution and high acid residue and emulsifying resistance. The acid fluid has low corrosion speed and good swelling inhibition and does not change the original water wetting characteristic of the stratum.
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Description

technical field

[0001] The invention belongs to the field of secondary oil recovery in oilfields, and in particular relates to a composite acid plugging removal fluid for oil-water wells in ultra-low permeability oilfields. Background technique

[0002] Reservoir damage is one of the main reasons for the decline in production capacity of oil and water wells. Acidizing plugging removal measures are an economical and effective method commonly used to relieve oil layer damage. Due to the differences in geological structure, reservoir structure and development history of oilfields in different regions, the effects of different technological measures vary greatly.

[0003] The purpose of the technology of the present invention is to provide a compound acid plugging fluid for oil-water wells adapted to the characteristics of the ultra-low permeability lithology reservoirs of the Triassic Yanchang Formation in Longdong Oilfield, so as to overcome the poor compatibility between the...

Examples

preparation example Construction

[0122] The preparation method of described composite clay stabilizer, comprises the following steps:

[0123] (1) Get the ammonium persulfate of 0.9 weight part, join in the deionized water of 140 times of its weight, stir, obtain initiator solution;

[0124] (2) Get the isothiazolinone of 1.5 weight parts, join in the dehydrated alcohol of its weight 5 times, stir evenly, obtain bacteriostatic alcohol solution;

[0125] (3) Get 35 parts by weight of methyl methacrylate and 6 parts by weight of ammonium chloride to mix, join in the above-mentioned bacteriostatic alcohol solution, stir evenly, send into the reactor, feed nitrogen, adjust the temperature of the reactor to 65°C, add the above-mentioned initiator solution, keep warm and stir for 4 hours, discharge and cool, and distill off ethanol to obtain the composite clay stabilizer emulsion.

[0126] Described preflush is made up of the raw material of following parts by weight:

[0127] 31% hydrochloric acid 45, corrosion ...

Embodiment 2

[0134] A composite acid plugging solution for oil-water wells in ultra-low permeability oilfields, which is composed of the following raw materials in parts by weight:

[0135] Foam flushing fluid 6, pre-fluid 30, main acid 100, post-fluid 20.

[0136] Described foam well washing liquid is made up of following raw materials of weight part:

[0137] Surfactant a2, composite clay stabilizer emulsion 50;

[0138] Described surfactant a is nonylphenol polyoxyethylene ether;

[0139] The preparation method of described composite clay stabilizer, comprises the following steps:

[0140] (1) Get the ammonium persulfate of 1 weight part, join in the deionized water of 160 times of its weight, stir, obtain initiator solution;

[0141] (2) Get the isothiazolinone of 2 weight parts, join in the dehydrated alcohol of its weight 6 times, stir evenly, obtain bacteriostatic alcohol solution;

[0142] (3) Get 40 parts by weight of methyl methacrylate and 6 parts by weight of ammonium chlor...