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Problems solved by technology
Although it has good thermal stability and high water shutoff rate, for high-temperature and high-salt oil reservoirs in western my country, this kind of polymer jelly still has many technical problems that need to be solved. Degradation, the structure is destroyed; high salinity will cause dehydration of jelly plugging agent in the formation, volume shrinkage, and reduction of plugging agent strength, etc.
CN 102040975 A discloses a silicate water blocking agent. Although it is convenient to configure and low in price, its strength is low, and the gelation time at high temperature is short, so the field application is limited
In addition, there is a gel composed of lignosulfonate, phenol, formaldehyde, and polymers. Due to the high toxicity of phenolic aldehydes, its use is also restricted on site, which is not conducive to environmental protection; and the gelation time, pH and temperature range are required. It has limitations and is not suitable for high temperature and high salinity reservoirs
Method used
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Embodiment 1
[0025] A1: Preparation of montmorillonite dispersion system
[0026] Add 10 g of montmorillonite to 82.2 g of aqueous solution which is being stirred under a stirrer and stir for 5 hours. The rotational speed of the stirrer is 200 r / min, so that the montmorillonite can be well dispersed in water to obtain a montmorillonite dispersion system.
[0027] A2: Preparation of main agent solution
[0028] The main agent prepared by 3g acrylamide (AM), 2g acrylic acid (AA) and 1g 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 0.8g phenolic crosslinking agent and 1g concentration of 1% azo Diisobutyronitrile initiator is added to the montmorillonite dispersion system prepared in step A1, stirred evenly with a glass rod, so that the main agent, crosslinking agent, and initiator can be well dissolved in the montmorillonite dispersion system to obtain the main agent solution.
[0029] A3: Preparation of blocking agent
[0030] Put the prepared solution into the aging tank, tighten th...
Embodiment 2
[0036] A1: Preparation of montmorillonite dispersion system
[0037] Add 6g of montmorillonite into 83.2g of the stirring aqueous solution, and stir for 4h to 5h, so that the montmorillonite is well dispersed in the water to obtain a montmorillonite dispersion system.
[0038] A2: Preparation of main agent solution
[0039] The main agent prepared by 4.5g acrylamide (AM), 1.5g 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and 3g acrylic acid (AA), 0.8g phenolic cross-linking agent and 1g concentration of 1% coupling The nitrogen diisobutyronitrile initiator is added to the montmorillonite dispersion system prepared in step A1, and stirred evenly, so that the main agent, crosslinking agent, and initiator can be well dissolved in the montmorillonite dispersion system to obtain a main agent solution.
[0040] A3: Preparation of blocking agent
[0041] After putting the prepared solution into the aging tank, tighten the bolts of the aging tank to seal it, put it in a 120°C ov...
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Abstract
The invention discloses a temperature-resistant, salt-resistant, high-expansion plugging agent for sealing large cracks and a preparation method thereof. The agent system is composed of the following components in mass percentage: main agent 6%-10%, crosslinking agent 0.6% ~1%, initiator 0.006%~0.01%, additive 6%~14%, all the other are water; The preparation method provided by the invention comprises the following steps: adding montmorillonite to water to prepare montmorillonite dispersion system; Add the crosslinking agent and initiator to the montmorillonite dispersion system to prepare the main agent solution; put the main agent solution in an oven at 90-120°C to make it gel for 9-48 hours, and the gelling strength of this agent system can reach H level. The expansion multiple is 50-80 times, the strength after expansion is good, and the water shutoff effect is good under the conditions of 140°C and salinity of 250,000. The present invention is suitable for profile control and water shutoff in high temperature and high salt reservoirs to seal large fracture water channeling channels Operation.
Description
technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to a temperature-resistant and salt-resistant high-expansion plugging agent for sealing large fractures and a preparation method thereof. Background technique [0002] High-temperature and high-salt reservoirs generally have high temperature (90-150°C) and high salinity (12×10 4 -20×10 4 mg / L), traditional plugging agents tend to have problems such as poor stability, easy dehydration, and poor strength under the conditions of high-temperature and high-salt reservoirs. When performing water plugging operations, if the strength of the plugging agent is not enough, there will be a series of problems such as high water content after water plugging, rapid decline in oil well production after recovery, and short validity period. The water shutoff effect in fractured-cavity reservoirs is one of the key factors for improving recovery and reducing costs in high water-...
Claims
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