A kind of anti-high temperature gel plugging agent for oil-based drilling fluid and its preparation method and application

Abstract

The invention provides a high temperature resistant gel plugging agent for oil-based drilling fluid and its preparation method and application. The gel plugging agent includes the following raw materials in parts by weight: 15-30 parts of gel agent, 2-2 parts of crosslinking agent 7 parts, 0.3-1 part of initiator, 60-80 parts of base oil, described gelling agent is diethylene glycol dimethacrylate, pentylene glycol diacrylate, cetyl methacrylate, A combination of two or more than three of polyurethane resins, the cross-linking agent is two or three of dibutylammonium oleate, zinc acrylate and divinylbenzene. The leak-stopping agent of the present invention enters the cracks under the action of the pressure difference, and automatically forms a gel to form a high-strength, high-temperature-resistant gel, thereby sealing the cracks; the leak-stopping agent of the present invention has good oil-based drilling resistance and can The wide range of cracks works, which has a good plugging effect on malignant leakage, and has the advantages of high temperature resistance, fast volume expansion, high gel formation strength and controllable gelation time.

Description

technical field [0001] The invention relates to an anti-high temperature gel plugging agent for oil-based drilling fluid, a preparation method and application thereof, and belongs to the technical field of drilling fluid plugging. Background technique [0002] In order to ensure the safety, speed and efficiency of the drilling process, the bottom hole pressure must be kept higher than the formation pressure during drilling, and this pressure difference will lead to the loss of drilling fluid when drilling into permeable or fractured formations. Loss of drilling fluid leads to the loss of a large amount of drilling fluid, which increases the drilling cost; and the lost drilling fluid will destroy the permeability of the reservoir and reduce the oil and gas field recovery after entering the formation, which is a problem that must be faced in oil and gas exploitation. [0003] Existing plugging technologies, such as bridging plugging, curable plugging and polymer plugging, have...

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Problems solved by technology

For example: Chinese patent document CN105646763A provides an oil-based gel plugging agent, which is composed of the following raw materials in parts by weight: 20-40 parts of styrene, 2-10 parts of biodiesel, 0.5-5 parts of divinylbenzene, dimethyl 0.1-5 parts of diethylene glycol acrylate and 0.01-1 part of azobisisobutyronitrile, but the volume expansion rate of the above-mentioned oil-based gel plugging agent is low, and the plugging effect is good when facing cracks of 3mm and above bad

Chinese patent document CN105199693A provides an oil-based gel plugging slurry, which is composed of 35-70 parts of base oil, 5-25 parts of curing agent, 0.1-1 part of activator, 0.5 -4 parts of water, 0-60 parts of weighting agent, the base oil is at least one of castor oil, soybean oil, rapeseed oil, peanut oil, animal oil, fatty acid methyl ester, dimethyl maleate, Described curing agent is at least one in calcium oxide, magnesium oxide, zinc oxide, sodium carbonate, sodium bicarbonate, magnesium carbonate, sodium acetate, and described activator is potassium hydroxide, sodium hydroxide, sodium carbonate, At least one of potassium carbonate, and the weighting agent is at least one of barite, limestone, and iron ore powder, but the gel formed by the oil-based gel plugging slurry has poor temperature resistance and cannot be applied to High temperature formation, and can't seal malignant leakage

[0006] At present, gel plugging agents suitable for oil-based drilling fluids generally have defects such as low gel strength and poor temperature resistance, and cannot be used in ultra-high temperature formations.

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