A slow-swelling and density-controllable flow channel adjustment agent system for fracture-vuggy reservoirs and its preparation method

Abstract

The invention relates to a fractured-vuggy reservoir slow-expansion density controllable channel adjusting agent system and a preparation method thereof. The agent system is prepared from, by mass, 8-14% of a main agent, 0.6-1.2% of a crosslinking agent, 0.006-0.01% of an initiator, 0.6%-0.8% of low-temperature slow-expansion granular hectorite nanoparticles, 10-30% of an additive and the balancewater, wherein the additive is a mixture composed of one or two of rubber particles and vermiculite and imvite. The preparation method comprises the following steps that the imvite is added into waterto prepare an imvite dispersion system; the main agent, the crosslinking agent, the initiator and the hectorite nanoparticles are added into the imvite dispersion system to prepare a main agent solution; the rubber particles or the vermiculite are added into the main agent solution to prepare a slow-expansion density controllable channel adjusting agent, and the channel adjusting agent system hascontrollable density and low-temperature slow expansion, and is suitable for deep increase and water plugging of a high-temperature high-salt fractured-vuggy reservoir channel with the mineralizationdegree of 250,000 at 140 DEG C.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to a flow path adjusting agent system with controllable slow-swelling density for fracture-cavity reservoirs and a preparation method thereof. Background technique [0002] The combination of fractures and caves in carbonate fractured-vuggy reservoirs is random, and the connection mode is extremely complex. The water cut of the oil well rises rapidly after water breakthrough, and even violent flooding occurs. Therefore, flow path adjustment for fractured-cavity reservoirs is an effective method to control the rise of water cut in reservoirs and improve oil recovery. [0003] At present, the flow channel adjustment agents developed mainly include precipitation, particle and gel flow channel adjustment agents. The representative system formula of precipitation is water glass + curing agent system and thermal precipitation modifier technology. For example, Dong...

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Problems solved by technology

[0004] Although the above-mentioned flow channel adjustment agent systems have played a great role in improving oil recovery, the density range of these agent systems is narrow, and the density distribution of injected water is wide due to the large difference in salinity, often due to the use of The large difference between the density of the agent system and the injected water causes problems such as stratification and deposition due to poor suspension in the injected water, and it is difficult to meet the requirements of the geological reservoir for a specific density agent system; moreover, for high-temperature and high-salt reservoirs, high-temperature It is easy to cause the degradation and structural damage of the agent system, and the final plugging agent has low strength. The high salinity will cause the agent system to dehydrate in the formation, and the volume shrinkage structure will be damaged, so the stability of the plugging agent formed is poor; in addition, currently The commonly used particle flow channel adjustment agent in the agent system is pre-crosslinked particles. At room temperature, the particles can expand to 40 to 200 times. The agent has a large expansion multiple under low temperature conditions, and the strength performance decreases significantly, making the particles difficult to Injecting into the deep part of the reservoir cannot achieve the purpose of deep adjustment and deep drive

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