Development And Performance Evaluation Of A Novel High Temperature In - Situ Polymerized Gel System

In this thesis, a water shutoff technology for high-temperature and high-salinity reservoirs was investigated. Furthemore, the following works had been completed and the corresponding results had been made. And the results show that the water shutoff agent overcomes the defects, such as too many components, too short gel time and poor stability.(1) According to the characteristics and requirements of high-temperature and high-salinity reservoirs, an in-situ polymerization gelling water plugging agent with good property of injection, controllable gel time, strong gel strength, powerful plugging ability, and excellent temperature-tolerant, salt-resistant and scour-resistant properties was developed. In addition, the appropriate composition of wate plugging agent formulation was determined.(2) Through the indoor static evaluation of the wate plugging agent, we confirmed the adapted pH value and investigated the effect of temperature and salinity on the gel performance.①The gelling solutions with an initial pH value from5.0to9.0has better strength and stability;②In the simulated formation water within25×104mg/L salinity, the strength can be maintained at a high level over90days;③Under a high temperature of120℃, it still maintains sufficient strength over90days, indicating that it has a good long-term thermal stability.(3) We performed the core physical simulation experiments.①The single-core flow experiments show that the water plugging agent with good good property of injection has a strong plugging ability, and its plugging ratio is greater than98%;②After30PV injected water erosion, its plugging ratio decreases slightly, which is still greater than97%, so it has good resistance to erosion;③The double parallel core flow experiments show that water plugging agent has good injection selectivity. It has preferential access to the high permeability layer, and its plugging ratio is greater than98%in the high permeability layer.These research results provide a theoretical reference and technical storage for the water shutoff of high-temperature and high-salinity reservoirs, and have certain guiding significance and actual application value.