| The CO2 enhanced oil recovery technology(CO2-EOR)has been widely used in the world because it can store a large amount of CO2 in the formation while using CO2 to enhance oil recovery.However,the CO2 that has been injected into the reservoir would leak through a variety of ways,enter the natural environment such as soil,water,and the atmosphere,causing ecological pollution and even endangering human health and safety.In order to reduce the risk of CO2 leakage,Long-term monitoring of stored CO2 is needed.Among the CO2 leak monitoring studies that have been carried out at home and abroad,most of them have studied soil and surface water separately without coupling to form a unified surface monitoring system.In addition,the lack of environmental suitability assessment of the CO2 leakage monitoring system has resulted in the monitoring system cannot meet the CO2 leakage monitoring in the special topography and climatic conditions similar to the Loess Tableland Region in southern Ordos.Aiming at the above problems,this thesis takes the Loess Tableland Region in southern Ordos as the research area,and comprehensively considers the complex terrain and morphology of the region and the climate and environmental characteristics,and develops a CO2 leakage monitoring system for Soil-Surface water ecosystem.This article reviews the related technologies of CO2-EOR storage and leakage monitoring;analyzes the CO2 flooding storage and leakage mechanism in the Loess Tableland Region;identifies the response characteristics and spatial-temporal changes of CO2 leakage indicators in the area;establishes the Soil-Surface water ecosystem,optimized the CO2 leakage monitoring index system and monitoring point layout in the Loess Tableland Region;and finally formed a surface monitoring system for CO2 leakage of CO2-EOR storage in Loess Tableland Region.Studies have shown that the monitoring system integrates the two major soil-surface water ecosystems to form a unified surface monitoring system,and can be appropriately optimized to meet the needs for surface monitoring of CO2 leakage under other complex topography and climatic conditions,and provide significant support and assistance for the further improvement of the CO2-EOR storage safety monitoring system. |
