随着应对气候变化的紧迫性日益增强，开发创新高效的碳封存策略，以捕获和储存工业来源的二氧化碳，已成为当务之急。本文综述了超临界二氧化碳-盐水注入（SAI）和水气交替注入（WAG）两种地质碳封存方法，并提出了一种与盐水处置井（SWD）相结合的新方法。
SAI-WAG策略包含两种方案：一是通过双结构井将CO₂和处理后的废水同时注入地质构造进行处置；二是通过单管或双管组合交替注入处理后的水和CO₂ 。后一种方案类似于传统的WAG工艺，后者将常规注水和CO₂注入方法相结合，称为CO₂-SWAG。同时注入也称为CO₂ - SWAG。
与 CO₂-WAG 注入相比， CO₂ - SWAG 注入能更好地控制流体流动性，并实现更稳定的气体驱替。尽管有这些优势，SWAG 注入也面临诸多挑战，包括高昂的完井、设备、作业成本以及复杂的设计。
SAI-WAG 策略无需为地质碳储存活动钻探额外的井，从而具有显著的经济优势。
As the urgency to combat climate change intensifies, developing innovative and efficient carbon-sequestration strategies to capture and store CO2 from industrial sources has become a critical priority. This paper reviews the simultaneous supercritical (SC) CO2-brine aquifer injection (SAI) and water-alternating-gas (WAG) methods for geologic carbon sequestration and proposes a novel integration with saltwater-disposal wells (SWDs).
The SAI-WAG strategy incorporates two scenarios: concurrent injection of CO2 and treated wastewater into a geological formation through a dual-structured well for disposal purposes, or alternating injection of treated water and CO2 by a single- or dual-string assembly. The latter scenario mirrors traditional WAG processes, which combine conventional waterflooding and CO2-injection methods into what is known as CO2-SWAG. Simultaneous injection also is called CO2-SWAG.
Compared with CO2-WAG injection, CO2-SWAG injection provides better control over fluid mobility and enables more-stable gas displacement. Despite these advantages, SWAG injection presents challenges, including high costs for well completion, equipment, operations, and complex design.
The SAI-WAG strategy offers significant economic advantages by eliminating the need to drill additional wells for geological carbon-storage activities.
