我国吉林油田大情字井区块CO2地下埋存试验区地质埋存格架

目前，我国在CO2地质埋存的试验研究才刚刚开始，其研究方法与研究思路需要不断探索。本文立足于吉林油田大情字井区块，从储层埋存潜力、埋存体稳定性及水文地质条件三个方面对试验区实施CO2地质埋存工程进行评价。通过对注CO2层段的储层砂体有效厚度、空间展布范围、储层物性及储层微观结构，以及在此基础上，对各砂体横向和垂向上的连续性、砂体间的连通性等等方面的分析和评价，试验区具备一定的埋存潜力,其有效储层厚度平均为273m；同时对试验区盖层的封盖性、断裂的稳定性及井筒的密封性三方面的评价，建立试验区埋存体稳定性评价体系。研究表明，试验区具备厚层泥岩封盖层、盖层内断裂不发育且比较单一以及储层内广泛发育隔夹层，可以有效地对CO2的运移或渗漏实施封盖和遮挡；另外，结合试验区矿化度、水化学成分的研究表明，试验区与邻近区域存在明显的矿化度分带特点、水化学成分也相对较单一以及含水层和隔水层均较发育。在一定程度上说明，试验区目的层段具有相对独立的地下水水体环境，比较有利于适合注入CO2，并进行地质埋存。通过这三方面的研究，建立大情字井区块适合CO2地质埋存的埋存格架，为该区实现CO2长期有效安全埋存奠定基础。

The geological storage framework of CO2 subsurface storage in the study area of the Daqingzijing district in Jilin Oilfield

At present, it is just a beginning to carry out the pilot project researches about injecting CO2 into subsurface oil reservoirs to successfully storage partial CO2 in our country, many research methods involving in how to storage CO2, therefore, need to be tried slowly step by step. This paper based on the Daqingzijing district in Jilin oilfield, evaluates the CO2 storage project operating in the study area in detail now from three main aspects, including the reservoir storage capacity, the storage stability and the hydrogeological conditions. Generally, the valid thickness of reservoir, the dimensional scale of sand distribution, the physical property and microstructure of reservoir, and at the same time, the vertical and horizontal succession and connectivity among various sands are the critical factors to evaluate the reservoir storage capacity. Regional reservoir studies demonstrate the storage capacity in the study area is large, and the effective thickness of reservoirs adapt to storage CO2 is nearly 273m on an average. In the meantime, some conditions, such as the caprock, the fault-fractured system and the injection and abandoned wells are very important to guarrantee to storage safely and decrease the possible leakage risk effectively. The studies indicate in the study area there are huge formations consist of closed muds mainly upper the reservoir, and there are few or simple faults or fractures inner the formations, which adapt to be taken regard as the favorable caprock, at the same time there are many insulations and interbeds consist of muds and silty-mud among the reservoir sand, which can be the barrier to CO2 movement or leakage. In addition, Hydrogeological data including total dissolved solids (TDS) and hydrochemistry mainly indicate there is obvious boundary of TDS between the study area and areas nearby, and there is simple chemical component, NaHCO3, which to some extent demonstrate there is a relative independent hydrogeological system in the study area. In summary, according to evaluate the three aspects above, the geological storage framework of CO2 subsurface storage can be built up, which indicate the geological setting of the Daqingzijing area is considered highly suitable for secure, long-term storage of CO2.