CCUS Source-sink Matching Model Based On Sink Well Placement Optimization

Achieving carbon peaking and carbon neutrality goals is a major strategic decision and a solemn commitment of China to address global climate change.Carbon capture,utilization and storage(CCUS)technology is an important method to achieve the goals,and source-sink matching technology is an important strategy of CCUS.Current CCUS source-sink matching models mainly carry out the optimization based on the overall storage capacity of sinks,and cannot accurately limit the injection capacity under different well placement schemes based on actual well placement projects.However,the implementation of CO2 geological sequestration must consider the well placement scheme.Therefore,the characteristic of sequestration sinks which changes dynamically with the well placement scheme is of great significance for the optimization matching of sources and sinks.Therefore,this paper builds a dynamic storage potential assessment model that can quickly evaluate the sink injection capacity under different well placement schemes,and constructs a source-sink matching model based on the sink well placement scheme for overall optimization by combining the dynamic storage potential assessment model.The combined model can take into account the limitation of injection capacity and the cost of well placement under different combinations of well number and inter-well distance,in order to achieve the correct matching and simultaneous optimization of the source-sink pipe network layout and well placement scheme.Based on the principle of minimum total cost,the model regards source-sink matching as a mixed integer linear programming(MILP)problem,and obtains the calculation results of the dynamic storage potential assessment model through the variables in the objective function and constraints to achieve the above objective.The additional calculation cost brought by the dynamic storage potential assessment model and the combination method is on the order of seconds.The current MILP source-sink matching model can adopt this idea to improve the accuracy of the model.In this paper,the dynamic storage potentials of two saline aquifers in the Ordos basin and Jianghan Basin is evaluated by the model built in this paper,and the effects of reservoir area and permeability on injection capacity are analyzed.It is found that the total injection rate of multiple wells shows a complex trend with the increase of the number of wells.Then,in a nationwide source-sink matching case,this paper compares the two pipe network layout schemes of transit connection and direct connection,and finds that the transit scheme can save nearly 30% of transportation cost by sharing transportation pipes between nodes.Finally in this paper,through a project scale source-sink matching case,the matching results given by the single source-sink matching model and the combined model constructed in this paper are compared,which illustrates the importance of dynamic storage potential assessment for sinks,and proves that the combined model can further reduce total cost of CCUS under the condition of safe sealing through simultaneous optimization of the pipe network layout and sink well placement scheme.