Optimization Design Of Gas Injection And Halogen Removal In Salt Cavern Gas Storage

As the second west to east gas pipeline project has been completed, serving as an important supporting project for West-to-East Gas Project, underground gas storage project is of great importance for peak adjustment and emergency gas supply. Our country has conducted many researches on optimal design, safeoperation and other aspects of salt cavern gas storages in recent years whose results focus on Simulation of building salt cavern, stability analysis and simulation of continuous injection-production in salt cavern, while little research has been done on fine/detailed geological modeling and the optimization of gas injection and brine discharge technology. Accurate 3D visualization geological modelling is beneficial for decision-makers to make reasonable judgments and provides important guidance for gas injection and brine discharge in gas storage, continuous injection-production and cavity-dilatancy. The research on gas injection and brine discharge can adjust reasonable construction parameter as well as optimize time limit for project. Nowadays, the research on gas storage at home is still in development. The research design and construction of gas storage lacks mature theory as a guide and corresponding standardized instruction. Therefore, based on West-east gas pipeline company of CNPC Jintan gas storage, this paper takes an actual gas storage as research project, and carry out the following research centered on fine/detailed geological modeling, cavity modeling and gas injection and brine discharge:1. In terms of the geological modeling in salt-cavity gas storage(1) Taking Sanduo Formation, Dainan Formation and Funing Formation as research object, the author make an interpretation of drilling stratum by using the data of well logging and core observation. Besides, the mechanical stability and leakage of gas storage have been discussed by analyzing the petrophysical parameters.(2) Under the theoretical guidance of geology, stratigraphy and geologic statistics, the author establishes a 3D geological model in research area by the software Petrel, imports the timely form of salt cavern into the three-dimension geological model thus, Thus, a3Dvisualizationmodelingof salt-caverngas storage has been achieved.2. In terms of cavity form(1) The author evaluates the leakage of cavity after building the cavity with Field test data in order to ensure the availability of cavity.(2) The author makes linearregression of the gas-liquid interface level in cavity by using the software Petrel to calculate the segmented volume of cavity. Analyzing and deducing the factors affecting the gas injection pressure at wellbore, the author predicate the gas injection pressure in different depth.(3) Having been processed by the modeling software UG, the 3D visualization model of cavity achieves a cloud converse modeling of irregular points3. In terms of optimization design of gas injection and brine discharge(1) Based on the theory of gas-liquid two-phase flow, the the author establishes a relationship of brine air-entraining under high pressure. The author also reveals the influence of the depth of halide discharge pipe and the remaining brine that can be discharged on the effect of gas injection and brine discharge by means of the numerical modeling of actualworkingconditions.(2) The authoranalyzes and elaborates the harm of residual water which formed after gas injection and brine discharge as well as the treatment methods of such water at home and abroad.