Full Field Reservoir Modeling And Analysis Of Ground Surface Deformation Caused By Gas Injection Into Reservoir

The large-scale development and utilization of fossil energy in the worldwide context, resulting in a significant increase in carbon dioxide emissions. The Earth’s rising atmospheric CO2 concentration began to affect natural ecosystems, and endanger the survival and development of human. As a technical measures of reducting net emissions of carbon dioxide, geological storage of carbon dioxide has great potential, and has getting widespread concern at home and abroad. With the features of deep and hidden, reservoir gas injection is different from the ordinary geotechnical engineerings, and once form a leakage pathways, the results would be ranging from a waste of resources and energy, to harming the environment,and harming human and animal life. Therefore, reservoir behavior monitoring and forecasting is particularly important. The simulation analysis of ground surface deformation causing by gas injection into reservoir can be used in disaster warning of reservoir engineering, guiding the placement of tiltmeter arrays, and calibrating geomechanical models, which is the basis of effectively monitoring ground surface deformation, history matching, inversing and predicting the reservoir behaviors.In order to offer effective method of modeling and analysis for this simulation, a user-manageable source program for large scale grid discrete was developed. This code can convert Eclipse near-field geomechanical model into FLAC3D full-field reservoir model and it can also convert the form of Eclipse reservoir simulation results, making which to be used in FLAC3D geomechanical modelling, thus realizes one-way coupled reservoir simulation-geomechanical modelling. Based on this, CO2 injection-induced ground surface deformation of a large-scale saline aquifer CO2 storage project was simulated. Rock mass deformation causing by gas-injection into reservoir is very small in far-field, which need high precision numerical calculation, nevertheless, conventional calculation process encountered the limitations of approximation capability.The cause of which was revealsed, and countermeasures were put forward.Finally, the impact of the thickness of underlying layer contained in geomechanical model on ground surface deformation simulation accuracy was analyzed.