Study On Reservoir Characteristic Of Volcanic Gas Reservoir And Numerical Simulation

The large scale of volcanic gas reservoir has been found in China now, but the development of volcanic gas reservoir has been started just now, and many problems need to be solved. In this paper, the reservoir characterization and development problems of volcanic gas reservoir are researched systematically by means of constant rare mercury penetration, nuclear magnetic resonance, filtration theory and numerical simulation of gas. The main research results we get are as following:1. Application of the research on the experiments with constant rare mercury penetration and X-CT scanning, micro pore structure characteristic of volcanic gas reservoir of Daqing Xushen Gas Field were tested, the pore radius, throat radius and pore throat ratio characteristic were analyzed, and investigating the effect of gas filtering flow in volcanic gas reservoir by the development extent of fracture, micro-fracture, air vent and vug. The results we get are as following: the core samples of volcanic gas reservoir with different permeability, which have different distribution of throat radius, and the bigger the permeability of core samples are, the smaller the pore throat ratio of core samples have.2. The irreducible water saturation of volcanic gas reservoir was measured using nuclear magnetic resonance tech of low magnetic field, it is confirmed that movable fluid T₂ cutoff value of volcanic gas reservoir in Daqing oilfield is 86.4ms, and compared the irreducible water saturation of volcanic gas reservoir in Xingcheng area with that in Shengping area. Research indicated that the irreducible water saturation of volcanic gas reservoir was relative to porosity and permeability, and with increasing of permeability of the volcanic gas reservoir, the movable fluid saturation increased, while the irreducible water saturation decreased.3. Rock stress sensitivity of volcanic gas reservoir was studied on the experiment with physical modeling tech. The changes of porosity, permeability and rock compressibility along with effective stress were researched, and analyzed productivity which effected by volcanic rock deformation.4. Exploitation law of Xushen I Block in Xushen Gas Field was studied from gas numericalsimulation. The development effect of volcanic gas reservoir which affected by gas producing rate, fracture deformation, interlayer interference and bottom water coning was analyzed, and give development advice for production.