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Use of Field Observations and X-ray Computed Tomography to Characterise Volcanic Reservoir Analogues
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 76th EAGE Conference and Exhibition 2014, Jun 2014, Volume 2014, p.1 - 5
Abstract
Volcanic reservoir rocks host significant hydrocarbon reserves but are poorly understood in terms of their reservoir properties: especially porosity and permeability characteristics. Basalt lava flows are of particular interest due to their global abundance. Field investigations confirmed that basaltic lava flows typically comprise three key facies: flow tops, flow cores and flow bases. Use of traditional poro-perm techniques, alongside high-resolution micro-focus X-ray computed tomography (μCT), enabled the pore architecture to be assessed alongside the quantification of porosity, effective porosity and permeability. Volcaniclastic rocks have the best reservoir potential, with higher porosities and permeabilities (mean = 51.04%). In contrast basaltic lava flows show variable poro-perm properties due to variations in pore types, size, distribution and connectivity. Flow tops exhibit the best reservoir potential (mean = 20.12%) where abundant vesicles and fractures contribute to the higher porosities and permeabilities. Flow cores are relatively tight (mean = 1.93%), with an absence of vesicles but abundant isolated micro-pores. Flow base facies show variable porosities, controlled by the degree of vesiculation and fracturing (mean = 8.61%).