Paleogene sediment complex - geological factors impacting on its reservoir quality and hydrocarbon potential

Tóm tắt

The Paleogene reservoir complex has diverse facies which change rapidly both laterally and vertically. Its depositional environments are determined as alluvial, deltaic, tidally affected lacustrine and, rarely, with a shoreline.
The variety in sedimentary facies and lithological heterogeneity are the main causes for the anisotropy in porosity and permeability of the Paleogene reservoirs, thus reducing field exploration and development efficiency as well as the application of secondary exploitation in order to increase the oil recovery.
Reservoir quality has resulted from the combined effects of primary diagenetic elements and secondary alteration. Secondary deformation has a bidirectional influence on the reservoir quality, reducing the primary porosity but also forming secondary porosity. Dual porosity is one of the important properties of the Paleogene reservoir that should be considered in production management.
Secondary fractures could potentially increase the flow in the tight Paleogene reservoirs.
The production from Paleogene reservoirs is still small, not corresponding to the potential of Paleogene formations as rich source rocks. The Late Eocene-Oligocene reservoir, therefore, needs to be investigated and sufficiently evaluated as a potential hydrocarbon bearing play in order to enhance production and reserves.