The Unconventional Global Endowment: Results of BHP Billiton's Global Assessment

Abstract

The magnitude of the unconventional petroleum resource base is of great importance to both the petroleum industry and to countries assessing their future petroleum resources. Our definition of an Unconventional resource play includes systems that are themselves source beds (e.g. the Eagle Ford) or else intimately associated with source rocks (e.g. Bakken Formation). Our screening method involved the assessment of three key parameters: - Reservoir Storage: estimation of a low, most likely and high technically recoverable resource volume of oil and gas for the play. Factors include net thickness, matrix and inorganic porosity, water saturation, formation volume / gas expansion factors and recovery factor. - Reservoir Deliverability: estimation of a low, most likely and high initial oil and gas well flow rate for the play. Factors include net thickness, pressure, permeability and viscosity. - Wellbore Deliverability: the amenity of the play to repeatable lateral well drilling and artificial fracture stimulation. Factors include structural simplicity, lateral continuity of source/storage facies, mineralogy and associated brittleness and expected drill depth. Sources of data include public and proprietary studies, data from BHBP's decades-long global conventional onshore exploration efforts and observations, learnings and workflows from BHP Billiton's US “Shale” Production Units. We leveraged relationships derived from integrated in-house core, petrophysical, and geochemical studies, and datasets including a database of 650,000 source rock samples. The adaptation and application of modern petroleum systems analysis concepts and tools proved invaluable in making projections of fluid compositions and properties. We found that historical “rules of thumb” from Conventional source maturity windows systematically under-estimate the gas-oil ratio in the “shale hosted” plays. These and other factors result in a lower Global Endowment estimate than that of the EIA (2013) for oil, by a factor of 4 and for gas, by a factor of 2. However these estimates reflect only storage of technically recoverable resources. For these resources to become reserves they will need to be producible at sufficiently high rates. Much of this resource, especially the oil, will only be recoverable at low rates, be marginally economic and may not compete with alternate sources of energy. Thus, ultimately, any estimates of the Global Unconventional Endowment may overstate the importance of this resource.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015