The Integration of Petrophysical and Formation Tester Data in the Creation of a Petrophysical Model for an Eastern Siberia Oilfield

摘要

The Verkhnechonskoye oil and gas field in Eastern Siberia produces from a highly complex Precambrian, lower Vendian sandstone. In this reservoir there has been significant post-depositional alteration due to diagenesis, secondary porosity is common and salt, anhydrite and carbonate cementation of the porosity frequently occurs. In short, the reservoir provides substantial petrophysical challenges. In the development of a petrophysical model three specific concerns were noted. Firstly, the effects of the salt-filled pore spaces complicate the determination of porosity and therefore permeability. Secondly, it is difficult to resolve permeability predictions from logs, core and formation testers. Finally, using conventional petrophysics, even with a comprehensive suite of logs and extensive core data, it is difficult to clearly delineate gas-filled porosity from oil- filled porosity and the determination of the gas-oil contact was therefore uncertain. This paper will discuss how petrophysical data from traditional triple-combo measurements was integrated with NMR measurements, core analysis data and formation tester data including permeabilities from pressure transient analysis (PTA) to produce a coherent and robust petrophysical model for permeability prediction.