Hydraulic (flow) unit determination and permeability prediction: A case study of Block Shen-95, Liaohe Oilfield, North-East China

Abstract

This study analyzes three prediction approaches of the Bayesian method for predicting Hydraulic Unit (HU) and consequently predicts permeability for Block Shen-95. These approaches are intersection of multiple well-logs, independent mulitple well-logs and mutually exclusive multiple well-logs. In this study, HU was delineated to efficiently compute permeability and served as the building block of structural model for enhanced simulation study. HU is defined by the flow zone indicator concept from the modified Kozcny-Carmcn equation. The Bayesian method was used to predict HU at uncored wells. This is done by first constructing a probability database through the integration of established HU and well-log responses at cored wells. HU is then inferred from the database using well-log responses. By comparison, estimated permeability from predicted HU gave an overall improved permeability match to that of traditional statistical methods. More so, mutually exclusive multiple well-logs proved more favourable. The highlight is that significant relationship exists by integrating reservoir performance with HU distribution indicating that reasonable prediction was obtained at uncored wells from the use of the mutually exclusive approach. The distribution was made possible by interwell HU correlation using depositional cycles as a framework but with modification. This integration step qualitatively examines prediction accuracy. © 2009 Asian Network for Scientific Information.