Uses and Misuses of Pressure Data for Reserve Estimation

Abstract

AbstractPressure data can be a critical component of a reserve estimate. This data can come in many forms including: Pore pressure data captured prior to a well's completionEstimated pore pressure taken during completionDrawdown data collected during productionPressure buildup data collected with a bottomhole pressure gauge.Each of these data sources requires its own analysis and quality check techniques. With the appropriate supporting geological and engineering data, pressure measurements and analysis of sufficient quality can potentially provide evidence for fluid contacts, reservoir continuity, rock properties, original hydrocarbons in place, and reservoir geometry.Often the Securities and Exchange Commission (SEC) and of the Society of Petroleum Engineers / World Petroleum Congress (SPE/WPC) definition requirements for "certainty", "reasonable certainty", and "known accumulations" disqualify some pressure interpretation methods for particular reserve estimation uses. This paper highlights some of the common pressure analysis applications that are not recognized by one or both of the reserve standards. Also presented are some applications that have been sanctioned for select reserve estimation applications.As can be expected for such a broad topic as pressure data, many issues are not black-and-white. In these cases, this paper outlines some of the critical concerns to be considered when evaluating a pressure analysis application for assigning reserves under SEC or SPE/WPC guidelines.