Pressure Index PI: A Practical Way to Normalize Formation Pressure in Offshore Malaysia

Abstract

Pressure analysis is concerned with the study of systematic variations of reservoir pore pressure with depth. The most common interpretation for pressure analysis is pressure-depth plot analysis, but other techniques that magnify understated pressure differences are also available. The measurement of formation pressure is of immense value in quantitative evaluation and prospect risk. Once the pressure data has been acquired, we need to understand how to interpret the data received because reservoir pressure data has numerous applications and misinterpreting it could make the results misleading. At equilibrium state (i.e. there are no net forces and no acceleration), a fluid in the system is called hydrostatic equilibrium. Hydrostatic pressure increases with depth measured from the surface due to the increasing weight of fluid exerting downward force from above. The traditional pressure evaluation is usually done in conventional unit such as psi, kPa, psi/feet, psi/m, kPa/m, ppg. The current work will introduce the concepts and definitions of formation pressure evaluation using Pressure Index (PI) with the unit g/cc. For better understanding of the application of PI, some reservoir studies are also discussed in this paper.