Correlations for Fluid Physical Property Prediction

Introduction

The evaluation of physical properties of hydrocarbon mixtures is an important step in the design of various stages of oilfield operations. The fluid properties, which change as pressure and temperature change, must be evaluated for both reservoir engineering and production design operations. For example, the production design operations. For example, the calculation of two-phase flowing pressure gradients occurring in piping systems requires prediction of fluid properties such as dissolved gas, formation volume factor (FVF), oil compressibility, and viscosity at various locations in the pipe, Even though laboratory measurements of these properties may be available as a function of pressure, the measurements usually are made at reservoir temperature only. The behavior of these properties with temperature change usually is predicted empirically.

Increasing emphasis is being placed on the necessity of having accurate estimates of fluid physical properties in advance of laboratory PVT physical properties in advance of laboratory PVT analyses of the reservoir fluids. Many times these properties are required at a time when the only properties are required at a time when the only information available consists of oil and gas gravities and reservoir pressure and temperature. The purpose of this study was to utilize a large base of laboratory. measured PVT data to develop improved empirical correlations to replace those commonly in use. Many of the presently used correlations were developed many years ago from limited data and are being used beyond the range for which they were intended.

JPT

P. 968