APPLICATION OF RESERVOIR GEOCHEMISTRY IN THE IAGIFU-HEDINIA FIELD, PAPUA NEW GUINEA

Abstract

In oilfield development and appraisal, a variety of tools are used to help define future reservoir performance. The identification of reservoir compartments, whether vertical or lateral, is a critical part of this evaluation. Reservoir compartments may develop over geologic or production timeframes depending on the characteristics of the reservoir seals. Frequently, the identification of some reservoir compartments is made only after the field is put on production.

Reservoir pressure data is commonly used to identify reservoir compartments. A powerful complement to the pressure data are the properties of the reservoir fluids themselves. This provides a direct measure of hydrocarbon continuity. Both physical properties, such as gravity, bubble point pressure and GOR, and molecular properties of the oil are used. The detailed hydrocarbon composition of the reservoir fluids can be determined by a number of geochemical methods. In this paper we use capillary gas chromatography to generate oil fingerprints based on the molecular composition. We show how the oil fingerprint data is a sensitive discriminator of reservoir compartments.

Reservoir studies of the Iagifu-Hedinia Field, Papua New Guinea, show the benefit of using a combination of geochemical, geological and engineering data. Each type of data reflects a different characteristic of the reservoir compartments. The combination of oil fingerprint and RFT pressure data demonstrated that some seals have been effective over geologic timeframes while others are effective only on a production timeframe. Geochemical data have also indicated the presence of reservoir compartments where other data were missing or inconclusive. Subsequently acquired production history data have confirmed the geochemically-based interpretations.