Papuan Basin Study

SUBJECT: PROPOSAL - CONSTRAINING THE TIMING, DISTRIBUTION AND ORIGIN OF HYDROCARBONS IN THE PAPUAN BASIN

The alliance members PetroConsult Pty Ltd, Geotrack International Pty Ltd and Keiraville Konsultants Pty Ltd are offering an integrated geochemical analysis of the Papuan Basin to assist in prospect evaluation. The non-exclusive study will attempt to model and predict hydrocarbon charge in the Foreland and Fold-Belt areas of Papua New Guinea. It will deliver predictions on the type (oil versus gas) and relative volumes of hydrocarbons generated, the effect of uplift, erosion and fresh water influx on hydrocarbon accumulations in areas targeted by the participating companies.

The participation and commitment of these three specialist companies, who have a long working history in the region, is required to answer these complex questions. A multi-disciplinary approach involving experts in their fields will address the many issues; from understanding the history of structuration to a rigorous assessment of maturity, and 2D modelling of maturation, generation and fluid movement.

Collaboration between the investigators and company personnel is critical to the success of this study. In addition to the collection of a range of possible data (AFTA, VR, FAMM, fluid inclusions, Rock-Eval etc), the study will require a number of seismic transects across the Foreland and Fold Belt. Lines adequate for this purpose may be available in the published literature. However, based on early indications, it is hoped that contributions will be made by the participating companies.

IIf you have any questions these may be directed to;

Kerry Hegarty GeoTrack Intenational Pty Ltd 03-9380 1077

Geoff Geary PetroConsult Pty Ltd 03-9849 0221

Ian Reid PetroConsult Pty Ltd 03-9534 6272

Alan Cook Keiraville Konsultants Pty Ltd 02-4229 9843

Constraining the timing, distribution and origin of hydrocarbons in the Papuan Basin

Introduction and objectives of this study

This proposed study program is designed to answer specific exploration questions that have long confronted explorationists working the Papuan Basin, PNG. Fundamental exploration issues in the Fold Belt and Foreland of PNG remain unresolved. These include:

Agreement on a unified tectono-stratigraphic framework for the Papuan Basin encompassing both Foreland and Fold Belt regions.

The relative effects (structural and thermal) of major tectonic events in the region.
Establishment of accurate thermal histories across the basin.
Evaluation of generation and charge history including local variances.
Determination of the type (oil versus gas) and relative volumes of hydrocarbons generated.
Effect of uplift, erosion and fresh water influx on hydrocarbon accumulations.

Recent drilling results and the extension of seismic data in both the Foreland and Fold Belt make this an appropriate time to re-evaluate the Papuan Basin in terms of the these issues. The timing is also very opportune given that in the near future, companies will have to make major decisions with respect to the future direction of oil and gas exploration in PNG.

Answers to these questions necessarily require a multi-disciplinary approach involving a strong, integrated group of people who have a long working history in the region. Such is the motivation by which Geotrack International, Keiraville Konsultants and PetroConsult have united to target the following key issues in the Papuan Basin.

MATURATION, GENERATION AND FLUID MOVEMENT: THE NEED FOR 2-D BASIN MODELLING:

The use of multi-dimensional basin modelling software such as PetroMod, is increasingly regarded as an important component of exploration programs. While one-dimensional (1-D) models have been used significantly in the past in PNG, they suffer from severe inherent limitations, particularly in their failure to account for lateral effects of temperature and pressure. They are also unable to account for fluid movement important in both hydrocarbon maturation and migration. 1-D results can therefore be sometimes very misleading.

While many workers assume that the hydrocarbons in the PNG Fold Belt were generated and emplaced prior to Late Tertiary thrusting and formation of the Fold Belt, other evidence suggests synchronous or even later generation and emplacement. Constrained answers to such questions concerning the timing of source rock maturation, hydrocarbon generation, oil versus gas and fluid migration questions are best answered by detailed structural modeling involving sophisticated 2-D (or even 3-D) models tied into and constrained by existing well control.

IMPROVED RESOLUTION OF MULTIPLE EVENTS:

Two major, late phases (Late Cretaceous/ Tertiary and latest Tertiary) of structuring affected the Papuan Basin. Although both events are considered important to the origin of hydrocarbons in the Papuan Basin, the significance of each is open to debate. While the Foreland and Fold Belt regions were both affected, the relative and absolute magnitude of each event varied across the regions. Understanding and measuring this variation is vital to modelling of hydrocarbon generation and entrapment. Using the latest AFTA technology, we will measure the timing and determine the magnitude of these events across the Fold Belt and Foreland. This will help constrain their effect on hydrocarbon generation and migration allowing better basin models to be built and tested.

RIGOROUS ASSESSMENT OF MATURITY:

As detailed in the discussion presented in the following Section, there are numerous apparent anomalies in the variation in maturity across the region. These perceived problems are a consequence of multiple factors such as:

the poor quality of some maturity data
unrecognised suppression and
complexities in the thermal history of the region.

A strategy to distinguish these factors and identify the way for future exploration strategies in the region is an important aim of this study.

The study objectives rely on the combined expertise and experience of Keiraville Konsultants (experts in source rock characteristics and maturity), Geotrack International (experts in measured thermal history), and PetroConsult (experts in 2-D basin modelling). The project is designed to provide constraints on the problems outlined above, and only when taken together, will they allow a better understanding of petroleum systems in the Papuan Basin. Such a project, bringing together world experts in their own field to answer fundamental unresolved questions in PNG, has not been attempted previously.

The full text of this proposal is available by contacting Geotrack International.

Information in this document is subject to change without notice. Other products and companies referred to herein are trademarks or registered trademarks of their respective companies or markholders.