It All Begins in The Field and Ends in The Field: How We Leverage Our 90-Year Legacy to Successfully Explore In PNG

Abstract

Oil Search has been exploring the Papuan Fold Belt (PFB) for nearly 90 years. About 7bboe have been discovered to date, resulting in the construction of an LNG terminal in 2010. The PFB has been considered one of the most difficult areas to explore for hydrocarbons worldwide. Exploration has progressed on the back of photo and satellite mapping, verified with field campaigns in highly forested and rugged terrain. Subsurface mapping was/is tackled via 2D seismic acquisition and interpretation adding the surface data constraints. Trap definition is the critical risk in the PFB, and even more so now as surface anticlines are being drilled-out. Seismic data in the fold belt continues to deliver mixed results in subsurface imaging to enable interpreters to identify subsurface traps and narrow-down the spectrum of viable interpretations. To the latter, our preferred workflow to map prospects establishes a hierarchy of data to interpret seismic data: 1) surface geological data, dip data, carbonate depth derived from Strontium age data; 2) offset well tops, true stratigraphic thickness and well dips; and 3) seismic dip panels to define structural discontinuities. Given the shortcomings of subsurface imaging, seismic interpretation proceeds by either honouring surface-well data and selectively picking seismic dip panels to develop a structural ‘seed’ interpretation or by ‘flexing’ forward models to the data. Some interpreters will use both approaches. The result is a wide range of viable (some admissible and some not) interpretations. Though the PFB shares the common challenges and risks of other fold belts, there are specific aspects to this geologic system that have required a fit for purpose toolkit to manage operations and to de-risk exploration targets. Examples of this “endemic” toolkit for exploration include LIDAR for planning and mapping, bridging for seismic acquisition and strontium isotope age to establish the base of carbonates. Oil Search leverages on the Papua New Guinean people who master the environment, their own communities and are incredibly resourceful in finding solutions to access the field during operations. Unfortunately, some of the practices of the past, such as surface geological mapping, have lost favor. In this talk, we make a case that LIDAR with traditional field calibration can still provide critical information that could optimize seismic acquisition, processing, interpretation and drilling. We present a set of recent examples, some in hindsight, that indicate that the best utilization of modern technology starts and ends on the ground. Our long presence in PNG and our technical and operational know-how on the ground has positioned us as one of the operators of choice in PNG.

AAPG Datapages/Search and Discovery Article #90371 © 2020 AAPG Asia Pacific Region, The 1st AAPG/EAGE PNG Geosciences Conference, PNG’s Oil and Gas Industry: Maturing Through Exploration and Production, Port Moresby, Papua New Guinea, February 25-27, 2020