oa Seismic acquisition and analysis of the Elk Carbonate Reservoir, Papua New Guinea

The Elk Trend Gas field in the Elk Reservoir was discovered in October of 2006 in a frontier area within the Eastern Papuan Basin in the Gulf Province, Papua New Guinea.

To overcome a lack of well and seismic data in this lightly explored area, InterOil has engaged in a comprehensive appraisal 2D and well seismic program. The stated objectives of this seismic program were to determine the overall structure of the Elk Reservoir with seismic data of dramatically increased quality and in addition to acquire seismic data in the follow-up appraisal Elk2 well to tie seismic character to well data including formation tops.

The increase in data quality is necessary to accurately define the dimensions of the Elk structure and, with well seismic from VSP programs, to enable strong correlation between the seismic data and reservoir properties from well bore measurements. To enable better quality data a series of parameter tests were performed which included analysing previous 2D data for noise content and strategies for noise removal, evaluating various shot and receiver arrays and also testing various shot hole depths, and charge sizes.

These parameter tests were highly successful with the data exceeding expectations. The demonstrated significant increase in data quality has allowed not only the gross reservoir structure to be mapped but has even allowed internal detail in the reservoir to be imaged. This data has allowed sequence stratigraphy to be attempted on land data from PNG for the first time.

VSP data collected from both zero offset and simultaneous walkaways has allowed robust correlations between formation tops and seismic to be performed. Future work with the VSP datasets and the new 2D seismic is intended to include AVO and inversion enabling petrophysical modelling of the Elk Reservoir.