Projects:  T/41P

Bass Basin Activities

3D Oil Limited was granted the T/41P Exploration Permit, located in the eastern Bass Basin, in June 2005 and has held it at 100% equity since that time. In early 2010 the six-year permit term was extended by 12 months, and is due to expire in June 2012.

Bass Basin Overview

The Bass Basin is a relatively under-explored basin on Australia’s southeastern margin, underlying the shallow seabed between Tasmania and the Victorian mainland. It has long been recognized to contain excellent quality source rocks and has had a high strike rate for intersecting hydrocarbons. Commercial success, however, has proven to be more difficult. This changed in 2006 with the opening of the Bass Gas project centred on the Yolla oil and gas discovery, approximately 40 km to the west of T/41P, with Proved and Probable Reserves of 330 petajoules of gas and 28 MMbbl of condensate and oil.

Since drilling commenced in the Bass Basin in 1965 fewer than 40 exploration wells have been drilled. Apart from the Yolla Field, discoveries in the Bass Basin include the Pelican gas/condensate field, the Cormorant oil discovery and the gas/condensate discoveries at White Ibis and Trefoil.

T/41P Permit

Image: Regional structural elements and permit location

Spanning around 2,805 square kilometres, T/41P is a very large permit in the eastern Bass Basin. It has only been lightly explored with one well, Chat-1, drilled in 1986. The well was located on a broad 2D seismic grid and tested a reactivated fault block. A residual oil column is interpreted in the well, suggesting that the trap was originally hydrocarbon-bearing, but subsequently leaked. Importantly, this indicates that the permit has had access to hydrocarbon charge.

Existing seismic coverage within T/41P was sparse, consisting of data from six surveys ranging in vintage from 1975 to 1990. Four moderate-sized leads (40-140 MMstb recoverable) were identified from the broad 2D grid, but more seismic was required to mature these to prospect status.

T41/P Work Programme Commitments

Work Programme

3D Oil acquired 2,200 km of 2D seismic in April to May 2008 over the permit area, infilling the existing sparse seismic coverage and targeting the south-west of the of the permit, where basin modelling suggested there was access to migrating hydrocabons. The seismic data was processed and interpreted, with the resulting mapping indicating that there is considerably more structuring than previously thought. The existing leads have been confirmed and new leads have been identified.

Historically, discoveries in the Bass Basin have been either at the top Eastern View Subgroup level or in the lower Eastern View Subgroup. 3D Oil’s preliminary mapping suggested that many of the new and existing leads have the potential for stacked objectives, with significant volume upside.

Image: Dalrymple Prospect

To follow up the promising leads identified in the south-west of the permit, in early 2011 3D Oil acquired the 264 square kilometre Dalrymple 3D seismic survey. This survey was acquired without any down time or HSE incidents in under five days.

In late March 2011, the minimum work programme for Year 6 in T/41P was varied by replacing an exploration well with geological and geophysical studies, including state-of-the-art processing and interpretation of the new 3D seismic data.

The Dalrymple 3D data is currently being processed, and is expected to be ready for interpretation starting in September 2011. Identification of suitable targets for exploration drilling in anticipated to be completed before Q2 2012.

Image: Prospects and leads in T/41P and area of Dalrymple 3D seismic survey