|Lease||PPL 328 (APDL 14)|
|Location||Gulf of Papua, Offshore Papua New Guinea|
|Water Depth||93 metres|
|Field Type||Liquids-rich gas-condensate accumulation in carbonate pinnacle reef|
|Status||Reserves proven, development plan completed and production licence pending final approval|
The Pasca A gas condensate field is a carbonate pinnacle reef that was discovered some 50 years ago but has lain dormant with no further technical follow-on work for nearly three decades as previously it appeared any development solution for the gas field would not be straightforward or commercially attractive. However improvements in drilling efficiency, production technology and development engineering have transformed the technical and commercial viability of the Pasca A gas condensate discovery.
The relatively shallow water depth (93 metres), benign tropical metocean conditions, close proximity to landfall (95 kilometres), and rich hydrocarbon liquids yield of the gas make the Pasca A field an ideal candidate for development.
Twinza unlocked the geological aspects of the field, through integration of a variety of data sources and development drilling. In addition to the historical data from the three wells drilled and previous 2D seismic surveys, Twinza improved the initial understanding of the field using 3D seismic data, innovative analysis combined with modern interpretation tools, and the application of modern core analysis techniques including derivation of digital rock properties. The integration of this data revealed an improved understanding of the field’s potential.
In September 2017 Twinza spudded the Pasca A4(AD-1) well with an objective to complete appraisal of the Pasca A field and suspend the well as a future development well for the first offshore field development in PNG. The well not only confirmed the pre-drill expectations but exceeded them, proving that the field resource was more than sufficient to underpin an economic development.
Twinza’s team of technical experts has completed a detailed plan of development which focuses on early condensate and LPG production and subsequent gas export as LNG. This concept supports the application for a Petroleum Development Licence (PDL).
The base case plan of development is a cost effective, low-footprint concept which is both highly efficient and has the potential for further optimisation and enhancement. Enhancements to the project cost, schedule and production forecasts continue to be incorporated into the plans as the Company refines the development plan.
Twinza applied for the petroleum prospecting licence in 2008 and was awarded PPL 328 in October 2011. Like all other PNG upstream assets, the government has a right to back-in and acquire up to 22.5% working interest in the project by paying back costs and forward costs. If the government exercises its right to back-in, the resulting working interest among the parties will be:
- Twinza (77.5%)
- Government Nominee (22.5%)
Since the award of the licence in 2011, better technical interpretation of the data combined with technological advances in drilling and development methods have transformed the opportunity. Twinza has re-interpreted all of the historical data and supplemented this with modern data and an appraisal well, which has resulted in the confirmation of the resource.
On 30 June 2015 Twinza, as the JV operator, submitted an application for a petroleum development licence together with the Pasca A field development plan. This application has been reviewed by the regulator.
In anticipation of the PDL grant, Twinza has undertaken all necessary work to prepare for execution of the project. These activities include completion of an environmental impact assessment at the field location in the Gulf of Papua and Twinza receiving the Environmental Permit for operations. Social mapping and landowner identification studies have been completed and the results provided to the government.
A third-party assessment of the recoverable resource volumes at the Pasca A field has been obtained. The assessment sets out the gas, condensate and LPG recoverable volumes in accordance with the guidelines set out in the Petroleum Resource Management System (PRMS) published by the Society of Petroleum Engineers. The most recent assessment was completed in April 2018 and classified recoverable reserves of 69.1 mmbbl condensate and LPG plus a recoverable gas resource of 326.7 bcf.
Twinza has completed the concept selection phase of the Pasca A development project. This phase included gathering of basic data including site survey, geotechnical soil investigation, metocean data gathering and analysis, and drilling of an appraisal well to obtain data related to rock and fluid properties. Concept engineering work into the well completion design, gas processing solution and utilities, and offshore infrastructure for production, storage and offloading has been completed. Twinza has undertaken pre-front end engineering and design (FEED) studies and commenced execution planning.
The development engineering is based on three wells: two production wells and a single injector. These wells are tied back to a minimal wellhead platform which is braced to an adjoining self-installing platform which hosts the processing and utilities topsides. Condensate and LPG extracted from the gas during Phase I is stored on a floating storage and offloading vessel accessible from the platform via a retractable gangway, whilst the residual dry gas is reinjected into the reservoir. For the second phase of development, a floating liquefaction storage and offloading (FLSO) vessel will be moored close to the central processing facility and the residual gas will be re-routed via a flowline to the FLSO. At this time injection well will be re-purposed as a production well simply by reversing the direction of flow in the well.
Concept selection work on the second phase of development associated with LNG export has commenced. Pre-FEED engineering has been completed and Twinza is currently readying to commence delivery of the first phase of the Pasca A field development project, starting with FEED work. It is anticipated that immediately after FEED for the first phase has been completed, the second phase of development will start. Whilst these two phases of development are separate, they are sequentially linked.