Photo: Ganymede ZD platform; Source: Chrysaor

Green light for Chrysaor’s decommissioning plan for Ganymede platform topsides

Chrysaor’s decommissioning plan for the Ganymede platform topsides, which is located on the Jupiter area in the UK sector of the North Sea, has been approved by UK authorities.

The Jupiter fields were developed in two phases to support the production from the Jupiter area using the LOGGS Gathering Station to transport the produced oil and gas from the field for further processing and sale.

The first phase was the development of the Ganymede ZD normally unmanned installation (NUI) platform and Callisto subsea tie-back to Ganymede in 1995.

The second phase was the development of the Europa EZ NUI platform and NW Bell ZX subsea tie-back to Callisto ZM in 2000.

The decline in production led to the cessation of production that was approved by OGA in 2016, enabling decommissioning activities to begin on the facilities in 2017. The platforms are in cold suspension, awaiting removal and disposal.

The Jupiter facilities currently consist of two Jupiter surface installations Ganymede ZD and Europa EZ, one subsea tee at the intersection of the Europa EZ to Callisto ZM, two Jupiter subsea tiebacks with wellhead protection structures – Callisto ZM and NW Bell ZX – and the inter-field pipelines.

Source: Chrysaor
Source: Chrysaor

Chrysaor, as the operator of the Jupiter fields, applied to the Offshore Petroleum Regulator for Environment and Decommissioning (OPRED) to obtain approval for the decommissioning of the following Ganymede ZD topsides.

The schedule outlined in the decommissioning programme started with the well plugging and abandonment in 2016 and will span approximately seven years.

As for the Ganymede topside, it weighs 1,082 tonnes and the installation stands in 33.5 metres of water. Other installations, including the Ganymede ZD jacket and pipelines in the Jupiter area, will be decommissioned at an appropriate time and covered by their own decommissioning programmes.

Jupiter fields

The Jupiter fields were discovered in 1972 by the 49/16-4 well which encountered 325 feet of gas column in the Rotliegendes Group Leman Sandstone Formation in what became the Ganymede Field. The exploration and appraisal programme continued through the 1990s with discoveries in the Europa, Callisto, and Sinope Fields.

The Jupiter fields consist of several separate gas accumulations which lie within blocks 49/16a, 49/17a,

49/22a, 49/22c, 49/22d and 49/23a (licences P.025 and P.033) in the Southern North Sea of the UKCS.

The Ganymede field is located approximately 132 kilometres east of the Theddlethorpe Gas Terminal (TGT) terminal. First production from the Ganymede Field and Callisto Field was in September 1995.

In 2000, NW Bell and Europa came online. This backed out Ganymede and some wells were shut-in. When NW Bell and Europa declined in 2001, the Ganymede wells were reinstated.

The Jupiter field was net cash flow negative in 2014 which initiated decommissioning activities on the installations to start and production to cease from Jupiter in November 2016.

The Ganymede ZD, Europa EZ, and subsea tiebacks Callisto ZM and NW Bell ZX produced 494 bscf of gas up to the termination of production in 2016.