UK GAS-Prices for immediate delivery fall due to oversupply

* System oversupply by 20 mcm

* UKCS flows higher as outages end

LONDON, Dec (Shanghai: 600875.SS - news) 30 (Reuters) - British wholesale gas prices declined on Friday morning due to increased flows from the UK Continental Shelf as several outages ended in the North Sea.

Gas for immediate delivery was down 1.05 pence at 51.50 pence per therm at 0841 GMT.

The system is oversupplied by around 20 million cubic metres, with demand forecast at 295 mcm and flows at 315 mcm/day, National Grid (LSE: NG.L - news) data shows.

Flows are back to 30 million cubic metres (mcm) per day from Shell (LSE: RDSB.L - news) 's St Fergus terminal after an outage ended and Engie E&p UK's Cygnus offshore facilities have returned to full operations.

Flows from the North Morecambe gas sub-terminal have also resumed following an outage.

However, day-ahead gas rose by 0.85 pence to 52.00 p/therm.

Thomson Reuters (Dusseldorf: TOC.DU - news) analysts said the temperature forecast for Saturday (Shenzhen: 002291.SZ - news) is 2.8 degrees Celsius below normal, which should boost demand for gas for heating.

Oil prices are on track for their biggest annual percentage gain since 2009 on the back of an agreement struck between OPEC and non-OPEC countries to cut crude production output.

In the European Union's carbon market, the benchmark Dec-17 carbon contract was 0.07 euro higher at 6.44 euros a tonne.

In the Netherlands, the day-ahead gas price at the TTF hub was 0.58 euro higher at 19.50 euros per megawatt hour. (Reporting by Nina Chestney)