UPDATE 1-Rockhopper says Falklands well could have 4,000 bopd

* Sea Lion 1 well produced over 2,000 bopd

* Estimates well could have flowed at 4,000 bopd

* Test affected by technical problems

* Shares open up 3.5 pct

(Adds detail, background, shares)

LONDON, Sept 24 (Reuters) - British explorer Rockhopper RKH.L said its controversial oil discovery offshore the Falklands Islands could have produced double the amount of oil had a test not been besieged by technical problems.

Rockhopper said a test at the Sea Lion 1 well had produced sustained rates of over 2,000 barrels per day (bopd), in line with the results of previous tests, but could have produced about 4,000 barrels of oil a day if the company hadn’t encountered a variety of problems.

“Rockhopper believes that the flow rate was inhibited by incomplete perforation, waxing of the tubing string above 800 metres, increased viscosity of the oil as it cooled in the upper part of the test string and a lack of specialist equipment,” the company said in a statement on Friday.

“Rockhopper also believes that, with a more optimal well location and horizontal well completions, significantly higher flow rates could be achieved from future production wells,” it added.

The company said last week it believed the oil discovery offshore the Falklands Islands will be commercially viable, sending its shares to an all-time high. [ID:nLDE68G1OJ]

The hotly anticipated Sea Lion well is the first oil find of an exploration programme offshore the islands by a suite of British explorers.

The drilling has sparked protests from Argentina, which claims sovereignty over the islands it calls the Malvinas.

Rockhopper shares were up 6.9 percent to 536 pence in early trade, taking the shares to another all-time high and valuing the company at over 1 billion pounds ($1.57 billion).

Shares in Desire Petroleum DES.L, which also has acreage in the North Falklands basin, were up 5.5 percent to 166 pence.