UK Oil & Gas plc (UKOG) has completed surface-based intervention operations at Horse Hill-1 well (HH-1) which has now been shut in for a long term pressure build-up test (PBU).
The company, which owns 85.635% of HH-1, said that the test would provide the data necessary to understand whether the Portland reperforation programme had achieved the “desired optimisation of well inflow performance.”
The intervention’s objective was to optimise oil flow by reperforating the full Portland oil producing section and inserting a new production tubing string in enable the downhole pump to be placed at a deeper level.
The intervention had originally been planned for April/May but was delayed by six months due to the pandemic.
The company added that the HH-1 intervention and other related activities were part of normal oil well optimisation. Such operations, along with the continual need to optimise pump performance, could result in “considerable down time” during which there would be no oil production.
UKOG reported that during the six-month period to the end of September 2020, it produced some 28,060 bbls of oil over approximately 135 operating days.
The company added: “It should also be noted that in the normal course of conventional oil well optimisations there can be a requirement to change the placement of the downhole pump should the flow characteristics change over time, this can be the result of various factors including the break-out of solution gas and increased water cut, translating directly into a production decline over time.
“It is also normal that individual conventional oil well production declines over time.”
The Horse Hill Portland and Kimmeridge oil field is operated by UKOG’s subsidiary company Horse Hill Developments Ltd (HHDL), in which UKOG has a direct 77.9% interest.
HHDL has a 65% interest in the field and surrounding PEDL137 and PEDL246 licences, with the remaining 35% interest held by UKOG’s wholly owned subsidiary, UKOG (137/246) Ltd.