(ShareCast News) - AIM-listed oil and gas company Parkmead increased its stake in the Perth and Dolphin oil fields in the North Sea, which significantly increased the company's oil reserves.The UK and Netherlands focused company raised its stake in the oil fields to 60.05%, thus increasing potential reserves by 19% to 27.9m barrels of oil equivalent.Perth and Dolphin, located in licences P218, P588 and P2154 in the Moray Firth area, are upper jurassic claymore sandstone accumulations which have produced up to 6,000 barrels of oil per day.This follows the company's August acquisition of an additional 50% equity in the Polecat and Marten oil fields, which the company said also have the potential to be "highly valuable" due their proximity to other oil fields and can be developed in the greater Perth-Dolphin-Lowlander oil hub project.Analysis by the company found that a joint development of the Perth, Dolphin and Lowlander fields could significantly increase the value of the project. It's expected that 80m barrels of oil will be recovered from the oil hub, which is double the initial recoverable reserves of the Perth field as a standalone project.The project, which has 13 wells drilled and contain over 400m barrels of oil in place, will use the same production facilities used by other project and provide a new long-term hub for future projects in the area.Executive Chairman Tom Cross said: "This growth step strengthens Parkmead's asset base in the centre of the company's major Perth-Dolphin-Lowlander oil hub project, which is one of the largest undeveloped oil projects in the North Sea."Parkmead is working intensively to evaluate and execute further value-adding opportunities in its core areas of the UK and Netherlands."Shares in Parkmead were up 12.18% to 55.25p at 1427 BST.