Matra Petroleum, the Russia focussed oil and gas company says the quality of oil produced at its Sokolovskoe field suggests "robust economics", in other words, sustained profitability.The next stage of development at Sokolovskoe will be a 3D seismic survey across the entire field.Revenue in the first half of 2011 totalled €0.29m, up from zero in the corresponding period of 2010.Loss before tax narrowed slightly to €0.6m from €0.7m the year before.The company's A13 well produced a total of 3,765 barrels of oil without significant water production. The production rate is expected to be improved when a down-hole pump is installed. The well is currently shut-in and in order to resume production, some surface production equipment will need to be installed on-site and a down-hole pump installed. The directors believe this will generate a positive cash flow after the deduction of production taxes and other costs.The A12 well has shown that it is capable of producing at an initial oil rate of around 1,000 barrels per day, the company said, but continues to be affected by water production. An attempt to shut-off water using a production packer was unsuccessful. At the time of reporting, an independent technical data review is in progress to assess the viability of further remedial action on well A-12 to shut-off water. Once this review is complete a decision on the future of the well will be taken.Peter Hind, Managing Director of Matra Petroleum commented: "Significant progress was made in the first half of 2011 with confirmation of a high quality reservoir. We look forward to the next stage of development with the drilling of well A-14 later this year which we expect to further improve the commerciality of the field."Shares in Matra were up 7% in early trading.BS