The deal means group production now stands at around 200 barrels of oil equivalent per day, comprising around 80 barrels of oil.
Proved and probable reserves now stand at 1.5mln boe, of which 0.9mln are in the proved category.
A new work programme has now begun in Canada. It aims to double production volumes. Work is focussing on the repair and replacement of equipment, and no drilling capital is necessary.
Northern Petroleum highlighted that the work programme costs have almost halved, and are now expected to be US$0.6mln.
"The completion of the Rainbow Assets acquisition has put the company on a much stronger financial footing,” said Keith Bush, Northern Petroleum chief executive.
“With a relatively low risk and low cost Canadian work programme, the company should be able to generate cashflow to help support the business through this year and beyond.
“Something that is extremely important during this difficult economic period for the industry.”
Elsewhere, in Italy, the company said an environmental submission is being prepared for a proposed appraisal well on the Giove oil discovery, estimated to contain 26mln barrels of contingent oil resources.
Also a 3D seismic is being planned for Northern’s permits in the southern Adriatic, including the potentially very large Cygnus prospect (estimated at 446mln barrels).
At the Cascina Alberto permit, onshore northern Italy, the Shell led exploration programme has now begun. This will include an assessment of the 300mln barrel Gattinara prospect.
Northern Petroleum told investors that it ended 2015 with about US$2.4mln of cash, after paying for the acquisition.
Costs for 2016 are estimated to be less than US$3mln and the company said positive cashflows are forecast from Canadian production, even in the current oil price environment.
Bush highlighted that the company is in a good position to progress its opportunities.
"The company has a very good mix of opportunities which have differing levels of risk and reward for shareholders that will mature over different time scales,” he added.