Energy-focused private investment firm Riverstone Energy Limited (REL) has announced an investment in Canadian International Oil Corp (CIOC), a private exploration and production company focused on liquids-rich unconventional resources in Western Canada.Since listing in London in October 2013, REL has invested in five energy companies spanning conventional and unconventional oil and gas activities in the Gulf of Mexico, the Continental US and now Western Canada.REL, along with parent company Riverstone Holdings, has committed a total of C$200m to CIOC, C$67m of which will come from REL. An initial capital call of C$100m will be funded on Thursday to support near-term drilling.CIOC, established in 2010, has one of the largest and most advantaged land positions in the emerging Montney and Duvernay formations of Western Canada's Deep Basin, according to REL.The company controls and operates 100% of its asset base, which comprises 400,000 acres and currently produces around 3,000 barrels of oil equivalents per day."This investment provides additional scale and diversification to REL's asset base, allows REL to deploy capital immediately in one of the most prolific trends in North America, and demonstrates continued delivery of the strategy that we presented to REL investors," said Pierre Lapeyre and David Leuschen, Co-Founders of Riverstone. The stock was up 0.46% at 893.05p in early trading on Thursday.BC