Canada - Nexen Inc said it concluded its recent three-well drilling program at Horn River shale gas property and was producing between 15 million cubic feet a day (mmcf/d) to 20 mmcf/d from its five shale gas wells.

The wells have a higher fracture density than the earlier wells and Nexen's land position in the area could support up to 500 to 700 wells, it said in a statement.

Nexen, Canada's No. 4 independent oil explorer, said it took advantage of improved equipment utilization and drilled longer wells.

We are currently in the process of developing a winter drilling program that will continue to advance our understanding of this resource and allow us to make more progress on costs and well productivity, Chief Executive Marvin Romanow said in a statement.

Nexen, which has about 88,000 acres in the Dilly Creek area of the Horn River basin, estimates its lands contain between 3 trillion cubic feet (TCF) and 6 TCF of contingent recoverable resource, which could double its existing total proved reserves.

Shares of the company, which have gained about 11 percent since last month, closed at C$25 Monday on the Toronto Stock Exchange. (Reporting by Ashutosh Joshi in Bangalore; Editing by Unnikrishnan Nair)