Enerplus Resources Fund (NYSE: ERF), a Foolish favorite among the high-yielding energy investment trusts, came out with a big press release this week. Let's step through the transactions and see what the future looks like for this Canadian oil and gas producer.

Enerplus may have surprised some folks by divesting its Kirby oil sands project, but there's certainly precedent here. Back in 2002, the firm acquired a 16% interest in Joslyn, a project now controlled by Total (NYSE: TOT), for $16 million. Enerplus swapped 1% of Joslyn for an equity stake in privately held Laricina Energy, now worth around $125 million based on a recent financing round. The company later unloaded its remaining 15% stake to Occidental Petroleum (NYSE: OXY) in 2008 for about $500 million. The company did very well by shareholders here.

Enerplus iced its remaining oil sands project in 2009. The company has now agreed to sell its 100%-owned Kirby project for around $393 million, or about 55% more than the company's total investment in the project to date. This may not be as big a score as the Joslyn investment, but it's nothing to sneeze at. There's no information at this point as to whether the buyer is an existing SAGD slugger like Cenovus Energy (NYSE: CVE) or a new entrant from overseas.

So, now that Enerplus is officially out of the oil sands game (save for its equity interest in Laricina), where can we expect the company to focus? Well, as stated at recent investor conferences, the firm is focused on resource plays, and the Marcellus and the Bakken in particular. No surprise, then, that this week's announcement includes acreage acquisitions in both of those plays.

The Bakken purchase is bringing in 46,500 "bolt-on" acres that are adjacent to Enerplus' existing land base. The price tag is $456 million, or roughly $9,800 an acre. There's a decent data point for those of you looking to value Bakken players like Northern Oil and Gas (AMEX: NOG) or Brigham Exploration (Nasdaq: BEXP).

In the Marcellus, Enerplus is picking up 58,500 undeveloped acres in West Virginia and Maryland. I was unaware that Maryland was even in contention as a potential Marcellus target. This acreage is pretty far from the main action in Pennsylvania. The company didn't break out its cost for this acquisition, but year to date, the firm's implied average cost comes in at more than $2,000 an acre. That's modest compared with the Bakken price tag, but not cheap, either, especially considering the largely unproven ZIP codes involved here.

Enerplus has proven a pretty savvy acquirer in the past, so I'll give it the benefit of the doubt here, but shareholders should keep a close eye on results in this off-the-beaten-path Marcellus play.