* North Sea Forties crude loadings delayed again
* Spain reforms lift markets (Adds investor data from CFTC)
NEW YORK, Sept 21 (Reuters) - Oil rose for a second straight session in light activity on Friday as supply concerns and economic optimism fuelled a rebound from a 7 percent slide earlier in the week.
Brent crude topped $111 a barrel but posted a 4.5 percent drop on the week due to a three-day rout that sent it plunging from $116 to $108. Oil dropped from Monday to Wednesday on rising U.S. inventories and Saudi efforts to tame prices.
The decline followed weeks of concern about the impact of higher oil and fuel costs on the struggling U.S. economy, which had prompted expectations the White House could tap emergency reserves to cool off prices.
Oil scraped lows not seen since early August on Thursday, before turning positive in a move that could be a sign the market is establishing a new range as traders digest a third round of U.S. quantitative easing, unrest in the Middle East and North Africa, and delays in North Sea oil shipments.
"I'm not really sure we've seen a turnaround yet. Oftentimes when the market sees a lot of liquidation pressure it rebounds when that dissipates," said Gene McGillian, analyst at Tradition Energy in Stamford, Connecticut.
"Going forward, I think the market has established a bit of a new trading range from $90 to $100 (a barrel for U.S. crude) and it's trying to find a value here and settle down."
Oil found some support from optimism over a move by Spain toward reform measures in anticipation of a bailout package. Equities markets rose.
November Brent futures settled up $1.39 at $111.42 a barrel, before trading up to $111.70 in post-settlement activity. Brent hit a low of around $107 on Thursday, its weakest since Aug. 3.
On Friday, it edged back above its 50-day moving average around $111.18, a technical indicator watched by traders.
Brent outpaced U.S. futures, sending the premium of the international benchmark - which is more sensitive to North Sea disruptions - to U.S. oil up 90 cents to near $18.50 a barrel.
U.S. futures ended down 6.2 percent for the week.
On Friday, November U.S. crude climbed 47 cents to settle at $92.89 a barrel, off highs of $93.84. The October contract for U.S. crude expired on Thursday at $91.87 a barrel, having tested the 100-day moving average of $90.73.
Trading was light, with U.S. crude volumes on the New York Mercantile Exchange nearly 30 percent below the 30-day moving average and Brent trade more than 20 percent below that average.
Comments from a Gulf source that OPEC kingpin Saudi Arabia wanted lower oil prices and was willing to supply more oil to the market set a bearish tone for much of the week.
The comments helped deflate expectations that a third round of stimulus announced by the U.S. Federal Reserve last week would send investors into oil and other riskier asset classes.
High prices and the economic downturn have helped drive down U.S. fuel demand in recent years, and a report released on Friday by industry group the American Petroleum Institute showed U.S. oil consumption hit the lowest level in 15 years for any August.
Hedge funds and other large investors have, however, been increasing bets on rising prices since June.
Data from the U.S. Commodity Futures Commission (CFTC) on Friday showed speculators raised their net long futures and options positions in U.S. crude oil by 18,006 contracts to 243,303 in the week to Tuesday. The net long position has risen by 65 percent in past three months.
NORTH SEA, LIBYA
Ongoing export delays of North Sea Forties oil, the most important of the four grades that form the Brent crude basket, stirred concerns about availabilities.
Two more cargoes of North Sea Forties crude loading in October were delayed due to maintenance at the 200,000-barrels-per-day Buzzard field, the largest connected to the Forties pipeline. The field was shut on Sept. 5 for 28 days of work, but traders now say that maintenance could be extended by three to five days.
In addition, the market was watching unrest in OPEC member Libya, Africa's third-biggest producer, that could further delay already-slow efforts to return expatriate oil workers to the country after last year's revolution.
Libya apologised on Thursday to visiting U.S. Deputy Secretary of State William Burns for an attack on the U.S. consulate in Benghazi last week in which U.S. ambassador Christopher Stevens and three other Americans died. (Reporting by Matthew Robinson and David Sheppard in New York, Peg Mackey in London and; Luke Pachymuthu in Singapore; Editing by Dale Hudson, Bob Burgdorfer and Leslie Gevirtz)