U.S. oil prices have set another record on the New York Mercantile Exchange, reaching $44.24 a barrel, the highest since NYMEX launched its crude contract in 1983. (...) Following are some of the factors behind oil's price surge. --RISING DEMAND ... -- LACK OF SPARE SUPPLY CAPACITY ... --REFINERY BOTTLENECKS ... --SCARCER OIL Big oil reservoirs are becoming harder to find and more expensive to develop. Many of the oil provinces outside OPEC are mature, which means that finds are now smaller, need more costly technology to develop and fall faster from peak production.