MILLBURN, N.J. ( Stockpickr) -- West Texas Intermediate crude oil prices dropped from a high of $114.80 per barrel on May 2 to a low of $74.90 per barrel on Oct. 4, representing a 35% decline. The Philadelphia Oil Service Sector and the Oil Service HLDRs ETF ( OIH) declined from high to low during the same period by about 40% each. Since the U.S. markets bottomed in a rather dramatic fashion on Oct. 4, WTI crude has risen by about $10 a barrel.Clearly the oil service and integrated oil company stocks are highly correlated to each other. WTI at close to $115 per barrel was caused by panic over political uncertainty in the Middle East. The low of nearly $75 per barrel was caused by a strong U.S. dollar and fears of a global recession. >>5 Stocks Under $10 With Big Upside Potential The double-dip theory took a hit when the September labor report indicated that payrolls rose by 103,000 in that month and that another 99,000 were added to the disappointing numbers previously reported for July and August. A reasonable expectation would be for WTI to trade up to around $90. With that in mind, I see some excellent opportunities in creating a diverse portfolio of stocks across the oil and gas energy complex.