A continued rebound in crude prices on Friday saw firms in the oil services sector rise after the price of the commodity collapsed over the past few weeks.Fears about an oversupply of oil saw West Texas Intermediate (WTI) crude drop below $80 a barrel this week, while Brent futures sank to four-year low of $83.78 a barrel.Oil services stocks have sunk sharply as of late on concerns that depressed oil prices may prompt producers to scale back their project spend.However, prices were on the rise for the second day on Friday after Goldman Sachs said the recent slump in oil was "too much, too early" given that a oversupply is yet to materialise.The bank said: "The 'supply glut' is not yet here today, it exists in expectations [...] The recent sell-off in oil has been mostly driven by positioning based upon expected fundamental shifts, as opposed to currently observable shifts."Overnight the Chicago Mercantile Exchange (CME) announced that it would be increasing margin levels on all oil liquids, with effect after the close of trading today. That may have led many traders to close out or trim their 'short' positions in what is often referred to as a 'short squeeze'.WTI futures were up 1.2% at $83.71 a barrel, while Brent futures were 0.7% higher at $86.40 a barrel.Petrofac was leading the risers in the oil services category in London, up 6.1%, after reassuring investors with a steady third-quarter trading update. The company said that activity levels had stepped up over the second half as expected, as it retained its guidance for net profits of $580m-600m in 2014.While this remains lower than the $650m earned in 2013 following a profit warning earlier in the year, Liberum said: "The market generally expected Petrofac to miss this year's guidance so confirmation should be met with relief."Others stocks were also making decent gain in the sector such as Amec, Hunting, Wood Group, Gulf Marine Services and KBC Advanced Tecehnologies. Top performing sectors so far todayOil Equipment, Services & Distribution 20,945.35 +3.50%Forestry & Paper 10,636.72 +3.29%Construction & Materials 3,512.96 +2.80%Automobiles & Parts 7,184.88 +2.57%Health Care Equipment & Services 5,423.06 +2.40%Bottom performing sectors so far todayAerospace and Defence 4,323.82 -6.07%Media 5,833.94 -0.16%