Oil and gas stocks closed another session mixed, as choppy trading prevailed throughout the day.  Independent E&Ps and independent refiners were the lead gainers, while the broader drillers group gave back recent gains. Trading volumes were slightly below average in individual energy stocks, while sector-specific ETF volumes were well below average, indicating a lack of hedge fund participation in the energy patch.

WTI crude oil prices closed higher by $1.13, or 1.14%, at $99.84, while Brent crude oil prices also gained over 1%.  The spread between the two contracts remained ...