With November Brent Crude futures expiring in Friday’s session, traders are expecting more volatility on the spread between Brent and WTI oil futures.

The spread rose to as high as $27 in Thursday’s session. Petromatrix analyst Olivier Jakob says the main trading action for the last two days has been a convergence trade on the front Brent spread and the Brent premium to West Texas Intermediate, or WTI.