sentences:  "In situ" means "in place," and refers to recovery techniques which apply heat or solvents to oil reservoirs beneath the earth.There are several varieties of "in situ" technique, but the ones that work best in the oil sands use heat.The first "in situ" experiment in Alberta took place in 1910, when a Pittsburgh-based outfit, the Barber Asphalt and Paving Company, drilled a bore hole into the bitumen and pumped in steam to liquefy the oil.