Abstract: A method for determining along relatively uniformly spaced apart parallel first and second wellbores situated in an underground hydrocarbon-containing formation, regions within the formation, including in particular regions between such wellbores, to inject a fluid at a pressure above formation dilation pressure, to stimulate production of oil into the second of the two wellbores, and subsequently injecting fluid at pressures above formation dilation pressures at the discrete regions along such wellbores determined to be in need. An initial information-gathering procedure is conducted, wherein fluid is supplied under a pressure less than formation dilation or fracture pressure, to discrete intervals along a first wellbore, and sensors in the second wellbore measure and data is recorded regarding the ease of penetration of such fluid into the various regions of the formation intermediate the two wellbores.

Abstract: A method for determining along a length of a wellbore situated in an underground hydrocarbon-containing formation, regions within the formation to inject a fluid at a pressure above formation dilation pressure, to stimulate production of oil into the wellbore. An initial information-gathering procedure is conducted prior to formation dilation/fracturing, wherein fluid is supplied under a pressure less than formation dilation or fracture pressure, to discrete intervals along the wellbore, and sensors measure and data is recorded regarding the ease of penetration of such fluid into the various regions of the formation. Regions of the formation exhibiting poor ease of fluid penetration or regions of higher oil saturation, are thereafter selected for subsequent stimulation or dilation, at pressures above formation dilation pressures. Where initial fluid pressures and/or formation dilation pressures are provided in cyclic pulses, a downhole tool is disclosed for such purpose.

Abstract: A method is taught for applying vacuum pulses to enhance multiphase vacuum extraction of vapours and liquids from contaminated subsurface wells. The method involves first initiating continuous multiphase vacuum extraction from the subsurface well. Then one or more short vacuum pulses are imparted to the subsurface environment, to momentarily interrupt flow of vapours and liquids in the subsurface well. Time is allowed for a vacuum to build up in the extraction apparatus; and then the vacuum build up is rapidly released to momentarily increase velocity of vapours and liquids being extracted from the subsurface well. A device is further taught for imparting vacuum pulses to enhance multiphase extraction from contaminated subsurface wells, comprising a vacuum pulse tool having an inlet in fluid communication with the subsurface well and an outlet and one or more multiphase extraction vacuum pumps, connected to the outlet of the vacuum pulse tool.