Abstract: The recovery of petroleum produced from an oil reservoir is enhanced by injecting water such as from a geopressured aquifer having a natural gas content at or near saturation at a temperature above 300.degree. F. into the oil reservoir at a flow rate sufficient to develop a back-pressure in the oil reservoir equal to between about 80% of its fracture pressure and a pressure below its fracture pressure and producing oil from the oil reservoir when the injection of water necessary to maintain the back-pressure below the oil reservoir fracture pressure drops below a predetermined level. The recovery of petroleum also is enhanced by using sand screening means to complete a portion of the well bore penetrating into the oil reservoir and a straddle packer assembly means which can be raised and lowered relative to the screening means.

Abstract: A method of natural gas production from wells drilled into geopressured aquifers containing methane saturated water, comprising using wells which permit initial flow of water with a complete absence of back pressure at the well head, and containing the flow of water until loss of pressure in the aquifer exsolves sufficient gas to reverse the gas/water permeability ratio, thus converting the flow entirely to natural gas and water vapor and creating a gas cap. A further embodiment is the subsequent use of rings of secondary wells of similar design, each ring located at approximately equal radial distances from the initial well, to produce similar gas caps which interact with-, and produce from-, the gas cap created by production from the initial well and the gas caps of the other secondary wells.