Abstract: A method for determining the CO.sub.2 minimum miscibility pressure (MMP) is disclosed which comprises filling a coiled capillary tube with oil at a predetermined temperature T.sub.1 and an initial predetermined pressure P.sub.1 less than the CO.sub.2 MMP. Carbon dioxide is injected into the capillary tube at a fixed flow rate F.sub.1 to displace the oil while maintaining the temperature of the oil at T.sub.1 and the pressure at P.sub.1. The pressure drop across the capillary tube and the volume of carbon dioxide injected is constantly measured. The pressure difference versus volume of carbon dioxide injected data is plotted and the pressure drop .DELTA.P.sub.1 at the point of inflection where the second derivative goes from a negative value to a positive value is determined graphically. The previous steps are repeated while maintaining T.sub.1 and F.sub.1 constant at a different pressure P.sub.2 less than the CO.sub.2 MMP and .DELTA.P.sub.2 at the inflection point of pressure versus volume of CO.sub.

Abstract: A method for determining the foaming characteristics of a crude oil stream at the wellhead comprising introducing the production crude oil stream from the wellhead into an elongated, horizontal separator under reduced pressure at a controlled flow rate, withdrawing evolved gas from the upper portion of the separator and measuring the flow rate thereof, withdrawing oil from the lower portion of the separator and measuring the flow rate thereof, controlling the pressure on the separator at a lower pressure than the wellhead pressure, controlling the liquid level of the oil in the separator, measuring the volume of oil in the separator, and measuring the volume of foam in the separator.

Abstract: Method and apparatus for mixing a gaseous oxidant (e.g., oxygen) and a lixiviant (e.g., an aqueous carbonate solution) at a downhole location before the oxygen-saturated lixiviant is injected into a formation to be leached. The invention involves establishing a mixing zone in the well by positioning a mixing means, comprising a housing, in the well at the downhole location. Lixiviant is flowed down the well and through a restrictive opening in the housing to substantially increase the flow velocity of the lixiviant. At the same time, gaseous oxidant is fed to the housing and is trapped therein by the increased velocity of the lixiviant and by packing material in said housing. The lixiviant flows through the trapped oxidant which, in turn, dissolves into the lixiviant to saturate same. Additional packing material is provided in the housing to remove undissolved oxidant from the saturated lixiviant before it is injected into a formation to be leached.