The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 26, 1984
Filed:
Dec. 07, 1982
Alvin S Cullick, Dallas, TX (US);
Melwyn L Mathis, Arlington, TX (US);
Bert J Warner, Dallas, TX (US);
Mobil Oil Corporation, New York, NY (US);
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.2 injected is determined. Additional CO.sub.2 displacement tests are conducted at the same temperature T.sub.1 and CO.sub.2 flow rate F.sub.1 at various pressure levels (at least two) above the CO.sub.2 MMP. The pressure drop at each pressure P.sub.3 and P.sub.4 above the CO.sub.2 MMP is plotted versus the volume of carbon dioxide injected. The pressure drop .DELTA.P.sub.3 and .DELTA.P.sub.4 at the point of inflection as previously defined is determined for the corresponding pressure P.sub.3 and P.sub.4. The corresponding pressure drop at the inflection point obtained for the pressure values below MMP and the pressure drop at the inflection point obtained for the pressure values above MMP minus the pressure drop for CO.sub.2 under the same test conditions as calculated by the Hagen-Poiseuille equation are plotted as a linear function of test pressure. The CO.sub.2 MMP is determined graphically as the pressure at the point where the two lines defining miscible and immiscible displacement intersect.