Method and apparatus for determining permeability

Claim 1

THE METHOD OF DETERMINING THE PERMEABILITY OF A CYLINDRICAL, POROUS SPECIMEN COMPRISING OBTAINING PRESSURE MEASUREMENTS BY (1) PLACING SAID SPECIMEN IN A FIRST CLOSED ZONE AT A FIRST KNOWN PRESSURE WITH THE FLAT ENDS OF SAID SPECIMEN SEALED AGAINST FLUID FLOW, (2) PLACING SAID FIRST CLOSED ZONE IN COMMUNICATION WITH A SECOND CLOSED ZONE CONTAINING A GAS AT A SECOND KNOWN PRESSURE WHICH IS GREATER THAN SAID FIRST KNOWN PRESSURE, (3) EXPANDING THE GAS FROM SAID SECOND CLOSED ZONE INTO SAID FIRST CLOSED ZONE UNTIL THE PRESSURES IN BOTH ZONES ARE SUBSTANTIALLY EQUALIZED, AND (4) MEASURING THE PRESSURE IN SAID FIRST CLOSED ZONE AT A PLURALITY OF INSTANTS DURING THE EXPANSION OF SAID GAS; AND (5) PLACING A SUBSTANTIALLY FLUID-IMPERMEABLE MEMBER IN SAID FIRST SECOND ZONE AT SAID FIRST KNOWN PRESSURE, SAID FLUID-IMPERMEABLE MEMBER HAVING SUBSTANTIALLY THE SAME VOLUME AND SHAPE AS SAID SPECIMEN, (6) PLACING SAID FIRST CLOSED ZONE IN COMMUNICATION WITH SAID SECOND CLOSED ZONE CONTAINING SAID GAS AT SAID SECOND KNOWN PRESSURE, (7) EXPANDING THE GAS FROM SAID SECOND CLOSED ZONE INTO SAID FIRST CLOSED ZONE UNTIL THE PRESSURES IN BOTH ZONES ARE SUBSTANTIALLY EQUALIZED, AND (8) MEASURING THE PRESSURE IN SAID FIRST CLOSED ZONE AT A PLURALITY OF INSTANTS DURING THE EXPANSION OF SAID GAS; AND (9) FROM SAID PRESSURE MEASUREMENTS CALCULATING THE PERMEABLITY OF SAID SPECIMEN.

Claim 2

THE METHOD OF DETERMINING THE PERMEABILITY OF A CYLINDRICAL, POROUS SPECIMEN COMPRISING OBTAINING PRESSURE MEASUREMENTS BY (1) PLACING SAID SPECIMEN IN A FIRST CLOSED ZONE AT A FIRST KNOWN PRESSURE WITH THE FLAT ENDS OF SAID SPECIMEN SEALED AGAINST FLUID FLOW, (2) PLACING SAID FIRST CLOSED ZONE IN COMMUNICATION WITH A SECOND CLOSED ZONE CONTAINING A GAS AT A SECOND KNOWN PRESSURE WHICH IS GREATER THAN SAID FIRST KNOWN PRESSURE, (3) EXPANDING THE GAS FROM SAID SECOND CLOSED ZONE INTO SAID FIRST CLOSED ZONE UNTIL THE PRESSURES IN BOTH ZONES ARE SUBSTANTIALLY EQUALIZED, AND (4) MEASURING THE PRESSURE IN SAID FIRST CLOSED ZONE AT A PLURALITY OF INSTANTS DURING THE EXPANSION OF SAID GAS; AND (5) PLACING A SUBSTANTIALLY FLUID-IMPERMEABLE MEMBER IN SAID FIRST SECOND ZONE AT SAID FIRST KNOWN PRESSURE, SAID FLUID-IMPERMEABLE MEMBER HAVING SUBSTANTIALLY THE SAME VOLUME AND SHAPE AS SAID SPECIMEN, (6) PLACING SAID FIRST CLOSED ZONE IN COMMUNICATION WITH SAID SECOND CLOSED ZONE CONTAINING SAID GAS AT SAID SECOND KNOWN PRESSURE, (7) EXPANDING THE GAS FROM SAID SECOND CLOSED ZONE INTO SAID FIRST CLOSED ZONE UNTIL THE PRESSURES IN BOTH ZONES ARE SUBSTANTIALLY EQUALIZED, AND (8) MEASURING THE PRESSURE IN SAID FIRST CLOSED ZONE AT A PLURALITY OF INSTANTS DURING THE EXPANSION OF SAID GAS; AND (9) FROM SAID PRESSURE MEASUREMENTS CALCULATING THE PERMEABLITY OF SAID SPECIMEN.