Production measurement in multiple completion wells

Claim 1

IN A METHOD OF DETERMINING THE RATES OF FLOW FROM TWO SURFACE HYDROCARBON-PRODUCING FORMATIONS, THE STEPS OF: (A) FLOWING FLUID FROM ONLY ONE FORMATION THROUGH AN ORIFICE AND THENCE THROUGH A CONDUIT TO THE SURFACE, (B) VARYING THE SURFACE PRESSURE IN SAID CONDUIT AND MEASURING THE CORRESPONDING RATE OF FLOW IN SAID CONDUIT AND ASO THE CORRESPONDING DOWNHOLE PRESSURE AT A POINT WITHIN SAID CONDUIT IMMEDIATELY DOWNSTREAM FROM SAID ORIFICE, (C) PLOTTING THE INTERRELATED RATE OF FLOW OF DOWNHOLE PRESSURE MEASUREMENTS TO DEFINE A PRODUCTION-PRESSURE CURVE HAVING A POINT OF INFLECTION, (D) FLOWING FLUID FROM BOTH FORMATIONS THROUGH SEPARATE ORIFICES AND THENCE COMMINGLED THROUGH A COMMON CONDUIT TO THE SURFACE, (E) MEASURING THE COMBINED RATE OF FLOW FROM BOTH FORMATIONS WHEN SO COMMINGLED, AND (F) MEASURING THE DOWNHOLE PRESSURE UNDER COMMINGLED FLOW CONDITIONS AT A POINT WITHIN SAID CONDUIT IMMEDIATELY DOWNSTREAM FROM THE ORIFICES; WHEREBY AFTER A COMPARISON OF THE LAST-MENTIONED PRESSURE WITH THE VALUE OF PRESSURE AT POINT OF INFLECTION OF SAID CURVE, THE RESPECTIVE RATES OF FLOW FROM THE TWO FORMATIONS, UNDER COMMINGLED FLOW CONDITIONS, MAY BE DETERMINED.