Patent ID: 7640133

Claim:
In an injector well having a wellhead at the earth's surface where a two phase fluid is supplied to the injector well for injection into a surrounding formation along a portion of the injector well, a method for determining at least one fluid property of the two phase fluid along the portion of the injector well, the method comprising: measuring temperatures and pressures of the two phase fluid at the wellhead; measuring the speed of sound in the two phase fluid at the wellhead using time-of-flight measurements of sonic pulses passing through the two phase fluid; measuring temperatures of the two phase fluid at a plurality of locations along the portion of the injector well; and determining at least one fluid property of the two phase fluid along the portion of the injector well from the temperatures, pressures, and speed of sound measured at the wellhead, and the temperatures measured at the plurality of locations along the portion of the injector well, wherein the at least one fluid property is selected from the group including i) vapor phase fractions of the two phase fluid at the plurality of locations along the portion of the injector well; ii) changes in mass flow rate of the two phase fluid at the plurality of locations along the portion of the injector well; iii) enthalpy flux of the two phase fluid at the plurality of locations along the portion of the injector well; and iv) data, derived from a calculation of enthalpy flux upstream of the portion of the injector well, the calculation derived from a plurality of calculated fluid properties including a) a vapor phase fraction of the two phase fluid, derived in accordance with the equation c 2 ≈ ρ υ ⁢ c υ 2 α ⁡ ( 1 - α ) ⁢ ρ l 2 where α is the vapor phase fraction of the two phase fluid; ρ v is a vapor phase density estimate of the two phase fluid at the temperature and pressure measured at the wellhead; ρ l is a liquid phase density estimate of the two phase fluid at the temperature and pressure measured at the wellhead; and c v is the speed of sound in the vapor phase of the two phase fluid at the wellhead under isothermal conditions; b) a homogeneous density estimate of the two phase fluid; c) volume flow rate of the two phase fluid; and d) mass flow rates of the vapor phase and liquid phase of the two phase fluid, the data characterizing energy of the two phase fluid along the portion of the injector well.