Downhole estimation of multiphase flows in production systems

Abstract

This disclosure relates to systems and methods with multiple sensors located in different zones of a hydrocarbon production system. The multiple sensors are configured to capture parameters about flow through multiple zones of a wellbore. The system also includes a processor that is configured to obtain data about a multiphase flow through the plurality of zones of the wellbore of the hydrocarbon production system from the multiple sensors and to solve an interpretation problem for a first unknown in a bottommost zone. The processor is configured to use a value for the first unknown in the bottommost zone to solve for a second unknown in an upper zone that is above the bottommost zone in the wellbore of the hydrocarbon production system. The processor is configured to change control parameters of the hydrocarbon production system based at least in part on the first unknown and the second unknown.

What is claimed is: 
     
         1 . A system, comprising:
 a plurality of sensors located in different zones of a hydrocarbon production system, wherein the plurality of sensors is configured to capture a plurality of parameters about flow through a plurality of zones of a wellbore of the hydrocarbon production system; and   a processor configured to:
 obtain data about a multiphase flow through the plurality of zones of the wellbore of the hydrocarbon production system from the plurality of sensors; 
 solve an interpretation problem for a first unknown in a bottommost zone of the plurality of zones; 
 use a value for the first unknown in the bottommost zone to solve for a second unknown in an upper zone of the plurality of zones that is above the bottommost zone in the wellbore of the hydrocarbon production system; and 
 change control parameters of the hydrocarbon production system based at least in part on the first unknown and the second unknown. 
   
     
     
         2 . The system of  claim 1 , wherein the upper zone is adjacent to the bottommost zone in the wellbore of the hydrocarbon production system. 
     
     
         3 . The system of  claim 1 , wherein the first unknown comprises a downstream flow rate for the bottommost zone. 
     
     
         4 . The system of  claim 3 , wherein the second unknown comprises a downstream flow rate of the upper zone, and solving for the second unknown comprises setting an upstream flow rate of the upper zone to the downstream flow rate of the bottommost zone. 
     
     
         5 . The system of  claim 4 , wherein solving the interpretation problem for the first unknown comprises setting an upstream flow rate of the bottommost zone to zero. 
     
     
         6 . The system of  claim 3 , wherein the downstream flow rate comprises a total downstream flow rate. 
     
     
         7 . The system of  claim 6 , wherein the processor is configured to determine a fractional flow rate of a phase of a mixture flowing from the bottommost zone into the upper zone using a phase fraction for a corresponding phase. 
     
     
         8 . The system of  claim 7 , wherein the processor is configured to receive the phase fraction from a simulator or via manual input. 
     
     
         9 . The system of  claim 3 , wherein the downstream flow rate comprises a fractional flow rate of a phase of a mixture flowing from the bottommost zone into the upper zone. 
     
     
         10 . The system of  claim 9 , wherein the processor is configured to determine a total flow rate using the fractional flow rate and a phase fraction for a corresponding phrase. 
     
     
         11 . The system of  claim 1 , wherein each of the plurality of zones comprises a flow control valve (FCV). 
     
     
         12 . The system of  claim 11 , wherein the data about the multiphase flow comprises:
 a pressure of an annulus around a casing in each of the plurality of zones;   a temperature of the annulus in each of the plurality of zones;   an upstream pressure for each of the plurality of zones inside the casing inside the respective zone upstream of the respective FCV of the zone;   an upstream temperature for each of the plurality of zones inside the casing inside the respective zone upstream of the respective FCV of the zone; and   a downstream temperature for each of the plurality of zones inside the casing inside the respective zone downstream of the respective FCV of the zone.   
     
     
         13 . The system of  claim 11 , wherein changing the control parameters comprises causing an aperture size of at least one of the FCVs to be adjusted based at least in part on the first unknown or the second unknown. 
     
     
         14 . A method, comprising:
 receiving measurements at a processor from a plurality of sensors in a plurality of zones of a wellbore of a hydrocarbon production system;   solving, via the processor, an interpretation problem for a first unknown in a bottommost zone of the plurality of zones;   using a first value for the first unknown in the bottommost zone to solve for a second unknown using the processor, wherein the second unknown pertains to a parameter in an upper zone of the plurality of zones that is above the bottommost zone in the wellbore of the hydrocarbon production system; and   causing, by the processor, a change in an aperture of a programmable flow control valve of the hydrocarbon production system based at least in part on the first unknown and the second unknown.   
     
     
         15 . The method of  claim 14 , wherein the first unknown comprises a downstream flow in tubing of the wellbore in the bottommost zone, and solving for the first unknown comprises assuming that an upstream flow in the tubing of the wellbore in the bottommost zone is zero. 
     
     
         16 . The method of  claim 15 , wherein the second unknown comprises a downstream flow in the tubing of the wellbore in the upper zone, and solving for the first unknown comprises estimating that an upstream flow in the tubing of the wellbore in the upper zone is equal to the solved downstream flow in the tubing of the wellbore in the bottommost zone. 
     
     
         17 . The method of  claim 15 , wherein the second unknown comprises a downstream flow in the tubing of the wellbore in the upper zone, and solving for the first unknown comprises estimating an upstream flow in the tubing of the wellbore in the upper zone based on an adjustment to the solved downstream flow in the tubing of the wellbore in the bottommost zone, wherein the method comprises receiving the adjustment using a well flow simulation model to determine that there is a pressure or temperature difference to be accounted for between an interior of the tubing in the bottommost zone and the upper zone. 
     
     
         18 . The method of  claim 14 , comprising using a second value for the second unknown in the upper zone to solve for a third unknown using the processor, wherein the third unknown pertains to an additional parameter in an additional upper zone that is above the upper zone in the wellbore of the hydrocarbon production system. 
     
     
         19 . A system, comprising:
 a plurality of pressure sensors configured to measure pressure in a plurality of zones in a wellbore in a hydrocarbon production system;   a plurality of field control valves in the plurality of zones configured to control flow from an annulus into tubing of the wellbore based at least in part on respective aperture sizes of the plurality of field control valves;   a plurality of temperature sensors configured to measure temperature in the plurality of zones; and   one or more processors configured to:
 receive the temperature measurements for the plurality of zones; 
 receive the pressure measurements for the plurality of zones; 
 estimate no upstream flow in a most upstream zone of the plurality of zones, wherein the most upstream zone is the furthest zone from a wellhead of the wellbore; 
 determine flow properties in the most upstream zone; 
 use the determined flow properties in the most upstream zone, respective temperature measurements, and respective pressure measurements to determine flow properties of each zone of the plurality of zones in a sequence of most upstream to most downstream; and 
 based at least in part on flow properties of at least one of the plurality of zones, cause at least one aperture of the plurality of field control valves to change. 
   
     
     
         20 . The system of  claim 19 , wherein the flow properties of the plurality of zones comprises a total flow of a mixture and one or more phasic flows of phases of the mixture.