Systems and methods for controlling parameters of drilling fluid

Abstract

Provided are methods, apparatus, and computer-readable media for controlling parameters of drilling fluid. In an example, provided is a method including (i) receiving, by a drilling fluid flow controller, information indicating a measured inflow rate of drilling fluid flowing into a wellbore; (ii) receiving, by the drilling fluid flow controller, information indicating a measured outflow rate of the drilling fluid flowing out of the wellbore; (iii) calculating a differential flowrate between the measured inflow rate and the measured outflow rate; (iv) calculating a proportional gain from the differential flowrate and a setpoint; (v) calculating an integral gain from the differential flowrate and the setpoint; (vi) calculating, by the drilling fluid flow controller, a choke control output by summing the proportional gain with the integral gain; and (vii) moving, responsive to the choke control output, a position of the choke valve. Other methods, systems, and computer-readable media are also disclosed.

What is claimed is: 
     
         1 . An apparatus for automatically controlling parameters of drilling fluid, comprising;
 a choke valve having a choke valve position;   an inflow flowmeter configured to generate information indicating a measured inflow rate of the drilling fluid flowing into a wellbore;   an outflow flowmeter configured to generate information indicating a measured outflow rate of the drilling fluid flowing out of the wellbore, wherein the outflow flowmeter is located downstream from the choke valve; and   a drilling fluid flow controller having a memory device storing instructions configured to cause the drilling fluid flow controller to automatically:
 receive the information indicating the measured inflow rate; 
 receive the information indicating the measured outflow rate; 
 calculate a differential flowrate between the measured inflow rate and the measured outflow rate; 
 calculate a proportional gain from the differential flowrate and a first setpoint; 
 calculate an integral gain from the differential flowrate and the first setpoint; and 
 calculate a choke control output by summing the proportional gain with the integral gain, 
   wherein the choke valve is configured to adjust, responsive to the choke control output, the choke valve position to control the measured outflow rate of the drilling fluid.   
     
     
         2 . The apparatus of  claim 1 , wherein the outflow flowmeter comprises a V-shaped flowmeter orifice. 
     
     
         3 . The apparatus of  claim 1 , wherein the memory further stores instructions configured to cause the drilling fluid flow controller to receive, from a user interface device, information describing the first setpoint. 
     
     
         4 . The apparatus of  claim 1 , further comprising:
 a hydraulic actuator configured to adjust the choke valve position of the choke valve;   a hydraulic accumulator storing pressurized hydraulic fluid; and   an electrically operated valve configured to:
 receive the choke control output from the drilling fluid flow controller; and 
 control, responsive to the received choke control output, a flowrate of the hydraulic fluid from the hydraulic accumulator to the hydraulic actuator. 
   
     
     
         5 . The apparatus of  claim 1 , wherein the memory further stores instructions configured to cause the drilling fluid flow controller to automatically:
 compare the differential flowrate to a second setpoint, wherein the second setpoint describes a maximum allowed differential flowrate; and   modify, when the differential flowrate is equal to or greater than the second setpoint, the choke control output to adjust the choke valve position to reduce the differential flowrate.   
     
     
         6 . The apparatus of  claim 5 , wherein the memory further stores instructions configured to cause the drilling fluid flow controller to receive, from a user interface device, information describing the second setpoint. 
     
     
         7 . The apparatus of  claim 1 , wherein the drilling fluid flow controller comprises at least one of a field programmable gate array, a programmable logic device, an application-specific integrated circuit, a non-generic special-purpose processor, a gated logic device, or a dedicated hardware finite state machine. 
     
     
         8 . The apparatus of  claim 1 , wherein the memory further stores instructions configured to cause the drilling fluid flow controller to automatically:
 convert the information indicating the measured outflow rate of the drilling fluid flowing out of the wellbore to a human-readable form; and   display the human-readable form of the information indicating the measured outflow rate of the drilling fluid flowing out of the wellbore on a user interface device.   
     
     
         9 . A method for automatically controlling parameters of drilling fluid, comprising;
 receiving, by a drilling fluid flow controller, information indicating a measured inflow rate of the drilling fluid flowing into a wellbore;   receiving, by the drilling fluid flow controller, information indicating a measured outflow rate of the drilling fluid flowing out of the wellbore and through an outflow flowmeter located downstream from a choke valve;   automatically calculating, by the drilling fluid flow controller, a differential flowrate between the measured inflow rate and the measured outflow rate;   automatically calculating, by the drilling fluid flow controller, a proportional gain from the differential flowrate and a first setpoint;   automatically calculating, by the drilling fluid flow controller, an integral gain from the differential flowrate and the first setpoint;   automatically calculating, by the drilling fluid flow controller, a choke control output by summing the proportional gain with the integral gain; and   automatically moving, responsive to the choke control output, a position of the choke valve.   
     
     
         10 . The method of  claim 9 , wherein the outflow flowmeter comprises a V-shaped flowmeter orifice. 
     
     
         11 . The method of  claim 9 , further comprising receiving, by the drilling fluid flow controller and from a user interface device, information describing the first setpoint. 
     
     
         12 . The method of  claim 9 , further comprising:
 automatically comparing, by the drilling fluid flow controller, the differential flowrate to a second setpoint, wherein the second setpoint describes a maximum allowed differential flowrate; and   automatically modifying, by the drilling fluid flow controller and when the differential flowrate is equal to or greater than the second setpoint, the choke control output to adjust the choke valve position to reduce the differential flowrate.   
     
     
         13 . The method of  claim 12 , further comprising receiving, by the drilling fluid flow controller and from a user interface device, information describing the second setpoint. 
     
     
         14 . The method of  claim 9 , further comprising:
 automatically converting the information indicating the measured outflow rate of the drilling fluid flowing out of the wellbore to a human-readable form; and   automatically displaying the human-readable form of the information indicating the measured outflow rate of the drilling fluid flowing out of the wellbore on a user interface device.   
     
     
         15 . A non-transitory computer-readable medium, comprising processor-executable instructions stored thereon configured to cause a processor to:
 initiate receiving information indicating a measured inflow rate of drilling fluid flowing into a wellbore;   initiate receiving information indicating a measured outflow rate of the drilling fluid flowing out of the wellbore and through an outflow flowmeter located downstream from a choke valve;   initiate calculating a differential flowrate between the measured inflow rate and the measured outflow rate;   initiate calculating a proportional gain from the differential flowrate and a first setpoint;   initiate calculating an integral gain from the differential flowrate and the first setpoint; and   initiate calculating a choke control output by summing the proportional gain with the integral gain.   
     
     
         16 . The non-transitory computer-readable medium of  claim 15 , further storing instructions configured to cause the processor to initiate receiving, by the processor and from a user interface device, information describing the first setpoint. 
     
     
         17 . The non-transitory computer-readable medium of  claim 15 , further storing instructions configured to cause the processor to:
 initiate automatically comparing, by the processor, the differential flowrate to a second setpoint, wherein the second setpoint describes a maximum allowed differential flowrate; and   initiate automatically modifying, by the processor and when the differential flowrate is equal to or greater than the second setpoint, the choke control output to adjust the choke valve position to reduce the differential flowrate.   
     
     
         18 . The non-transitory computer-readable medium of  claim 17 , further storing instructions configured to cause the processor to initiate receiving, by the processor and from a user interface device, information describing the second setpoint. 
     
     
         19 . The non-transitory computer-readable medium of  claim 15 , wherein the processor is a drilling fluid flow controller. 
     
     
         20 . The non-transitory computer-readable medium of  claim 15 , further storing instructions configured to cause the processor to:
 initiate automatically converting the information indicating the measured outflow rate of the drilling fluid flowing out of the wellbore to a human-readable form; and   initiate automatically displaying the human-readable form of the information indicating the measured outflow rate of the drilling fluid flowing out of the wellbore on a user interface device.