Automated Fluid System

Abstract

A method of controlling the composition of a drilling fluid comprises receiving measurements of properties of a drilling fluid; determining a concentration of the components of the drilling fluid by inputting the measured properties to a fluid model that relates the properties of the drilling fluid to the concentrations of each of the components; determining a desired concentration of each of the plurality of components of the drilling fluid, by inputting desired properties of the drilling fluid to the fluid model; and determining a quantity of one or more additives to be added to the drilling fluid to achieve the desired concentration of each of the plurality of components. The invention includes a controller (20) for controlling the method and a system (1) therefore.

1 . A method of controlling composition of a drilling fluid,
 comprising: receiving measurements of properties of a drilling fluid;   determining a concentration of each of a plurality of components of the drilling fluid, by inputting the measured properties to a fluid model that relates the properties of the drilling fluid to the concentrations of each of the components;
 determining a desired concentration of each of the plurality of components of the drilling fluid, by inputting desired properties of the drilling fluid to the fluid model; and 
   determining a quantity of one or more additives to be added to the drilling fluid to achieve the desired concentration of each of the plurality of components.   
     
     
         2 . A method in accordance with  claim 1 , wherein determining the desired concentration of each of the plurality of components of the drilling fluid comprises:
 randomly selecting a concentration of each of the plurality of components of the drilling fluid; and
 using the fluid model to estimate properties of a drilling fluid having the randomly selected concentrations. 
   
     
     
         3 . A method in accordance with  claim 2 , further comprising:
 comparing the desired properties of the drilling fluid with the estimated properties of a drilling fluid having the randomly selected concentrations.   
     
     
         4 . A method in accordance with  claim 3 , further comprising:
 determining a composition of the drilling fluid having properties that most closely match the desired properties by repeatedly performing the operations of randomly selecting a concentration of each of the plurality of components of the drilling fluid, using the fluid model to estimate properties of a drilling fluid having the randomly selected concentrations, and comparing the desired properties of the drilling fluid with the estimated properties of a drilling fluid having the randomly selected concentrations.   
     
     
         5 . A method in accordance with  any of the preceding claims , wherein determining a concentration of each of the plurality of components of the drilling fluid comprises:
 estimating a concentration of a component of the drilling fluid using a mass balance equation.   
     
     
         6 . A method in accordance with  claim 5 , further comprising:
 solving the mass balance equation using an estimated quantity of a component of the drilling fluid that has been depleted during a drilling process.   
     
     
         7 . A method in accordance with  claim 6 , further comprising:
 estimating the quantity of a component of the drilling fluid that has been depleted   
       using a depletion model that relates depletion of the component to one or more variables of the drilling process. 
     
     
         8 . A method in accordance with  claim 7 , further comprising:
 updating a depletion coefficient of the depletion model based on measurements   
       of the one or more variables made during the drilling process. 
     
     
         9 . A method in accordance with any of  claims 5 to 8 , further comprising:
 solving the mass balance equation using a known quantity of an additive that has been added to the drilling fluid during a drilling process.   
     
     
         10 . A method in accordance with any of  claims 5 to 9 , wherein determining a concentration of each of the plurality of components of the drilling fluid further comprises:
 determining a plurality of candidate concentrations of each of the plurality of components of the drilling fluid by inputting the measured properties to the fluid model; and   eliminating a candidate concentration that is inconsistent with the estimated   
       concentration. 
     
     
         11 . A method in accordance with  any of the preceding claims , wherein the 
       one or more additives include a polysaccharide. 
     
     
         12 . A method in accordance with  any of the preceding claims , further comprising:
 measuring the properties of the drilling fluid using one or more sensors on a drilling rig.   
     
     
         13 . A method in accordance with  claim 12 , wherein the properties include one or more of: viscosity; density; a rheological property; filtrate data; a measured concentration of one or more ions; a measured concentration of one or more chemicals;
 and filtration/fluid loss.   
     
     
         14 . A method in accordance with  any of the preceding claims , further comprising:
 controlling a chemical dosing apparatus to add the determined quantity of the one or more additives to the drilling fluid.   
     
     
         15 . A controller for controlling composition of a drilling fluid, the controller
 comprising:
 one or more processors; and 
   a processor-readable medium storing instructions that, when executed by the one or more processors, cause the controller to perform a method in accordance with  any of the preceding claims .   
     
     
         16 . A drilling rig comprising a controller in accordance with  claim 15 . 
     
     
         17 . A drilling rig in accordance with  claim 16 , further comprising:
 one or more sensors configured to measure properties of a drilling fluid, and to   
       provide the measured properties to the controller; and/or
 a chemical dosing apparatus for adding the determined quantity of the one or 
 
       more additives to the drilling fluid. 
     
     
         18 . A processor-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform a method in accordance with any of  claims 1 to 14 . 
     
     
         19 . A computer program comprising instructions that, when executed by a computer, cause the computer to perform a method in accordance with any of  claims 1 to 14 .