Method and apparatus for characterizing inorganic scale formation conditions employing a microfludic device

Abstract

A test method and apparatus employs a microfluidic device to characterize properties of a fluid. The microfluidic device has an inlet port, an outlet port, and a microchannel as part of a fluid path between the inlet port and the outlet port. While a fluid is introduced into the microchannel, the fluid temperature is maintained while the fluid pressure in the microchannel is varied to characterize the properties of the fluid in the microchannel. The properties of the fluid can relate to a scale onset condition of the fluid at the pressure of the flow through the microchannel. In one aspect, fluid pressure in the microchannel is maintained while the fluid temperature is varied to characterize the properties of the fluid. In another aspect, flow rate of the fluid through the microchannel is varied while the fluid temperature is maintained to characterize the properties of the fluid in the microchannel.

What is claimed is: 
     
         1 . A test method for characterizing properties of a fluid, comprising:
 providing a microfluidic device having at least an inlet port, an outlet port, and a microchannel as part of a fluid path between the first inlet port and the outlet port;   generating a flow of the fluid through the microchannel at a variable flow rate;   maintaining a temperature of the fluid flowing through the microchannel;   measuring and recording a pressure difference of the fluid across the microchannel and an average pressure of the fluid between an inlet and an outlet of the microchannel;   evaluating or analyzing the pressure difference while the flow rate is varied to determine whether the fluid in the microchannel flowing through the microchannel exhibits characteristics indicative of the presence of scale formation.   
     
     
         2 . A test method according to  claim 1 , wherein evaluating or analyzing the pressure difference includes determining if the pressure difference varies linearly with the flow rate, wherein, if it is determined that the pressure difference varies linearly with the flow rate, then it is further determined that the fluid in the microchannel does not exhibit characteristics indicative of the presence of scale formation, and if it is determined that the pressure difference varies non-linearly with the flow rate, then it is further determined that the fluid in the microchannel does exhibit characteristics indicative of the presence of scale formation. 
     
     
         3 . A test method according to  claim 2 , further comprising identifying a scale onset pressure where scale begins to form as the average pressure recorded at a transition point where the pressure difference transitions between varying linearly and non-linearly with the flow rate and between varying non-linearly and linearly with the flow rate. 
     
     
         4 . A test method according to  claim 3 , wherein the fluid includes at least one of a reservoir fluid, a scale inhibitor, water, and a gas. 
     
     
         5 . A test method for characterizing properties of a fluid, comprising:
 providing a microfluidic device having at least an inlet port, an outlet port, and a microchannel as part of a fluid path between the first inlet port and the outlet port;   introducing the fluid into the microchannel;   maintaining a constant pressure to the fluid in the microchannel;   measuring and recording pressure and temperature of the fluid in the microchannel;   adjusting the temperature of the fluid in the microchannel;   evaluating the fluid while the temperature of the fluid is adjusted;   characterizing properties of the fluid in the microchannel based on the evaluation of the fluid.   
     
     
         6 . A test method according to  claim 5 , wherein the properties of the fluid relate to the scale onset formation condition of the fluid at the applied pressure and a scale onset temperature. 
     
     
         7 . A test method according to  claim 6 , further comprising repeating adjusting the temperature of the fluid in the microchannel, evaluating the fluid while the temperature of the fluid is adjusted, and characterizing properties of the fluid in the microchannel based on the evaluation of the fluid until the scale onset formation condition occurs. 
     
     
         8 . A test method according to  claim 7 , further comprising capturing images of the fluid in the microchannel. 
     
     
         9 . A test method according to  claim 8 , wherein evaluating the fluid includes analyzing the captured images in order to determine whether such images include information that indicates the presence of scale formation in the fluid in the microchannel. 
     
     
         10 . A test method according to  claim 9 , wherein the fluid introduced into the microchannel includes at least one of a reservoir fluid, a scale inhibitor, water, and a gas. 
     
     
         11 . A test apparatus for characterizing properties of a fluid, comprising:
 a microfluidic device having at least an inlet port, an outlet port, and a microchannel as part of a fluid path between the first inlet port and the outlet port;   a temperature-controlled surface that is thermally-coupled to the microfluidic device and configured to maintain a temperature of the microchannel of the microfluidic device;   at least one temperature sensor for measuring a temperature characteristic of the microchannel of the microfluidic device; and   means for introducing the fluid into the microchannel;   a pressure sensor configured to measure pressure of the fluid in the microchannel;   means for adjusting the pressure of the fluid in the microchannel while the temperature characteristic is maintained for evaluation of the fluid while the pressure is adjusted to characterize properties of the fluid in the microchannel based on the evaluation of the fluid.   
     
     
         12 . A test apparatus according to  claim 11 , further comprising a light source and camera configured to capture images of the microchannel of the microfluidic device and fluid in the microchannel. 
     
     
         13 . A test apparatus according to  claim 12 , further comprising:
 means for evaluating or analyzing the images captured by the camera in order to determine whether such images include information that indicates the presence of scale formation in the fluid that flows through the microchannel of the microfluidic device at a respective adjusted pressure; and   wherein the means for adjusting the fluid pressure is constructed to iteratively adjust the fluid pressure and the means for evaluating or analyzing the images is constructed to iteratively evaluate the images captured by the camera of the fluid in the microchannel corresponding to each iterative adjustment of the fluid pressure.   
     
     
         14 . A test apparatus for characterizing properties of a fluid, comprising:
 a microfluidic device having at least an inlet port, an outlet port, and a microchannel as part of a fluid path between the first inlet port and the outlet port;   means for generating a flow of the fluid through the microchannel at a variable flow rate;   a temperature-controlled surface that is thermally-coupled to the microfluidic device and configured to maintain a temperature of the microchannel of the microfluidic device;   an inlet pressure sensor configured to measure an inlet pressure of the fluid at the inlet of the microchannel;   an outlet pressure sensor configured to measure an outlet pressure of the fluid at the outlet of the microchannel;   measurement and recording means for measuring and recording a pressure difference between the inlet and outlet pressures and measuring and recording an average of the inlet and outlet pressures;   means for evaluating or analyzing the pressure difference while the flow rate is varied to determine whether the fluid in the microchannel flowing through the microchannel exhibits characteristics indicative of the presence of scale formation.   
     
     
         15 . A test apparatus according to  claim 14 , wherein the means for evaluating or analyzing the pressure difference determine if the pressure difference varies linearly with the flow rate, wherein, if it is determined that the pressure difference varies linearly with the flow rate, then it is further determined that the fluid in the microchannel does not exhibit characteristics indicative of the presence of scale formation, and if it is determined that the pressure difference varies non-linearly with the flow rate, then it is further determined that the fluid in the microchannel does exhibit characteristics indicative of the presence of scale formation. 
     
     
         16 . A test method according to  claim 15 , wherein the means for evaluating or analyzing the pressure difference identify a scale onset pressure, where scale begins to form, as the average pressure recorded at a transition point where the pressure difference transitions between varying linearly and non-linearly with the flow rate and between varying non-linearly and linearly with the flow rate. 
     
     
         17 . A test apparatus for characterizing properties of a fluid, comprising:
 a microfluidic device having at least an inlet port, an outlet port, and a microchannel as part of a fluid path between the first inlet port and the outlet port;   means for introducing the fluid into the microchannel;   means for maintaining a constant pressure of the fluid in the microchannel;   a temperature-controlled surface that is thermally-coupled to the microfluidic device and configured to adjust a temperature of the microchannel of the microfluidic device;   a pressure sensor configured to measure the pressure of fluid in the microchannel;   a temperature sensor configured to measure the temperature of fluid in the microchannel; and   means for evaluating the fluid while the temperature of the fluid is adjusted.   
     
     
         18 . A test apparatus according to  claim 17 , wherein the properties of the fluid relate to the scale onset formation condition of the fluid at the applied pressure and a scale onset temperature. 
     
     
         19 . A test apparatus according to  claim 18 , wherein the means for evaluating the fluid include a light source and camera configured to capture images of the microchannel of the microfluidic device and fluid in the microchannel. 
     
     
         20 . A test method according to  claim 19 , further comprising means for characterizing properties of the fluid in the microchannel based on the evaluation of the fluid, the means constructed to determine, responsive to analyzing the captured images, whether the images include information that indicates the presence of scale formation in the fluid in the microchannel.