Spectroscopic pH measurement at high-temperature and/or high-pressure

• US 7,402,424 B2
• Filed: 02/01/2006
• Issued: 07/22/2008
• Est. Priority Date: 02/01/2006
• Status: Expired due to Fees

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Borman, Craig, Raghuraman, Bhavani, Rabbito, Philip, Gustavson, Gale, Muhammad, Moin, Gao, Jinglin
• Primary Examiner(s): Weber; Jon P
• Assistant Examiner(s): Shen; Bin
• Application Number:
  US11/345,460
• Publication Number:
  US 20070178595A1
• Time in Patent Office: 902 Days
• Field of Search: None
• US Class Current: 435/287.1
• CPC Class Codes: G01N 21/80 Indicating pH value
• CPC Class Codes: Y10T 436/11 Automated chemical analysis

Abstract

Methods and apparatuses for high-temperature and high-pressure measurement of pH and/or alkalinity of a fluid is described.

Claims

1. A method of high-temperature and high-pressure measurement of pH of a fluid, the method comprising:

a. inputting an amount of dye solution into a dye chamber;

b. inputting an amount of water into a fluid sample chamber;

c. adjusting the pressure of the dye solution with a first pressure regulating means and adjusting the pressure of the water with a second pressure regulating means to a measurement pressure;

d. measuring a spectrum of the water;

e. displacing the water with a fluid sample, while ensuring that the second pressure does not drop below the measurement pressure;

f. measuring a spectrum of the fluid sample;

g. inputting a desired amount of the dye solution into the fluid sample chamber, while ensuring that the first pressure does not drop below the measurement pressure; and

h. measuring a spectrum of the dye solution and the fluid sample mixture;

i. determining the pH of the fluid sample using the measured spectrum.

2. The method of claim 1, further comprising:

maintaining the temperature of the dye solution and the water to a measurement temperature prior to measuring the spectrum of the water.

3. The method of claim 1, further comprising:

adjusting the pressure of the dye solution and the fluid sample mixture to one or more additional measurement pressures;

measuring a spectrum of the dye solution and the fluid sample mixture; and

determining a pressure sensitivity of the pH of the fluid sample.

4. The method of claim 2, further comprising:

adjusting the temperature of the dye solution and the fluid sample mixture to one or more additional measurement temperatures;

measuring a spectrum of the dye solution and the fluid sample mixture; and

determining a temperature sensitivity of the pH of the fluid sample.

5. A method of high temperature and high pressure measurement pH of a fluid, the method comprising:

a. filling lines, pump cylinders, and a container capable of withstanding high temperature and high pressure with water at a measurement pressure and a measurement temperature, such that the container is in operable communication with at least one pressure regulating means and at least one temperature regulating means;

b. measuring the spectrum of the water;

c. displacing at least a portion of the water with a fluid sample at measurement pressure and temperature, while ensuring that the pressure does not drop below the measurement pressure and the temperature is maintained at the measurement temperature;

d. measuring the spectrum of the fluid sample at measurement pressure and temperature;

e. mixing a known amount of a dye solution with the fluid sample, while ensuring that the pressure does not drop below the measurement pressure and the temperature is maintained at the measurement temperature; and

f. measuring the spectrum of the dye/fluid sample mixture at measurement pressure and temperature;

g. determining the pH of the dye/fluid sample mixture from the spectrum of the dye/fluid sample mixture.

6. The method of claim 5, further comprising:

h. adjusting the pressure of the dye/fluid sample mixture to one or more additional measurement pressures;

i. measuring the spectrum of the pressure adjusted dye/fluid sample mixture;

j. determining the pressure sensitivity of the pH of the fluid sample using the spectrum of (i).

7. The method of claim 5, further comprising:

h. adjusting the temperature of the dye/fluid sample mixture to one or more additional measurement temperatures;

i. measuring the spectrum of the temperature adjusted dye/fluid sample mixture;

j. determining the temperature sensitivity of the pH of the fluid sample using the spectrum of (i).