Measuring process of dynamic viscosity of heavy live crude from the reservoir pressure up to atmospheric pressure, including bubble point pressure, based on an electromagnetic viscometer

Patent metadata

Field	Value
Publication number	US-9255871-B2
Application number	US-201213430979-A
Country	US
Kind code	B2
Filing date	Mar 27, 2012
Priority date	Mar 28, 2011
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

The object of the present invention is to provide a process for experimental determination of heavy live crude oil dynamic viscosities reliable at a constant temperature (from ambient temperature to 463 K) and pressures from 68.9 MPa to the atmospheric pressure, including the dynamic viscosity at the bubble point pressure and by below of this point, based on a simple, reliable and accurate apparatus. The apparatus used in the present invention is based on an electromagnetic concept, only using a mobile element (piston) through a fluid at a constant force. The time required for the piston to travel a fixed distance is related exactly to the dynamic viscosity of the fluid contained in a measuring chamber. When the fluid contained in the inner part of the measuring chamber is more viscous, the piston displacement will be slower.

First claim

Having described our invention enough, we consider it as an innovation and therefore, we reclaim it as our exclusive property the content in the following claims:

1. A process for determining dynamic viscosities of monophasic samples extracted from a crude oil well comprising:
measuring the viscosity of a 20 to 50 mL crude oil sample at a first temperature up to 463 K and a first pressure greater than the atmospheric pressure;
decrementally reducing the pressure from the first pressure to a second pressure, subsequently stabilizing the sample at the first temperature, and thereafter measuring the viscosity at each pressure decrement and at the first temperature to determine a bubble point pressure and the dynamic viscosity at the bubble point pressure of the sample;
measuring the bubble point pressure p b ;
extracting a gas cap from the sample to create a new sample;
re-pressurizing the new sample above the bubble point pressure p b of the sample after extracting the gas cap; and
decreasing the pressure and measuring the viscosity μ b from below the bubble point pressure to a phase transition.

2. A process as defined in claim 1 comprising:
loading the sample into a viscosity measuring system;
measuring the viscosity from the viscosity μ o at the reservoir pressure to the viscosity μ ob at the bubble point pressure; and
measuring the viscosity μ od at atmospheric pressure.

3. A process as defined in claim 2 , further comprising isothermally and isobarically transferring the crude oil sample into the viscosity measuring system.

4. A process as defined in claim 2 comprising reducing the pressure below the bubble point pressure to form the gas cap.

5. A process as defined in claim 2 wherein at the atmospheric pressure all gas is extracted from the sample.

6. A process as defined in claim 2 , wherein the viscosity measuring system comprises,
a measuring chamber having a piston,
a pressure transducer having a digital indicator operable with the measuring chamber,
a circulating bath operable with the measuring chamber,
the measuring chamber including a high pressure stainless steel vessel, and the piston including a stainless steel floating piston,
⅛ in. inner diameter high pressure stainless steel tubing operable with the measuring chamber,
a high pressure stainless steel valve operable with the measuring chamber to control crude oil flow,
a computer for recording and storing of data from the measuring chamber,
a positive displacement pump and pressurization fluid to generate and control system pressure in the measuring chamber,
a temperature sensor welded to the lower part of the measuring chamber,
a vacuum pump operable with the measuring chamber,
⅛ in. inner diameter plastic tubing operable with the measuring chamber, and
a temperature controller operable with the measuring chamber.

7. A process for determining the dynamic viscosity of a crude oil in a well comprising;
placing a 20 to 50 mL sample of crude oil in a measuring chamber at a first temperature and a first pressure;
decrementally reducing the pressure from the first pressure, subsequently stabilizing the sample at the first temperature, and thereafter measuring the viscosity of the sample at the first temperature and the reduced pressures;
identifying a bubble point viscosity and bubble point pressure of the sample;
decreasing the pressure from the bubble point pressure and placing the measuring chamber in a vertical orientation to form a gas cap;
removing the gas cap by increasing the pressure to a predetermined amount to create a new sample; and
raising the pressure of the new sample to a second pressure and subsequently stabilizing the temperature at the first temperature,
wherein the second pressure is at least double the bubble point pressure of the sample.

8. The process of claim 7 , further comprising decrementally reducing the pressure from the second pressure, subsequently stabilizing the sample at the first temperature, and thereafter measuring the viscosity of the sample at the first temperature and the reduced pressures.

9. The process of claim 8 , further comprising repeating the process until all gas is removed from the sample.

10. The process of claim 7 , wherein the first pressure is the reservoir pressure and the first temperature is the reservoir temperature.

11. A process for determining the dynamic viscosity of a crude oil in a well comprising;
obtaining a 20 to 50 mL sample of live crude oil;
isothermally and isobarically transferring the crude oil sample into a viscosity measuring device;
stabilizing the sample at a reservoir temperature and reservoir pressure;
measuring the viscosity of the sample at the reservoir pressure;
reducing the pressure from the reservoir pressure in a series of steps, subsequently stabilizing the sample at the reservoir temperature, and thereafter measuring the viscosity at each step at the reservoir temperature until a change in slope of the viscosity measurements is detected to determine the bubble point pressure;
further decrease the pressure from the bubble point pressure;
orient the viscosity measuring device to form a first gas cap;
removing the first gas cap to create a first new sample;
raising the pressure of the first new sample to a second pressure at least double the bubble point pressure of the sample and subsequently stabilizing the temperature at the reservoir temperature;
reducing the pressure from the second pressure in a series of steps, subsequently stabilizing the sample at the reservoir temperature, and thereafter measuring the viscosity at each step at the reservoir temperature;
orient the viscosity measuring device to form a second gas cap;
removing the second gas cap to create a second new sample;
continuing to increase the pressure, decrease the pressure in steps, form a gas cap, and removing the formed gas cap until no gas is left in the sample.

12. The process of claim 11 , wherein the sample is live heavy crude oil.

Assignees

• Mendoza De La Cruz José Luis
• Ruiz Ortega Roberto Carlos
• Durán Valencia Cecilia De Los Ángeles
• López Ramírez Simón
• Ríos Reyes Alfredo
• Orozco Caballero Oscar
• Pizano Gallardo Luis Manuel
• Mexicano Inst Petrol

Inventors

• Mendoza De La Cruz José Luis
• Ruiz Ortega Roberto Carlos
• Durán Valencia Cecilia De Los Ángeles
• López Ramírez Simón
• Ríos Reyes Alfredo
• Orozco Caballero Oscar
• Pizano Gallardo Luis Manuel

Classifications

• G01N11/10

  by moving a body within the material · CPC title

• G01N2011/002

  Controlling sample temperature; Thermal cycling during measurement · CPC title

• G01N11/08 Primary

  by measuring pressure required to produce a known flow · CPC title