Monitoring injected nonhydrocarbon and nonaqueous fluids through downhole fluid analysis

Abstract

A method of monitoring a nonhydrocarbon and nonaqueous fluid injected into the earth's subsurface through a first wellbore that involves positioning a fluid analysis tool within a second wellbore and determining the presence of the injected nonhydrocarbon and nonaqueous fluid by making a measurement downhole on the injected nonhydrocarbon and nonaqueous fluid using the fluid analysis tool. Also a related method of enhancing hydrocarbon production from a subsurface area having first and second wellbores that involves injecting a nonhydrocarbon and nonaqueous fluid into the subsurface through the first wellbore, positioning a fluid analysis tool within the second wellbore, and determining the presence of the injected nonhydrocarbon and nonaqueous fluid by making a measurement downhole on the injected nonhydrocarbon and nonaqueous fluid using the fluid analysis tool. Further, a related method of determining the relative or absolute quantity of a nonhydrocarbon and nonaqueous fluid injected into the earth's subsurface through a first wellbore that involves positioning a fluid analysis tool within a second wellbore, measuring the near-infrared spectroscopy signature of fluid downhole using the fluid analysis tool, measuring the downhole temperature and pressure using the fluid analysis tool, and estimating a relative or absolute quantity of the injected nonhydrocarbon and nonaqueous fluid within said downhole fluid using the measured near-infrared spectroscopy signature, the temperature, and the pressure to estimate a partial pressure of hydrocarbon constituents of the downhole fluid.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]A claim of priority is made to U.S. Provisional Patent Application No. 60 / 809,887 filed Jun. 1, 2006 entitled DOWNHOLE FLUID ANALYSIS OF INJECTED NONHYDROCARBON AND NONAQUEOUS FLUIDS FOR PRODUCTION ENHANCEMENT, which is incorporated by reference.FIELD OF THE INVENTION[0002]This invention relates to the monitoring of nonhydrocarbon and nonaqueous fluids that have been injected into the subsurface of the Earth and, more particularly, to methods for monitoring nonhydrocarbon and nonaqueous fluids that have been injected into the subsurface of the Earth through the use of downhole fluid analysis and / or related techniques, particularly in connection with enhancing hydrocarbon production from a subsurface area.BACKGROUND[0003]In certain hydrocarbon reservoirs, such the giant Cantarell field in Mexico, nonhydrocarbon and nonaqueous fluids are injected to enhance hydrocarbon production. In the Cantarell field, one billion cubic feet of nitrogen a...

AI Technical Summary

Benefits of technology

The patent describes a method for monitoring and measuring the presence and quantity of nonhydrocarbon and nonaqueous fluids injected into the earth's subsurface through a wellbore. This is achieved by positioning a fluid analysis tool in a nearby wellbore and using it to make measurements downhole on the injected fluid. The method can help to improve oil production from underground reservoirs and better understand the composition of the injected fluids.

Problems solved by technology

Clearly, if the injected fluid bypasses oil pockets or if the fluid reaches nonequilibrium concentrations in the hydrocarbons in place, whether gas or oil, then the efficiency of production enhancement can be greatly compromised.

One significant problem with this approach is that it is difficult to adequately investigate likely fluid and reservoir complexities using a reasonable sample acquisition program because downhole fluid sampling tools can typically acquire a very limited number of samples, typically less than ten, in a single logging run.

It is also possible to acquire samples of the produced fluid at the surface and analyze the concentration of the injected fluid in the produced fluid, but by the time the fluid reaches the surface, it is typically difficult or impossible to accurately determine the fraction of injected fluid in the reservoir fluid as it enters the borehole or to determine at which location the injected fluid is entering the borehole.

However, if significant fluid complexities are discovered, then additional DFA station tests can be performed.

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