Multi-zone formation fluid evaluation system and method for use of same

Abstract

A formation fluid evaluation system (800) interconnected within a tubular string (818) for operation in a wellbore (802) having multiple zones (806, 808, 810). The evaluation system (800) includes a set of straddle packers (820, 822) that is operable to sequentially isolate the multiple zones (806, 808, 810). A test valve (824) is disposed between the straddle packers (820, 822). A fluid unloading assembly (828) is positioned uphole of the straddle packers (820, 822). The fluid unloading assembly (828) is operable to draw fluid (834) from the isolated zone (808) into the tubular string (818) through the test valve (824) in response to the circulation of a drive fluid down the tubular string (818). A formation evaluation instrument (836) is disposed within the tubular string (818) and determines a characteristic of the fluid (834) received from the isolated zone (808).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is a continuation-in-part application of co-pending application Ser. No. 11 / 811,761 filed on Jun. 11, 2007.TECHNICAL FIELD OF THE INVENTION[0002]The present invention relates, in general, to testing and evaluation of subterranean formation fluids and, in particular, to a single trip, multi-zone formation fluid evaluation system and method for unloading fluids from each zone prior to evaluating reservoir fluids at reservoir conditions.BACKGROUND OF THE INVENTION[0003]Without limiting the scope of the present invention, its background is described with reference to testing hydrocarbon formations, as an example.[0004]It is well known in the subterranean well drilling and completion art to perform tests on formations intersected by a wellbore. Such tests are typically performed in order to determine geological or other physical properties of the formations and the fluids contained therein. For example, parameters such as permeability, po...

AI Technical Summary

Benefits of technology

The present invention provides a system and method for evaluating reservoir fluids from multiple zones in a single trip in a wellbore. This system includes a formation fluid evaluation instrument that is interconnected within a tubular string and positioned proximate one zone of the multiple zones. The system also includes a test valve and a fluid unloading assembly that is positioned uphole of the straddle packers. The test valve receives fluid from the isolated zone and the fluid unloading assembly draws fluid from the isolated zone and receives it into the tubular string. The evaluation instrument determines a characteristic of the fluid and the data obtained is transmitted to the surface or stored in a memory of the instrument. This system and method allow for sequential isolation and evaluation of individual zones in a single trip, reducing the time and cost of well construction.

Problems solved by technology

Accordingly, use of such sampling techniques can be quite time consuming in wellbores having multiple zones.

In addition, it has been found that fluid loss into certain formations occurs during the drilling, cementing and completions phases of well construction.

This swabbing process may take hours for each zone causing days of delay in wells having multiple zones.

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