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METHOD AND APPARATUS OF FLUID SAMPLING USING FLUID RE-INJECTION

IP.com Disclosure Number: IPCOM000203288D
Publication Date: 2011-Jan-21
Document File: 1 page(s) / 14K

Publishing Venue

The IP.com Prior Art Database

Abstract

The formation tester has three probes: sample, middle, and outer. The middle probe surrounds the sample probe, while the outer probe surrounds the middle probe. During sampling operation, both sample and middle probes withdraw fluid, while the outer probe injects fluid which is collected from the sample probe (or both sample and middle probes). This device can be used on either a wireline or a drillstring.

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METHOD AND APPARATUS OF FLUID SAMPLING USING FLUID RE-INJECTION

Abstract:

The formation tester has three probes: sample, middle, and outer. The middle probe surrounds the sample probe, while the outer probe surrounds the middle probe. During sampling operation, both sample and middle probes withdraw fluid, while the outer probe injects fluid which is collected from the sample probe (or both sample and middle probes). This device can be used on either a wireline or a drillstring.

Description:

As shown in Fig.1, probe 1 is the sample probe, probe 2 is the middle probe, and probe 3 is the outer probe. There is rubber pad between probes 1 and 2.  The preferred manner of practicing the invention including the following three steps: (1) Fluid is withdrawn from formation through probes 1 and 2.  The pumping rate of probe 2 is higher than that of probe 1.   (2) Fluid pumped though probe 1 is injected back into formation through probe 3.   (3) When the contamination level of fluids from probe 1 reaches the planned level, the fluid from probe 1 is diverted into a sample tank.  This new design is better than the old manner (with only sample and perimeter probes).  The advantages are: (1) because probe 2 is pumping at a much higher rate than probe 1, the pressure around probe 2 is smaller than that around probe 1. The pressure differential between probes 1 and 2 may cause damage to the rubber pad in between.  When fluids is injected back into formation through probe 3, the pres...