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Downhole cooling by evaporating water and pumping its vapor into a waste tank

IP.com Disclosure Number: IPCOM000246478D
Publication Date: 2016-Jun-09
Document File: 1 page(s) / 14K

Publishing Venue

The IP.com Prior Art Database

Abstract

A region of a downhole logging tool, such as the inside of a flask, is cooled by the evaporation of water inside of a tank located within the flask. The water vapor that is produced is pumped out through a check valve into another tank elsewhere in the tool. This other tank acts as a waste water receptacle and as a heat sink and it is in thermal contact with the tool housing, which is in thermal contact with the borehole fluid. Using a temperature sensor in the region being cooled, one can determine when to turn on the pump for more cooling and, in this way, one can control the temperature in the cooled region.

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Title:  Downhole cooling by evaporating water and pumping its vapor into a waste tank

Abstract:  A region of a downhole logging tool, such as the inside of a flask, is cooled by the evaporation of water inside of a tank located within the flask.  The water vapor that is produced is pumped out through a check valve into another tank elsewhere in the tool.  This other tank acts as a waste water receptacle and as a heat sink and it is in thermal contact with the tool housing, which is in thermal contact with the borehole fluid.  Using a temperature sensor in the region being cooled, one can determine when to turn on the pump for more cooling and, in this way, one can control the temperature in the cooled region.

Description:  For an, ambient downhole temperature of 232 C, the vapor pressure of water is 421 psi.  Therefore, at most, one only needs a pump that can pump 500 psi of steam into a waste tank, because, at this pressure, one can maintain the water in the waste tank in the liquid state (0.81 g/cc) up to 240 C. Therefore, the size of the waste tank could be comparable to the size of the source tank (123% of its size). This is much easier than the engineering challenge of pumping the steam to wellbore, whose fluid pressure could be as high as 30 000 psi.   After a run, a 3-way valve can be turned to return the waste water back into the source tank so that the entire system can be immediately regenerated without applying any heat to the waste water tank and while s...