Method and apparatus for monitoring borehole conditions
First Claim
1. In a method for monitoring flow conditions within a test interval of a borehole, the borehole being filled with a substantially incompressible fluid capable of flow between the test interval and the surrounding formation, the steps comprisingdeveloping a pressure differential between the test interval and the surrounding formation for inducing flow therebetween,arranging a variable volume device in communication with the test interval, andvarying the effective volume of the variable volume device in order to limit pressure variation in the test interval and minimize system compliance effects while simultaneously monitoring selected flow conditions within the test interval, operation of the variable volume device being regulated in order to maintain substantially constant pressure within the test interval.
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Abstract
A method and apparatus is disclosed for monitoring flow conditions in boreholes or the like wherein a test interval is defined by a packer system and contains a substantially incompressible fluid or liquid making it difficult to conduct measurements from the surface. According to the method and apparatus of the present invention, a variable volume device is arranged within the test interval along with a suitable flow monitor which may comprise the variable volume device itself, the variable volume device being operable to limit pressure variation within the test interval and thereby minimize compliance effects over a predetermined test period. Preferably, the variable volume device is coupled with a pressure monitor for maintaining substantially constant pressure in the test interval. In different embodiments, an initial pressure differential is established between the test interval and the surrounding formation by operation of the same variable volume device or by means of a second variable volume device. Where the test interval is defined by a guarded straddle packer forming a guard zone at one or both ends of the test interval, the apparatus and method of the invention may be employed for monitoring flow conditions in a guard zone or guard zones with or without corresponding use of the method and apparatus in the test interval.
60 Citations
35 Claims
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1. In a method for monitoring flow conditions within a test interval of a borehole, the borehole being filled with a substantially incompressible fluid capable of flow between the test interval and the surrounding formation, the steps comprising
developing a pressure differential between the test interval and the surrounding formation for inducing flow therebetween, arranging a variable volume device in communication with the test interval, and varying the effective volume of the variable volume device in order to limit pressure variation in the test interval and minimize system compliance effects while simultaneously monitoring selected flow conditions within the test interval, operation of the variable volume device being regulated in order to maintain substantially constant pressure within the test interval.
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15. In a method for monitoring flow conditions within a test interval of a borehole, the borehole being filled with a substantially incompressible fluid capable of flow between the test interval and the surrounding formation, the steps comprising
developing a pressure differential between the test interval and the surrounding formation for inducing flow therebetween, arranging a variable volume device in communication with the test interval, and varying the effective volume of the variable volume device in order to limit pressure variation in the test interval and minimize system compliance effects while simultaneously monitoring selected flow conditions within the test interval, and further comprising means for initially developing the pressure differential between the test interval and the surrounding formation, said means for developing the pressure differential comprising a second variable volume device.
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16. In a method for monitoring flow conditions within a test interval of a borehole, the borehole being filled with a substantially incompressible fluid capable of flow between the test interval and the surrounding formation, the steps comprising
developing a pressure differential between the test interval and the surrounding formation for inducing flow therebetween, arranging a variable volume device in communication with the interval, and varying the effective volume of the variable volume device in order to limit pressure variation in the test interval and minimize system compliance effects while simultaneously monitoring selected flow conditions within the test interval, the variable volume device being initially operable for developing the pressure differential between the test interval and the surrounding formation, effective volume of the variable device thereafter being varied in order to limit pressure variation within the test interval.
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18. Apparatus for monitoring flow conditions within a test interval of a borehole filled with a substantially incompressible fluid capable of flow between the test interval and the surrounding formation, comprising
a packer assembly for defining the test interval along the borehole, means for developing a pressure differential between the test interval and the surrounding formation for inducing flow therebetween, a variable volume device arranged in communication with the test interval, means for regulating operation of the variable volume device in order to limit pressure variation in the test interval and minimize system compliance effects, and means for simultaneously monitoring selected flow conditions within the test interval, the means for regulating the variable volume device being adapted to maintain substantially constant pressure within the test interval.
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28. In a method for monitoring flow conditions within a borehole containing substantially incompressible fluid capable of flow between the test interval and the surrounding formation, the steps comprising
forming a test interval and at least one adjacent guard zone within the borehole by means of expandable packers, arranging a variable volume device in communication with the guard zone, developing a pressure differential between the test interval and the surrounding formation for inducing flow therebetween, and monitoring selected flow conditions within the test interval and simultaneously varying the effective volume of the variable volume device in order to limit pressure variation in the guard zone while simultaneously monitoring selected flow conditions therein, the test interval being formed between a primary packer and an end of the borehole.
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30. In a method for monitoring flow conditions within a borehole containing substantially incompressible fluid capable of flow between the test interval and the surrounding formation, the steps comprising,
forming a test interval and at least one adjacent guard zone within the borehole by means of expandable packers, arranging a variable volume device in communication with the guard zone, developing a pressure differential between the test interval and the surrounding formation for inducing flow therebetween, and monitoring selected flow conditions within the test interval and simultaneously varying the effective volume of the variable volume device in order to limit pressure variation in the guard zone while simultaneously monitoring selected flow conditions therein, the test interval being formed between two primary packers, two additional expandable guard packers being arranged in respective spaced-apart relation to the primary packers for forming guard zones at each end of the test interval, flow conditions within each guard zone being similarly monitored by means of a variable volume device.
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32. Apparatus for monitoring flow conditions within a borehole containing a substantially incompressible fluid capable of flow between the borehole and the surrounding formation, comprising
a packer assembly for defining a test interval along the borehole and at least one guard zone adjacent one end of the test interval, means for developing a pressure differential between the test interval and the surrounding formation for inducing flow therebetween, means for monitoring selected flow conditions within the test interval, a variable volume device arranged in communication with the guard zone, and means for regulating operation of the variable volume device in order to limit pressure variation in the guard zone and for simultaneously monitoring selected flow conditions within the guard zone, the test interval being formed between a primary packer and an end of the borehole.
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34. Apparatus for monitoring flow conditions within a borehole containing a substantially incompressible fluid capable of flow between the borehole and the surrounding formation, comprising
a packer assembly for defining a test interval along the borehole and at least one guard zone adjacent one end of the test interval, means for developing a pressure differential between the test interval and the surrounding formation for inducing flow therebetween, means for monitoring selected flow conditions within the test interval, a variable volume device arranged in communication with the guard zone, and means for regulating operation of the variable volume device in order to limit pressure variation in the guard zone and for simultaneously monitoring selected flow conditions within the guard zone, the test interval being formed between two primary packers, two additional expandable guard packers being arranged in respective spaced-apart relation to the primary packers for forming guard zones at each end of the test interval, flow conditions within each guard zone being similarly monitored by means of a variable volume device.
Specification
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- Resources
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Current AssigneeMaxwell Laboratories, Inc. (UCAP Power, Inc.)
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Original AssigneeS-Cubed
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InventorsPeterson, Edward W., Lagus, Peter L., Hicks, William O.
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Primary Examiner(s)Birmiel, Howard A.
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Application NumberUS06/249,622Time in Patent Office833 DaysField of Search73/155, 166/250, 166/324, 175/40US Class Current73/152.41CPC Class CodesE21B 47/10 Locating fluid leaks, intru...
