Fracture monitoring
First Claim
1. A method of downhole monitoring of hydraulic fracturing comprising the steps of:
- interrogating an optic fibre arranged down the path of a well bore to provide a distributed acoustic sensor,sampling data from a plurality of longitudinal portions of the fibre; and
processing said data to provide an indication of at least one fracturing characteristic wherein the indication of at least one fracturing characteristic comprises an indication of at least of;
(a) intensity levels;
(b) frequencies; and
(c) spread of frequencies of acoustic disturbances in at least one longitudinal sensing portion of the fibre in a vicinity of the fracture site, and wherein said indication(s) are used to provide an indication of the flow of proppant and fluid into a fracture.
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Accused Products
Abstract
This application relates to methods and apparatus for monitoring hydraulic fracturing during oil/gas well formation. A fiber optic cable (102) deployed down a well bore (106), which may be the well bore in which fracturing is performed, is interrogated to provide a distributed acoustic sensor. Data is sampled from at least one longitudinal sensing portion of the fiber and processed to provide at least fracturing characteristic. The fracturing characteristic may comprise the characteristics of high frequency transients indicative of fracturing events (606). The intensity, frequency, duration and signal evolution of the transients may be monitored to provide the fracturing characteristic. Additionally or alternatively the fracturing characteristic may comprise the longer term acoustic noise generated by fracture fluid flow to the fracture sites. The intensity and frequency of the noise may be analyzed to determine the fracturing characteristic. The method allows real-time control of the fracturing process.
48 Citations
65 Claims
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1. A method of downhole monitoring of hydraulic fracturing comprising the steps of:
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interrogating an optic fibre arranged down the path of a well bore to provide a distributed acoustic sensor, sampling data from a plurality of longitudinal portions of the fibre; and processing said data to provide an indication of at least one fracturing characteristic wherein the indication of at least one fracturing characteristic comprises an indication of at least of;
(a) intensity levels;
(b) frequencies; and
(c) spread of frequencies of acoustic disturbances in at least one longitudinal sensing portion of the fibre in a vicinity of the fracture site, and wherein said indication(s) are used to provide an indication of the flow of proppant and fluid into a fracture. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 55, 56, 57, 58)
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25. A method of downhole monitoring of hydraulic fracturing comprising the steps of:
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interrogating an optic fibre arranged down the path of a well bore to provide a distributed acoustic sensor; sampling data from a plurality of longitudinal portions of the fibre; and processing said data to provide an indication of at least one fracturing characteristic, wherein the indication of at least one fracturing characteristic comprises an indication of proppant wash-out. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method of downhole monitoring of hydraulic fracturing comprising the steps of:
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interrogating an optic fibre arranged down the path of a well bore to provide distributed acoustic sensing; sampling data from a plurality of longitudinal portions of the fibre; and processing said data to provide an indication of at least one fracturing characteristic comprising the step of performing transient detection to determine at least one of a direction to, a range to or a location of the origin of the transient. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
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59. A system for downhole monitoring, said system comprising:
- a fibre optic interrogator adapted to provide distributed acoustic sensing on an optic fibre arranged along the path of a well bore;
a sampler arranged to sample a plurality of channels output from said interrogator to provide acoustic data from a plurality of portions of said fibre at each of a plurality of times; and
a data analyser adapted to process said sampled data to detect fracture characteristics and provide indications of said fracture characteristics wherein the indication of at least one fracturing characteristic comprises an indication of at least one of;
(a) the intensity levels;
(b) the frequencies, and (c) the spread of the frequencies of acoustic disturbances in at least one longitudinal sensing portion of the fibre in the vicinity of a fracture site, and wherein said indication(s) are used to provide an indication of the flow of proppant and fluid into a fracture. - View Dependent Claims (60, 61)
- a fibre optic interrogator adapted to provide distributed acoustic sensing on an optic fibre arranged along the path of a well bore;
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62. A system for downhole monitoring, said system comprising:
- a fibre optic interrogator adapted to provide distributed acoustic sensing on an optic fibre arranged along the path of a well bore;
a sampler arranged to sample a plurality of channels output from said interrogator to provide acoustic data from a plurality of portions of said fibre at each of a plurality of times; and
a data analyser adapted to process said sampled data to detect fracture characteristics and provide indications of said fracture characteristics, wherein the indication of at least one fracture characteristic comprises an indication of proppant wash-out. - View Dependent Claims (63)
- a fibre optic interrogator adapted to provide distributed acoustic sensing on an optic fibre arranged along the path of a well bore;
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64. A system for downhole monitoring, said system comprising:
- a fibre optic interrogator adapted to provide distributed acoustic sensing on an optic fibre arranged along the path of a well bore;
a sampler arranged to sample a plurality of channels output from said interrogator to provide acoustic data from a plurality of portions of said fibre at each of a plurality of times; and
a data analyser adapted to process said sampled data to detect fracture characteristics, provide indications of said fracture characteristics, to perform a transient detection, and to determine at least one of a direction to, a range to, or a location of the origin of the transient. - View Dependent Claims (65)
- a fibre optic interrogator adapted to provide distributed acoustic sensing on an optic fibre arranged along the path of a well bore;
Specification