Back to results
US 10,095,828 B2Granted
Production logs from distributed acoustic sensors
AssigneeConocoPhillips Company
InventorsHerbert W. Swan, Ge Jin, Kyle R. Krueger, Baishali Roy
Life of this patent
Estimating the term…
Abstract
A system and method for monitoring oil flow rates along a producing oil or gas well using a Distributed Acoustic Sensing fiber is described. This system uses the low-frequency component of the acoustic signal as a measurement of temperature variations within the well. The relative flow contributions can then be inferred from these temperature fluctuations.
Claims15
A method of monitoring oil flow rates along a hydrocarbon reservoir comprising:
- a) installing one or more fiber optic cables along a wellbore in a hydrocarbon formation;
- b) installing one or more interrogators on at least one of said fiber optic cables;
- c) interrogating at least one of said fiber optic cables with an interrogation signal during production;
- d) obtaining one or more datasets of data from at least one of said interrogators;
- e) converting one or more of said datasets from at least one of said interrogators into a continuous record;
- f) transforming the continuous record with a low-pass filter to 1-100 milliHz while down sampling the data into a transformed well signal;
- g) approximating flow velocities at a given depth by calculating the slope of temperature variation as a function of depth from the transformed well signal;
- and
- h) estimating from the slope of temperature variation as a function of depth a cumulative production rate of hydrocarbons from said hydrocarbon formation.
6 more elements
A method of monitoring oil flow rates along a hydrocarbon reservoir comprising:
- a) installing one or more fiber optic cables along a wellbore in a hydrocarbon formation;
- b) installing one or more interrogators on at least one of said fiber optic cables;
- c) interrogating at least one of said fiber optic cables with an interrogation signal during production;
- d) obtaining one or more datasets of data from at least one of said interrogators;
- e) converting one or more of said datasets from at least one of said interrogators into a continuous record;
- f) transforming the continuous record with a low-pass filter to 1-100 milliHz while down sampling the data into a transformed well signal;
- g) quantitatively measuring flow velocities by removing the effect of constant-temperature produced fluids from the transformed well signal to generate a differentiated distributed acoustic sensing (DAS) signal;
- h) computing a semblance function for the differentiated DAS signal;
- and
- i) determining from the semblance function for the differentiated DAS signal a cumulative production rate of hydrocarbons from said hydrocarbon formation.
7 more elements
A method of monitoring oil flow rates along a hydrocarbon reservoir comprising:
- a) installing one or more fiber optic cables along a wellbore in a hydrocarbon formation;
- b) installing one or more interrogators on at least one of said fiber optic cables;
- c) interrogating at least one of said fiber optic cables with an interrogation signal during production;
- d) obtaining one or more datasets of data from at least one of said interrogators;
- e) converting one or more of said datasets from at least one of said interrogators into a continuous record;
- f) transforming the continuous record with a low-pass filter to 1-100 milliHz while down sampling the data into a transformed well signal;
- g) quantitatively measuring flow velocities from the transformed well signal comprising:
- i) use and initial estimate of fluid velocity to compute a traveltime function f(x),
- ii) numerically form an inverse function through piece-wise interpolation,
- iii) form a series of traveltime functions and their inverses,
- iv) compute a semblance over a range of changes in time (δτ),
- v) set a new traveltime function f(x) at a trial function g(x, δτ), and
- vi) repeat (i)-(v) until convergence is achieved;
- and
- h) determining from the measured flow velocities a cumulative production rate of hydrocarbons from said hydrocarbon formation.
12 more elements
Dependencies are inferred from the claim text.