Fracture characterisation
AssigneeOptasense Holdings Limited
InventorsMagnus McEwen-King, David John Hill, Menno Mathieu Molenaar
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Abstract
This application relates to methods and apparatus for monitoring hydraulic fracturing in well formation and fracture characterization using distributed acoustic sensing (DAS). The method involves interrogating an optic fiber arranged down the path of a borehole to provide a distributed acoustic sensor and also monitoring flow properties of fracturing liquid pumped into the well where the acoustic data from the distributed acoustic sensor is processed together with the flow properties data to provide an indication of at least one fracture characteristic.
Claims17
A method of fracture characterisation of a downwell hydraulic fracturing process comprising:
- interrogating an optic fibre arranged down the path of a well bore to provide a distributed acoustic sensor;
- monitoring flow properties of fracturing fluid as it flows into the well bore;
- and
- processing acoustic data from the distributed acoustic sensor together with flow data from monitoring the flow properties to provide an indication of at least one fracture characteristic,
- wherein providing said indication of at least one fracture characteristic comprises determining an amount of fracturing fluid and/or proppant supplied to each fracture site;
- wherein the acoustic data for a sensing portion at a single location of the fibre in the vicinity of a fracturing site is divided into two or more spectral bands and an average intensity determined for each of said spectral bands, and analyzing the acoustic data by comparing intensity levels of acoustic disturbances in the vicinity of each of a number of different fracture sites to determine the relative flow rates of the fracture fluid and/or proppant to individual fracture sites.
A system for fracture characterisation, 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 optic fibre at each of a plurality of times;
- a flow monitor adapted to monitor flow properties of fracture fluid into the well bore to be fractured and provide flow data and a data analyser adapted to process said sampled acoustic data with said flow data to determine at least one fracture characteristic, where said processing comprises determining the amount of fracturing fluid and/or proppant supplied to each fracture site wherein the acoustic data for a sensing portion at a single location of the fibre in the vicinity of a fracturing site is divided into one two or more spectral bands and an average intensity determined for each of said spectral bands and analyzing the acoustic data by comparing intensity levels of acoustic disturbances in the vicinity of each of a number of different fracture sites to determine the relative flow rates of the fracture fluid and/or proppant to individual fracture sites.
A method comprising:
- accessing a first data set corresponding to acoustic data obtained by interrogating an optic fibre arranged down the path of a well bore to provide a distributed acoustic sensor during a downwell hydraulic fracturing process;
- accessing a second data set corresponding to flow data obtained by monitoring flow properties of fracturing fluid as it flows into the well bore during the downwell hydraulic fracturing process;
- and
- processing the acoustic data together with the flow data to determine an amount of fracturing fluid and/or proppant supplied to each fracture site by dividing the acoustic data for a sensing portion at a single location of the fibre in the vicinity of a fracturing site into two or more spectral bands and an average intensity determined for each of said spectral bands and analyzing the acoustic data by comparing intensity levels of acoustic disturbances in the vicinity of each of a number of different fracture sites to determine the relative flow rates of the fracture fluid and/or proppant to individual fracture sites.
Dependencies are inferred from the claim text.