US 2013/0075159 A1 · METHOD OF EVALUATING ROCK PROPERTIES WHILE DRILLING USING DOWNHOLE ACOUSTIC SENSORS AND TELEMETRY SYSTEM

Abstract

Methods of identifying rock properties in real-time during drilling, are provided. An example of method includes connecting a downhole sensor subassembly between a drill bit and a drill string, operably coupling acoustic sensors to a downhole processor, operably coupling a borehole telemetry system, downhole and surface data transmitting interfaces, and a surface computer to the downhole data transmitting interface. The method also includes receiving raw acoustic sensor data resulting from rotational contact of the drill bit with rock by the downhole processor, transforming the raw acoustic sensor data into the frequency domain, filtering the transformed data, and deriving acoustic characteristics from the filtered data. The method also includes the surface computer receiving the acoustic characteristics and deriving petrophysical properties from the acoustic characteristics directly or by utilizing a petrophysical properties evaluation algorithm.

Claims23

Dependent claims

A method of analyzing properties of rock in a formation in real-time during drilling, the method comprising the steps of:

receiving raw acoustic sensor data from one or more acoustic sensors by a downhole processor assembly, the one or more acoustic sensors carried by a downhole sensor subassembly positioned adjacent a drill bit and between a drill string and the drill bit, the downhole processor assembly positioned in close proximity to the one or more acoustic sensors and operably coupled thereto, the raw acoustic sensor data representing an acoustic signal generated real-time as a result of rotational contact of a drill bit with rock during drilling;
and
processing the raw acoustic sensor data by the downhole processor assembly, the step of processing including deriving a plurality of acoustic characteristics from the raw acoustic sensor data, the plurality of acoustics characteristics including mean frequency and normalized deviation of frequency.

A method of analyzing properties of rock in a formation in real-time during drilling, the method comprising the steps of:

receiving acoustic characteristics data from a downhole processor assembly by a surface computer, the acoustic characteristics data providing one or more acoustic characteristics evaluated from an acoustic signal provided by one or more acoustic sensors positioned adjacent a drill bit generated real-time as a result of rotational contact of the drill bit with rock during drilling;
and
performing one or more of the following processing steps:
identifying lithology type of rock being encountered by the drill bit utilizing mean frequency and normalized deviation of frequency evaluated from the acoustic signal, and
deriving petrophysical properties of rock being encountered by the drill bit utilizing a petrophysical properties evaluation algorithm employable to predict one or more petrophysical properties of rock undergoing drilling utilizing the one or more acoustic characteristics.

2 more elements

A method of analyzing properties of rock in a formation in real-time during drilling, the method comprising the steps of:

providing a downhole sensor subassembly, a downhole processor assembly, a downhole data transmitting interface, a surface data transmitting interface, a borehole telemetry system, and a surface computer;
connecting the downhole sensor subassembly adjacent a drill bit for drilling rock and between a drill string and the drill bit, the downhole sensor subassembly carrying one or more acoustic sensors positioned to detect drill sounds during drilling operations;
operably coupling the downhole processor assembly to at least one of the one or more acoustic sensors to receive and process real-time raw acoustic sensor data associated with the contact of the drill bit with rocks during operational drilling;
operably coupling the downhole processor assembly to the surface computer to receive and process acoustic characteristics data generated by the downhole processor assembly;
receiving digitized raw acoustic sensor data from the one or more acoustic sensors by the downhole processor assembly, the raw acoustic sensor data representing an acoustic signal generated real-time as a result of rotational contact of the drill bit with rock during drilling;
processing the raw acoustic sensor data by the downhole processor assembly, the step of processing including deriving a plurality of acoustic characteristics from the raw acoustic sensor data, the plurality of acoustics characteristics including mean frequency and normalized deviation of frequency;
receiving acoustic characteristics data from the downhole processor assembly, the acoustic characteristics data providing the plurality of acoustic characteristics;
and
performing one or more of the following processing steps:
identifying lithology type of rock being encountered by the drill bit utilizing the mean frequency and the normalized deviation of frequency, and
deriving petrophysical properties of rock being encountered by the drill bit utilizing a petrophysical properties evaluation algorithm employable to predict one or more petrophysical properties of rock undergoing drilling utilizing one or more of the plurality of acoustic characteristics.

8 more elements

Dependencies are inferred from the claim text.

Method of evaluating rock properties while drilling using downhole acoustic sensors and telemetry system

Life of this patent

Method of evaluating rock properties while drilling using downhole acoustic sensors and telemetry system

Life of this patent

Abstract

Claims23