Methods for evaluating rock properties while drilling using drilling rig-mounted acoustic sensors

摘要

Methods for identifying rock properties in real-time during drilling, are provided. An example of an embodiment of such a method includes positioning one or more acoustic sensors to detect drill sounds emanating from the drill bit and the rock encountered during drilling operations, connecting the sensors to select components of a drilling rig to maximally pick up the drill sounds of the drill bit engaging rock during drilling operations. The method also includes providing and deploying an inductive telemetry, wireless telemetry, or wired transmitting system. The method also includes providing and configuring a computer to analyze the “raw” acoustic signals received from the acoustic sensors through the respective transmitting system.

主权项

1. A method of identifying rock properties in real-time during drilling, the method comprising the steps of:
providing an acoustic signal recording and transmitting system including an acoustic sensor; connecting the acoustic sensor to one of the following: (i) a drive shaft of a drill rig, the drive shaft having a plurality of extensions and (ii) an extension of the plurality of extensions of the drive shaft, the drive shaft connected to a drill string, a drill bit connected to the downhole end of the drill string; operably coupling a computer to one or more components of the acoustic signal recording and transmitting system to establish communications therebetween; receiving an acoustic sensor data signal from the acoustic signal recording and transmitting system by the computer, the acoustic sensor data signal representing an acoustic signal generated real-time by the acoustic sensor as a result of rotational contact of the drill bit with rock during drilling; and analyzing the acoustic sensor data signal by the computer to determine, in real-time, one or more of the following: (i) lithology type, and (ii) one or more petrophysical properties of rock engaged by the drill bit during drilling operations, the analyzing the acoustic sensor data signal comprising the steps of:
deriving a plurality of acoustic characteristics from the acoustic sensor data signal, the plurality of acoustic characteristics including mean frequency, mean amplitude, normalized deviation of frequency, normalized deviation of amplitude, and apparent power, andcorrelating the mean frequency, the mean amplitude, the normalized deviation of frequency, the normalized deviation of amplitude, and the apparent power with the same types of the acoustic characteristics of a rock sample of known lithology type to identify, in real-time, one or more of the following: the lithology type and one or more petrophysical properties of the rock engaged by the drill bit during drilling operations.