System and method for downhole telemetry

A method for transmitting data in a wellbore to a surface receiver, said wellbore having a drill string, said method comprising the steps of:

• providing an interface between an EM tool and a mud pulse tool
• said EM tool intercepting a data signal normally provided by said mud pulse tool to a mud pulser via said interface, said data signal being indicative of at least one parameter acquired by said mud pulse tool from at least one sensor;
• generating an EM signal using said EM tool according to information provided by said data signal, said EM signal being modulated to provide a substantially square waveform to mimic a mud pulse signal;
• transmitting said EM signal to said surface receiver;
• instructing said EM tool to operate in a mud-pulse telemetry mode;
• redirecting said data signal to said mud-pulser;
• generating a sequence of pressure pulses using said mud-pulser according to said information provided by said data signal;
• transmitting said sequence of pressure pulses to a pressure transducer in fluid communication with said mud-pulser;
• and
• transmitting a second data signal from said pressure transducer to said surface receiver.

A measurement while drilling (MWD) tool for transmitting data in a wellbore, said wellbore having a drill string, said tool comprising:

• a controller for intercepting via an interface between said controller and a mud pulse tool, a data signal indicative of at least one parameter acquired from at least one sensor, said data signal normally provided by said mud pulse tool to a mud pulser;
• a surface receiver;
• an EM transmitter for generating an EM signal according to information provided by said data signal, said EM signal being modulated to provide a substantially square waveform to mimic a mud pulse signal and being transmitted by said EM transmitter to said surface receiver;
• said mud-pulser for generating a sequence of pressure pulses according to information provided by said data signal and for transmitting said sequence of pressure pulses through a mud-column in said drill string to a pressure transducer, said pressure transducer being in communication with said surface receiver;
• and
• a switching mechanism interposed between said controller and said EM transmitter and said mud-pulser, said switching mechanism being capable of directing said data signal to either said EM transmitter or said mud-pulser in response to a control signal generated by said controller.

An EM measurement while drilling (MWD) tool for transmitting data in a wellbore, said wellbore having a drill string, said tool comprising:

• a controller for intercepting a data signal normally provided by a mud pulse tool to a mud pulser, said data signal indicative of at least one parameter acquired by said mud pulse tool from at least one sensor;
• an interface between said controller and said mud pulse tool for enabling said controller to intercept said data signal;
• and
• an EM transmitter for generating an EM signal according to information provided by said data signal, said EM signal being modulated to provide a substantially square waveform to mimic a mud pulse signal and being transmitted by said transmitter to a surface receiver.

A method for adapting a mud pulse measurement while drilling (MWD) tool to utilize electromagnetic (EM) telemetry, said mud pulse MWD tool comprising a mud pulser for generating a sequence of pressure pulses according to information provided by a data signal indicative of at least one parameter acquired from at least one sensor and a surface receiver, said method comprising:

• providing an EM transmitter configured to interface with said mud pulse MWD tool to intercept said data signal normally provided to said mud pulser downhole in a wellbore;
• interfacing said EM transmitter with said mud pulse MWD tool to enable said data signal to be obtained by said EM transmitter, to enable an EM signal to be generated using said data signal and to enable said EM signal to be transmitted from said EM transmitter to said surface receiver;
• providing an EM receiver module configured to obtain said EM signal and condition said EM signal to be compatible with said surface receiver;
• and
• interfacing said EM receiver module with said surface receiver to provide a conditioned signal to said surface receiver that mimics a mud-pulse signal.

A system for adapting a mud pulse measurement while drilling (MWD) tool to utilize electromagnetic (EM) telemetry, said mud pulse MWD tool comprising a mud pulser for generating a sequence of pressure pulses according to information provided by a data signal indicative of at least one parameter acquired from at least one sensor and a surface receiver, said system comprising:

• an EM transmitter configured to interface with said mud pulse MWD tool to intercept said data signal normally provided to said mud pulser downhole in a wellbore, configured to obtain said data signal, configured to generate an EM signal using said data signal and configured to transmit said EM signal from said EM transmitter to said surface receiver;
• an EM receiver module configured to obtain said EM signal, configured to condition said EM signal to be compatible with said surface receiver and configured to interface with said surface receiver to provide a conditioned signal to said surface receiver that mimics a mud-pulse signal;
• and
• a power supply to provide power to said EM transmitter while downhole.

A dual telemetry measurement while drilling (MWD) system capable of transmitting data in a wellbore to a surface receiver using either or both electromagnetic (EM) telemetry and mud-pulse telemetry, said system comprise;

• an EM transmitter configured to interface with a mud pulse tool to intercept a data signal normally provided to a mud pulser downhole in a wellbore, configured to generate an EM signal using said data signal and configured to transmit said EM signal from said EM transmitter to a surface receiver, said data signal indicative of at least one parameter acquired by said mud pulse tool from at least one sensor;
• a power supply to provide power to said EM transmitter while downhole;
• a first switching circuit configured to direct said data signal to said EM transmitter for operating in an EM telemetry mode and configured to direct said data signal to said mud-pulser for operating in a mud-pulse telemetry mode;
• an EM receiver module configured to obtain said EM signal and configured to condition said EM signal to be compatible with said surface receiver;
• a second switching circuit configured to direct a conditioned signal to said surface receiver in said EM telemetry mode and configured to direct a mud-pulse signal provided by a transducer to said surface receiver in said mud-pulse telemetry mode;
• and
• control logic for operating said switching circuits to switch between said telemetry modes.