System and method for managing batteries for use in a downhole drilling application

Abstract

The present disclosure is directed at methods, systems, and techniques for managing batteries for use in a downhole drilling application. The system includes a power bus, pairs of battery terminals for connecting to batteries, switching circuitry that connects and disconnects the batteries to the power bus, data collection circuitry that obtains battery parameters obtained during system operation, and a controller that controls the switching circuitry and receives the battery parameters. A control line connects the controller to the switching circuitry and a data line connects the controller to the data collection circuitry, with the control and data lines being distinct such that control and data signals are not multiplexed with each other.

What is claimed is: 
     
         1 . A system for use in a downhole drilling application to adjust signal-to-noise ratio (“SNR”) of a telemetry signal sent from a downhole location to surface, wherein the SNR and a minimum SNR required to accurately decode the telemetry signal are measured at the surface, and wherein a downlink signal indicating that the SNR is to be reduced is sent downhole when the SNR exceeds the minimum SNR by a sufficiently large margin, the system comprising:
 (a) a signal transmitter located downhole for transmitting the telemetry signal; 
 (b) a signal receiver located downhole for receiving the downlink signal; and 
 (c) a processor communicative with the signal transmitter and signal receiver, wherein upon receipt of the downlink signal by the signal receiver, the processor is configured to decrease the SNR by reducing signal strength while maintaining the SNR above the minimum SNR. 
 
     
     
         2 . The system of  claim 1  wherein the signal transmitter comprises an electromagnetic transmitter. 
     
     
         3 . The system of  claim 1  wherein the signal transmitter comprises a fluid pressure pulse generator. 
     
     
         4 . The system of  claim 1  wherein the processor is further configured to:
 (a) when the SNR is less than the minimum SNR, receive a downlink signal from the surface indicating that the SNR is to be increased; and 
 (b) increase the SNR above the minimum SNR by increasing signal strength. 
 
     
     
         5 . A method for adjusting signal-to-noise ratio (“SNR”) of a telemetry signal sent from a downhole location to surface, the method comprising:
 (a) at the surface,
 (i) determining the SNR of the telemetry signal; 
 (ii) comparing the SNR of the telemetry signal to a minimum SNR required to accurately decode the telemetry signal; 
 (iii) when the SNR exceeds the minimum SNR by a sufficiently large margin, sending a downlink signal from the surface instructing that the power of the telemetry signal be reduced; and 
 
 (b) at the downhole location, decreasing the SNR upon receipt of the downhole signal by reducing signal strength while maintaining the SNR above the minimum SNR. 
 
     
     
         6 . The method of  claim 5  wherein the telemetry signal is an electromagnetic signal. 
     
     
         7 . The method of  claim 5  wherein the telemetry signal is a mud pulse signal. 
     
     
         8 . The method of  claim 5  further comprising, when the SNR is below the minimum SNR:
 (a) sending a downlink signal from the surface instructing that the power of the telemetry signal be increased above the minimum SNR; and 
 (b) increasing the SNR above the minimum SNR by increasing signal strength. 
 
     
     
         9 . A non-transitory computer readable medium having encoded thereon statements and instructions to cause a controller to perform the method of  claim 5 .