| CPC E21B 47/13 (2020.05) [E21B 47/008 (2020.05)] | 2 Claims |
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1. A method for polling data of downhole transmission devices in measurement-while-drilling (MWD) comprising:
step 1, before the downhole transmission devices are lowered into a well, determining the data of the downhole transmission devices required for a drilling process; based on the data of the downhole transmission devices, and configuring a service table and then downloading the service table into a read-only memory (ROM) of a central controller and saving the service table in the ROM;
step 2, after downloading the service table into the ROM of the central controller and saving the service table in the ROM, lowering the downhole transmission devices in the well to start the drilling process, followed by initiating the central controller to wait for a first data acquisition command from the downhole transmission devices;
step 3, upon receiving the first data acquisition command by the central controller from the downhole transmission devices, taking a first data frame in the service table as a target data frame, polling the data of the downhole transmission devices by the central controller according to the target data frame in the service table, beginning with a first data item that needs to be acquired of data items of the target data frame and ending with a last data item that needs to be acquired of the data items of the target data frame, sending instructions to the downhole transmission devices to request corresponding data one by one, and acquiring the data items of the target data frame from the downhole transmission devices;
step 4, after acquiring the data items of the target data frame, concatenating and integrating the data items of the target data frame according to a valid bit number of each of the data items of the target data frame and a valid byte number of the target data frame to obtain a target processed data frame, wherein the valid bit number is configured to indicate a bit number of a data item after discarding a high-order invalid zero of the data item, the high-order invalid zero is removed by the central controller based on the valid bit number, and multiple data from a same frame are spliced to form new data;
step 5, after concatenating and integrating the data items of the target data frame to obtain the target processed data frame, encapsulating the target processed data frame according to a protocol to obtain a target encapsulated data frame, sending the target encapsulated data frame corresponding to the target data frame to the downhole transmission devices for uploading to a ground device; determining whether a polling process for the target data frame is completed, in response to the polling process for the target data frame being completed, recording a total polling frame number and an error polling frame number of the target data frame, and updating the total polling frame number and the error polling frame number in the service table;
step 6, after sending the target encapsulated data frame of the target data frame to the downhole transmission devices, waiting for, by the central controller, a second data acquisition command from the downhole transmission devices; upon receiving the second data acquisition command from the downhole transmission devices, taking each of remaining data frames after the target data frame in the service table as the target data frame and repeatedly performing the steps 3, 4, and 5 until all data frames in the service table are sent to the downhole transmission devices;
step 7, determining whether a working status of the downhole transmission devices is needed to be sent based on configuration information in the service table; in response to the working status of the downhole transmission devices being needed to be sent, sending monitoring information comprising a downhole transmission device bus voltage, a downhole transmission device bus current, and whether the polling process performed by the central controller is normal; and
step 8, taking a third data frame in the service table as the target data frame, and repeatedly performing the steps 3 to 7, without resending the first date frame and a second data frame, as pump startup sequences, in the service table;
wherein the service table comprises the configuration information as follows:
a frame number, configured to identify a data frame for downhole transmission;
a number of data items of the data frame, configured to indicate the number of the data items of the data frame configured for the data frame and configured for uploading;
a number of cycles of the data frame in the polling process, configured to indicate a number of times of sending the data frame to the downhole transmission devices for uploading the data frame to the ground device during the polling process;
a device address of each of the data items of the data frame, configured to identify a target underground device of the downhole transmission devices from which the data item is obtained;
a measurement parameter, configured to indicate a parameter of the target underground device corresponding to the data item;
the valid bit number, configured to indicate the bit number of the data item after discarding the high-order invalid zero of the data item;
the valid byte number of the data frame, configured to indicate a byte number of the data frame after the data frame is concatenated, compressed and encapsulated;
a total frame number, configured to indicate a total number of data frames configured in the service table, and configured to determine a number of data frames in the polling process;
a total polling frame number H and a total polling frame number L, configured to record a number of data frames sent to the downhole transmission devices for polling monitoring by the central controller;
an error polling frame number H and an error polling frame number L, configured to record a number of data frames with polling errors for the polling monitoring by the central controller; and
a transmission status bit flag, configured to indicate whether the working status of the downhole transmission devices needs to be uploaded, and configured to determine whether there is a fault; wherein a drilling process is stopped when the fault is detected;
wherein each item of the configuration information is configured using one byte;
wherein the total polling frame number H, the total polling frame number L, the error polling frame number H and the error polling frame number L are configured as 0 before the downhole transmission devices are lowered into the well;
wherein the polling errors comprise polling device response timeout or polling device data reception error; and
wherein the working status comprises the downhole transmission device bus voltage, the downhole transmission device bus current, and the whether the polling process performed by the central controller is normal.
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