A method for encoding and decoding measurement data of a while-drilling inclinometer based on position combination verification

Abstract

The present invention discloses a coding and decoding method for a while-drilling inclinometer based on position combination verification. The coding method comprises the following steps: defining the time length corresponding to each data wave as a set time period T, dividing the time period T into a plurality of equally spaced time slots Tn, specifying the number and positions of time slots containing data waves within the time period T, where different numbers and positions of time slots containing data waves correspond to different data; setting pulse wave time sequence combinations for all data according to the pulse wave time sequence combination rules, and storing the generated coding table; and after an inclinometer coding unit receives downhole data measured by an inclinometer sensor, querying the coding table for a time sequence combination rule corresponding to the data, encoding the data according to the time sequence combination rule, and outputting a pulse wave time sequence signal. Under conditions of low signal-to-noise ratio, this data set is used to improve data signal recognition and eliminate interference caused by relatively large background noise.

Description

Technical Field

[0001] The present invention relates to the technical field of oil drilling engineering equipment, and in particular to an encoding and decoding method of a while-drilling inclinometer based on position combination verification. Background Art

[0002] In recent years, as oil and gas extraction has deepened, drilling projects have faced various challenges in deep-earth telemetry encoding and decoding technology. These include the attenuation of telemetry signal pressure waves within long, high-density, and high-viscosity fluid columns. Furthermore, as deep-earth exploration and development drilling encounters more complex terrain, drilling operations require the use of specialized downhole tools adapted to the demands of deep drilling. This increases irregular downhole vibration and rotation, introducing unpredictable background noise into the telemetry signal and significantly reducing the signal-to-noise ratio (SNR). A major limitation is that after telemetry data is transmitted from the bottom of the well to the surface via the pulse waveform generated by mud hydraulic pulse modulation at the bottom of the well, the surface-mounted riser pressure sensor receives the data waveform with a low signal-to-noise ratio. This low SNR makes it difficult to effectively distinguish between noise and data waveforms, resulting in a delay in timely acquisition of various downhole engineering and geological parameters during drilling operations, impacting the drilling cycle.

[0003] The Chinese invention patent application with application publication number CN110661580A discloses a mud pulse data encoding method, which determines the number of pressure pulse combinations and the number of binary bits according to the range of the data to be transmitted and the required accuracy; performs base conversion on the binary system, and divides the converted base into time segments according to the digits, each segment including a different number of time slots; uses pressure pulse combinations of different amplitudes to represent the value of each digit, and encodes the amplitude, number of pulse pressures and the corresponding positions of the pulses in an arranged and combined manner, and establishes an encoding protocol based on the values ​​and time slot positions of the different amplitudes to complete the mud pulse data encoding. This encoding method still makes it difficult to distinguish between useful pulse signals and noise wave signals, resulting in inaccurate data parameters. Summary of the Invention

[0004] The purpose of the present invention is to provide a coding and decoding method for a while drilling inclinometer based on position combination verification, which is used to solve the technical problem in the prior art that noise and data waveforms cannot be effectively distinguished.

[0005] The technical solution of the present invention to solve the technical problem is:

[0006] A method for encoding and decoding measurement data of a while-drilling inclinometer based on position combination verification is disclosed. The inclinometer encoding unit receives downhole data measured by the inclinometer sensor, encodes it according to a set encoding method, and outputs a pulse wave timing signal. A pulse generator converts the pulse wave timing signal into a pulse wave and transmits the pulse wave to a surface pressure sensor through a mud channel. The electrical signal output by the surface pressure sensor is converted into serial port data by a data processor and output to a host computer. The host computer decodes the data according to a set decoding method. The encoding method is as follows:

[0007] (1) Set the pulse wave timing combination rules:

[0008] The time length corresponding to each data is defined as a set time period T, and the time period T is divided into several equally spaced time slots Tn, where n = 1, 2, 3...N, and N is the number of time slots. The length of the time slot interval with data waves is set to Tp, and the length of the time slot interval without data waves is set to Tnp, where Tp = Tnp = Tn, and the time period T = Tn*N;

[0009] The number and position of time slots with data waves within the time period T are specified, and time slots with different numbers and positions of data waves correspond to different data;

[0010] (2) setting the pulse wave timing combination of all data according to the pulse wave timing combination rule, and storing and generating a coding table;

[0011] (3) After the inclinometer encoding unit receives the downhole data measured by the inclinometer sensor, it searches the coding table for the timing combination rule corresponding to the data, encodes the data according to the timing combination rule, and outputs a pulse wave timing signal. The host computer stores the same coding table. After the host computer receives the serial port data output by the data processor, it analyzes the timing combination rule contained in the serial port data, searches the coding table, and decodes and outputs the data represented by the corresponding timing combination rule in the coding table.

[0012] In the pulse wave timing combination, the number of time slots with data wave p is greater than 2, and there is no data wave np between two adjacent time slots with data wave p. The last time slot in a time period T is no data wave np.

[0013] The time slot is set to Tn = 1s.

[0014] The number of time slots N in one time period T is 22, and the number of time slots with data waves p is 3.

[0015] The decoding method of the host computer specifically comprises the following steps:

[0016] (1) Check sparsity and calculate the number of time slots with data wave p from the start time slot to the end time slot;

[0017] (2) Verify the no-data wave np. Any waveform in the first time slot following the confirmed data wave p is considered as the no-data wave np and its validity is excluded.

[0018] (3) After checking the sparsity, the position of the last wave with data p is known, and the waveforms from this position to the end time slot are all considered to be waves without data np;

[0019] (4) Based on the obtained valid waveform combination, query the coding table for comparison, output the actual data, and display it on the PC.

[0020] The beneficial effects of the present invention are:

[0021] The inclinometer encoding unit sets a pulse wave time sequence combination to represent all data. The number and position of time slots containing data waves within a time period T are determined. Different numbers and positions of time slots containing data waves correspond to different data. After receiving downhole data measured by the inclinometer sensor, the inclinometer encoding unit searches a coding table for a time sequence combination rule corresponding to the data, encodes the data according to the time sequence combination rule, and outputs the data. The data is then transmitted to the surface through a mud channel.

[0022] The upper computer on the ground stores the same coding table. After receiving the serial port data output by the data processor, the upper computer analyzes the timing combination rules contained in the serial port data, queries the coding table, and decodes and outputs the data represented by the corresponding timing combination rules in the coding table. This method can improve the accuracy of data signal recognition under conditions with low signal-to-noise ratios through this data set, eliminate interference caused by more background noise, and improve the signal recognition capability of the while-drilling inclinometer under drilling operations with low signal-to-noise ratios. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram for setting data waves within time period T;

[0024] Figure 2 Schematic diagram of the time interval encoding and decoding method with a period T of 10s, the number of time slots N of 10, and the number of data pulses P of 1;

[0025] Figure 3 Schematic diagram of the time interval encoding and decoding method with a period T of 10s, the number of time slots N of 10, and the number of data pulses P of 2;

[0026] Figure 4 This is a schematic diagram of the encoding, decoding and data transmission process of the present invention;

[0027] Figure 5Schematic diagram of the encoding process of the present invention (the dotted box in the figure is the specific encoding process in the inclinometer encoding unit);

[0028] Figure 6 Schematic diagram of the decoding process of the host computer in the present invention (the dotted box in the figure is the specific decoding process inside the host computer). DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0030] A method for encoding and decoding measurement data of a while-drilling inclinometer based on position combination verification is disclosed. The inclinometer encoding unit receives downhole data measured by the inclinometer sensor, encodes it according to a set encoding method, and outputs a pulse wave timing signal. A pulse generator converts the pulse wave timing signal into a pulse wave and transmits the pulse wave to a surface pressure sensor through a mud channel. The electrical signal output by the surface pressure sensor is converted into serial port data by a data processor and output to a host computer. The host computer decodes the data according to a set decoding method. The encoding method is as follows:

[0031] (1) Set the pulse wave timing combination rules:

[0032] The time length corresponding to each data wave is defined as a set time period T, and the time period T is divided into several equally spaced time slots Tn, where n = 1, 2, 3...N, and N is the number of time slots. The length of the time slot interval with data waves is set to Tp, and the length of the time slot interval without data waves is set to Tnp, where Tp = Tnp = Tn, and the time period T = Tn*N;

[0033] The number and position of time slots with data waves within the time period T are specified, and time slots with different numbers and positions of data waves correspond to different data;

[0034] (2) setting the pulse wave timing combination of all data according to the pulse wave timing combination rule, and storing the generated coding table;

[0035] (3) After the inclinometer encoding unit receives the downhole data measured by the inclinometer sensor, it searches the coding table for the timing combination rule corresponding to the data, encodes the data according to the timing combination rule, and outputs a pulse wave timing signal. The host computer stores the same coding table. After the host computer receives the serial port data output by the data processor, it analyzes the timing combination rule contained in the serial port data, searches the coding table, and decodes and outputs the data represented by the corresponding timing combination rule in the coding table.

[0036] When the data wave comes, the coding table is used to select the data wave combination required to send this data, the number of data wave pulses P, no data wave np, and the microcontroller simulation period T, and a high-level signal is generated at Tp.

[0037] Since the pulse waveform generated by mud hydraulic pulses is not very continuous and is sparse in actual applications, a rule is set in the design to allow sparsity to play its unique role, that is, there must be at least one no-data wave np between data waves p, and the last time slot of the data cycle must be a no-data wave np, and there must be no data wave before the first time slot of the next data cycle.

[0038] As shown in Figure 2, taking the period T = 10s, N = 10, Tn = 1s, and the number of data waves P = 1 as an example, that is, within the 10 intervals, each interval is an equidistant time slot Tn = 1s, T = Tn * N, the length of the data wave interval Tp = 1s, the length of the interval without data waves Tnp = 1s, Tp = Tnp = 1s, and the number of data waves P = 1 within the period T. Figure 2 The left half uses a pulse wave diagram to represent the timing combination rule. When a time period T ends and only time slot 1 is detected to have a data wave, this period represents data 0. Similarly, when a data wave is identified in the second time slot within period T, the data wave of this period represents data 1. By analogy, the entire encoding rule can represent data 0 to 8. Figure 2 The right half uses a table to represent data. A gray grid indicates that there is a data wave at this time slot, and the data displayed in the gray grid is the data represented by this data wave at the end of the cycle.

[0039] As shown in Figure 3, a simple extension is made based on the example of the basic timing combination rule to obtain the representation of more data. The period T = 10s is maintained and divided into 10 intervals. Each interval is an equidistant time slot Tn = 1s, the data wave interval length Tp = 1s, and the interval length without data waves Tnp = 1s. Tp = Tnp = 1s. The number of data waves P in the period T is increased to 2, that is, P = 2. Two data waves are used to represent one data, and the two waves are arranged and combined in accordance with the rules within the period. Figure 3 The left half uses a pulse wave diagram to represent this data rule. When a time period T ends and data waves are detected in time slots 1 and 3, the data wave combination of this period represents data 0. Similarly, within period T, data waves are detected in time slots 1 and 4, and the data wave combination of this period represents data 1. By analogy, this encoding rule can represent data 0 to 27. Figure 3 The right half describes the complete coding rules in tabular form, which is used to conveniently and completely deduce all the data that a certain design combination can represent when designing coding rules.

[0040] according to Figure 1 and Figure 2 The example illustrates the method for representing the timing combination rules, which can represent the 8-bit data 0 to 255 by arranging and combining 3 data waves in 22 time slots to form a set of position combination check code tables. The arrangement and combination is that when the 3 data waves p1, p2, and p3 appear at the time slots 1, 3, and 5 positions at the same time, the data wave combination of this group of time slots represents data 0; when they appear at the positions 1, 3, and 7 at the same time, the data wave combination of this group of time slots represents data 1; when they appear at the positions 1, 3, and 9 at the same time, the data wave combination of this group of time slots represents data 2, and so on until 255 data combinations are completed. According to the requirements of the timing combination rules, there is no data wave in the 22nd second of each group of time slots.

[0041] Figure 4 shows a schematic diagram of the encoding, decoding, and data transmission process. The downhole inclinometer sensor transmits measurement data to the inclinometer's encoding unit. A corresponding embedded program is developed within the encoding unit's single-chip microcomputer, which encodes the data according to a combination rule dataset and outputs a pulse wave timing signal. This data is then transmitted via a pulse generator and mud channels to a surface pressure sensor. The surface pressure sensor collects the pressure signal from the bottom of the well, converts it into an electrical signal, and transmits it to a data processor. The data processor then converts the electrical signal into serial data and transmits it to the host software on a PC. The host software decodes the data according to the combination rule dataset and displays the decoded data on the PC.

[0042] Figure 5 is a schematic diagram of the encoding process. When the data measured by the inclinometer sensor is transmitted to the encoding unit, the microcontroller embedded program in the encoding unit will search the data wave position combination corresponding to the data according to the set encoding table. The microcontroller then simulates the period T corresponding to this encoding table and generates a high-level signal at time Tp according to the found data wave position within the period. After encoding the data according to the timing combination rules, it outputs a pulse wave timing signal. Once the pulse generator receives the high-level signal, it will generate a pressure change at the bottom of the mud channel through the mechanical structure, which is transmitted to the ground as a data wave.

[0043] When the pressure sensor receives pressure changes downhole, it converts them into electrical signals and transmits them to the data processor. The data processor then converts the electrical signals into serial data and sends them to the PC. The host software on the PC first converts the serial data into pressure changes downhole, and then synchronously simulates a data cycle T according to the set coding rules, and verifies the data wave within the cycle T.

[0044] Figure 6 shows a schematic diagram of the host computer decoding process, which includes the following steps:

[0045] (1) Check sparsity and calculate the number of time slots with data wave p from the start time slot to the end time slot;

[0046] (2) Verify the no-data wave np. Any waveform in the first time slot following the confirmed data wave p is considered as the no-data wave np and its validity is excluded.

[0047] (3) After checking the sparsity, the position of the last wave with data p is known, and the waveforms from this position to the end time slot are all considered to be waves without data np;

[0048] (4) Based on the obtained valid waveform combination, query the coding table for comparison, output the actual data, and display it on the PC.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several changes and improvements can be made without departing from the overall concept of the present invention, and these should also be regarded as the scope of protection of the present invention.

Claims

1. A method for encoding and decoding measurement data of a while-drilling inclinometer based on position combination verification, wherein the inclinometer encoding unit receives downhole data measured by the inclinometer sensor, encodes the data according to a set encoding method, and outputs a pulse wave timing signal. A pulse generator converts the pulse wave timing signal into a pulse wave and transmits the pulse wave to a surface pressure sensor through a mud channel. The electrical signal output by the surface pressure sensor is converted into serial port data by a data processor and output to a host computer. The host computer decodes the data according to a set decoding method. The method is characterized in that: The encoding method is: (1) Set the pulse wave timing combination rules: The time length corresponding to each data is defined as a set time period T, and the time period T is divided into several equally spaced time slots Tn, where n = 1, 2, 3...N, and N is the number of time slots. The length of the time slot interval with data waves is set to Tp, and the length of the time slot interval without data waves is set to Tnp, where Tp = Tnp = Tn, and the time period T = Tn*N; The number and position of time slots with data waves within the time period T are specified, and time slots with different numbers and positions of data waves correspond to different data; (2) setting the pulse wave timing combination of all data according to the pulse wave timing combination rule, and storing and generating a coding table; (3) After the inclinometer encoding unit receives the downhole data measured by the inclinometer sensor, it searches the encoding table for the timing combination rule corresponding to the data, encodes the data according to the timing combination rule, and outputs a pulse wave timing signal; the host computer stores the same encoding table, and after receiving the serial port data output by the data processing instrument, it analyzes the timing combination rule contained in the serial port data, searches the encoding table, and decodes and outputs the data represented by the corresponding timing combination rule in the encoding table; The decoding method of the host computer specifically comprises the following steps: (1) Check sparsity and calculate the number of time slots with data wave p from the start time slot to the end time slot; (2) Verify the no-data wave np. Any waveform in the first time slot following the confirmed data wave p is considered as the no-data wave np and its validity is excluded. (3) After checking the sparsity, the position of the last wave with data p is known, and the waveforms from this position to the end time slot are all considered to be waves without data np; (4) Based on the obtained valid waveform combination, query the coding table for comparison, output the actual data, and display it on the PC.

2. The method for encoding and decoding measurement data of a while drilling inclinometer based on position combination verification according to claim 1, characterized in that: In the pulse wave timing combination, the number of time slots with data wave p is greater than 2, and there is no data wave np between two adjacent time slots with data wave p. The last time slot in a time period T is no data wave np.

3. The method for encoding and decoding measurement data of a while drilling inclinometer based on position combination verification according to claim 2, characterized in that: The time slot is set to Tn = 1s.

4. The method for encoding and decoding measurement data of a while drilling inclinometer based on position combination verification according to claim 2, characterized in that: The number of time slots N in one time period T is 22, and the number of time slots with data waves p is 3.

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