Medium-and-small-scale analog-digital mixed underground high-temperature instrument and bus transmission method thereof

Abstract

The invention discloses a medium-and-small-scale analog-to-digital mixed underground high-temperature instrument and a bus transmission method thereof, and belongs to the technical field of underground high-temperature instruments. The medium-and-small-scale analog-to-digital mixed underground high-temperature instrument comprises a multi-channel analog switch, and the input end of the multi-channel analog switch is coupled with multiple groups of voltage frequency and current frequency conversion modules; the input end of the multi-way analog switch is further coupled with a synchronization, counting, starting and circulation control logic circuit, the output end of the multi-way analog switch is coupled with an amplitude modulation circuit, the output end of the amplitude modulation circuit is coupled with a current loop, and the current loop is electrically connected with a power supply and a load in series.

Description

Technical Field

[0001] The invention relates to a downhole high temperature instrument, in particular to a small- to medium-scale analog-digital hybrid downhole high temperature instrument and a bus transmission method thereof, belonging to the technical field of downhole high temperature instruments. Background Art

[0002] Oil and gas exploration and development are increasingly concentrated in deep formations and deep waters. As the depth increases, the ambient temperature reaches 200℃~265℃, and the temperature resistance requirements of drilling instruments are getting higher and higher. High-temperature electronic components have always been the bottleneck of the development of instruments in the field of oil drilling. The types and quantities of electronic components exceeding 200℃ are limited internationally, especially the types of high-temperature digital processors (microcontrollers) and programmable gate array chips; the types of electronic components exceeding 200℃ in China are also few. Therefore, a small-scale mixed analog-digital underground high-temperature instrument and its bus transmission method are designed to solve the above problems. Summary of the invention

[0003] The main purpose of the present invention is to provide a small- to medium-scale analog-digital hybrid downhole high-temperature instrument and a bus transmission method thereof.

[0004] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0005] A small- to medium-sized downhole high-temperature mixed analog-digital instrument, in which pulse signals whose frequencies vary linearly with the analog outputs of each measured quantity are combined in a set logic and number sequence to form an asynchronous serial sequence;

[0006] The amplitude modulated asynchronous serial sequence and the additional bias are fed into the current loop to generate a bias plus pulse modulated current signal sequence.

[0007] A small- to medium-scale mixed analog-digital underground high-temperature instrument bus transmission method comprises the following steps:

[0008] The number of pulse signals of each measured quantity is 2 to 4, the generating circuits of each pulse signal are independent or shared, and the frequency range of each pulse signal is consistent;

[0009] In the modulated current signal sequence containing state and working mode information, the bias current is higher than the minimum current of the current loop, and the pulse signal modulated current amplitude is determined according to the bus communication protocol.

[0010] Preferably, the instrument uses small and medium-scale analog and digital devices to form downhole high-temperature instrument circuits and control logic, and has bus communication capabilities;

[0011] It adopts simplex communication mode, 15 downhole measuring instruments are connected to the bus, and adopts multiple field bus communication protocols.

[0012] Beneficial technical effects of the present invention:

[0013] The present invention provides a small- to medium-scale mixed analog-digital underground high-temperature instrument and a bus transmission method thereof, which all adopt high-temperature small- to medium-scale analog and digital circuits, and promote the development of domestic underground high-temperature measuring instruments.

[0014] By adopting logic control and sequence combination, the bus signal transmission of multiple measurement quantities is realized through bias and pulse amplitude modulation and sending into the current loop. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flow chart of a bus transmission method according to a preferred embodiment of a small- to medium-scale mixed analog-digital underground high-temperature instrument and a bus transmission method thereof according to the present invention;

[0016] Figure 2 The bus current sequence diagram is a preferred embodiment of a small- to medium-scale mixed analog-digital downhole high-temperature instrument and a bus transmission method thereof according to the present invention. DETAILED DESCRIPTION

[0017] In order to make the technical solution of the present invention more clear and specific to those skilled in the art, the present invention is further described in detail below in conjunction with embodiments and drawings, but the implementation manner of the present invention is not limited thereto.

[0018] Figure 1 The present invention provides a method for underground high temperature measurement and bus transmission based on small and medium-scale analog and digital hybrid, such as Figure 1 As shown, it includes: all measured quantities are converted into frequency quantities, the variation range of the measured quantities may be different, and the output frequency variation range of the conversion circuit is the same; all measured quantities are combined into an asynchronous serial pulse sequence through a multi-way analog switch according to a time series; the measured quantity pulse sequence and the bias and zero point are combined together through a modulation circuit and sent to the current loop; and the load end extracts the measurement information.

[0019] Each measurement sequence is maintained for at least 2 to 4 pulse cycles so that the load end can sample at least the pulse frequency after the first complete sequence.

[0020] Considering the real-time measurement data and the temperature control requirements of the transmission circuit, the maximum pulse frequency can be as low as 100-300KHz.

[0021] It has frequency and range correction functions, and outputs a sequence signal at a fixed time. Its frequency has agreed characteristics, such as the same frequency or a combination of DC, minimum and maximum frequencies; its amplitude includes fixed offset, maximum and minimum values.

[0022] All components use small and medium-scale analog and digital hybrid circuits that can operate stably for a long time at 200°C.

[0023] Pulse signals whose frequencies vary linearly with the analog outputs of each measured quantity are combined according to the set logic and number order to form an asynchronous serial sequence; the number of pulse signals of each measured quantity can be 2 to 4; the pulse signals of each measured quantity can be generated independently or shared, and the minimum and maximum frequencies of each pulse signal are consistent.

[0024] The amplitude modulated measurement quantity asynchronous serial sequence and additional bias are sent into the current loop to generate a bias plus pulse modulated current signal sequence; the bias current is higher than the minimum current of the current loop, and the pulse signal modulated current amplitude is determined according to the bus communication protocol; the bias current and the pulse current signal modulation amplitude can both represent the measurement status and working mode.

[0025] It completely adopts small and medium-scale analog and digital devices, and does not use special control chips such as digital processors (microcontrollers) or programmable logic arrays, to form the downhole high-temperature instrument circuit and control logic, and has bus communication function; it adopts simplex communication and can connect up to 15 downhole measuring instruments.

[0026] It has frequency and range calibration functions at various temperatures.

[0027] All analog and digital devices can work for at least 100 hours in an environment above 200°C.

[0028] The high-temperature downhole instrument and bus transmission method thereof provided in the embodiment of the present invention adopt currently available high-temperature small and medium-scale integrated circuits to superimpose bias and amplitude modulated frequency pulse signals to form a pulse sequence of measurement signals, which are transmitted through a current loop to achieve downhole measurement and data transmission requirements above 200°C.

[0029] The above description is only a further embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the scope disclosed by the present invention, which belong to the protection scope of the present invention.

Claims

1. A small to medium scale mixed analog and digital downhole high temperature instrument, characterized by: The pulse signals whose frequencies vary linearly with the analog outputs of each measured quantity are combined in sequence according to the set logic and number to form an asynchronous serial sequence; The amplitude modulated asynchronous serial sequence and the additional bias are fed into the current loop to generate a bias plus pulse modulated current signal sequence.

2. A bus transmission method for a small- to medium-scale analog-to-digital hybrid downhole high-temperature instrument, based on the small- to medium-scale analog-to-digital hybrid downhole high-temperature instrument of claim 1, characterized in that: The steps include: The number of pulse signals of each measured quantity is 2 to 4, the generating circuits of each pulse signal are independent or shared, and the frequency range of each pulse signal is consistent; In the modulated current signal sequence containing state and working mode information, the bias current is higher than the minimum current of the current loop, and the pulse signal modulated current amplitude is determined according to the bus communication protocol.

3. A small- to medium-scale mixed analog-digital underground high-temperature instrument bus transmission method according to claim 2, characterized in that: The instrument uses small and medium-scale analog and digital devices to form underground high-temperature instrument circuits and control logic, and has bus communication function; It adopts simplex communication mode, 15 downhole measuring instruments are connected to the bus, and adopts multiple field bus communication protocols.

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