The ZTMWD-48 system consists of a surface decoding system and downhole instruments. All circuits in the downhole instruments are manufactured using high-temperature Multi-Chip Module (MCM) technology, which enhances reliability and lifespan in high-temperature and high-vibration environments while reducing the instrument size. The directional probe integrates self-developed accelerometers and fluxgate sensors, combined with high-precision compensation and calibration algorithms, enabling accurate inclination and azimuth measurements across the full temperature range. Additionally, it supports rotary inclination and azimuth measurement, improving directional drilling efficiency.
The components and specifications of system:
The Wireless Measurement While Drilling (MWD) System can be divided into two components: the surface system and downhole instruments.
Ⅰ. Surface System
Industrial Control Computer (IPC): Provides a user-friendly interface for visualized human-machine interaction, displaying instrument communication and various data.
Surface Decoding Unit: Decodes the encoded measurement data from downhole instruments into recognizable parameters.
Programming Unit: Used for programming the downhole probe and downloading data.
Battery Testing/Activation Unit: Tests battery functionality and activates the battery.
Instrument String Testing Unit: Simulates downhole conditions to verify the operational status of the entire instrument assembly.
Driller’s Display Unit: Installed on the drilling rig to display essential drilling parameters.
Standpipe Pressure Sensor: Mounted on the standpipe manifold to convert mud pressure signals into electrical signals.
Sensor Signal Cable: Provides signal transmission channels for various sensors.
Ⅱ.Downhole instruments
The downhole instruments consist of a mud pulse generator and a directional probe.
1. Mud Pulse Generator
The mud pulse generator creates pressure pulse signals by increasing and decreasing the pressure inside the drill string. During rotation, it can shear off plugging materials that might obstruct the pulse generator. The pulse generator is composed of: Valve assembly, Mechanical components, Motion control components, Centralizers. ZT’s rotary valve mud pulse generator is fully compatible with APS pulse generators. Its motor drive circuit employs a PCB-free, fully metal-encased high-temperature MCM technology. Comprehensive upgrades to the circuit components of the pulse generator have significantly enhanced the system’s lifespan and vibration resistance.
2. Power output
The instrument is powered by betteries and can be powered simultaneously by two batteries in parallel.
3. Directional Probe
The directional probe consists of two main components: the directional sensor and the main control sub. All circuits are manufactured using high-temperature MCM technology.
The directional sensor includes: Three high-temperature fluxgate sensors, Three-axis high-temperature accelerometers , One temperature sensor. Inclination angle and gravity tool face angle are measured using the three-axis accelerometer. Once inclination and gravity toolface angles are determined, the three-axis fluxgate sensors measure the sensor azimuth angle. The accuracy of Inclination and gravity toolface angle is ±0.1° , the accuracy of Azimuth angle is ±0.3°. Additionally, The sensor can also measure: 1. Gravity vector magnitude 2. Total magnetic field strength 3. Magnetic toolface angle 4. Geomagnetic dip angle 5. Temperature 6. Rotation speed. The main control sub integrates Vibration sensor and 64MB memory. The Vibration sensor enables flow switch functionality to detect pump activity by measuring vibrations and the vibration signals within a ±40g range. The main control sub uses an RS485 bus interface, which supports connection to other instruments such as resistivity and azimuth gamma tools.
Ⅲ.Environmental testing
All downhole instruments undergo 100% environmental stress screening tests before leaving the factory. Various simulated stress conditions are applied to eliminate products with potential defects, ensuring the reliability of products delivered to customers.
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