ZT-100 Water Cut Analyzers
Continuous inline water-in-oil measurement for the petroleum industry
Know Your Water Cut in Real Time
Accurate water cut measurement is fundamental to production accounting, custody transfer, and process optimisation. Whether calculating net oil volumes for fiscal reporting, detecting water breakthrough at the wellhead, or verifying separator performance, knowing the water fraction in your hydrocarbon stream is the basis for sound operational decisions.
The ZT-100 exploits the large difference in dielectric constant between oil (k ≈ 2.3) and water (k ≈ 80) to determine water content continuously and inline. An RF signal applied to the sensing element measures the capacitance of the surrounding fluid — as water content rises, so does capacitance, giving a direct and predictable relationship to water cut. No sampling, no bypass loops, no moving parts.
Key Features
Wide Measurement Range
0 to 100% water cut coverage — from near-dry crude to high-water-cut wells approaching the inversion point and beyond.
Hazardous Area Certified
ATEX and IECEx certified for Zone 1 and Zone 2 explosive atmospheres. Designed from the ground up for upstream oil & gas environments.
Minimal Maintenance
Solid-state sensing element with no moving parts, no consumables, and coatings resistant to paraffin buildup and erosive, sand-bearing mixtures.
Robust Construction
SS316L or other Austenitic Steel wetted parts and IP rated enclosures built for offshore platforms, desert wellpads, and everything in between.
Standard Communication
4–20mA, HART, Modbus RTU for direct integration with DCS, SCADA, and PLC control systems.
Fast, Continuous Output
Real-time measurement update rate enables closed-loop process control, automatic well testing, and immediate detection of process upsets.
Automatic Temperature Compensation
The dielectric constant of water drops significantly with temperature — from approximately 88 at 0°C to 48 at 100°C. Oil dielectric also changes over temperature. Without compensation, a water cut reading calibrated at ambient conditions would drift substantially at elevated process temperatures. But temperature also affects the oil phase: crude oil dielectric decreases from roughly 2.3 at 0°C to 2.1 at 100°C.
Every ZT-100 includes an integrated process temperature sensor and firmware that compensates for both effects simultaneously. The water dielectric is corrected using a linear temperature model derived from published data for pure and produced water. The oil dielectric is corrected using a product-specific lookup table that can be configured per installation. These compensated values feed into a physics-based mixing model that calculates the true water volume fraction from the measured capacitance — regardless of process temperature.
The result is accurate water cut measurement across the full operating range of −20°C to +120°C without manual recalibration when process conditions change.
Water Phase Correction
Dielectric constant modelled as a function of temperature. Compensates for the large permittivity change in water across the operating range.
Oil/Product Phase Correction
Configurable product dielectric table accounts for the temperature behaviour of the specific hydrocarbon being measured — crude oil, condensate, or refined product.
Board Electronics Compensation
A separate compensation layer corrects for temperature-induced drift in the measurement electronics, normalised to a 25°C reference point.
Product Range
ZT-100 F-Series
Inline Measurement Spool
Full-bore flanged water cut analyzer with weld neck flanges that allow full radiographic (X-ray) weld inspection. Isokinetic measurement geometry with no flow distortions. 4″ to 48″ nominal sizes, up to Class 1500#.
- Weld neck flanges — 100% radiographically inspectable
- Isokinetic, full-bore measurement
- Optional integrated static mixer (FM-Series)
ZT-100 S-Series
Inline Measurement Spool
Threaded and slip-on flange water cut analyzer for smaller pipelines. Threaded connections (NPT, BSP, BSPT) from 1″ to 3″, flanged from 1″ to 8″. Inline or bypass installation.
- Slip-on flanges or threaded process connections
- Inline or bypass installation
- Optional integrated static mixer (SM-Series)
ZT-100 I-Series Flanged
Flanged Insertion Probe
Permanently installed flanged insertion probe for high-pressure, large-diameter pipelines. Bolts directly to a flanged nozzle — no retraction mechanism required. Up to ANSI Class 1500 (250 barg), for line sizes 12″ to 48″.
- Permanent installation via 2″ or 3″ flanged nozzle
- Rated up to ANSI Class 1500 (250 barg)
- Simpler, more compact than retractable variant
ZT-100 I-Series Retractable
Retractable Insertion Probe
Blow-out proof retractable insertion probe for large-diameter pipelines. Install and retract under full process pressure up to ANSI Class 1500 (250 barg). 2″ or 3″ nozzle entry, for line sizes 12″ to 48″.
- Blow-out proof, retractable under pressure
- Hot-tappable — zero downtime installation
- Retraction kit with packing gland, guide tube, and locking collar
Measurement Range Options
| Low Cut | High Cut | |
| Measurement Range | 0 – 25% water cut | 0 – 65% water cut |
| Accuracy | ±0.1% of reading | ±0.25% of reading |
| Repeatability | ±0.05% | ±0.1% |
| Response Time | < 1 second | < 1 second |
| Measurement Principle | Capacitance-based (RF excitation) | |
| Process Temperature | −20°C to +120°C | |
| Wetted Materials | 316L Stainless Steel, PEEK, Viton | |
| Enclosure Rating | IP67 | |
| Hazardous Area | ATEX II 1/2 G Ex d IIB T4, IECEx | |
| Typical Applications | Custody transfer, LACT, desalters, separator outlets, dry crude | Production monitoring, high-watercut wells, test separators |
Need 0–100% full range? See the ZT-100FC Full Cut Analyzer with dual capacitance + conductivity measurement.
Electronics
| Principle of Operation | High Frequency Digital Capacitance |
| Output Signal | 4–20mA |
| Digital Communication | Modbus RTU (RS-485) |
| Power Supply | 24VDC (4-wire) |
| Power Consumption | 2W Max |
| Measurement Rate | 1000 per second |
| Ambient Temperature | –20°C to +60°C |
| Ingress Protection | IP66 |
Applications
Custody Transfer & LACT Units
Determine net oil volume during ownership transfers by measuring the water fraction inline. The ZT-100 provides the water cut input for fiscal calculations and can trigger automatic divert if water content exceeds contractual limits.
Production Monitoring
Track water cut trends at wellheads, test separators, and production manifolds to detect water breakthrough early, optimise artificial lift, and allocate production across commingled wells.
Separator Performance
Monitor oil-phase quality at separator and heater-treater outlets to verify separation efficiency, control emulsion treatment, and ensure export-quality crude before pipeline entry.
Automatic Well Testing
Integrated into well test units to measure net oil per well. Combined with flow metering and level measurement, the ZT-100 enables automated test cycles across large fields without manual sampling.
Desalter Monitoring
Measure water content at desalter inlets and outlets to optimise wash water injection rates, verify salt removal efficiency, and protect downstream refinery equipment.
Pipeline Quality Assurance
Continuous inline monitoring of crude oil and product pipelines to detect off-spec conditions, emulsion carry-over, or water slugs before they reach terminals or processing facilities.
Configure Your ZT-100
Our engineering team can help you select the right configuration for your application, including pipe size, process connections, materials, and certifications.
