XSENS WHITEPAPER – Field trial: Clamp-On Water Cut & Flow Rate Results With Global Tier 1 Oil Company

Water Cut Testing on Bulk Crude Oil Line from Offshore

The Tier 1 client requested XSENS to test its patented clamp-on meter, which measures 0-100% water cut with +/-1% accuracy absolute and flow rate with +/-1% accuracy of actual flow. Measurement was conducted on three different pipelines, both onshore and offshore. The focus was on water cut measurement of the crude oil-water mixture.

XSENS – Offshore trial location September 2025

For trial purposes, a portable XSENS unit (slightly lower accuracy ) was used instead of the fixed, highest accuracy XSENS unit intended for permanent installation. XSENS successfully compared its results against the Client’s reference turbine meters and manual BS&W sampling during a supervised trial in September 2025.

Reference data from the oil company was handed over to XSENS after XSENS delivered its measurement results to the oil company. This blind test demonstrated the technology’s performance and versatility across different bulk lines.

Installation

The XSENS Portable Meter was installed on three different pipelines with sizes 18” and 10″ (bulk) and 12” (crude to wash tank). Flow rates were compared against existing Turbine Flow Meters and water cut measurement was compared against manual BS&W sampling. Densities of the oil from the different pipes were 38, 41 and 28 API. Water cut variated from 0% to 60%. Flow velocity ranged from 0.4m/s to 1.2m/s.

The XSENS meter calculates water cut based on measured Speed of Sound (SoS) of the water/oil mixture inside the pipe. Before start-up, XSENS measures Speed Of Sound (SoS) of pure oil as well as water-salinity, which is used as an input to the the water cut calculation. Temperature is measured by the XSENS Meter to update the water cut model with changing temperatures.

Onshore installation with portable kit showing transducers strapped to pipe, electronics pelicase, battery and PT100 temperature sensor.

Offshore installation of portable kit with XSENS personnel and local partner support.

Test Measurements

Below figures show Water Cut and Flow Rate results for the 18″, 10″ and 12″ lines.

Test Results – Water Cut

As illustrated in the figures, the 18” and 10” pipelines maintained an average water cut of 40–60%. The XSENS Meter measurements were largely consistent with manual sampling, though some minor discrepancies were noted.

In the 18” line, manual sampling was performed at the top of the pipe. At flow rates of approximately 1 m/s, some water-oil separation is expected; this likely caused the manual samples to reflect a lower water cut than the actual pipeline average. For the 10” line, the specific location of the sampling point was not provided.

No manual sampling was conducted for the 12” line, as the operator assumed a constant 0.5% water cut. However, the XSENS Meter detected significant spikes reaching 12–13% during high-flow sequences. Furthermore, the meter’s multipath capabilities (measuring at both the 3 o’clock and 6 o’clock positions) allowed us to verify water separation during a period of zero flow (15:30–15:55). This was confirmed by the Speed of Sound (SoS) data: the SoS decreased at the 3 o’clock position and increased at the 6 o’clock position, indicating a higher concentration of water at the bottom of the pipe.

Test Results – Flow Rate

Although flow rate comparison was not the primary focus of these tests, data for the 18” line is included below. On average, the XSENS Portable Meter showed a 4% difference compared to the reference turbine meter. This performance aligns with the portable unit’s trial specifications. For comparison, a permanently installed XSENS Meter maintains a higher accuracy specification of ±1%.

Reference Turbine Meter used for comparison to XSENS flow measurement results.

XSENS Flow Rate results compared to Reference meters.

XSENS Flow Rates compared to Reference meters

Test Summary

Discussion – Water Cut

12” Pipeline

XSENS water cut readings remained consistently low (near 0%) but successfully captured intermittent spikes of 12–13%. During zero-flow periods, the meter’s multiple measurement paths detected a change in the Speed of Sound, clearly identifying the onset of oil-water separation. This confirms the XSENS Meter’s ability to detect stratified layers and provide accurate measurements even under separated flow conditions.

18” Pipeline

XSENS readings compared to manual sampling showed a consistent average absolute difference of 2.5%. Manual samples were slightly lower than XSENS data; however, because samples were drawn from the top of the horizontal pipe, they likely missed water settled at the bottom. This sampling position likely accounts for the minor variance.

10” Pipeline

Comparison with manual sampling showed an average absolute difference of 6.5% across three samples. The XSENS Meter captured rapid fluctuations, including shifts exceeding 20% water cut in under 10 minutes. These highly dynamic conditions make manual sampling comparisons difficult, as even slight timing discrepancies between the sample pull and the digital reading can lead to variance.

Discussion – Flow Rate

The 4% variance between the XSENS Portable Meter and the reference turbine meter is well within the trial specifications for the portable unit. These results confirm a strong correlation between the two technologies.

Conclusions

Water Cut Accuracy: Excellent correspondence was observed, particularly in the 40–60% range. The meter proved more reliable than manual sampling in capturing rapid fluctuations.
Flow & Volume: The ~4% average deviation in 30-minute accumulated volumes aligns with the XSENS Portable Meter specifications, demonstrating high measurement reliability.
Phase Separation & Transient Detection: The trials successfully validated the meter’s ability to detect oil-water separation and identify transient water spikes that manual sampling would otherwise miss.