Commissioning of the produced water monitoring system is one of the most critical milestones on the path to first oil on an FPSO project. Before produced water discharge can begin, the monitoring system must be inspected, verified and signed off confirming that it is correctly installed, calibrated, integrated and documented to support compliance discharge operations.
A commissioning inspection that reveals deficiencies in the monitoring system can delay first oil, the most expensive outcome on any offshore project. Understanding what inspectors check, what must be in place and where the most common commissioning risks lie allows EPC commissioning teams and FPSO operators to prepare effectively. For the regulatory consequences of monitoring failures once the FPSO is in service, see What Happens If FPSO Produced Water Discharge Fails an Inspection?.
| Key thing to remember Commissioning the produced water monitoring system is not just about verifying that the analyser produces a reading. The complete monitoring loop from the sample tap through the analyser to the alarm output and the discharge shut-off valve must be functionally tested and documented before the FPSO can begin compliance discharge operations. A reading without a functioning discharge shut-off is not a compliant monitoring system. |
What Is a Produced Water System Commissioning Inspection?
A produced water system commissioning inspection is a formal verification process carried out before first oil that confirms the produced water treatment and monitoring system is ready to support compliance discharge operations. It covers both the physical installation and the documentary record.
The inspection is typically carried out as part of the Site Acceptance Test (SAT) for the monitoring system, a structured test in the installed configuration that verifies the complete system from sample tap to control room alarm and discharge shut-off valve.
On an FPSO project, the commissioning inspection may be witnessed by:
- The EPC commissioning team and the FPSO operator’s commissioning manager
- The oil-in-water monitor manufacturer or their authorised service representative
- The flag state authority or classification society inspector, where flag state commissioning requirements apply
- The regulatory authority inspector, in jurisdictions where regulatory sign-off before first discharge is required
What Is the Difference Between a FAT and a SAT for Produced Water Monitoring?
Factory Acceptance Test
The Factory Acceptance Test (FAT) is carried out at the monitor manufacturer’s facility before the equipment is shipped to the FPSO. It verifies that the analyser meets its specification in a controlled environment confirming measurement accuracy against a calibration reference, response time, alarm function and output signal integrity.
The FAT is a necessary prerequisite for the SAT but it does not verify the installed system. A monitor that passes the FAT at the factory must still be verified in the installed configuration on the FPSO before it can be relied upon for compliance discharge operations. For a detailed explanation of what each test covers, see How Do You Test an Oil-in-Water Monitor Offshore?.
Site Acceptance Test
The Site Acceptance Test (SAT) is carried out after the monitor has been installed on the FPSO, connected to the sample conditioning system, integrated with the DCS or ICSS, and wired to the discharge control valve. It is the primary commissioning inspection event for the produced water monitoring system.
The SAT verifies the complete installed system not just the analyser in isolation. Every element of the monitoring loop must be tested from end to end: from the sample point through the analyser, through the alarm output to the control room, and through the discharge shut-off signal to the valve.
What Does a Produced Water Monitoring SAT Check?
The table below sets out the ten key checks that must be covered during a produced water monitoring SAT. Each check produces a pass or fail outcome and any fail must be remediated and retested before the SAT can be signed off.
| Commissioning check | What is verified | Outcome |
| Physical installation | Monitor correctly installed at the treatment package outlet; sample tap and isolation valve accessible; sample line free of leaks | Pass or fail with remedial action required |
| Sample conditioning | Pressure, temperature and flow at the sample point within the analyser operating range; filtration in place and clean | Pass or fail; sample conditioning outside range prevents accurate measurement |
| Calibration certificate | Valid calibration certificate available onboard; crude oil reference matches the FPSO crude type; certificate not expired | Pass or fail; expired or mismatched calibration certificate is a compliance gap |
| Analogue output verification | 4 to 20mA output from the analyser correctly received and displayed at the DCS or ICSS; engineering units correct | Pass or fail; incorrect scaling prevents operators from reading oil concentration accurately |
| Alarm function test | High oil alarm activates at the correct set point; alarm is received at the control room; alarm resets correctly when oil concentration returns below the threshold | Pass or fail; alarm failure means operators will not be alerted to a compliance breach |
| Discharge shut-off functional test | Simulated high oil signal causes the discharge valve to close within the required response time; valve closure confirmed physically | Pass or fail; this is the most critical functional test failure means the monitoring system cannot automatically prevent a compliance breach |
| Data logging verification | Oil concentration readings are being captured in the data logging system with correct timestamps; alarm events are logged | Pass or fail; without a functioning data log there is no compliance record |
| Oil Record Book interface | Discharge data is being captured in the format required by the applicable regulatory authority or operator standard | Pass or fail; incorrect format may not satisfy regulatory reporting requirements |
| Operator training confirmation | Operating crew have received training on alarm response, manual override, routine maintenance and calibration schedule | Pass or fail; untrained operators create a risk of incorrect response to alarms or maintenance failures |
| Documentation package completeness | Type approval certificate, ATEX certificate, FAT report, calibration certificate, O&M manual and SAT report available and complete | Pass or fail; incomplete documentation is a commissioning hold point and a regulatory inspection risk |
The discharge shut-off functional test at check 6 is the single most important test in the entire SAT. It is not sufficient to confirm that the wiring is correct the complete functional loop must be tested by simulating a high oil condition and physically confirming that the discharge valve closes within the required response time. This test must be documented in the SAT report.
What Must Be in Place Before the SAT Begins?
Several prerequisites must be in place before the produced water monitoring SAT can be started. Attempting to begin the SAT without these in place wastes time and creates a risk of failing checks that could have been resolved in advance:
- The oil-in-water analyser must be physically installed at the correct monitoring point at the treatment package outlet, after all treatment stages and before the discharge valve
- The sample conditioning system must be installed, connected and capable of delivering sample to the analyser at the correct pressure, temperature and flow rate
- All electrical connections between the analyser, the DCS or ICSS and the discharge control valve must be completed and loop-checked
- The analyser must be calibrated against the FPSO crude oil type the calibration certificate must be available and must reference the correct crude oil
- The FAT report must be available and complete
- The type approval certificate and ATEX or IECEx certification must be available and verified
- The discharge control valve must be installed, operational and capable of remote actuation from the control system
- Operator training must be scheduled if not already completed before handover to operations
| Do not attempt to close out commissioning with outstanding items A common commissioning pressure is to attempt to sign off the SAT with outstanding items listed as punch list items to be resolved after first oil. For the produced water monitoring system, this is not acceptable. The discharge shut-off functional test, calibration certificate verification and documentation completeness are not punch list items they are commissioning hold points. First oil discharge cannot begin without them. |
What Are the Most Common Commissioning Risks for Produced Water Monitoring?
Experience across FPSO commissioning projects has identified seven recurring risks that cause delays or failures during produced water monitoring commissioning. The table below sets out each risk, what it means and how to resolve it.
| Common risk | What it means | How to resolve |
| Calibration certificate mismatch | Calibration carried out on a different crude oil type from the FPSO crude readings may be systematically inaccurate | Recalibration against the correct crude oil reference before first oil |
| Sample conditioning outside specification | Analyser receiving sample at incorrect pressure, temperature or flow rate measurement unreliable | Adjust sample conditioning system; verify operating conditions at the sample point |
| Discharge shut-off not connected | Analyser installed but not wired to the discharge valve automatic protection not functional | Complete the control loop; retest the full functional loop before first oil |
| Alarm set point incorrect | Alarm set point not aligned to the field permit discharge limit alarm may trigger too late or not at all | Confirm the permit discharge limit; set the alarm at or below the limit; retest |
| Data log not recording correctly | Readings being captured but timestamps incorrect, units wrong or data not reaching the compliance record system | Correct the data logging configuration; verify format against regulatory reporting requirements |
| Documentation incomplete | Missing FAT report, ATEX certificate or calibration certificate commissioning cannot be signed off | Obtain and verify missing documents before the SAT is completed |
| Operator training not completed | Crew unfamiliar with alarm response, manual override or maintenance procedures | Complete operator training before handover; document training records |
All of these risks are avoidable through correct specification and procurement. The specification decisions that create commissioning risks are made months before the SAT which is why early advisory input from Rivertrace at the FEED and procurement stage is valuable. For a full guide to the specification process, see How to Specify an Oil-in-Water Monitor for FPSO Produced Water Discharge.
What Documentation Must Be in Place Before First Oil Discharge?
The documentary record for the produced water monitoring system must be complete before first oil discharge can begin. Inspectors whether from the flag state authority, the regulatory authority or the operator’s HSE team will review this record as part of any commissioning or pre-discharge verification. The required documents are:
- FAT report signed and dated, confirming the analyser met its specification at the manufacturer’s facility
- SAT report signed and dated, covering all ten commissioning checks including the discharge shut-off functional test result
- Calibration certificate current, referencing the FPSO crude oil type, with expiry date clearly stated
- Type approval certificate confirming the analyser meets the applicable MEPC resolution or permit requirement for the discharge stream
- ATEX or IECEx hazardous area certificate confirming the analyser is certified for the zone classification of the installation location
- O&M manual confirming routine maintenance procedures, calibration intervals and alarm response instructions are available to the operating crew
- Operator training records confirming that the crew responsible for the produced water monitoring system have received training before first oil
How Does Rivertrace Support FPSO Produced Water Commissioning?
Rivertrace provides commissioning support for produced water monitoring systems as part of the advisory service available to EPC and FPSO operator teams. The full scope of Rivertrace’s support for FPSO produced water projects is set out on the Produced Water Discharge Monitoring for FPSOs page.
Commissioning support from Rivertrace includes:
- FAT attendance and witnessing at the manufacturer’s facility
- SAT support including commissioning of the SMART PFM 107 and other Rivertrace products in the installed configuration on the FPSO
- Calibration verification and onsite calibration adjustment against the FPSO crude oil type
- Discharge shut-off functional test support confirming the complete loop from analyser through to valve closure
- Documentation package review confirming all required certificates and records are complete before the SAT sign-off
- Operator training covering alarm response, manual override, routine maintenance and calibration schedule
Frequently Asked Questions
What is a produced water monitoring SAT on an FPSO?
A Site Acceptance Test (SAT) for produced water monitoring is a formal commissioning inspection carried out after the oil-in-water monitor has been installed on the FPSO. It verifies the complete installed system from sample tap through the analyser to the alarm output and discharge shut-off valve confirming that the system is correctly installed, calibrated, integrated and documented to support compliance discharge operations.
What is the most important test during produced water monitoring commissioning?
The discharge shut-off functional test is the most important commissioning check. It verifies that a simulated high oil signal causes the discharge valve to close within the required response time. This confirms that the monitoring system can automatically prevent a compliance breach if oil concentration exceeds the permit discharge limit. It must be physically confirmed and documented in the SAT report.
What documents must be in place before first oil discharge from an FPSO produced water system?
The documentary record must include the FAT report, the SAT report, the current calibration certificate referencing the FPSO crude oil type, the type approval certificate, the ATEX or IECEx hazardous area certificate, the O&M manual and operator training records. All documents must be complete and available for inspection before first oil discharge can begin.
What are the most common causes of commissioning delay for produced water monitoring?
The most common causes are calibration certificates that reference the wrong crude oil type, sample conditioning systems delivering sample outside the analyser operating range, discharge shut-off valves not connected to the monitoring system, alarm set points not aligned to the field permit discharge limit, incomplete documentation packages and operator training not completed before first oil.
Does Rivertrace attend FPSO commissioning and provide SAT support?
Yes. Rivertrace provides FAT and SAT support for produced water monitoring commissioning on FPSO projects, including calibration verification against the FPSO crude oil type, discharge shut-off functional test support, documentation package review and operator training.