●Annual CP Survey Report
CV-CP-2026-014 Rev 01 · PL-06″ SGPC–TIPU · issued for useDocument control
| Report number | CV-CP-2026-014 |
| Revision | Rev 01 — issued for use |
| Client | Mari Energies Limited |
| Facility | Sui Gas Processing Complex |
| Structure | PL-06″ SGPC–TIPU, KP 0.0–16.4 |
| Survey type | Annual test-post + CIPS |
| Survey window | 11–13 March 2026 |
| Contractor | Corrovision Field Services |
| Surveyor | A. Sattar — ISO 15257 Level 2 |
| Reviewed by | M. Iqbal — ISO 15257 Level 3 |
| Issue date | 20 March 2026 |
Survey conditions
| Weather | Dry, 31–38 °C |
| Soil condition | Dry sandy loam, no recent rainfall |
| Soil resistivity | 2,400 – 9,600 Ω·cm (Wenner 4-pin) |
| Ground cover | Cultivated 0–8 KP, scrub 8–16.4 KP |
| Access | Full; no restricted sections |
| Deviations | None. All 16 test posts read. |
1. Executive summary
The annual test-post survey and concurrent close-interval potential survey of PL-06″ SGPC–TIPU were completed over 11–13 March 2026. All 16 test posts were read and the full 16.4 km was walked.
12 of 16 test posts (75%) meet the −850 mV instant-OFF criterion. A continuous 4.0 km section between KP 10.0 and KP 14.0 fails, with a minimum recorded instant-OFF of −698 mV at KP 12.4. A concurrent DCVG survey located a Category-2 coating holiday at the same chainage (34% IR).
The failing section is attributed to a single localised coating defect draining protective current, not to inadequate CP capacity — potentials either side of the defect are comfortably within criterion. The recommended remedy is therefore a local excavation and recoat, not a CP redesign. Five deficiencies are listed at §5 with prioritised recommendations at §6.
2. Scope & methodology
| Parameter | Applied | Reference |
|---|---|---|
| Criterion applied | −850 mV instant-OFF vs Cu/CuSO₄ | AMPP SP0169 §6.2.2.1.1 |
| Secondary criterion | 100 mV cathodic polarisation decay | AMPP SP0169 §6.2.2.1.2 |
| Survey method | Close-interval potential survey, 1.5 m spacing | NACE SP0207 |
| Interruption cycle | 4 s ON / 1 s OFF, GPS-synchronised across TR-01 and TR-04 | NACE SP0207 §5 |
| Reference electrode | Cu/CuSO₄ portable, calibrated 09 Mar 2026 (±5 mV) | NACE TM0497 |
| Instrumentation | High-impedance DVM > 10 MΩ, datalogger, GPS ±2 m | NACE TM0497 §3 |
| Coating survey | DCVG, %IR method, run concurrently | NACE SP0502 |
| AC interference | Coupon current density at HV crossing KP 9.4 | EN ISO 18086 |
3. Results against criteria
| Measure | Result | Rate | Assessment |
|---|---|---|---|
| Test posts surveyed | 16 of 16 | 100% | Pass |
| Meeting −850 mV instant-OFF | 12 of 16 | 75% | Attention |
| Meeting 100 mV polarisation | 14 of 16 | 88% | Pass |
| CIPS length surveyed | 16.4 km of 16.4 km | 100% | Pass |
| Section below criterion | KP 10.0 – 14.0 (4.0 km) | 24% of length | Fail |
| DCVG indications | 7 recorded, 1 Cat-2 | — | Attention |
| AC current density (KP 9.4) | 18 A/m² | low risk | Pass |
5. Deficiency list
2 critical| Ref | Location | Deficiency | Probable cause | Severity |
|---|---|---|---|---|
| D-01 | KP 12.4 | Instant-OFF −698 mV; DCVG Cat-2 holiday at 34% IR | Coating holiday draining CP current | Critical |
| D-02 | KP 10.0–14.0 | Section fails −850 mV instant-OFF over 4.0 km | Consequence of D-01 | Critical |
| D-03 | TP-0112 | Test post lead resistance 4.2 Ω (expected < 1 Ω) | Corroded cable connection | Major |
| D-04 | TR-04 | Tap at 5/2 delivering 31.0 V — near rated capacity | Rising circuit resistance | Major |
| D-05 | GB-01 | Groundbed resistance 1.8 Ω vs 1.1 Ω at commissioning | Anode consumption, 46% depleted | Minor |
6. Recommendations
| Ref | Recommended action | Priority | Timeframe | Closes | Reference |
|---|---|---|---|---|---|
| R-01 | Excavate KP 12.4, assess and recoat the holiday; holiday-test before backfill | Immediate | 30 days | D-01 | SP0502 §6 |
| R-02 | Re-survey KP 8.0–16.4 after repair to confirm the section returns to criterion | Immediate | Within 30 days of repair | D-02 | SP0169 §10 |
| R-03 | Replace TP-0112 test lead and re-terminate at the pipe | Short-term | 90 days | D-03 | 192.469 |
| R-04 | Review TR-04 sizing against present circuit resistance; consider uprating | Short-term | 90 days | D-04 | ISO 15589-1 §7 |
| R-05 | Budget GB-01 groundbed replacement in FY28 based on depletion trend | Long-term | FY28 | D-05 | ISO 15589-1 §7 |
7. Certification
A. Sattar
ISO 15257 Level 2 · 13 Mar 2026M. Iqbal
ISO 15257 Level 3 · 18 Mar 2026Mari Energies Limited
Integrity Dept · 20 Mar 2026Signatory competence per ISO 15257. Records retained for the life of the pipeline per 49 CFR 192.491.