PRE-COMMISSIONING INFIELD SUBSEA SYSTEM TECHNICAL AND OPERATIONAL

1.  GENERAL

This specification defines the minimum technical and operational requirements governing flow-line pre-commissioning of the Infield System. This specification is to be used in conjunction with the following documents:
         Basis of Design 84506-60-00-2L-060
         General Specification 84506-60-00-2L-000 - Definitions and Specification Directory
         General Specification 84506-60-00-2L-010 - Quality Assurance / Quality Control
         General Specification 84506-60-00-2L-020 – General Offshore Specification
         General Specification 84506-60-30-2L-390 – Cleaning, Gauging and Hydrotesting

This specification defines the minimum technical and operational requirements governing flowline pre-commissioning of the Infield System. This specification is to be used in conjunction with the following documents:
2.  PROCEDURES
2.1       CONTRACTOR shall supply all equipment, materials and manpower to successfully complete all pre-commissioning operations for the infield system, to the satisfaction of COMPANY.
2.2       CONTRACTOR shall develop detailed pipeline pre-commissioning procedures for the infield flowlines, pipelines and risers, and submit for COMPANY approval 30 days prior to the commencement of pre-commissioning activities. These procedures shall include, as a minimum, the proposed equipment and operations for the following:
         Dewatering pig train designed arrangement
         Disposal plan for fill water and chemical additive certificates
         Introduction of first gas
         Handover to commissioning/operations

2.3         Instrument stand(s) shall be manned at all times during pre-commissioning operations.  CONTRACTOR shall furnish communication equipment for use by CONTRACTOR and COMPANY during pipeline pre-commissioning, where CONTRACTOR employs personnel at different locations.
2.4       Detailed acceptance criteria for each flowline, pipeline, or pipeline section shall be agreed between COMPANY and CONTRACTOR prior to start of pre-commissioning operations.

3.  PIG DESIGN

3.1       The design of pipeline pigs for bulk dewatering and introduction of first gas shall be the responsibility of the CONTRACTOR.  CONTRACTOR shall demonstrate to the satisfaction of COMPANY the suitability of any pig design.
3.2       The design of pipeline pig trains for bulk de-watering and introduction of first gas shall be the responsibility of the CONTRACTOR.  CONTRACTOR shall demonstrate to the satisfaction of COMPANY the suitability of any pig train design.
3.3       Pigs used during pre-commissioning may be launched from and received in temporary traps furnished and installed by CONTRACTOR for pipeline cleaning, gauging and hydrotesting.
3.4       COMPANY acceptance of any design or procedure will not absolve CONTRACTOR of his responsibility to complete the work in as diligent and as timely a manner as is practically possible.
3.5       Every pig shall be permanently marked with a unique number that shall be clearly visible in a photograph.  The condition of all pigs shall be recorded photographically prior to and following the pigging operation.
3.6         If in COMPANY opinion de-watering pigs have not adequately de-watered the pipeline, the dewatering operation shall be repeated until results obtained are satisfactory to COMPANY.
3.7         Refer Cleaning Gauging and Hydrotesting Specification 84506-60-30-2L-390 page 8 paragraphs 4.7 & 4.8
 

4.  DEWATERING REQUIREMENTS

4.1       CONTRACTOR shall dewater the flowlines, pipelines and risers by running an adequate number of pigs in tandem through the lines ahead of production gas to clear the lines of any water. 
4.2       A flow meter of sufficient size and accuracy shall be used to measure the quantities of all additives required to bulk dewater each flowline, pipeline or pipeline section.  CONTRACTOR’s detailed pre-commissioning procedures shall include methods and equipment used to measure and monitor pumping rates, and hence pig speeds.
4.3       During bulk de-watering, samples of water shall be taken from between each pig batch for salt testing.  Acceptance of the first bulk de-watering operation shall be based on the test results of the last fresh water batch.  The salt content in the last batch shall be less than 200 ppm.  Should the salt content exceed 200 ppm, CONTRACTOR shall re-swab the pipeline with additional fresh water batches.
4.4       CONTRACTOR shall be responsible for proper dilution and disposal of any chemical additives that were used to fill the lines for hydrotesting and corrosion inhibition, subject to prior approval by both COMPANY and AUTHORITIES.
4.5       When discharging water, CONTRACTOR shall install temporary piping from the receiving level to discharge water below, at, or near the surface of the water.  CONTRACTOR shall submit his temporary piping layout and water discharging plans to COMPANY for approval.
Water not discharged in this way shall be swept through the line into the MOgPU separator by the production gas from the subsea wells.

5.  DEWATERING PIG VELOCITY AND DRIVING PRESSURE

5.1       Dewatering pigs shall be driven at a speed of between 0.3 meters/second and 0.7 m/sec for the initial bulk de-watering run, and a speed of between 0.5 meters/second and 0.7 m/sec for additional runs if required. 
5.2       Driving pressure shall be recorded on a COMPANY approved recording pressure chart.  Chart time shall correspond to actual time.  Charts and other data relating to dewatering operations shall be submitted to COMPANY at the completion of each run.
5.3       Pumps shall be capable of driving pigs at the required speed and pressure range.  Pressure, volume and temperature shall be monitored and recorded at all times during the pigging operations.
5.4         Should any pig become stuck, operations shall be shut down, the pig located and cut out of the pipeline and the pipeline shall be repaired.  Repaired pipeline sections shall then be cleaned, regauged & re-hydrotested (as per specification number 84506-60-30-2L-390), and dewatered.
5.5         Refer Cleaning Gauging and Hydrotesting specification 84506-60-30-2L-390 page 5 section 3 pig design.

6.   DEMOBILISATION

Once the dewatering operation has been accepted, Contractor shall remove temporary pig launchers and receivers as appropriate.
The Contractor shall ensure that all consumables, temporary equipment and personnel are removed from site in a timely manner.  The Contractor shall leave the site in a condition as good or better than it was before mobilization.

7.  ACCEPTANCE CRITERIA

Acceptance criteria for dewatering shall be subject to COMPANY approval. Minimum requirements shall include, but not be limited to:
         All the dewatering pigs shall traverse the pipeline and the last three pig’s sealing disc diameters shall remain greater than the nominal pipe bore.
         Relatively small volumes of water shall precede the last two pigs.
         Water preceding the final pig shall have a salt content less than 200 ppm.

8.  SUBMISSIONS BY THE CONTRACTOR

In addition to the requirements stated herein, CONTRACTOR shall combine and submit to COMPANY all documents, records, charts and test certificates in a detailed final report within seven (7) days of practical completion of the job.
All data shall be submitted to COMPANY in both hard copy and electronic format.

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