The Khalda Petroleum Company is undertaking the 24” AG/ DAH Pipeline Repair Project. The project is under the supervision of the Project Managers Neil Clark and Engineer Mohamed Ismail, and was contracted by PETROJET.
The project started on September 29th 2012, and will be completed by end of October 2013 (mechanical completion). The budget stated for this project $27.50mm.
The Pipeline Details:
The pipeline was originally constructed and designed in 1974. The pipeline from the Abu Gharadig Plant to the Dahshour Plant is 262.5 kilometers long and is a
24-diameter pipe with a wall thickness of 7.1mm (0.28) and a MAOP (Maximum Available Operating pressure) of 795 psig. Additionally, the pipeline has line-break valves installed along the length of the pipeline. The route of the pipeline runs through mainly uninhabited desert.
As a result of the identification of corrosion by the previous operator (GUPCO) a number of repairs were carried out, however further inspection recommended that the MAOP be reduced and a MAOP of 690 psig implemented.
The Dahshour Gas Plant must receive gas at a minimum pressure of 550 psig to enable extraction LPG from the “rich” gas and deliver “sales” gas to GASCO.
Khalda became the operator of the pipeline and associated assets in February 2011. At this time the pipeline was inspected using an intelligent pig with the objective to detect internal and external corrosion, buckles, dents, coating dis-bonding, etc. This testing was done to ensure that the line could continue to operate at the required MAOP of 795psig and as based on the original Location Class of the pipeline.
The inspection was completed and the final report, published in August 2011, identified that an immediate repair was required for wall thickness reduction exceeding 80% of the original w.t. (wall thickness). However, the report also identified w.t. reductions of over 50% of the original w.t. at other locations. Due to the severity of the identified external corrosion the pipeline was de-rated and limited to a maximum 400 psig operating pressure.
In the period between January and March 2012 a second pipeline inspection was carried out for identification metal loss, extended geometry and high resolution-mapping. This inspection provided more precise and accurate coordinates in order to ensure correct identification and location of line sections to be repaired and replaced.
In April 2012, it was identified to Operations that two sections of the pipeline have dwellings/ buildings located close to the pipeline route (6th October City & Dahshour Military Camp). The proximity of the buildings together with the Operations Departments instruction to restore the pipeline to its original MAOP (Maximum Allowable Operating Pressure) of 795 psig resulted in a “Location Class“ change, as defined by ANSI 331.8, to Location Class 4.
Based on the above information the full mechanical scope of work to be performed by Petrojet on the pipeline to return the pipeline to its original MAOP and meet the location class changed comprises the following:
- Replacement of pipe at 53 digs out locations subsequent to combining a number of dig outs and associated reinstatement.
- Installation of 5 Km of pipe in a new trench and tied in to the existing pipeline.
- Isolation and sealing ends of 5km of redundant pipeline in place, replaced by new line.
- Installation of isolation joints and associated civil works.
- Installation of 7 new rail and road crossing, tie-in to exiting pipeline nd associated reinstatement. Two crossings combined and formed by HDD technique.
- Installation of 1 automatic line break valve and associated civil works (final scope dependent on valve delivery) and reinstatement.
- Installation of 6 manual (hand operated) 24” valves (Qarun) and associated civil work (final scope dependent on valve delivery) and reinstatement (subject to valve delivery).
- Installation of 1 off-take (8’) for East Baharia Power Station (Qarun) and associated civil work and reinstatement.
The Project Total Costs:
- The total project budget: $27.5mm
- PETROJET construction contract awarded at: $17.78mm
- KPC allocated cost for engineering, materials, studies, procurement, and contingency was: $9.72mm.
- Down payment to PETROJET against construction contract was: $3.5mm.
By: Tatianna Duran