Malampaya Deep Water Gas-to-Power Project: Onshore Gas Plant Value Engineering and Flawless Start Up

Abstract

Abstract The Malampaya field development comprises subsea wells in 820 metres water-depth producing via a subsea manifold and two 16 inch diameter inconel clad flowlines to a shallow water platform 30 km distant. Condensate is removed on the platform and the dry gas is then transported via a 504 km long 24 inch export pipeline to an onshore gas plant at Tabangao (Batangas, Luzon Island) for extraction of H2S. The condensate is stored in the platform CGS caisson prior to export via a short 3 km long 24 inch diameter pipeline and CALM buoy. The Malampaya Onshore Gas Plant (OGP) at Batangas is a vital part of the overall Shell Philippines Exploration B.V. (SPEX) Malampaya Deep Water Gas-to-Power Development. The plant design and execution schedule was from the outset extremely tight, mainly due to uncertainties during the definition stage on the exact requirements for H2S removal. Consequently, the project awarded the main Engineering Procurement and Construction (EPC) contract ahead of final design optimisation. To ensure an optimised design and to reduce cost without scarifying the functional requirements, the project executed a Value Engineering exercise prior to start of detail design. The exercise not only resulted in a reduction of overall cost of20%, it also produced a better design. In addition to discussing the benefits gained through the Value Engineering process, this paper will address the fast track nature of the Project and the application of the conceptof Flawless Start-Up to meet the tight schedule. This involved the necessary up front work in detailed engineering, procurement and construction, as well as commissioning, start up planning and risk analysis to support a short and trouble free start up. The paper also addresses key aspect of HSE management in construction and start up for this green field project in Batangas, Philippines. The OGP executed some 11.3 manhours without a Lost Time Incident (LTI) utilising mainly local, in most cases unskilled, labour. The project was also certified to ISO 14001 from start of construction and through until start up and full operation. Introduction The OGP facilities are designed to take the sour dehydrated gas from the Malampaya gas export pipeline, which lands at Batangas and process up to 500 MMscf/d of natural gas. The treated gas feeds three power stations with a cumulative capacity of 2700 MW of electric power for domestic consumption (Fig. 1). The OGP is designed to remove up to 1000 ppm H2S from the gas, using an amine process and deliver specification gas(less than 20 ppm H2S) to the customers. The facility also includes fiscal metering for the three customers, a sulphur recovery unit and various utilities. The plant has two process trains with common inlet and outlet facilities.