ABSTRACT

A simulation model is being developed to track the operation of a two-phase wet gas pipeline in Indonesia. The on-line model continually receives SCADA updates assuring accurate conformance to the actual pipeline. The information generated by the model supports the Pipeline Management System (PMS) applications, which include Inventory Management, Line Pack, Over/Under Pressure Analysis, Instrument Analysis, and Look-A-Head Analysis. The simulation model is capable of simulating gas pipelines, liquid pipelines, as well as transient operation in either single or two-phase. The simulation model is run in conjunction with the SCADA system. All alarms are presented to the operator through the SCADA alarm management system. All data, trends, and profiles from the simulation model are also presented to the pipeline operators through the SCADA graphics management system. The paper concludes with a discussion of the dynamic testing of transients in the two-phase model when multiple components are present.

West Java Gas Transmission Pipeline Overview

The West Java gas transmission pipeline was put into operation in 1977. The 280 mile (740 km) pipeline network, transports natural gas through cities and suburbs while serving heavy industrial customers; fertilizer plants, cement plants, steel plants, power plants and other industries in West Java. The onshore pipeline network is composed of 9 sources/inputs, 5 compressor stations and 18 consumers/outputs receiving up to 400 MMSCFD of natural gas. The pipeline, delivering gas in an east to west direction, having a maximum design pressure of 720 psi (50 kg/cm2) is composed of X52 and X42 grade pipe segments. The diameter of these segments varies from 8 to 32 inches, with most of the mainline piping at 24 inches. The pipeline is externally coated, cathodically protected and buried 3 to 5 ft (1 to 1.5 meters) underground. 2 Compressor stations are composed of centrifugal units driven by gas turbine engines. High pressure and low-pressure sources supply gas from both onshore and offshore gas fields. Wet gas is mixed with dry gas after the scrubbing and dehydrating processes. Gas component information is available at source and consumer locations via chromatography readings.

System Architecture

Data from the individual RTU's will be polled and gathered by the communications server of the SCADA system. This data is presented to the simulation model at the same time it is presented to the Graphics and Alarm systems for the operator to see. The simulation model processes the data and performs its application calculations every quarter of a second. Upon completion of the application calculations, the model submits the results to the Graphics and Alarm systems allowing the operator to interact with the simulation model and respond to alarms exclusively through the regular operator console and environment. The operators will never interact physically with the Pipeline Management System (PMS) computer that houses both the model and the PMS applications. Data from the master or host SCADA communications server will be submitted to the PMS computer. Output from the PMS computer will be sent back to the host computer.

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