Recent Gas Studies

The following is a list of the clients and the studies undertaken by Hydraulic Analysis Group (Hydraulic Analysis Ltd. and Simulation Software Ltd) for gas pipelines. The document lists recent studies undertaken and provides additional description for some of the specific systems.

Project: Janice Gas Compression System

Client: Kerr McGee

The Janice gas compression system uses a complex control system to control two trains and two stages of compression. The system control export rate, prevents over pressure, balances the trains and optimises the balance between flare loading and pressure rise. The whole system was simulated to reduce the commissioning time and ensure that the control system performs its designed role.

Project: Wanaea/Cossack FPSO Gas Compression

Client: Kvaerner/Woodside Petroleum

The Wanaea/Cossack project has three stages of separation, an IP and LP compressor and two parallel trains of two stage compression. Suction control and a CCC anti-surge system are the main control elements. A dynamic simulation model of the topsides of the FPSO was used to design compressor start-up and shutdown procedures, anti-surge valve sizing and to determine the parallel compressor train control philosophy.

Project: Connah’s Quay Power Station

Client: Costain/Powergen

Connah’s Quay power station is fed from two sources (a BHP supply and from the NTS) and an AGI station is used to control and balance these two simultaneous suppliers. The simulation study was used to define suitable operating procedures, tune controllers and specify shutdown valves and system to prevent overpressure.

Project: SAGE Processing Plant

Client: Mobil North Sea/Fluor Daniel

A simulation model of the whole of the SAGE and STE plants (from offshore pipeline through the processing facilities, the expanders and compressors) was developed to ensure that excessive pressure are not developed, to optimise relief capacity and to limit the flare loads to within the capacity of the flare system.

Project: Dunbar Slug catcher and Compression

Client: AMEC/Total

A dynamic simulation model was used to determine the size and frequency of hydrodynamic and severe slugs. The impact on the topside control was then studied and a suitable control system was recommended. The control system minimised the impact of slug arrival on the compression whilst minimising flare gas. The control system could be configured to control severe slug sizes.

Project: Bu Hasa Refrigeration Compressors

Client: GASCO

Investigation of problems which occurred within the existing compressor train. Operation procedures and controller settings were refined ensuring safe operation and preventing a reoccurrence of the problem.

Project: Ninian Southern Platform

Client: Chevron UK

Dynamic simulation of platform topsides including separation, compression and oil export facilities. Facilities also process gas from Conoco’s Lyell and Lasmo’s staffa fields. Study focused on anti surge control whilst additionally optimising overall platform control to ensure stability during slugging in the separators.

Project: Snorre Field

Client: Saga/Granherne

The Snorre platform receives two phase flow through subsea flow bundles; the separated gas and oil are then transported separately. Following detailed design, our services were used as design verification. Results showed that improvements could be made to start-up/shutdown and day-to-day running of the system. The capability of the system to accept slug flow was verified. Design optimisation of the hot-gas bypass was recommended to improve surging control and limit flare loading.

Project: Forties Gas Lift

Client: B.P.

Gas lift systems were proposed for all of the Forties platforms. The entire gas plant and well were simulated for both shallow and deep gas lift. The study as a whole can be discussed in three major areas:-

  • Control and Operability: Simulations were used to optimise valve and controller selection, and to specify set points and control parameters.
  • Safety: Many failure cases were considered to establish limits on system safety and to confirm the capacity of relief systems.
  • Flare Loading: Simulations of normal and abnormal events were undertaken to confirm the capacity of the flare system and the flare system controller.

Project: Statpipe Gas gathering System

Client: Phillips Petroleum

The Statpipe system transports the natural gas produced at 7 North Sea platforms, boosts the pressure at Ekofisk and transports the gas to shore for treatment. Pressures range from 60 to 140 barg, pipeline diameters to 36 inch. In total, the system incorporates some 400km of transport pipeline. The study investigated dynamic operation to advise on ESD and control. Each producing, booster and receiving station has independent control and metering facilities.

Project: North Sea Gas Gathering

Client: BP Trading

Two major production platforms each with compression metering and pressure regulation facilities, 150 miles of 16 inch and 36 inch diameter pipeline. Conceptual design study which investigated start up, shutdown and line break to assess control systems, SCADA and leak detection.

Project: Indonesian Pipeline

Client: McDermot S.E.A. PTE.

Full transient analysis of gas transportation line. Including pipeline start up and shutdown and analysis of pipeline blowdown.

Project: Bacton Receiving Facilities

Client: Global Engineering/Amoco

Gas gathered from the Hamilton Brothers field in the North Sea is transported to the onshore treatment facilities at Bacton then into the British National Grid. The control of the plant with respect to the distribution and gathering systems was the prime area of the study. To define set point, high pressure shutdown settings for ESD which is included in SCADA.

Project: Bu-Hasa High Yield Plant

Client: Foster Wheeler Francaise

Gas is gathered and fed into high yield treatment plant prior to distribution to end users. An expander/compressor system was recently added to improve efficiency of this unit and the study was commissioned to investigate the effect on the rest of the plant and gathering/distribution lines.

Project: BGP Onshore Plant (St Fergus)

Client: Ralph M Parsons

Gas from offshore platforms is treated onshore prior to distribution. Failure of the plant inlet pressure control valves could cause excessively high pressures in the plant. A high integrity protection system (HIPS) was designed by using the transient flow program to simulate the failure cases. Additional flare loading scenarios were studied.

Project: Wytch Farm

Client: Foster Wheeler

Two phase well fluid is collected, separated and the resulting oil is pumped to Fawley. Extreme slug flow was predicted, hence stable separator operation was critical. For a range of slug sizes and frequencies, simulations were carried out to enable us to specify the control parameters and verify separator sizes. The crude oil pipeline to Fawley could thus be operated in a stable, safe and efficient mode.

Project: Ekofisk Gas Compression Facilities

Client: Phillips Petroleum

Four studies over 10 years during the operation, design and expansion of the Ekofisk gas compression facilities. Emergency shutdown valves were designed and specified and validation work against on-site pressures measurements showed accuracy of 7psi in a 1300psi operating pressure. Simulations of flare loading were performed to calculated and optimise flare loading.

Project: Papua New Guinea Liquified Natural Gas

Client: Aker Solutions

The Papua New Guinea Liquefied Natural Gas (PNG LNG) Project will commercialise gas resources located in the southern highlands of PNG. A number of production well choke valves and re-injection well choke valves are to be automated to regulate inlet and outlet pressures of the CPF by controlling the production and re-injection rates of the produced gas. A simulation study was undertaken to review the response and interaction between associated gas (AG) production, compression and re-injection/export following implementation of the AGRP for the CPF. The study comprehensively includes the control system of the re-injection gas and the interaction with the CPF area and its control systems. A transient simulator of the CPF area and the re-injection wells pipework was created and steady state operation was fully verified prior to the transient study of critical re-injection scenarios being undertaken.