Richard Nolan - Santos

Santos Siemens SGT400 Fleet:Commissioning, Start-up and Initial Operations

Richard Nolan, Team Leader Reliability Engineering23rd November 2016

Fleet Overview

Availability Case Study

Commissioning

RCA Investigations

─ GG Inlet Vibration

─ GTC Aux GB Shaft Failure RCA

Conclusions

Fleet Overview

16 SGT400 Packages across three upstream compression facilities

─ 7 Mechanical Drives (2 stage and 3 stage centrif GTCs)

─ 9 Generator Sets

─ Houston packaged, global supply chain

SGT400 Common Driver

─ 13MW, twin-shaft design

─ 2 stage CT and PT

─ Lincoln, UK supply

GTC Package

─ STC-SV 2 stage and 3 stage centrifugal compressors

─ Main export compressors for gas transmission to Curtis Island LNG plant

GTA Package

─ Converteam/GE Alternator

─ 11kV 50 Hz

─ Provide power to compression facilities, camps and well overhead feeders

Installed 2013

Commissioning 2014/15

First Annual services 2015/16

Availability Case Study

Fairview GTC fleet priority for production and availability

Final package handover May 2015

‘Bad Actor’ Rectification

─ Thermocouple Node Vibration

─ BOVs

─ Combustion Dynamics

─ Process Equipment

─ Seal Gas Panels

Transition from Reactive to Proactive

RCA Investigations and Rectification

Remote Condition Monitoring Capability Commissioning Close Out

RCA Investigations, Bad Actor Rectification

RCA Rectification, Steady Ops

Commissioning

12 month total duration (16 packages handed over to ops)

Operations staff embedded during commissioning phase

Overseas OEM GT commissioning team

Key Issues

─ PLC code mods and config control

─ LO Flushing

─ LO Pressure Stability

─ GTA load sharing

─ Seal gas panel PCV control

─ Centrif compressor casing drains

─ GTA Alignment

Operator/OEM Relationship

RCA Investigations

GG Inlet Vibration

─ Characterised by initial start to start variability

─ Joint investigation and collaboration between Santos and Siemens

─ Rectification covered under warranty

─ Fleet mitigated with upgraded GG inlet no 1 bearing

Aux GB Output Shaft Failure

─ Loss of drive to main LO pump

─ Damage to GG, PT and LP centrifugal compressor

─ Joint RCA between Santos and Siemens (ongoing)

─ RCA focus on Aux GB: Main LO pump coupling

─ Follow up LO system investigation

GG Inlet Vibration RCA: 3 Month Trend

Start to Start Variance

Bearing Degradation

GG Inlet Vibration RCA Spectrums: 24 hr cycles

GG Inlet Vibration RCA

Engine removed from service and returned to UK

Significant 9 month investigation

Synchronous Vibration and variance due to more than one GG rotor characteristic

─ Disc 9/Exis Stub Shaft eccentric growth

─ Blade scatter

─ Demonstrated via modelling and HSB testing

Sub Synchronous vibration attributed to fretting of inlet bearing radial pads

Key Activities

─ HSB testing of failed bearing

─ 3rd party analysis (OEM supplier and Tribology)

─ Fleet retrofit of upgraded bearing

Upstream Teeth

Downstream Teeth

Compressor Disc 9 and Exit Stub Shaft HirthTeeth Interface

- Thermal effects cause relative radial movement (150 – 200 um) at Disc 9/ESS HT interface, demonstrated by wear markings

- Asymmetric or eccentric growth at Disc 9/ESS has highest impact on rotor balance as shown by rotor modelling sensitivity analysis


HSB testing focused on start to start repeatability of SGT400 rotor

─ No thermal effects

─ Testing with CT attached and removed

─ Full stop and slow speed spin testing

Poor repeatability demonstrated when full stops carried out between runs, variation of 20um visible.

Improved repeatability when rotor reduced to 900rpm between runs

Poor repeatability is not significant enough to be the only root cause

14300rpm – full stop 14300rpm – 900rpm spin


GTC Aux GB Shaft Failure RCA



- 6 weeks downtime. GG, PT, Aux GB, Main LO Pump, LP Bundle Replaced.

- Root cause focused on installation and material vulnerability of Aux GB to Main LO pump coupling

- Returned to service and shutdown following 24hr increase in dP across LO Filters

- Main LO pump damage cause of high filter dP

- OEM pump supplier inspection on site

- GTC Fleet Inspection and pump retrofit

- Significant collaborative effort between operator and OEM required

Conclusions

Commissioning

─ Resource Consistency (Operator and OEM)

─ Configuration management across sites

─ Prioritising full close out of technical issues

─ First real opportunity to develop operator/OEM relationship

Operational Support

─ Operator and Maintenance teams package familiarity

─ Remote condition monitoring capability

─ OEM Embedded Engineer

─ Training (right people, right time)

RCA Activities

─ Huge international collaborative effort (and challenge)

─ Separate technical/commercial as far as possible

─ Significant time and expense spent by OEM

Operator/OEM Relationship