Summary

ALS was requested by an operator to provide support for a high profile workover operation on a platform located offshore Gabon. Two dual pod ESP systems had experienced consecutive, infant failures, and were in need of being replaced quickly while simultaneously seeking to identify the root cause of the failure and provide a remedy that could be implemented on the immediate install.

ALS was tasked with providing an offshore expert for wellsite inspection (WSI), as well as an ESP Systems Reliability expert to be stationed onshore at the supplier facility for the dismantle, inspection, failure analysis (DIFA). Both of the ALS consultants reported directly to the operator, with additional support from remote consultants for guidance. Additionally, the remote consultants assisted with generating daily reports, organizing findings and photos, and preparing the final report for submission to the operator.

ALS maintained constant communication with both operator and supplier, with the goal of creating a streamlined process and offering expert third-party analysis to the operation. ALS involvement was to provide the operator with real-time information, in order to facilitate informed decision-making on any necessary changes to the replacement ESP’s, since they were to be installed immediately following the pulls. The ultimate goal was to identify a root cause as early as possible, so the failure mechanism could be remedied and applied to the installs, so repeat failures could be mitigated and avoided.

Scope of Work

Offshore Field Engineering Consultant (WSI)

  • Ensure all findings properly noted/photographed on behalf of operator

  • Witness pulls of the failed ESP systems – attempt to identify any potential modes of failure

  • Ensure electrical testing performed correctly

  • Witness installation of new ESP systems – ensure procedures were followed as discussed

  • Report critical findings directly to operator for early decision-making

  • Offer third-party oversight of WSI operations

  • Liaison with supplier and operator onsite and via regular conference calls

Onshore ESP Systems Reliability Consultant (DIFA)

  • Prepare supplier facility - ensure facility is organized and proper tooling is in place

  • Oversee DIFA, record/photograph findings, ensure procedures followed

  • Report critical findings directly to operator for early decision-making

  • Generate daily reports to be sent to Remote Supporting Consultants

  • Offer third-party oversight of DIFA operations

  • Offer third-party oversight of WSI operations

  • Liaison with supplier and operator onsite and via regular conference calls

Remote Supporting Consultants

  • Participate in all conference calls to offer oversight, input, and planning

  • Finalize daily reports from WSI and DIFA operations to be sent to operator

  • Compile and organize all findings into cloud storage for operator access

  • Generate final DIFA reports to be presented to operator

  • Following the offshore operations, a Remote Consultant was requested to attend follow-up laboratory analysis on some of the failed ESP components which resulted in the ESP system failures.

Results

It was discovered that both ESP’s on each of the dual pod ESP systems had experienced similar failure mechanisms. At the WSI, the M valves and G valves at the base of the motors were noted to be leaking. Upon removal, a considerable amount of degradation was observed on the lead gaskets. The leaking gaskets had allowed well fluid to enter into the motors, resulting in grounding and electrical failure.

The root cause of the lead degradation was not able to be determined from observations in the field or at dismantle. It was recommended that the damaged components be sent into a laboratory for testing. Various mechanical and chemical tests were performed and reports were generated. The results of the laboratory analysis indicated that the lead was not pure, but consisted of other elements which may have contributed to its failure. The failure mechanism was stated to be mechanical, with corrosion effects likely occurring after the failure.