COTEMAR S.A. DE C.V.

FUNCTIONAL SAFETY LIFE CYCLE FOR SAFETY INSTRUMENTED FUNCTIONS OF THE EMERGENCY SHUTDOWN SYSTEM IN C.P. EK-A.

CONTEXT OF THE PROJECT

As a result of the Modernization of the safety systems, auxiliary services and of the instrument air network on the drilling platform Ek-A belonging to the Cantarell Production Asset located in the Gulf of Mexico, and in regulatory compliance with the Process Risk Management and Functional Safety Life Cycle (FSLC) according to the current standards of Petróleos Mexicanos (PEMEX) / IEC 61511.

OBJECTIVE

Design an Emergency Shutdown System (ESS) that complies with the regulations of IEC-61511, IEC-61508 and ANSI/ISA 84.00.01 to take the level of risk to a tolerable level increasing reliability and reducing the false alarms of each Safety Instrumented Function (SIF) belonging to the ESS.

TECHNICAL CONTEXT

As part of the development of the Functional Safety Life Cycle (FSLC) in the C.P. EK-A the hazards and hazardous events of the process and their associated equipment were determined, as well as the sequence of events that lead to the hazardous events, the associated process risk resulting from the hazardous events, the risk reduction requirements, the safety functions required to obtain the necessary risk reduction and to determine if any of those safety functions suggested are safety instrumented functions.


The Safety Integrity Level (SIL) Objective of each Safety Instrumented Function (SIF) was determined based on the risk reduction requirements specifying the safety requirements of the Safety Instrumented System (SIS).


The calculation of PFDavg and MTTFs as parameters of performance of the SPPE, were defined in this project as a Verification of SIL measure based on the required safety integrity level (SIL Objective).


Subsequently the Emergency Shutdown Logical Matrix of the Safety Instrumented System (SIS) and the operations philosophy were developed. In these documents the functional relations between the elements of each SIF with respect to the process were developed, indicating primary and secondary actions (effects), as well as the indications of functioning and diagnosis in the Machine Human Interface (MHI).


The functional testing procedures of the SIF were prepared, to maintain the functional safety during their useful life to monitor and register the failures that could be revealed and the conditions of functioning.

As part of the CVSF the static and dynamic simulation of the process is modeled through specialized commercial software with a focus on functional safety determining the process parameters and conditions according to the logic of the SPPE (Capacity and response time of the performance – Process Safety Time and analysis of operating deviations of the activation of the logic of the SPPE).

RESULTS OBTAINED

The principal benefits obtained by the Client once this project was concluded were: