Development and Application of Risk Evaluation Methods for a Bay of Campeche Offshore Platform
Authors: Chavez Mario , Hopper David , Roberts Robert , Bea Robert , Valdes Victor , Valle Oscar 
Published: October 2008

An ad-hoc methodology was developed for identifying, quantifying, and ranking risk reduction alternatives for Pol-A, a jacket type compression platform of PEMEX located in the Bay of Campeche. The platform risks associated to its operational and to natural hazards were considered. For the former risk the methodology included: the Dow Fire and Explosion Index Analysis, the Zurich Hazard Analysis, a Reliability and Availability Analysis, and a Profit-Risk Analysis. For the latter risk the methodology utilized: the results of regional metocean and seismic hazard analyses, ambient vibration test of the platform, and structural ultimate limit state and reliability analyses. The methodology was applied to estimate Pol-A operational and natural risks. Among other results the following can be mentioned:a total (operational plus natural) annual probability of failure of 1.65 × 10–3 for a catastrophic incident was found. From this value 61%, 24%, 5%, 2%, and 8%, corresponded to the: operational, hurricane, earthquake, collision during a hurricane, and non-hurricane induced collision, respectively.The annual expected availability of Pol-A four compressors for 1997 was of only 69%.The frequency and/or severity of incidents with catastrophic consequences can be mitigated by the following categorical remedies:Installation of emergency isolation valves and enhancement of inspection, testing and maintenance in the sour gas treating section;Enhancement of the fire water system.With relation to the production of gas it appears that it can be increased by:Altering and rerating the compressors;Upgrading selected compressors systems instrumentation elements;Modifying predictive and preventive maintenance practices;Tightening operation control settings.

Introduction

In this work we present the results of the development and application of methods to estimate the risks of Pol-A, a jacket type compression platform of PEMEX located in the Bay of Campeche, at a distance of about 50miles northwest of Ciudad del Cannen, Campeche, Mexico. The risk assessment includes: the mechanical integrity of the process equipment, the reliability of process systems, as well as the risks associated to environmental initiators, possible colissions, and to the structural capacity of the platform. Risk is defined here as the product of two factors, one is the probability that an adequate or acceptable quality has not been reached (associated to the occurrence of an unwanted incident) and the second includes the consequences related to the quality that has not been reached (those consequences have an economical cost). Pol-A compression (PAC) is one of the platforms which makes up the Pol-A complex (Fig. 1). The latter, and the nearby Abkatun complex are utilized by PEMEX to produce the light Istmo crude oil and the associated gas. The operation of both is interdependent, and between the two handle large production volumes (about 400 thousands barrels per day) which are send onshore through pipelines (the crude oil to Dos Bocas, Tabasco and the gas to Atasta, Campeche). From Fig.l it can be seen that the Pol-A complex is made up of a drilling platform, a link platform, an habitation platform, a production platform, two flare tripods, and a telecommunication tripod. Those platforms and tripods are linked by several bridges.