Risk Assessment and Safety Assurance Program for The Heidrun Field

Abstract

Abstract Starting with the Concept Development Phase in 1989, Conoco Norway Inc. (CN1) conducted a comprehensive risk assessment and safety assurance program for its Heidrun Field Development Project in Norway. Stringent Operating Phase risk acceptance criteria were set and risk assessments with increasing levels of detail and accuracy were performed during each major Project phase to demonstrate that these criteria are met. Risk reducing measurers were investigated and recommended at each phase of the Risk Assessment Program, whenever these were needed, to the risk acceptance criteria and/or further reduce risk to As 1.OWAs Reasonably Practicable (ALARP) levels. These studies formed the basis for the specification of the dimensioning (design) accidental loads, and the design of the Heidrun escape and evacuation systems and emergency preparedness measures. Results demonstrate that the Heidrun Field operations met the quantitative risk acceptance criteria set against loss of life and environment and property damage, at the Project initiation. Accidental design events specified as part of these studies result in uniform platform reliability. Most risk reducing measures recommended as part of these studies were accepted and implemented during the Heidrun Field Development. Introduction and Methodology Heidrun Field is located about 175 km (109 miles) off the coast of Norway (Fig. 1) in the Norwegian Sea. The water depth is approximately 350 meters (1 ]48 ft.). The Heidrun Field consists OP (1) A light weight aggregate reinforced and 1, rcstrcssed concrete Tension Leg Platform (TLP) with two concrete Module Support Beams (MSBS) supporting the Living Quarters, Utility, Drillers, Well Bay, and Process modules designed to produce an annual average of 200,000 BOPD - Fig. 2, (2) An oil off take system with two Direct Shuttle Loading (DSL) tankers moored by Submerged Tethered Loading (STL) buoys connecting to the TLP via two oil pipelines, (3) Subsea Systems consisting of a well template with 56 well slots plus riser connections to the injection wells, oil and gas export risers, and flowlines to water injection templates and to the future fields. Heidrun Risk Assessment and Safety Assurance Program consisted of the following activities:Establish Heidmn Field Risk Acceptance Criteria (RAC) for loss of human life, personal injury, damage to the environment, smd loss of assets and financial interests, in compliance with the Norwegian Statutory Authority Requirements and compatible with the currently recognized Norwegian Sea offshore standards, practice, and CN1'S safety philosophy,Specify dimensioning (design) accidental events and associated load effects for design and instruction of the major Heidrun Field components,Through a planned and continuous risk and safetyassessment program, demonstrate that the Heidrun Field RAC for loss of human life, personal injury, damage to environment, and loss of assets and financial interests, are satisfied and the Norwegian Statuary requirements are met.Recommend risk (probability and consequence) reducing measures to further reduce the Heidrun Field risks to ALARP levels,