Rig Inspection and Safety Relationship
Authors: Lefebre M. , Muir K. 
Published: December 2007

Preventing the occurrence of accidents in drilling and well servicing operations is a constant and major concern for any company or contractor acting in the upstream business. Analysis of accidents often identifies a number of contributing factors and/or anomalies, among which the equipment related items play a significant role. This article concentrates on the rig inspection process as a consistent method of detecting equipment related anomalies before operations commence. These inspections enable the necessary corrections to be made in due time, thereby limiting the occurrence of accidents once the rig is in operation.

When in-depth and systematic rig inspections are carried out, it is that the percentage of accidents where equipment failure is the major cause remains very low. However, equipment condition factors contributing to the accidents still remain present in a large number of cases.

Introduction

Rig Inspection activities are normally an important part of the drilling safety programme. The inspection objective is both to prevent the occurrence of accidents, to limit their consequences and to minimise non-productive time linked to equipment failure. Analysis of the accidents occurring during rig operations indicates that equipment is often involved as a contributory factor. As rig equipment maintenance standards have, in general, suffered from depressed rig rates during the past ten years, the need for detailed inspection has become more important.

Rig inspections normally consist of an independent and thorough survey of the rig drilling, mechanical, electrical, well control, marine and safety equipment. This allows specialised expertise to be targeted at the equipment maintenance standards, including full testing of equipment safety devices, to determine the level of equipment maintenance and safe working condition.

The objective of this paper is to present the conclusions and lessons learnt from these inspections, based on the survey of 75 rigs carried out since 1991. This paper also demonstrates the benefits of this integrated philosophy, which includes a better safety approach, a worldwide standard, the rapid inclusion and verification of relevant safety bulletins and alerts, plus appropriate examples of the system achievements, and confirms the old saying that "a poorly maintained rig can never be a truly safe rig".

3. FACTORS AFFECTING SAFETY IN RIG OPERATIONS

It is important to establish the added value of inspection among the actions taken by Contractors/Companies to improve rig operations with respect to safety results. In this search for improvement, one of the necessary steps is to organise a consistent incident reporting and analysis system during rig operations. This system should apply not only to accidents and near-misses, but also to anomalies, i.e. unsafe acts, unsafe equipment and incomplete procedures which can be seen by the rig personnel as contributing factors to the occurrence of accidents. For deep analysis of incidents, methods such as the Cause Tree Analysis can be used. This investigation method enables accurate identification of the contributing factors to the accidents, and those which need to be corrected to prevent accident reoccurrence. A survey of over 41 LTA's occurring over one year of drilling activity indicates that the contributing factors leading to accidents can be split into three main groups:

Group 1: Human Behaviour Factors. These factors typically cover the human qualities necessary to minimise the occurrence of and exposure to accidents during rig operations. They are always present and generally constitute the major cause of accidents. These factors can be minimised by a comprehensive safety programme, including the set up of clear corporate objectives, proper management of human resources, safety incentives, safety training, etc. If properly organised, this safety programme promotes the detection of anomalies on the rig site which will fuel further improvements. By nature, these factors are more subjective than objective; they are highly dependant on the area environment (such as safety culture), and improving them generally requires significant time and effort.

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