Wireline Perforating EFI System
Authors: Robertson W.E. , Beck W.A. 
Published: October 2008

A new, safer, more flexible technology is now available for use by the oil & gas well wireline perforation industry. This new technology applies U. S. Department of Energy (DoE) developed Exploding Foil Initiator (EPI) technology to the problem of safe, economical control of explosives utilized in perforating & other wireline operations. Hardware has been designed, developed and extensively tested to demonstrate the improved safety, reliability, and system flexibility offered by an all electronic controlled EFI wireline initiation system. This technology utilizes no sensitive primary explosives or initiating materials which eliminates the need for shutdown of well support or adjacent well operations during perforating.

This paper discusses Wireline Initiation System test data from an engineering and field tests aspect. The test sequence and conditions are described and the significance of the resultant data discussed. The most significant aspect of the EFI technology utilized in this Wireline EFI Initiation System is the resultant safety that allows for its use in high risk areas such as off-shore platforms and vessels. This very insensitive initiating system will avoid costly shut-downs during perforating operations with enhanced safety.

INTRODUCTION

A Department of Energy (DoE) technology has been adapted to the oil and gas wireline industry during the past two years. Hardware has been developed and successfully tested in the field by both major oil and well services companies. This technology utilizes an Exploding Foil Initiator (EFI) to directly initiate Hexanitrostilbene (HNS), a high temperature insensitive secondary explosive material. The EFI has made possible the development of an extremely safe wireline initiation system that is insensitive to shock, very high temperatures (200°C), ElectroMagnetic Interference (EMI), ElectroStatic Discharge (ESD), and stray ground currents. The Wireline EFI initiation System is most applicable to off-shore applications where safety is paramount and well shut-down cost are at a premium.

This paper defines the problem that currently exists on oil & gas platforms during perforating and other wireline operations that utilize explosives. A potential solution is discussed utilizing a wireline EFI initiation system. The theory of operation of EFI initiators are covered to familiarize the reader with this technology, followed by a discussion of a complete EPI based initiation system.

PROBLEM DEFINITION

Perforating safety is a major concern at all well sites and particularly at off-shore sites due to the following sources of energy individually or in combination that represent hazards:EMI from Radar, Welding, Radios, Motors, etc.Stray Currents from Cathodic Protection, Welders, & Other Electrical EquipmentESD From Handling Personnel & Equipment.Inadvertent Application Of 120 /220 Vac, 60hz During Gun Installation.The Inherent Sensitivity of Primary Explosives (i.e.: blasting caps) to heat, shock, & ESD.

These safety concerns require the shut-down of rig operations as well as some adjacent operations during assembly and running of wireline perforating guns. Additionally, even with all operations shut-down, the inherent sensitivity of primary explosive materials is such that safety continues to be of concern.