Well Abandonment of Offshore Aging Gas Fields Using New Section Milling Technology Reduces Time and Costs to Set a Permanent Barrier- A Case Study of Section Milling 100 ft of 13-3/8? Casing to Set Cement Plug

Abstract

In recent years plug and abandonment (P&A) technologies are receiving greater attention around the world as more and more fields reach the end of their productive life. Permanent P&A is done with the objective of the well being sealed and isolated forever. Over the years the market for permanent P&A has grown into estimates of several billions of dollars. There are thousands of wells world wide, both onshore and offshore, that require P&A operations to safely abandon the erstwhile producing asset while maintaining environmental regulations and standards. Since the P&A operations do not result in increase in revenue or any asset value, the attitude of almost all operators is that the least amount be allocated towards this operation in the well life cycle plan. This means that newer technologies must be developed in order to increase efficiencies and reduce the overall costs and foot prints for P&A operations. Many times existing conventional technologies do not fill in these requirements, and thus there is a need to develop and deploy newer downhole technologies.

This paper will discuss well abandonment P&A introduction, methods for preparing a well before setting cement plugs, a brief comparison between different methods, development of section milling technology to dual string, field application on an offshore gas field abandonment campaign, and finally conclusions regarding this new and emerging dual string milling technology.