Improving Well Completion System Reliability using Intelligent Well Technology
Authors: Brownlee Fred , Eriksen Remi , Goldsmith Riley , Wylie Glenda 
Published: October 2008

Chevron, Halliburton and Det Norske Veritas have developed a methodology and a corresponding software tool to estimate the financial consequences (well intervention cost and reduced revenues) associated with component failure of different high rate completion systems. While this methodology has application for all completions, this paper will limit itself to the discussion of intelligent well technology in deepwater completions. The methodology predicts the life cycle intervention cost for a particular system based on the reliability and the repair requirements for individual completion components (including reservoir-related problems). Failure data for the completion components were derived from industry databases (Wellmaster) when historical data was available. When historical data were not available, industry experts were polled to establish a data set for the failure modes of the particular components. A Monte Carlo simulation program was developed to calculate the expected number of completion failures and, hence, the cost of required well interventions.

By using this methodology and software tool, the overall financial advantages of incorporating higher reliability completion components can be quantified based on the reduced number of well interventions over the life of a well. This tool can also quantify the value of extended qualification testing to increase expected reliability performance. It has been recognized for many years that the act of well intervention itself introduces additional potential hazards that can effect the expected operating life of the well. These hazards or risks can now be quantified and used to highlight the advantages of application of intelligent well completion technologies. This paper presents the methodology developed by this joint initiative and illustrates how it can be used to improve deepwater high-rate well completion systems.

Introduction

The economics of deepwater developments are different from existing offshore activities. Deepwater is characterized by high capital expenditures with relatively low operational expenditures and high sustainable production rates - hence high consequence costs for production interruption.

Field development profitability is a function of many income and expense factors such as capital expenditures (CAPEX), operating expenditures (OPEX), production rate, product price and the frequency of completion failures. Completion failures reduce the field total profitability through decreased revenue (decreased system availability) and increased OPEX (more workover costs).

Until recently, deepwater ventures used a decision making process which focussed on optimizing the balance between potential revenue, (CAPEX) and operational expenditures (OPEX) according to the equation:

Profit = Max (Revenue - CAPEX - OPEX) (1)

The shortcoming in this approach is that it does not take into account unscheduled and unplanned events. These can include events that have the potential to destroy a facility, tarnish a company's reputation, pollute the environment, and/or shut down production for a long time.