Well Drilling, Completion, and Maintenance Technology Gaps
Authors: Chitwood James E. , Hunter William A. 
Published: October 2008

Abstract
Deepwater wells represent a significant percentage of the cost for a deepwater development. The technology gaps that limit drilling of deepwater wells are examined as well as the various enhancers, which will help to reduce the cost of well construction and maintenance. This paper analyzes both wet and dry tree completions that may be drilled with either a MODU or with a platform rig. These gaps are identified to focus R & D efforts on high-value opportunities in this study area.

Introduction
This paper of Well Technology Gaps reports DeepStar sponsored work that supported systems engineering in the areas of well construction, completion and well intervention. The effort was aimed at identifying, valuing and ranking well technology gaps that exist in 6,000 - 10,000 ft water-depth field developments.
The field development scenarios were provided for various conceptual field developments in 6,000 ft and 10,000 ft. They included wells for Spar's, TLP's, Semi's, and, FPSO's as the host platforms supporting the required facilities. Some cases had full drilling capability prescribed and others had no drilling capability. A related paper documents the various base case scenarios used in the DeepStar analysis.
In order to provide base case definition, the drilling requirements, rig requirements, rig weights and costs, and well costs, for each case were estimated. This information was also used to compare against potential technology enhancements.
Deepwater well technology gaps for field development in 6,000 - 10,000 ft water depth were identified by developing sets of FAST charts and presenting them in two workshops to obtain Industry input. These charts represent in a logical format the well drilling, completion and maintenance process.
Although not a rigid FAST analysis, the format allowed documentation of the process and served as a base to gather input from a wide range of sources.
The resulting technology gaps were ranked according to a pre-determined formula that identified technology gaps having a large field development cost impact. The six high-impact technologies identified are:Well TestingEarly Production SystemUnder-balanced DrillingDual Gradient DrillingTender Assisted DrillingWell Intervention / Completion Vessel
This is not the exhaustive list of interesting technology gaps, but simply the areas where there may be large prizes. There were many detailed gaps that are of keen interest to people in the industry. Many of these gaps, although important to those working in a particular area, simply would not generate the large capital cost reduction prizes that DeepStar was attempting to identify.
With the list selected, each of the topics was reviewed to determine the potential value of the technology to the applicable base case field developments.

Conceptual Drilling Program
In order to frame the evaluation and provide the specifications, weights and costs for various drilling systems, a conceptual drilling program was developed. This was also used for defining the well construction time and cost estimates. The wells were in 6,000 ft and 10,000 ft water depths.