Subsea MMX, Year 2010
Authors: Gjersvik Tor B. , Faanes Audun , Egerdahl Bjørn A. 
Published: October 2008

An initiative has been undertaken to develop methods and technologies for increasing the oil recovery from subsea fields. The program is inspired by the experiences won in later years from increased oil recovery (IOR) technologies and methods used on platform wells. This encompasses everything from improved exploration technologies, through more frequent well interventions, to the drilling of new well bores to new targets. The paper discusses the need for reducing the cost for new drainage points subsea as interesting targets become smaller over the life of a field.

The need for drilling new wells subsea for IOR purposes is in itself a proof that a field is ultimately developed in stages. That is subsea developments should be undertaken with systems offering flexibility and scalability. How such features can be attained is discussed in the paper.

Experiences by others have proven that reducing the "gross well volume" - i.e. reducing the well volume outside the production tubular - can reduce well cost. Methods for slender wells will be implemented in the project, and the practical approach to how to implement this is also discussed. Health, Safety, and Environment (HSE) is an overriding concern and a major issue in our industry. Technologies for zero harmful emission and other HSE issues will be implemented and are also discussed.

The Subsea MMX project shall lead to systems for slender well drilling and more flexible and scalable subsea systems becoming available from the year 2010 (Roman numeral ‘MMX’).

Background

As it becomes more difficult to discover new reservoirs, oil companies seek to improve recovery from reservoirs already in production. This also applies to fields developed with subsea wells, where the oil recovery generally has been significantly lower than for platform operated wells. In Statoil, the technology development program, Subsea Increased Oil Recovery (SIOR), was started in 2003 with the goal to enable a 55% oil recovery from subsea fields. The program goals and approach are further discussed by StrØm and Utseth (ref. 1).

Experience from platform operations has revealed that one important factor to increase the recovery is to drill more drainage points. In order to implement this strategy, profitability must be shown for a larger number of drainage points, which in turn requires a reduced development cost for each drainage point.

The total cost of a drainage point includes the cost for well and completion, associated subsea infrastructure, and tie-in costs. In Norwegian waters this cost may approach 100 million USD per drainage point. The SIOR low cost drainage point ambition is to cut the total drainage cost by 50%. Four focus areas to reduce the cost have therefore been chosen for the initiative:Slender well technologyFlexible and scalable subsea systemLight drilling and completion rigLow cost pipelines

This paper focuses on the first two areas: Designing a flexible subsea system that will be developed in order to exploit the benefits from a slender well system, and that will enable the use of lighter drilling, workover and completion vessels.

The MMX project was conceived through the SIOR program and is currently in the early stages of the concept and feasibility evaluation phase, exploring various technical options. Preliminary technical options will be presented. In addition to reducing total cost, HSE and standardization are critical issues that will be addressed.

Objectives and Requirements

The Subsea MMX project has three main objectives:Improve HSE performance of the subsea technology