Previous Talks

Wednesday, September 12th, 2007

Lunskoye Big Bore Gas Wells: The Impact of Sandface Completion Selection and Sand Rates on Well Design and Inflow Performance

Mike Gunningham, Phillippe Brassart, Jeroen Webers, Hamed Subhi (Sakhalin Energy Investment Company) and Tony Addis (Shell International Exploration & Production)

Abstract

The Lunskoye gas field development is a part of the Sakhalin Phase II project. The gas from Lunskoye will provide the majority of the Sakhalin LNG plant capacity with 1800 MMscf/d for plateau production. The 1st six wells, which will initially feed this LNG plant, are expected to produce 300 MMscf/d per well.

This presentation will provide an overview of how the completion design has impacted the project. Developments with Shell’s Fully Integrated Sand Failure Prediction Tool enabled the sand volumes to be quantified and used for the first time during completion selection in Shell. The results predicted that unmanageable sand volumes would occur upon start-up, for open hole completions with pre-drilled liners (PDL).

This led to a revision of the sandface completion concept from PDL to cased and selectively perforated liner (C&P). A sand management strategy was developed, where the weakest zones are not perforated. Further studies from the exploration and appraisal wells indicated that, less than 10% of the net reservoir should be left un-perforated. The possibility of lower well productivities, resulting from C&P completion was assessed using inflow models. The resultant lower well deliverability has been more than compensated for, by deviating wells from near vertical to 55º through the reservoir and maximising the tubing size to a 9.5/8” monobore design. Well potentials are now over 500 MMscf/d, although they will be beaned back due to surface constraints.

With the selected completion minor amounts of produced sand are expected for C&P completions during the first 15-20 years of field-life, beyond which manageable amounts of transient sand are expected for remaining production lifetime. A sand management plan has been developed, to ensure the facilities and personnel are prepared and able to manage sand, in these high rate gas wells.

Speaker Biography

Tony Addis is currently the team leader for the Geomechanics Research & Development team and is also a Geomechanics specialist & Senior Production Technologist at Shell International Exploration & Production. Tony is also the (caretaker) team leader for an emerging Deployment Geomechanics team which applies geomechanics technologies and design considerations early into the field development plans.

Tony has a BSc in Geology & Chemistry, and a PhD in Geology from the University of London and he specialises in wellbore stability, sand management and reservoir compaction. He started his career at the Norwegian Geotechnical Institute in Oslo, and between 1989 and 1994 he worked for BP Exploration in Sunbury and Houston. At BP, he worked on various aspects of rock mechanics and well engineering as applied to field problems, including the well stability problems in the Cusiana field. Following this, he spent 5 years in Melbourne at CSIRO leading the wellbore stability team. Since 1999, Tony has been with Shell in Rijswijk, The Netherlands.