Abstract

The Keong subsea development is located in Indonesia's Natuna Sea section of the South China Sea in the Block B concession operated by ConocoPhillips on behalf of itself and its co-venturers ChevronTexaco and Inpex. This gas field is one in a series of ConocoPhillips' subsea developments currently underway to fulfill key Southeast Asian long-term gas supply contracts. Therefore, high performance completions are required to drive efficiency in capital-intensive floater operations and subsea environments.

Keong 1 was planned as a cased hole perforated, fracpacked, multi-zone producer. The well was designed to develop a series of laminated high gross to net unconsolidated sands in the temporarily abandoned discovery well, saving both time and money over a new drill. Four separate sand bodies were targeted in the completion. The type of completion was selected to match the existing wellbore configuration, reservoir properties and productivity needs. A sand exclusion completion was designed that would enable the development of the highly laminated reserves.

A single trip, fracpacking, sand exclusion liner completion system to minimize expensive floater rig time and to minimize reservoir/near wellbore damage from well killing operations was also required. A novel combination of multi-zone Alternate Path Technology (APT) isolation packers, with APT sand exclusion liners enabled the simultaneous fracpacking of the three individual zones in a single fracpacking operation. Details of the fracpack design, tool modifications, field application and field observations are discussed.

Acquired pressure data from downhole sensors demonstrates that effective fracpacking of all zones was achieved. Results from subsequent production and pressure build-up data prove the attainment of a zero to negative skin verifying the applicability of the tools and process. This application resulted in savings to ConocoPhillips in completion costs, in addition to the production acceleration benefits of an efficient completion.

The objective of this paper is to present a "conception to production" high performance sand exclusion completion case history from ConocoPhillips' Keong subsea development in the South China Sea. Throughout the paper the design, implementation, operational problems, well performance results and key learnings will be discussed in detail in order to advance the technology and document the proposed completion methodology as an alternative for high deliverability wells.

Background and Geologic Setting

The Keong subsea development is a part of the ConocoPhillips West Natuna Sea gas production area located approximately 200 miles north/northeast of Singapore near the Indonesian/Malaysian border.1 See Figure 1. The Keong field was developed as a part of the Phase II Additional Dry Gas Fields (ADGF) development to supply natural gas to Malaysia. The Keong field is currently comprised of 3 subsea wells. Two of the three wells (Keong 2 and Keong 3) were specially designed high rate horizontal stand alone sand exclusion liner wells targeting the two large gas accumulations in the field.

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