Solid Expandable liners have been used extensively over the past 10 years for drilling liners, but rarely as production liners, much less in high risk environments where the expandable liner becomes differentially stuck as soon as it reaches the end of the horizontal hole section. This environment requires the liner to be cemented and expanded in one of the most (if not the most) difficult well conditions it can be subjected. The expandable liners discussed in this paper so far have shown positive field status as production liners.
When an expandable liner, that is not differentially stuck, is expanded using a swage it typically "shrinks" in length as it expands in diameter as part of material balance physics. This shrinkage is typically 4 to 6%. That is, if a 1,000 ft liner is expanded 5% in diameter, the expanded length would be reduced to ~950 ft. To compensate for this shrinkage, an additional length of liner is run to ensure that the final length of liner required is delivered. However, when the expandable liner becomes differentially stuck or can not move along the length of the wellbore during expansion, it can not gain the material for its growth in diameter from the liner's length. Therefore, the material is sacrificed within the liner's wall and its connectors. This environment is considered one of the most strenuous a solid expandable liner can be subjected to during expansion.
Combining insightful engineering with a stringent qualification regime of the expandable system and the tubulars and connectors that it utilizes, solid expandable production liners can be installed that will service these types of complex wells.
While extensive engineering and lab testing of an expandable system is critical, the ultimate testing is in multiple field applications to best develop effective reservoir sweeping of a mature field. Several case histories of field installations will be reviewed. The installation, zonal isolation, and tubular performance of these liners will be evaluated and reviewed using downhole tubular inspection logs, observed installation phenomenon, and performance over time. This empirical data will give the potential end users fundamental knowledge and good case history information on how to best qualify and use solid expandable liners for the ultimate benefit of gaining more oil production and reducing overall well cost.
Introduction
It is necessary to have a basic knowledge of how solid expandable openhole liners are installed to extract a firm understanding of the information in this paper. While this paper reviews the basics, a host of technical papers and articles expound on the fundamentals of solid expandable liner installation. (Filippov 1999; Dupal 2000; Dupal 2001; Zhou 2004; Furlow 2000)
With this foundation of understanding, an explanation of the wellbore environment of these complex wells will be provided. An investigation of the openhole production liner system qualification process will highlight the critical factors that significantly reduce operational risks. This paper probes several factors, specific to the wells of a major operator in Saudi Arabia, prior to and within the installation process that also reduce the end user's risk. Finally, an in-depth study of these several case histories will be examined to provide a deeper understanding through this situational analysis.
