Design Methodology for Selection of Horizontal Open-Hole Sand Control Completions Supported by Field Case Histories

Abstract

Abstract Reservoirs requiring sand control pose a major challenge for selection of a suitable completion method. Horizontal open-hole completions have been successfully utilised in such reservoirs to eliminate sand production, while maximising productivity/injectivity and well deliverability throughout the expected life of the completion and minimising risk and complexity. Although horizontal open hole sand control completions have been applied widely in the last decade, ranging from pre-perforated/slotted liners to gravel packs, and many case histories have been discussed in the literature, a systematic methodology for selecting these completion methods remains to be documented. It is the objective of this paper to propose such a design methodology by unifying the broad experience and understanding from a global and technically integrated perspective. The paper first discusses a generalised and unified methodology for determining when to install sand control, what to install for sand control and how to install sand control in horizontal open-hole completions. Specific factors recognised as affecting "when" are in-situ stresses and pore pressure decline (sand prediction), expected well life, production rate, hydrocarbon and well type, gross product value, sand tolerance capacity, environmental limitations and intervention capabilities, whilst the integration of all these factors have an impact on the overall risk analysis. In addition to many of the previous factors, critical drivers affecting "what" are identified as wellbore architecture, reservoir lithology and petrophysical properties, and sandface equipment reliability. Additional parameters impacting "how" are reservoir drilling fluid, displacement and cleanup methodology, screen type, operational implementation/assurance (risk management, operational timing and location logistics), torque and drag analysis, and gravel placement simulations. Secondly, examples of this methodology are presented in detailed case histories pertaining to different types of horizontal openhole sandface completions including slotted liners, standalone screens (including expandable) and gravel packs as well as various integrated cleanup methods, along with a summary of lessons learnt by each company. Introduction and Literature Review Open-hole horizontal completions have been widely used in oil and gas industry for effective exploitation of hydrocarbon reserves over the last two decades, in both sandstone and carbonate formations. In sandstones, a major issue has been whether sand control is required during the life of a particular well, and if so, what technique to use in order to minimise overall completion and remediation costs, thus to increase profitability. Most recently Bennett1 has developed a cross plot (Figure 1) that looks at the likelihood of wellbore failure with respect to formation quality and has used this to provide guidelines as to sandface completion methodology, based on experienced gained in the North Sea and Gulf of Mexico wells.