Summary
Well geomechanics and “smart” completion designs in many of Saudi Aramco’s
fields are essential in supporting the company’s efforts to apply the
extended-reach and MRC well technologies. MRC wells are being aggressively
targeted to optimize development economics, enhance recovery, maximize
production, minimize differential drawdown across the sand face, reduce sanding
potential, and defer water coning. In addition, many unconsolidated sandstone
reservoirs require positive sand-control measures. As such, Expandable Sand
Screen (ESS) tubulars have seen a recent surge in applicability for completing
conventional and MRC wells in sand-prone, troublesome formations. Today, solid
expandable tubulars are being tested on a number of wells in a
pseudo-monodiameter structure. Though attractive, the long-term performance of
these tools in the Arabian Reservoir environments is yet to be explored.
This paper simulates the impact of reservoir production and depletion on
expandable tubulars and sand-screen completions when the compacting reservoir
behaves as a permeable poroelastic medium. A general poroelastic solution model
encompassing a multitude of boundary and initial conditions is discussed in
this paper. The model simulates the uniaxial (Ko) testing of solid and hollow
geomaterial cylinders (Geertsma 2005). Thus, it helps infer about potential
problems that might influence the survivability of “expandables” and disrupt
the outflow from the well. The proof cases on reservoir and caprocks presented
herein are supported with numerical application, experimental validation, and
physical interpretation of the coupled poromechanical processes that are
reflected in the anisotropic, time-dependent rock responses during testing. The
manuscript also demonstrates that this enhanced approach to modeling
visualization will ultimately ease the tractability of the pertinent physical
phenomena as well as support the model’s computational credibility to engineers
and experimentalists in the oil and gas industry.
Introduction
Many applications in our industry take place in fluid-saturated rocks that
exhibit rock matrix anisotropy due to their mode of geological deposition or
diagenesis. These applications are commonly subjected to nonisothermal
conditions. The theory of anisotropic poroelasticity was developed by Biot
(1955), improved by Biot and Willis (1957), and reformulated with applications
to civil and petroleum engineering problems by Thompson and Willis (1991) and
Abousleiman and Cui (2000), among others. The reformulation of the anisotropic
poroelastic theory while using laboratory techniques for the measurements of
the anisotropic poromechanical parameters (Scott and Abousleiman 2002) had been
of great help in assessing the effects of the parameters anisotropy in a few of
the engineering applications. These applications included, for example,
borehole and cylinder analyses (Abousleiman and Cui 1998; Kanj et al. 2003) and
the Mandel problem (Abousleiman et al. 1996).
Sherwood (1993) proposed a modification of the Biot theory of poroelasticity
(Biot 1941) to include the chemical potentials of all chemical species, within
the pore fluid. Within this context, Sherwood and Bailey (1994) conducted an
axisymmetric, plane-strain analysis of shale swelling around a wellbore and
extended it to include the case of a finite hollow-cylindrical shale sample
being subjected to a hydrostatic state of stress. In a more rigorous approach,
chemical effects can be addressed by considering the pore fluid to comprise two
constituents, solute and solvent, and appropriately accounting for the solute
and solvent transport in and out of the porous matrix (Sherwood 1994; Ekbote
and Abousleiman 2005).
© 2007. Society of Petroleum Engineers
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History
- Original manuscript received:
13 July 2005
- Meeting paper published:
9 October 2005
- Revised manuscript received:
1 April 2007
- Manuscript approved:
24 June 2007
- Version of record:
20 September 2007
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