Summary
The method of distributed volumetric sources (DVS) has been applied to
predict gas production from a horizontal well with multiple transverse
fractures in a bounded reservoir. Combining the quasianalytical DVS method,
which provides us with the opportunity to predict pressure and production
behavior of complex well/fracture configurations, with non-Darcy flow in the
fracture enables us to calculate the optimum configuration in terms of the
number and dimensions of fractures per well for a certain amount of proppant of
a given type. The method is applied to an example case of a tight gas reservoir
to maximize the production performance of this complex well/fracture
configuration. Comparing results with and without inclusion of the non-Darcy
effect in the fracture shows that a decrease in production occurs because of
non-Darcy flow in all cases. However, a systematic screening of a realistic set
of well/fracture configurations reveals that the detrimental effect of
non-Darcy flow can be substantially compensated for by selecting the right
number of fractures and shifting the fracture dimensions in favor of thicker
fractures. While a simultaneous decrease in optimum lateral (and vertical)
extension is necessary, it has limited effect on productivity. The simplicity,
robustness, and small computational demand of the model allow seamless
integration with external economic and operational constraints, providing a
tool to screen and optimize a large set of possible configurations most suited
for the development of economically marginal fields.
Introduction
Modern drilling and completion technologies have now provided us the
opportunity to design and implement complex well fracture configurations. These
complex configurations are used mainly in development of economically marginal
reserves, where nonfractured vertical wells would be uneconomical. Among the
complex completion schemes of particular importance is the horizontal well
completed with multiple transverse fractures. This completion scheme is now
widely used in offshore and tight gas development projects.
The main goal of this paper is to provide a practical tool for prediction of
the pressure and productivity behavior of such completions. Development of the
method of DVS and the formulation of the problem for the case of a horizontal
well with multiple fractures are discussed.
Because one of the main applications of this type of completion is in tight
gas and the inertial effect for high-velocity gas flow is significant, in this
work, the DVS method is implemented, taking into account the non-Darcy-flow
effect in the fracture. A simple optimum search procedure is presented to
achieve maximum production performance from a given amount of resources. The
procedure is then applied to a tight-gas-field case, and it is demonstrated
that, by selecting the right configuration, the detrimental effect of non-Darcy
flow can be largely compensated for.
© 2009. Society of Petroleum Engineers
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History
- Original manuscript received:
30 July 2008
- Revised manuscript received:
26 February 2009
- Manuscript approved:
28 February 2009
- Published online:
17 November 2009
- Version of record:
12 March 2010
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