SPE Production & Operations
Published techniques for analysis of after-closure fracture data usually
assume single-phase flow. These procedures generally rely on the techniques
developed for the analysis of buildup tests. Applying the buildup techniques
implies that the injected fluid and reservoir fluid have approximately the same
properties. This assumption is generally incorrect in case of minifrac tests
where the injected fluid may be very different from the reservoir fluids. This
situation is at an extreme when the minifrac test is conducted on a gas
reservoir and the injected fluid may be a relatively high-viscosity gelled
In this paper, we review the basic theory behind after-closure analysis.
Using a numerical simulator, minifrac tests are simulated and analyzed for both
oil- and gas-reservoir cases where an aqueous phase is injected as a fracturing
fluid. Analyses of the numerically simulated falloff data are presented.
Guidelines for the analysis of such data have been developed and presented.
Field data are also presented. In one case, breakdown, step-rate, and
fluid-efficiency tests (FETs) were performed on a tight gas formation and the
data were analyzed. The results of using these various techniques are
presented. The consistency of results validates conclusions achieved using the
numerically simulated data.
© 2011. Society of Petroleum Engineers
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- Original manuscript received:
2 March 2010
- Meeting paper published:
15 February 2010
- Revised manuscript received:
10 August 2010
- Manuscript approved:
28 November 2010
- Published online:
17 March 2011
- Version of record:
16 May 2011