The pressure decay process during the so-called pressure pulse test is analyzed for evaluating in situ hydraulic properties of rocks deep in the earth's crust. The present analysis takes the effects of the compliance of the tubular connecting the straddle packer to the pressurizing pump and the compliance of the well bore on the pressure decay process into account; these effects are ignored in the conventional approach. The results show that the pressure decay curve is highly dependent on the tubular compliance, and, as a result, the hydraulic properties obtained using the conventional method, which assumes that the tubular is rigid against pressure, induce large errors. Based on the analysis, a new method is proposed for evaluating in situ hydraulic properties from pressure decay curves, taking the effect of the tubular compliance into account, and the method was successfully applied to a set of experimental data of the pressure pulse test performed at a geothermal model field.
|Number of pages||5|
|Journal||JSME International Journal, Series 1: Solid Mechanics, Strength of Materials|
|Publication status||Published - 1991|
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