Standard Test Method for Determining Transmissivity and Storage Coefficient of Low-Permeability Rocks by In Situ Measurements Using the Constant Head Injection Test

Importancia y uso:

5.1 Test Method—The constant pressure injection test method is used to determine the transmissivity and storativity of low-permeability formations surrounding packed-off intervals. Advantages of the method are: (1) it avoids the effect of well-bore storage, (2) it may be employed over a wide range of rock mass permeabilities, and (3) it is considerably shorter in duration than the conventional pump and slug tests used in more permeable rocks.

5.2 Analysis—The transient water flow rate data obtained using the suggested test method are evaluated by the curve-matching technique described by Jacob and Lohman (1)4 and extended to analysis of single fractures by Doe et al. (2). If the water flow rate attains steady state, it may be used to calculate the transmissivity of the test interval (3).

Note 2: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.

Note 3: The function of wells in any unconfined setting in a fractured terrain might make the determination of k problematic because the wells might only intersect tributary or subsidiary channels or conduits. The problems determining the k of a channel or conduit notwithstanding, the partial penetration of tributary channels may make determination of a meaningful number difficult. If plots of k in carbonates and other fractured settings are made and compared, they may show no indication that there are conduits or channels present, except when with the lowest probability one maybe intersected by a borehole and can be verified, such problems are described by Worthington (4) and Smart, 1999 (5). Additional guidance can be found in Guide D5717.

Subcomité:

D18.21

Referida por:

D7492_D7492M-16AR24, D4043-17, D6286_D6286M-20, D0420-18, D5876_D5876M-17R24

Volúmen:

04.08

Número ICS:

07.060 (Geology. Meteorology. Hydrology)

Palabras clave:

borehole; constant head testing; faultzones; field testing; flow; flow and flow rate; in situ; permeability; pressure testing; rock; saturation; storativity; transmissivity; viscosity; water; water saturation;