Estimating reservoir parameter using Gringarten-Bourdet Type Curve excel spreadsheet for a vertical well in a homogeneous reservoir with constant WBS and skin factor

The Gringarten-Bourdet Type Curve describes the pressure for a vertical well with constant WBS and skin in an infinite-acting reservoir.

The dimensionless pressure-derivative function \(P'_D\) is plotted as a function of \(t_D/C_D\) for various values of the correlating parameter \(C_De^{2s}\)

The \(P_D\) and \(P'_D\) type curves are in a single plot, permiting simultaneous type-curve analysis with both pressure and pressure-derivative curves and reducing the ambiguity.

Interpretation Process

- Field data (\(\Delta P\) and \(\Delta P'\) vs. \(t\) for DD, \(\Delta P\) and \(\Delta P'\) vs. \(\Delta t\) or \(t_e\) for BU ) are plotted on log-log scale

Identify the IARF period indicated by the horizontal portion od the derivative and the WBS-dominated period, indicated by the unit-slope portion of the derivative.

Match the data on the curves, then pick any convenient point (match point, red point)

- Read \(\Delta P\) and \(P_D\) corresponding to the match point, read \(t\) and \(t_D/C_D\) corresponding to the match point and read the matching value of \(C_De^{2s}\)

- Calculate well test parameters with the following equations

\[k = \frac{141.2qB \mu}{h} \left(\frac{P_D}{\Delta P}\right)_{MP}\]

\[C_D = \frac{0.0002637k}{\phi\mu c_t r_{w}^2} \left(\frac{t}{t_D/C_D}\right)_{MP}\]

\[C_D = \frac{\phi c_t h r_{w}^2}{0.894} C_D\]

\[s = 0.5ln\left(\frac{C_De^{2s}}{C_D}\right)\]

Example

References

Lee, J. & Spivey, J. (2013) Applied Well Test Interpretation using the recommended procedure

For attribution, please cite this work as

Vazquez (2021, Sept. 23). Chato Solutions: Log-Log type curve analysis. Retrieved from https://www.chatosolutions.com/posts/2021-09-23-ptatypecurves/

BibTeX citation

@misc{vazquez2021log-log, author = {Vazquez, Rigoberto Chandomi}, title = {Chato Solutions: Log-Log type curve analysis}, url = {https://www.chatosolutions.com/posts/2021-09-23-ptatypecurves/}, year = {2021} }