Step-rate test · e TEXAS The University of at Austin 700 650 600 550 500 450 400 350 300 250 200...

Step-rate test

© Cambridge University Press (Fig. 7.5, pp. 216)Zoback, Reservoir Geomechanics

Be careful!

When integrate density logs

© Cambridge University Press (Fig. 7.4, pp. 214)Zoback, Reservoir Geomechanics

What about ?

so

or

Does it work?Consider a system with compressibility

Answer: Not very well.

Occurance of both drilling induced tensile

fractures and breakouts

Allows for estimate of rock strength in-situ

Recall: from breakout data

Recall: From Kirsch solution

Geomechanical case study: Cook Inlet Alaska

To case or not to case?

© Cambridge University Press (Fig. 10.21, pp. 334)Zoback, Reservoir Geomechanics

Emperical strength model from cores

© Cambridge University Press (Table 4.1, Eq. 5, pp. 113)Zoback, Reservoir Geomechanics

Pressure drawdown and sand production

500 psi slow drawdown breakouts

1000 psi rapid drawdown breakouts

© Cambridge University Press (Fig. 10.22, pp. 335)Zoback, Reservoir Geomechanics

Preventing sand production by limitingproduction rate

© Cambridge University Press (Fig. 10.23, pp. 336)Zoback, Reservoir Geomechanics

Preventing sand production withperforation orientation

© Cambridge University Press (Fig. 10.24a, pp. 337)Zoback, Reservoir Geomechanics

© Cambridge University Press (Fig. 10.25, pp. 338)Zoback, Reservoir Geomechanics

Preventing sand production with azimuthchanges

Considering �xed horizontal perforations

© Cambridge University Press (Fig. 10.24b, pp. 337)Zoback, Reservoir Geomechanics