Formation evaluation

Inversion of Full Waveform Sonic Data Assists Calibration of Geomechanics Model

This paper describes a technique used to derive stresses for a gas-storage field and then calibrate the 1D mechanical earth model of the field.

Fig. 1—(a) Stress streamlines (red lines) in a core; (b) cross section of a borehole in a stress field consisting of Shmin and SHmax.
Fig. 1—(a) Stress streamlines (red lines) in a core; (b) cross section of a borehole in a stress field consisting of Shmin and SHmax.

In 1D geomechanics projects, calibration of stress is extremely important in the construction of a valid mechanical earth model (MEM). The effective minimum horizontal stress (Shmin) data usually are available from traditional measurements, but these have a few deficiencies. The complete paper presents a technique for deriving stresses in which the radial variation of acoustic velocity from an advanced dipole sonic logging tool is inverted to obtain stress. These derived stresses are then used to calibrate the 1D MEM for a gas storage field.

Regional Geology

The field is in the Otway Basin in Western Victoria. Gas is trapped in the Late Cretaceous Waarre formation at depths between 1155 and 1200 m subsea.

SPE_logo_CMYK_trans_sm.png
Restricted Content
We're sorry, but this content is reserved for SPE Members. If you are a member, please sign in for access. If you are not a member and you find JPT content valuable, we encourage you to become a part of the SPE member community.