Core-derived acoustic, porosity & permeability correlations for computation pseudo-logs

Abstract

In order to improve hydrocarbon production, it is often necessary to obtain more accurate rock, fluid and petrophysical information. For example, to obtain a reservoir porosity map using seismic data as reference, it is necessary to generate reliable correlations between seismic attributes and petrophysical properties like porosity and permeability. Again, to optimize drilling and/or hydraulic fracturing programs, it is also necessary to estimate better formation static mechanical behaviour from geophysical data. The main goal of this work is to establish for an offshore Brazilian field, relationships between compressional and shear wave velocities and petrophysical properties such as porosity and permeability.The large number of limestone samples (120) gave us a precise empirical relationship between Vs and Vp for limestone. In order to obtain a calibration reference, we also made, with the same samples, simultaneous measurements of dynamic and static elastic constants. Using all these laboratory relationships, it was possible to generate unmeasured pseudo-logs of in situ parameters, which include: shear wave velocity, static and dynamic elastic constants and permeability. The good experimental relationships obtained between k-~b and Vp-~b in this work together with available logs give us an additional method to estimate permeability which is impossible to obtain from in situ measurements.

Predicting rock mechanical properties of carbonates from wireline logs (A case study: Arab-D reservoir, Ghawar field, Saudi Arabia)

“…Edlmann et al (1998) used laboratory measured porosity and rock mechanical parameters for North Sea reservoirs to establish direct correlations between the porosity and the rock mechanical parameters and to produce continuous rock mechanical logs. Bastos et al (1998), established relationship between compressional and shear wave velocity and petrophysical properties for an offshore Brazilian field using laboratory tests on 120 limestone samples. Widarsono et al (2001) presented a new approach for the estimation of the elastic properties of clastic rocks in boreholes with limited log suites.…”

Breakouts derived from image logs aid the estimation of maximum horizontal stress: A case study from Perth Basin, Western Australia

“…In order to determine elastic parameters of rock formations penetrated by wellbores, compressional and shear wave velocities combined with bulk density data of the subsurface layers are required (Zoback et al, 2003;Fjar et al, 2008;Archer and Rasouli, 2012). Elastic parameters are of importance in geomechanics as they provide useful assessments of wellbore stability and reservoir characterization (Tixier et al, 1975;Farquhar et al, 1994;Bastos et al, 1998;Edimann et al, 1998;Faraji et al, 2017). The Eqs.…”

Theoretical basis for evaluating the deformability of rock blocks

“…The Static deformation modulus E stat , can roughly be correlated with dynamic deformation modulus E dyn using different empirical formulations (Bastos et al. [71], McCann and Entwisle [72], Starzec [73] and Horsrud [74]). The values of E stat obtained with the above formulations are presented in Table 3.…”