Skip to main content
Top of the Page

3D PETROPHYSICS FOR HAWE: CASE STUDIES

Most conventional log interpretation technics use the radial model, which was developed for vertical wells and work well in them. But, applying this model to horizontal wells can result in false conclusions. The reasons for this are property changes in the vertical direction and different depth of investigation (DOI) of logging tools. DOI area probably can include a response from different layers with different properties. All of this complicates petrophysical modeling.

The 3D approach for high-angle well evaluation (HAWE) is forward modeling in 3D. For this modeling, it is necessary to identify the geological concept near the horizontal well section using multiscale data. The accuracy of modeling depends on the details of the accepted geological model based on the data of borehole images, logs, geosteering inversion, and seismic data.

The 3D modeling can be applied to improve the accuracy of reservoir characterization, well placement, and completion. The radial model is often useless for HAWE because LWD tools have different DOI, and the invasion zone was not formed. But, the difference between volumetric and azimuthal measurements is important for comprehensive interpretation because various formations have different properties in vertical directions. Resistivity tools have the biggest DOI. It is important to understand and be able to determine the reason for changes in log response: a change in the properties of the current layer or approaching the layers with other properties. For this, it is necessary to know the distance to the boundaries of formations with various properties and, therefore, to understand the geological structure of the discovered deposits, and such information on the scale of well logs can be obtained either by modeling or by using extra-deep resistivity inversion (mapping). The largest amount of multidisciplinary information is needed for modeling purposes—from images and logs to mapping and seismic data.

Case studies include successful examples from Western Siberia clastic formations. In the frame of the cases, different tasks have been solved: developed geological concept, updated petrophysical properties for STOIIP and completion, and provided solutions during geosteering. Multiscale modeling, which includes seismic, geosteering mapping data, LWD, and imagers, has been used for all cases.

A more accurate determination of the effective lengths and formation properties helps optimize well completion design. In studied wells, the planned flow rate from conventional log analysis differed from the actual flow rate by 30%. The 3D petrophysical approach to interpretation improved reliability by three times, reducing the discrepancy between planned and actual flow rate to 9%.

Using the 3D petrophysical modeling provides true petrophysical properties of all layers in the geological model along the horizontal section of the wellbore. These true properties can be used for the quantitative interpretation of reservoir rock properties. The 3D petrophysical approach excludes polarization effects and influence of nearby reservoirs on well logs that allow optimization of well placement and well completion.
Discounted member price: 1.00
10.00
You could save: 90.0%
Back to Top
SPWLA Business Office Address
8866 Gulf Freeway, Suite 320
Houston, TX 77017

SPWLA Contact Numbers
Phone: +1 (713) 947-8727
Fax: +1 (713) 947-8747

Copyright 1959 – 2024 SPWLA

Terms of Use  |  Privacy & Cookie Policy

Our vision is to advance the science of formation evaluation through electrical, nuclear, lithological, and other well logging techniques; to promote the proper application of these techniques to exploration for and exploitation of gas, oil and other naturally occurring substances; to maintain high ethical standards and to further the interests of persons professionally engaged in these endeavors. With the support of our Oil and Gas, Service, Software and Educational Institutions we can make a difference in the industry.