Determining the structural discontinuities in fractured carbonate reservoirs using FMS and VSP logs in the one of oil fields on West of Zagros

Volume 1 , Issue 1 , January 2016 , Pages 437-443

Authors

¹ M.Sc. in oil exploration at Imam Khomeini International University

² Associate professor at Imam Khomeini International University

³ Lecturer at department of petroleum engineering Soran University

A study is made into the structural discontinuities in an oil field to the west of the Zagros

mountain range, on the border between Iran and Iraq. Many oil reservoirs in the west of

Iran and in the Kurdistan Region of Iraq are of fractured carbonate type. Faults and folds

can change the structure of the reservoir. In such reservoirs, the study of the structural

discontinuity leads to the discovery of complex geological structures. This complexity

can impact on the discovery of a path to the reservoir. In one such oil field in western

Zagros the reservoir was expected to be located at a particular depth but the new drilling

well did not meet the reservoir. In this paper, Formation Micro Scanner (FMS) and

Vertical Seismic Profile (VSP) have been used to determine the location of the structural

discontinuities. Due to the low resolution of the VSP seismic data we find that it

discovers the major faults and the formations borders, but will not be able to determine

the small changes and complexity of the structure. Conversely, the FMS log(?) easily

recognizes these microstructures. Therefore, with a combination of large-scale VSP data

and small-scale FMS data we construct a 3D model. The results show that the well has

been cut by five faults that dip to the north with the exception of a first fault to the south

slope. To create the faults planes, AutoCAD software was also applied and the results are

shown in this study.

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