Improvement of petrophysical evaluation of the Asmari reservoir by using of well log tomography method in an oil field from southwest of Iran


1 Department of Geology, Faculty of Earth Sciences, Kharazmi University

2 National Iranian Oil Company, Oil Exploration Management, National Iranian Oil Company

3 Ph.D Candidate of Petroleum Engineering-Exploration, Amirkabir University of Technology


In this study, the Asmari reservoir in 39 wells in one of the oil fields of southwestern Zagros, located in the Dezful region, was investigated using well log tomography of Gamma ray logs and core porosity data. For this purpose, two-dimensional and three-dimensional models of gamma and core porosity logs in 4 reservoir zones of Asmari Formation have been designed by Petrel software. Among the slice of Gama log and porosity data, 2 slice were selected from the upper and lower sections of the zones, and a total of 8 tomographic sections from 10 key wells were prepared and compared with each other. The results of gamma logs and porosity tomography models are very close and compatible with each other and show that there is an inverse relationship between gamma values and porosity in the slices made by Asmari Formation in the studied wells. Also, with increasing dolomitization in the zones, the petrophysical characteristics have changed and the amount of porosity has increased. Based on the well log tomography model of the studied oil field, it was found that zone 2 with the lowest gamma value and the highest dolomite value, has higher porosity than other zones and can be the main target of production wells in the field. Since drilling wells is expensive and time consuming, it is possible to achieve very close and accurate results of well drilling using well log tomography. Therefore, tomography studies can be very useful before increasing excavations in the area for general information.


Aghanbati, A., 2006. Geology of Iran, Publications of the Geological Survey of Iran, p. 586.
Aghli, GH., Moussavi-Harami, R., Tokhmechi, B., 2020a. Integration of sonic and resistivity conventional logs for identification of fracture parameters in the carbonate reservoirs (A case study, Carbonate Asmari Formation, Zagros Basin, SW Iran). Journal of Petroleum Science and Engineering 186, 106728.
Aghli, GH., Moussavi-Harami, R., Mohammadian, R., 2020b. Reservoir heterogeneity and fracture parameter determination using electrical image logs and petrophysical data (a case study, carbonate Asmari Formation, Zagros Basin, SW Iran). Petroleum Science 17, 51–69.
Ahmadhadi, F., Lacombe, O., Daniel, J.M., 2007. Early reactivation of basement faults in Central Zagros (SW Iran): evidence from pre-folding fracture populations in Asmari Formation and lower Tertiary paleogeography. In Thrust Belts and Foreland Basins (pp. 205-228), Springer, Berlin, Heidelberg.
Aki, K., Christoffersson, A., Husebye, E.S.,1977. Determination of 3-dimensional seismic structure of the lithosphere. Journal Geophysics Reservoir 82(2), 277-296.
Alavi, M., 2007. Structures of the Zagros fold-thrust belt in Iran. American Journal of Science 307, 1064-1095.
Aminzadeh, S.A., Mirjerdavi, N., Nouri Taleghani, M., 2013. Static modeling of oil and gas reservoirs and seismic interpretation using Petrel software. Azadeh Publications, p. 304.
Berberian, M., King, G.C.P., 1981. Towards a paleogeography and tectonic evolution of Iran. Canadian journal of Earth Sciences 18(2), pp. 210-265.
Cormack, A.M., 1963. Representation of a function by its line integrals, with same radiological application. Journal of Applied Physics 34(9), 2722-2727.
Farshi, M., Moussavi-Harami, R., Mahboubi, A., Khanehbada. M., Golafshani, T., 2019. Reservoir rock typing using integrating geological and petrophysical properties for the Asmari Formation in the Gachsaran oil field, Zagros basin. Journal of Petroleum Science and Engineering 176, 161-171.
Feyz Aghaei, F., 2015. Three-dimensional tomography of volumetric waves of local earthquakes in the northwestern region of Iran, M.Sc. Thesis, Zanjan University, p. 181.
Gharecheloua, S., Aminia, A., Bohlolib, B., Swennenc, R., 2020. Relationship between the sedimentary microfacies and geomechanical behavior of the Asmari Formation carbonates, southwestern Iran. Marine and Petroleum Geology 116, 104-306.
Heydari, E., 2008. Tectonics versus eustatic control on supersequences of the Zagros Mountains of Iran. Tectonophysics 251, 56-70.
Jafari, J., Mahboubi, A., Moussavi-Harami, R., Al-Aasm, I.S., 2020. The effects of diagenesis on the petrophysical and geochemical attributes of the Asmari Formation, Marun oil field, southwest Iran. Petroleum Science 17, 292–316.
Le, M.A., 2004. Application of well log tomography to the Dundee and Rogers City Limestones, Michigan Basin, USA. M.ScThesis, Michigan Technological University, Honghton, Michigan, p. 123.
Maghsoudi, M., 2001. Structural map of Zagros. Exploration Management of the National Iranian Oil Company.
Motiei, H., 1995. Petroleum geology of Zagros. In: Hushmandzadeh, A. (Ed.), Treatise on the Geology of Iran. Geological Survey of Iran. p.1009.
Sharghi, Y., 2009. Estimation of seismic wave propagation speed in Bakhtiari dam supports using tomography and statistical methods, PhD Thesis, Amirkabir University of Technology, p. 210.
Stewart, R.R., 1991. Exploration Seismic Tomography: Fundamentals, Society of Exploration Geophysicists.
Wylie, Jr, A.S., Huntoon, J.E., 2003. Log-curve amplitude slicing: Visualization of log data and depositional trends in the Middle Devonian Traverse Group, Michigan basin, United States. American Association of Petroleum Geologists Bulletin 87(4), 581-608.
Wylie, Jr, A.S., Wood, J.R., 2005. Well-log tomography and 3-D imaging of core and log-curve amplitudes in a Niagaran reef, Belle River Mills field, St. Clair County, Michigan, United States. American Association of Petroleum Geologists Bulletin 89(4), 409-433.