Rock typing and reservoir zonation based on the NMR logging and geological attributes in the mixed carbonate-siliciclastic Asmari Reservoir

Document Type: Research Paper


1 School of geology, College of science, university of Tehran, Tehran, Iran.

2 Department of Geology, Faculty of Science, University of Tehran, Tehran, Iran

3 Earth Science Department, University of Tabriz, Tabriz, 14355-9785, Iran

4 Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, 15445-9123 Iran

5 Research Institute of Petroleum Industry, Petroleum Geology Department, Tehran, 14167-6654, Iran


Rock typing is known as the best way in heterogeneous reservoirs characterization. The rock typing methods confine to various aspects of the rocks such as multi-scale and multi-modal pore types and size, rock texture, diagenetic modifications and integration of static/dynamic data. Integration of static and dynamic behavior of rocks and their sedimentary features are practiced in this study. Porosity, permeability and pore size distributions are investigated as the static and capillary pressure, water saturation and irreducible water saturation as dynamic behavior of the rocks. Results from core data analysis in some intervals and continuously NMR data through the whole well are also involved. Initially, based on Flow Zone Index method, while considering geological attributes, 7 rock types are determined. The petrophysical properties of the rock types including Pc, SW and SWir are combined into the rock types. Afterward, pore types, facies characteristics, texture and diagenetic overprints are involved in the rock type’s classification to capture spatial trends and relationships. Eventually, the rock types are defined in the cored intervals by these parameters and predicted in non-cored intervals by NMR. The rock types are established to provide a clue on the high and low permeable zones and accurate reservoir zonation


Article Title [Persian]


Abbaszadeh, M., Fujii, H., Fujimoto, F., 1996. Permeability prediction by hydraulic flow unit’s theory and applications, SPE Formation Evaluation, 11: 263-271.##

Abbaszadeh, M., Koide, N., Murahashi, Y., 2000. Integrated characterization and flow modeling of a Heterogeneous Carbonate Reservoir in Daleel Field, Oman. Paper SPE-62514, SPE Reservoir Evaluation & Engineering, 3: 150–159.##

Al-Ajmi, F.A., Holditch, S.A., 2000. Permeability estimation using hydraulic flow units in a Central Arabia reservoir. Paper SPE-63254, presented at SPE Annual Technical Conference and Exhibition, Dallas, Texas, USA, 1-4 October.##

Al Ameri, M.B., Shebl, H.T., 2011. Reservoir rock typing of a giant carbonate field, Paper SPE-148073, presented at SPE Reservoir Characterisation and Simulation Conference and Exhibition, Abu Dhabi, UAE, 9-11 October.##

Agarwal, G., Sagar, R., Behera, B., 2011. Rock Type classification and saturation modeling in a heterogeneous low-permeability reservoir from offshore India. International Petroleum Technology Conference, Bangkok, Thailand, 15-17 November.##

Aliakbardoust, E., Rahimpour-Bonab, H., 2013. Integration of rock typing methods for carbonate reservoir characterization. Journal of Geophysics and Engineering, 10(5): 1-13.##

Allen, M., Jackson, J., Walker, R., 2004. Late Cenozoic reorganization of the Arabia‐Eurasia collision and the comparison of short‐term and long‐term deformation rates. Tectonics, 23(2).##

Altunbay, M., Martain, R., Robinson, M., 2001. Capillary pressure data from NMR logs and its implications on field economics. Paper SPE-71703, Presented at SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, 30 September-3 October.##

Amaefule, J.O., Altunbay, M., Tiab, D., Kersey, D.G., Keelan, D.K., 1993. Enhanced Reservoir Description: Using Core and Log Data to Identify Hydraulic (Flow) Units and Predict Permeability in Uncored Intervals/Wells, Paper SPE-26436, presented at SPE Annual Technical Conference and Exhibition, Houston, Texas, 3-6 October.##

Basioni, M. R. E., Negahban, S., Dawood, A., El Mahdi, A., Bahamaish, J., 2008. Reservoir rock typing from crest to flank is there a link?. Paper SPE-11, presented at the 2008 Abu Dhabi International Petroleum Exhibition and Conference, 5–6 November.##

Berg, R.R., 1970. Method for determining permeability from reservoir rock properties. Gulf Coast Association of Geological Societies Transactions, 20, 303–317.##

Blasingame, T.A., Huet, C.H., Rushing, J.A., Newsham, K.E., 2007. Estimating Klinkenberg-corrected permeability from mercury-injection capillary pressure data: A new semianalytical model for tight gas sands. paper SPE-102890, presented at Rocky Mountain Oil & Gas Technology Symposium, Denver, Colorado, U.S.A, 16-18 April.##

Bust, V. K., Majid, A. A., Oleto, J.U., Worthington, P. F., 2011. The petrophysics of shale gas reservoirs: Challenges and Pragmatic solutions. International Petroleum Technology Conference, Volume 2, (IPTC 14631), Society of Petroleum Engineers, Richardson, TX, 1440–1454.##

Buxton, M.W.N., Pedley, H.M., 1989. Short Paper: A standardized model for Tethyan Tertiary carbonate ramps. Journal of the Geological Society, 146(5): 746-748.##

Carman, P.C., 1937. Fluid flow through granular beds. Transactions-Institution of Chemical Engineers, 15, 150-166.##

Chandra, V., Barnett, A., Corbett, P., Geiger, S., Wright, P., Steele, R., Milroy, P., 2015, Effective integration of reservoir rock-typing and simulation using near-wellbore upscaling. Marine and Petroleum Geology, 67: 307-326.##

Chekani, M., Kharrat, R., 2009. Reservoir rock typing in a carbonate reservoir-cooperation of core and log data: case study. Paper SPE-123703, presented at SPE/EAGE Reservoir Characterization and Simulation Conference, Abu Dhabi, UAE, 19-21 October.##

Christoffersen, K.R., Whitson, C.H., 1995. Gas/oil capillary pressure of chalk at elevated pressures. SPE Formation Evaluation, 10(03): 153-159.##

Choquette, P. W. and Pray, L. C., 1970. Geologic nomenclature and classification of porosity in sedimentary carbonates. American Association of Petroleum Geologists Bulletin, 54: 207–250.##

Coates, G.R., Galford, J., Mardon, D., Marschall, D., 1998. A new characterization of bulk-volume irreducible using magnetic resonance. The Log Analyst, 39(01).##

Coates, G.R., Peveraro, R.C.A., Hardwick, A., Roberts, D., 1991. The magnetic resonance imaging log characterized by comparison with petrophysical properties and laboratory core data. Paper SPE-22723, presented at SPE Annual Technical Conference and Exhibition, Dallas, Texas, 6-9 October.##

Coates, G.R., Xiao, L., Prammer, M.G., 1999. NMR logging: principles and applications. Houston, TX: Gulf Publishing Company.##

Comisky, J.T., Santiago, M., McCollom, B., Buddhala, A., Newsham, K.E., 2011. Sample size effects on the application of mercury injection capillary pressure for determining the storage capacity of tight gas and oil shales. Paper SPE-149432, Canadian Unconventional Resources Conference, Calgary, Canada, November, 15-17.##

Delle Piane, C., Esteban, L., Timms, N.E., Ramesh Israni, S., 2013. Physical properties of Mesozoic sedimentary rocks from the Perth Basin, Western Australia. Australian Journal of Earth Sciences, 60: 735-745.##

De Marsily, M., 1986. Quantitative hydrogeology; groundwater hydrology for engineers. Academic Press, San Diego.##

Dernaika, M. R., Basioni, M. A., Dawoud, A., Kalam, M. Z., 2012. Variations in bounding and scanning relative permeability curves with different carbonate rock types. Paper SPE-162265, Paper presented at the Abu Dhabi International Petroleum Exhibition and Conference, 11–14 November.##

Dillinger, A., Esteban, L., 2014. Experimental evaluation of reservoir quality in Mesozoic formations of the Perth Basin (Western Australia) by using a laboratory low field Nuclear Magnetic Resonance. Marine and Petroleum Geology, 57: 455-469.##

Dunham, R.J., 1962. Classification of carbonate rocks according to depositional textures. AAPG Mem, 1: 108–121.##

Dunn, K.J., Bergman, D.J., LaTorraca, G.A., 2002. Nuclear magnetic resonance: petrophysical and logging applications (1st Edition). Elsevier, 312 pp.##

Ebanks, W.J., 1987. Flow unit concept-integrated approach to reservoir description for engineering projects, AAPG Meet Abstract, 1: 521–522.##

Edwards, C.M., 2005. A review of capillary pressure estimates from NMR data, Capillary pressure prediction from rock models reconstructed using well log data. Society of Petroleum Engineers, paper no. 159761.##

Embry, A. F., Klovan, J. E., 1971. A late devonian reef tract on Northeastern Banks Island, NWT. Canadian Petroleum Geology Bulletin, 19: 730–781.##

Enayati-Bidgoli, A., Rahimpour-Bonab, H., 2016. A geological based reservoir zonation scheme in a sequence stratigraphic framework: A case study from the Permo–Triassic gas reservoirs, Offshore Iran. Marine and Petroleum Geology, 73: 36-58.##

Flügel, E., 2010. Microfacies of Carbonate Rocks Analysis, Interpretation and Application, Springer, Berlin, 984 pp.##

Francesconi, A., Bigoni, F., Balossino, P., Bona, N., Martchini, F. & Cozzi, M. 2009. Reservoir rock types application–Kashagan. Paper SPE-125342, Paper presented at the SPE/EAGE Reservoir Characterization Conference, Abu Dhabi, UAE, October 19–21.##

Frank, S., Narayanan, R., Hansen, P., Allen, D.F., Albrechtsen, T., Steinhardt, H., Raven, M.J., Fordham, E., Bize, E., Rose, D.A., 2005. Carbonate rock typing using NMR data: a case study from Al Shaheen field, offshore Qatar. IPTC-10889, presented at International Petroleum Technology Conference, Doha, Qatar, November 21-23.##

Freedman, R. 2006. Advances in NMR logging. Journal of Petroleum Technology, 58: 60-66.##

Ghedan, S. G., 2007. Dynamic rock types for generating reliable and consistent saturation functions for simulation models. Paper presented at the SPE/EAGE Reservoir Characterization and Simulation Conference, Abu Dhabi, UAE, 28–31 October.##

Gharechelou, S., Amini, A., Kadkhodaie-Ilkhchi, A., Moradi, B., 2015. An integrated approach for determination of pore-type distribution in carbonate-siliciclastic Asmari Reservoir, Cheshmeh-Khosh Oilfield, SW Iran. Journal of Geophysics and Engineering, 12 (5): 793-809.##

Gharechelou, S., Daraei, M., Amini, A., 2016. Pore types distribution and their reservoir properties in the sequence stratigraphic framework: a case study from the Oligo-Miocene Asmari Formation, SW Iran. Arabian Journal of Geosciences, 9 (3): 194.##

Gharechelou S., Sohrabi, S., Kadkhodaie, A., Rahimpour-Bonab, H., Honarmand, J., Montazeri, Gh., A seismic-driven 3D model of rock mechanical facies: An example from the Asmari reservoir, SW Iran. Journal of Petroleum Science and Engineering, 146: 983–998.##

Glover, P.W., Zadjali, I.I., Frew, K.A., 2006. Permeability prediction from MICP and NMR data using an electrokinetic approach. Geophysics, 71(4): F49-F60.##

Gomes, J.S., Ribeiro, M.T., Strohmenger, C.J., Naghban, S., and Kalam, M.Z., 2008. Carbonate reservoir rock typing-the link between geology and SCAL. Paper SPE- 118284, presented at SPE Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, UAE, 3-6 November.##

Hamon, G., 2003. Two phase flow rock typing: another approach. Paper SPE-84035, Paper presented at the SPE Annual Technical Conference and Exhibition, Denver, CO, 5–8 October 2003.##

Hassall, J., Johnston, J., Reboul, R., 2015. A Pragmatic Approach to Rock Typing in Carbonate Formations with Limited MICP Data and Several Vintages of Wireline Logs. Paper SPE-137357, Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, UAE, 9-12 November.##

Haynes, S.J., McQuillan, H., 1974. Evolution of the Zagros suture zone, southern Iran. Geological Society of America Bulletin, 85(5): 739-744.##

Henderson, S., 2004. Nuclear magnetic resonance logging, in Asquith, G. and Krygowski, D., 2004 Basic Well Log Analysis. AAPG Methods in Exploration, 16: 103–113.##

 Hidajat, I., Singh, M., Cooper, J., Mohanty, K.K., 2002. Permeability of porous media from simulated NMR response. Transport in Porous Media, 48(2): 225-247.##

Hidajat, I., Mohanty, K.K., Flaum, M., Hirasaki, G., 2004. Study of vuggy carbonates using NMR and X-Ray CT scanning. SPE Reservoir Evaluation & Engineering, 7(05): 365-377.##

Honarmand, J., Amini A., 2012. Diagenetic processes and reservoir properties in the ooid grainstones of the Asmari Formation, Cheshmeh-Khush oil field, SW Iran. J Pet Sci Eng, 81: 70–79.##

Honarmand, J., 2013. Sedimentological and diagenetic controls on reservoir properties of the Asmari formation, Cheshmeh–Khosh field, northern part of Dezful Embayment, SW Iran. Ph.D. dissertation University of Tehran, Tehran.##

Hossain, Z., Grattoni, C.A., Solymar, M., Fabricius, I.L., 2011. Petrophysical properties of greensand as predicted from NMR measurements. Petroleum Geoscience, 17(2): 111-125.##

Hozayen, M.A., Shuaib, M.T., 2010. Sedimentation and Diagenesis for Improved Reservoir Characterization-Upper Cretaceous Carbonate, Onshore Oil Field, Abu Dhabi (United Arab Emirates). GEO Conference, poster presentation.##

Jin, G., Manakovv, A.V., Chen, J., Zhang, J., 2012. Capillary pressure prediction from rock models reconstructed using well log data. Paper SPE-159761, presented at SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 8-10 October.##

Johnson, K., Barnett, A. and Wright, V. P., 2010. An evaluation of existing carbonate pore system classifications and rock-typing approaches. Paper presented at the AAPG Annual Convention and Exhibition, New Orleans, LA, 11–14 April.##

New Orleans, LA, 11–14 April 2010. Jorand, R., Fehr, A., Koch, A., Clauser, C., 2011, Study of the variation of thermal conductivity with water saturation using nuclear magnetic resonance. Journal of Geophysical Research: Solid Earth, 116(B8).##

Karimi, S., Saidian, M., Prasad, M., Kazemi, H., 2015. Reservoir rock characterization using centrifuge and nuclear magnetic resonance: A laboratory study of middle bakken cores. Paper SPE-175069, presented at SPE Annual Technical Conference and Exhibition, Houston, Texas, USA, 28-30 September.##

Kenter, J. A. M., Harris, P. M., Collins, J. F., Weber, L. J., Kuanysheva, G. & Fisher, D. J., 2006. Late Visean to Bashkirian platform cyclicity in the central Tengiz buildup, Pricaspian basin, Kazakhstan: depositional evolution and reservoir development. In: Harris, P. M. and Weber, L. J. (eds) Giant Hydrocarbon Reservoirs of the World: From Rocks to Reservoir Characterization and Modeling. American Association of Petroleum Geologists, Memoirs, 88: 7–54.##

Kenyon, W.E., 1997. Petrophysical principles of applications of NMR logging, The Log Analyst, 38(02): 21-43.##

Kenyon, W.E., Day, P.I., Straley, C., Willemsen, J.F., 1988. A three-part study of NMR longitudinal relaxation properties of water-saturated sandstones, SPE formation evaluation, 3(03): 622-636.##

Kosari, E., Ghareh-Cheloo, S., Kadkhodaie-Ilkhchi, A., Bahroudi, A., 2015. Fracture characterization by fusion of geophysical and geomechanical data: a case study from the Asmari reservoir, the Central Zagros fold-thrust belt. J. Geophys. Eng. 12 (1), 130.##

Kralik, J.G., Guice, K. and Meissner, J.P., 2010. Methods and Tools for the Development of Consistent Reservoir Rock Type Based Relative Permeability and Capillary Pressure Models for Reservoir Simulation. Paper SPE-137357, Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, UAE, 1-4 November.##

Lala, A.M.S., El-Sayed, N.A.E.M., 2015. Calculating absolute permeability using nuclear magnetic resonance models. Arabian Journal of Geosciences, 8(10): 7955-7960.##

Lehmann, C., Al Hosany, K., Cobb, D. O. and Al-Hend, A., 2008. Rock typing of upper Jurassic (Arab) carbonates, offshore Abu Dhabi. Paper SPE-117889, Paper presented at the International Petroleum Exhibition and Conference, Abu Dhabi, UAE, 5–6 November.##

Lucia, F. J., 1983. Petrophysical parameters estimated from visual descriptions of carbonate rocks: A field classification of carbonate pore space. Journal of Petroleum Petrology, 35: 629–637.##

Lucia, F. J., 1995. Rock-fabric/petrophysical classification of carbonate pore space for reservoir characterization. American Association of Petroleum Geologists Bulletin, 79: 1275–1300.##

Lucia, F. J., 2007. Carbonate Reservoir Characterization: An Integrated Approach (2nd edition) Springer, New York, 336 pp.##

Masalmeh, S. K., Jing, X. D., 2004. Carbonate SCAL: Characterization of carbonate rock types for determination of saturation functions and residual oil saturations. Paper presented at the International Symposium of the Society of Core Analysts, Abu Dhabi, UAE, 5–9 October.##

Miall, A.D., 2016. Stratigraphy: A Modern Synthesis, Springer International Publishing, 454 pp.##

 Motiei, H., 1993. Geology of Iran, the Stratigraphy of Zagros, Geological Survey of Iran, 536pp. (In Persian).##

O'Meara Jr, D.J., Hirasaki, G.J., Rohan, J.A., 1992. Centrifuge measurements of capillary pressure: Part 1-Outflow boundary condition. SPE reservoir engineering, 7(01): 133-142.##

Peralta, O.O., 2009. Rock types and flow units in static and dynamic reservoir modeling: application to mature fields. Paper SPE-122227, Presented at Latin American and Caribbean Petroleum Engineering Conference, Cartagena de Indias, Colombia, 31 May-3 June.##

Prammer, M.G., 1994. NMR pore size distributions and permeability at the well site. Paper SPE-28368, presented at SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, 25-28 September.##

Prammer, M.G., Drack, E.D., Brouton, J.C., Gardner, J.S., 1996. Measurements of clay-bound water and total porosity by magnetic resonance logging. Log Analyst, 37(6): 61-69.##

Purcell, W.R., 1949. Capillary pressures-their measurement using mercury and the calculation of permeability therefrom. Journal of Petroleum Technology, 1(02): 39-48.##

Rahimpour-Bonab, H., Mehrabi, H., Navidtalab, A., Izadi-Mazidi, E., 2012, Flow unit distribution and reservoir modelling in cretaceous carbonates of the Sarvak Formation, Abteymour Oilfield, Dezful Embayment, SW Iran. J Pet Geol, 35(3): 213-236.##

Rajan, R.R., 1986. Theoretically correct analytical solution for calculating capillary pressure-saturation from centrifuge experiments, SPWLA 27th Annual Logging Symposium, Houston, Texas, 9-13 June.##

Rebelle, M., Al-Neaimi, M. A., Ribeiro, M. T., Gottlib-Zeh, S., Valsardieu, B. and Moss, B., 2005. Quantitative and statistical approach for a new rock and log-typing model: Example of onshore Abu Dhabi Upper Thamama. (IPTC paper 10273), International Petroleum Technology Conference, Doha, Qatar, 21–23 November.##

Regard, V., Bellier, O., Thomas, J.C., Abbassi, M.R., Mercier, J., Shabanian, E., Feghhi, K., Soleymani, S., 2004. Accommodation of Arabia‐Eurasia convergence in the Zagros‐Makran transfer zone, SE Iran: A transition between collision and subduction through a young deforming system. Tectonics, 23(4).##

 Revil, A., Florsch, N., 2010. Determination of permeability from spectral induced polarization in granular media. Geophysical Journal International, 181(3): 1480-1498.##

Salman, M. S. and Sameer, B., 2009. Rock typing: An integrated reservoir characterization tool to construct a robust geological model in Abu Dhabi carbonate oil field. Paper presented at the SPE/EAGE Reservoir Characterization and Simulation Conference in Abu Dhabi, UAE, 19–21 October.##

Serra, O., Abbott, H., 1980. The contribution of logging data to sedimentology and stratigraphy. Paper SPE-9270, Paper presented at the 55th Annual Fall Technical Conference and Exhibition of the Society of Petroleum Engineers of AIME, Dallas, TX, 21–24 September.##

Shabaninejad, M., Haghighi, M.B., 2011. Rock typing and generalization of permeability-porosity relationship for an Iranian carbonate gas reservoir. Paper SPE-150819, Nigeria Annual International Conference and Exhibition, Abuja, Nigeria, 30 July - 3 August.##

Shahvar, M.B., Kharrat, R. 2012. Multiple-Zones Flow Unit Modeling of Ilam and Sarvak Carbonate Formations of Iran through an Integrated Approach, Paper SPE-163008, Nigeria Annual International Conference and Exhibition, Lagos, Nigeria, 6-8 August.##

Skalinski, M. T., Kenter, J. A.M., Jenkins, S., 2009. Rock type definition and pore type classification of a carbonate platform, Tengiz Field, Republic of Kazakhstan. Paper presented at the SPWLA 50th Annual Logging Symposium, 21–24 June.##

Skalinski, M., Kenter, J.A., 2013. Pore typing workflow for complex carbonate systems. Presented at AAPG Annual Convention and Exhibition Pittsburgh Pennsylvania.##

Skalinski, M., Kenter, J.A., 2015. Carbonate petrophysical rock typing: integrating geological attributes and petrophysical properties while linking with dynamic behaviour. Geological Society London Special Publications, 406(1): 229-259.##

Song, Y.Q., 2013. Magnetic resonance of porous media (MRPM): a perspective. Journal of Magnetic Resonance, 229: 12-24.##

Southworth, R.A., Miller, J., El Hadidi, K., 2013. An integrated approach to rock typing and its impact on well and reservoir performance in a middle east tight gas field, Paper SPE-164015, SPE Unconventional Gas Conference and Exhibition, Muscat, Oman, 28-30 January.##

Swanson, B.F., 1981. A simple correlation between permeabilities and mercury capillary pressures. Journal of Petroleum Technology, 33(12): 2498-2504.##

 Thomeer, J.H.M., 1960. Introduction of a pore geometrical factor defined by the capillary pressure curve, Journal of Petroleum Technology, 12(03): 73-77.##

Tiab, D., Donaldson, E.C. 2015. Petrophysics: theory and practice of measuring reservoir rock and fluid transport properties (4rd Edition). Gulf professional publishing, 918 pp.##

Tillero, E., 2012. Stepping forward: an automated rock type index and a new predictive capillary pressure function for better estimation of permeability and water saturation case study, Urdaneta-01 heavy oil reservoir, Paper SPE-151602, presented at SPE Latin America and Caribbean Petroleum Engineering Conference, Mexico City, Mexico, 16-18 April.##

Timms, N.E., Olierook, H.K., Wilson, M.E., Delle Piane, C., Hamilton, P.J., Cope, P., Stütenbecker, L., 2015. Sedimentary facies analysis, mineralogy and diagenesis of the Mesozoic aquifers of the central Perth Basin, Western Australia, Marine and Petroleum Geology, 60: 54-78.##

 Timur, A., 1968. An investigation of permeability, porosity and residual water saturation relationships for sandstone reservoirs. The Log Analyst, 9: 8–17.##

Uguru, C.I., Onyeagoro, U.O., Lin, J., Okkerman, J., Sikiru, I.O., 2005. Permeability prediction using genetic unit averages of flow zone indicators (FZIs) and neural networks, Paper SPE-98828, Nigeria Annual International Conference and Exhibition Abuja, Nigeria, 1-3 August.##

Van Buchem, F.S.P., Allan, T., Laursen, G.V., Lotfpour, M., Moallemi, A., Monibi, S., Motiei, H., Pickard, N., Tahmasbi, A.R., Vedrenne, V., Vincent, B., 2009. Sequence Stratigraphy and Sr Isotope Stratigraphy of the Oligo-Miocene Deposits in the Dezful Embayment (Asmari and Pabdeh Formations, SW Iran)-Implications for Reservoir Characterisation. 1st EAGE International Petroleum Conference and Exhibition.##

Washburn, E.W., 1921. The dynamics of capillary flow, Physical review, 17(3): 273-283.##

Weller, A., Nordsiek, S., Debschütz, W., 2010. Estimating permeability of sandstone samples by nuclear magnetic resonance and spectral-induced polarization. Geophysics, 75(6): E215-E226.##

Weller, A., Slater, L., Nordsiek, S., 2013. On the relationship between induced polarization and surface conductivity: implications for petrophysical interpretation of electrical measurements. Geophysics, 78(5): D315–D325.##

Wennberg, O.P., Svånå, T., Azizzadeh, M., Aqrawi, A.M.M., Brockbank, P., Lyslo, K.B., Ogilvie, S. 2006. Fracture intensity vs. mechanical stratigraphy in platform top carbonates: the Aquitanian of the Asmari Formation, Khaviz Anticline, Zagros, SW Iran. Petroleum Geoscience, 12(3): 235-246.##

Wilson, J.L., 1975, Carbonate facies in geologic history, Springer-Verlag New York, 471 pp.##

Wolff, M., Pellissier-Combescure, J., 1982. FACIOLOG–Automatic electrofacies determination. Paper presented at the SPWLA Annual Logging Symposium, Corpus Christi, 6–9 July 1982.##

 Xiao, L., Liu, X.P., Zou, C.C., Hu, X.X., Mao, Z.Q., Shi, Y.J., Guo, H.P., Li, G.R., 2014. Comparative study of models for predicting permeability from nuclear magnetic resonance (NMR) logs in two Chinese tight sandstone reservoirs. Acta Geophysica, 62(1): 116-141.##

Xiao, Z.X., Zhang, C. and Xiao, L. 2008. Using porosity and permeability parameters to construct capillary pressure curves, Petroleum Geology, 29(5): 635-637.##

Xiao, L., Zhang W., 2008. A new method to construct reservoir capillary pressure curves using NMR log data and its application, Applied Geophysics, 5(2):92–98.##

Xu, C., Heidari, Z., Torres Verdin, C., 2012. Rock Classification in Carbonate Reservoirs Based on Static and Dynamic Petrophysical Properties Estimated from Conventional Well Logs. SPE paper no. 159991.##