This study provides a new rock-typing approach for low-resistive and low-permeable clastic rocks. The approach includes integrated interpretation of routine core analysis data with microstructural characteristics, acquired from computed tomography (CT) and nuclear-magnetic resonance (NMR) data.
The studied formation comprises siltstones in its bottom, which are replaced by sandstones in its top. Sandstones form the main part of the oil reservoir, whereas siltstones were originally considered as water-saturated. The reserves calculation was performed based on a single Archie equation for the whole formation.
Despite on apparent water saturation and low permeability of the siltstones, incidental perforation showed considerable oil inflow from them as well. In order to delineate missed productive intervals within the low-resistive siltstones, we had to develop a new rock-typing approach, acknowledging rock multimineral composition, diversity of microstructures, a wide range of porosity, permeability, and residual water saturation values.
Designed laboratory program included porosity, permeability, electrical resistivity measurements, capillary, NMR and CT tests. The experiments were performed on the same core samples that enabled reliable correlation between measured parameters.
The joint interpretation of flow zone indicator, calculated as a function of porosity and residual water saturation, together with the results of petrophysical and microstructural measurements allowed reliable rock-typing of the clastic formation. It will serve as a petrophysical basis for identification of the missed productive intervals.
The developed laboratory program and rock-typing algorithm can be implemented in other oilfields.
CT-scanning, NMR, rock-typing, clastic reservoirs, low-resistive reservoirs, low-permeable formations
- Amaefule J.O., Altunbay M., Tiab D., Kersey D.G., and Keelan D.K. (1993). Enhanced reservoir description: using core and log data to identify hydraulic (flow) units and predict permeability in uncored intervals. SPE Annual Technical Conference and Exhibition, pp. 205–220. https://doi.org/10.2118/26436-MS
- Archie G.E. (1942). The Electrical Resistivity Log as an Aid in Determining Some Reservoir Characteristics. Petroleum Transactions of the AIME, 146, pp. 54–62. https://doi.org/10.2118/942054-G
- Bogdanovich N.N., Kazak A.V., Yakimchuk I.V. et al. (2014). Low-permeable productive dolomites of Preobrazhenskiy horizon of Verkhne chonskoye field. Neft, Gaz, Novatsii, 183(4), pp. 41–91. (In Russ.)
- Coates G.R., Xiao,L., Prammer M.G. (1999). NMR Logging. Ebooks, 253 p.
- Eltom H.A. (2020). Limitation of laboratory measurements in evaluating rock properties of bioturbated strata: A case study of the Upper Jubaila Member in central Saudi Arabia. Sedimentary Geology, 398, 105573. https://doi.org/10.1016/j.sedgeo.2019.105573
- Fheed A., Krzyżak A., Świerczewska A. (2018). Exploring a carbonate reef reservoir – nuclear magnetic resonance and computed microtomography confronted with narrow channel and fracture porosity. Journal of Applied Geophysics, 151, pp. 343–358. https://doi.org/10.1016/j.jappgeo.2018.03.004
- Fitzsimons D., Oeltzschner G., Ovens C., Radies D., Schulze F. (2016). Integration and Data Analysis of Conventional Core Data with NMR and CT Data to Characterize An Evaporitic Carbonate Reservoir. Abu Dhabi International Petroleum Exhibition & Conference. Abu Dhabi, UAE, p. D031S068R002. https://doi.org/10.2118/183145-MS
- Gholami V., Mohaghegh S.D. (2009). Intelligent upscaling of static and dynamic reservoir properties. SPE Annual Technical Conference and Exhibition, pp. 2238–2252. https://doi.org/10.2118/124477-MS
- Haikel S., Rosid M.S., Haidar M.W. (2018). Study comparative rock typing methods to classify rock type carbonate reservoir Field “s” East Java. Journal of Physics: Conference Series. Institute of Physics Publishing. 10.1088/1742-6596/1120/1/012047
- Kolodzie S. (1980). Analysis of pore throat size and use of the waxman-smits equation to determine OOIP in spindle field, Colorado. SPE Annual Technical Conference and Exhibition. https://doi.org/10.2118/9382-MS
- Liu X. et al. (2017). Pore-scale characterization of tight sandstone in Yanchang Formation Ordos Basin China using micro-CT and SEM imaging from nm- to cm-scale. Fuel, 209, pp. 254–264. https://doi.org/10.1016/j.fuel.2017.07.068
- McPhee C., Reed J., Zubizarreta I. (2015). Core Analysis: A Best Practice Guide. Developments in Petroleum Science, 64, pp. 2–829.
- Mirzaei-Paiaman A., Ostadhassan M., Chen Z. (2018). A new approach in petrophysical rock typing. Journal of Petroleum Science and Engineering, 166, pp. 445–464. https://doi:10.1016/j.petrol.2018.03.075
- Mustafa A., A.Mahmoud M., Abdulraheem A. (2019). A Review of Pore Structure Characterization of Unconventional Tight Reservoirs. Abu Dhabi International Petroleum Exhibition & Conference. Abu Dhabi, UAE, p. D031S098R001. https://doi.org/10.2118/197825-MS
- Pires L.O., Fiorelli G.L., Winter A., Trevisan O.V. (2017). Petrophysical Characterization of Carbonates Heterogeneity. OTC Brasil. Rio de Janeiro, Brazil, p. D021S015R001. https://doi.org/10.4043/28098-MS
- Pires L.O., Winter A., Trevisan O.V. (2019). Dolomite cores evaluated by NMR. Journal of Petroleum Science and Engineering, 176, pp. 1187–1197. https://doi.org/10.1016/j.petrol.2018.06.026
- Pittman E.D. (1992). Relationship of porosity and permeability to various parameters derived from mercury injection-capillary pressure curves for sandstone. American Association of Petroleum Geologists Bulletin, 76, pp. 191–198. https://doi.org/10.1306/BDFF87A4-1718-11D7-8645000102C1865D
- Salimidelshad Y. et al. (2019). Experimental investigation of changes in petrophysical properties and structural deformation of carbonate reservoirs. Petroleum Exploration and Development, 46, pp. 565–575. https://doi.org/10.1016/S1876-3804(19)60036-4
- Saxena N., et al. (2019). Rock properties from micro-CT images: Digital rock transforms for resolution, pore volume, and field of view. Advances in Water Resources, 134, p. 103419. https://doi.org/10.1016/j.advwatres.2019.103419
- Skalinski M., et al. (2010). Updated Rock Type Definition and Pore Type Classification of a Carbonate Buildup, Tengiz Field, Republic of Kazakhstan (Russian). SPE Caspian Carbonates Technology Conference. SPE Caspian Carbonates Technology Conference, Society of Petroleum Engineers. Atyrau, Kazakhstan. https://doi.org/10.2118/139986-RU
- Skalinski M., Kenter J.A.M. (2015). Carbonate petrophysical rock typing: integrating geological attributes and petrophysical properties while linking with dynamic behaviour. Geological Society, London, Special Publications, 406, pp. 229–259. https://doi.org/10.1144/SP406.6
- Tiab D., Donaldson E.C. (2016). Petrophysics (Fourth Edition). Elsevier Inc. https://doi.org/10.1016/C2014-0-03707-0
- Wang M., et al. (2020). Determination of NMR T2 Cutoff and CT Scanning for Pore Structure Evaluation in Mixed Siliciclastic–Carbonate Rocks before and after Acidification. Energies, 13, p. 1338. https://doi.org/10.3390/en13061338
- Xiao D., et al. (2016). Combining nuclear magnetic resonance and rate-controlled porosimetry to probe the pore-throat structure of tight sandstones. Petroleum Exploration and Development, 43, pp. 1049–1059. https://doi.org/10.1016/S1876-3804(16)30122-7
- Yarmohammadi S., Kadkhodaie A., Hosseinzadeh S. (2020). An integrated approach for heterogeneity analysis of carbonate reservoirs by using image log based porosity distributions, NMR T2 curves, velocity deviation log and petrographic studies: A case study from the South Pars gas field, Persian Gulf Basin. Journal of Petroleum Science and Engineering, 192. https://doi.org/10.1016/j.petrol.2020.107283
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Alexei A. Tchistiakov – Professor, Center for Hydrocarbon Recovery
Skolkovo Institute of Science and Technology
Sikorsky str., 11, Moscow, 121205, Russian Federation
Elizaveta V. Shvalyuk – Postgraduate Student, Center for Hydrocarbon Recovery
Skolkovo Institute of Science and Technology
Sikorsky str., 11, Moscow, 121205, Russian Federation
Alexandr A. Kalugin – Head of the Department
LUKOIL-Engineering JSC
Pokrovsky boul., 3, build. 1, Moscow, 109028, Russian Federation
Tchistiakov A.A., Shvalyuk E.V., Kalugin A.A.(2022). The rock typing of complex clastic formation by means of computed tomography and nuclear magnetic resonance. Georesursy = Georesources, 24(4), pp. 102–116. https://doi.org/10.18599/grs.2022.4.9