Affiliation:
1. Skolkovo Institute of Science and Technology
2. LUKOIL-Engineering JSC
Abstract
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.
Reference25 articles.
1. 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
2. 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
3. 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.)
4. Coates G.R., Xiao,L., Prammer M.G. (1999). NMR Logging. Ebooks, 253 p.
5. 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
Cited by
5 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献