Geomechanical and lithological characteristics of the Vereysky horizon in the Middle Carboniferous for prediction of hydraulic fracturing technology, on the example of the Ivinskoye field in the South-East of Tatarstan

The method of acid hydraulic fracturing has been actively used in recent years, for the deposits of the Vereysky horizon of the Moscowian strata in the south-east of Tatarstan. Design development and the use of hydraulic fracturing requires full-fledged studies of the geomechanical characteristics of rocks, including the prediction of the propagation of emerging fractures. It is considered the main geomechanical characteristics for reservoir rocks and dense rocks involved in the structure of the sections, on the example of the study of polyfacial reservoirs of the Vereysky horizon of the Ivinskoye oil field. It was revealed that the carbonate reservoir rocks of the middle and upper parts of the Vereysky horizon (C₂ vr3 and C₂ vr5) have the least strength properties and a greater susceptibility to fracturing. More durable were sandstones of the upper part of the horizon, marls and mudstones of the middle and upper parts of the horizon, as well as mudstone and dense packstone, typical for the lower part of the Vereysky horizon. The presented data can be valid for most of the sections of the Vereysky horizon of the southeast of Tatarstan and are used for the choice of optimal solutions when applying the hydraulic fracturing technology.

1. Barry N., Whittaker N.R., Singh S.G. (1992). Rock fracture mechanics principles design and applications. Elsevier, Amsterdam-London-New York-Tokyo.

2. Dunham R.J. (1962). Classification of carbonate rocks according to depositional texture. Classification of carbonate rocks. Simp. Amer. Assoc. Petrol. Geol. Mem. Ed. W.E. Ham. V.1, pp. 108–121.

3. Geology of Tatarstan: stratigraphy and tectonics (2003). Ed. B.V. Burova. Moscow: GEOS, 402 p. (In Russ.)

4. Khisamov R.S., Gubaidullin A.A., Bazarevskaya V.G., Yudintsev E.A. (2010). Geology of complexly constructed carbonate reservoirs of the Devonian and Carboniferous of Tatarstan. Kazan: Fen, 283 p. (In Russ.)

5. Kolchugin A.N., Della Porta G., Morozov V.P., Korolev E.A., Temaya N.V., Gareev B.I. (2020). Facies variability of pennsylvanian oil-saturated carbonate rocks (constraints from Bashkirian reservoirs of the south-east Tatarstan). Georesursy = Georesources, 22(2), pp. 29–36. https://doi.org/10.18599/grs.2020.2.29-36

6. Korolev E.A., Kol’chugin A.N., Morozov V.P., Nizamutdinov N.M., Pronin N.V. (2014). Causes of low oil recovery of the Vereisk horizon of the Akanskoye field. Neftyanoe khozyaistvo = Oil industry, 10, pp. 57–59. (In Russ.)

7. Larochkina I.A. (2011). Perspectives of oil output development in the Republic of Tatarstan. Georesursy = Georesources, 40(4), pp. 2-6. (In Russ.)

8. Mavko G., Mukerji T., Dvorkin J. (2009). The rock physics handbook. 2nd ed. Cambridge University Press, 511 р.

9. Salimov V.G., Ibragimov N.G., Nasybullin A.V., Salimov O.V. (2013). Hydraulic fracturing of carbonate formations. Moscow: Neftyanoe khozyaistvo, 472 p. (In Russ.)

10. Ziganshin E.R. (2021). Relationship between elastic and capacitive properties of carbonate reservoirs (on the example of the Carboniferous deposits of the Republic of Tatarstan). Cand. geol.-min. sci. diss. Kazan, 192 p. (In Russ.)

11. Zoback M.D. (2007). Reservoir Geomechanics. Cambridge: Cambridge University Press, 449 p.