Gunashli field: Net pay thickness in the objective assessment of hydrocarbon reserves
https://doi.org/10.32454/0016-7762-2025-67-4-23-29
Abstract
Background. The Gunashli field located at a depth of 80–300 m in the deep-water part of the Caspian Sea represents another hinge undulation of the Absheron-Balkhan tectonic zone to the southeast of the Oil Rocks field.
Aim. To study the Lower Pliocene deposits as a productive area (PA), i.e., the main object of oil and gas content.
Materials and methods. The calculation of oil and gas reserves of the Gunashli field mainly include the volumetric method formula with six parameters. One of the main parameters is the net pay thickness (NPT), which is the ratio of the volume of pores, voids and caverns saturated with oil to the total volume of the rock.
Results. Similar to the adjacent areas, the PA is lithologically represented by alternating layers of sand, sandstone, silt, and clay of varying thickness. The main developed object is the Fasilya suite and X horizon of the Balakhan suite, which contain 90% of the oil from total field reserves. Based on the constructed maps, the weighted average NPT values of the Fasilya suite and X horizon of the Balakhan suite are calculated for the blocks of the field. The NPT is one of the main parameters significantly affecting the error in determining hydrocarbon reserves. The NPT value determined in this study by two methods of arithmetic and weighted means significantly differ by 15–20%. The hydrocarbon reserves of the Gunashli field for the Fasilya suite and X horizon are assessed using weighted average NPT values.
Conclusion. NPT values can be used for determining the direction of improving petrophysical properties of rocks and number of projected wells, as well as for predicting the phase states of hydro- carbons at the stage before field exploration.
About the Authors
G. Vagifgizi
SOCAR NIPIneftegaz
Azerbaijan
Competing Interests:
Azerbaijan
Gunay Vagifgizi — DPh, Engineer
88 G. Zardabi Ave., AZ1122 Baku
tel.: +994 (050) 681-03-29
Competing Interests:
the authors declare that there is no conflict of interest
O. A. Yagubov
SOCAR NIPIneftegaz
Azerbaijan
Competing Interests:
Azerbaijan
Orkhan А. Yagubov — Senior Researcher of Oil and Gas Reserves Estimation Laboratory
88 G. Zardabi Ave., AZ1122 Baku
tel.: +994 (050) 380-41-36
Competing Interests:
the authors declare that there is no conflict of interest
G. G. Abbasova
Azerbaijan State University of Oil and Industry
Azerbaijan
Competing Interests:
Azerbaijan
Gizgayit G. Abbasova — Associate Professor — teacher
20, Azadlıq Ave., AZ1010 Baku
tel.: +994 (050) 899-03-70
Competing Interests:
the authors declare that there is no conflict of interest
R. F. Alıyeva
Oil and Gas Institute of the Ministry of Science and Education of the Republic of Azerbaijan
Azerbaijan
Competing Interests:
Azerbaijan
Ruhiyya F. Alıyeva — Engineer
9, Fikret Amirov str., AZ1000 Baku
tel.: +994 (050) 746-48-80
Competing Interests:
the authors declare that there is no conflict of interest
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Review
For citations:
Vagifgizi G., Yagubov O.A., Abbasova G.G., Alıyeva R.F. Gunashli field: Net pay thickness in the objective assessment of hydrocarbon reserves. Proceedings of higher educational establishments. Geology and Exploration. 2025;67(4):23-29. (In Russ.) https://doi.org/10.32454/0016-7762-2025-67-4-23-29
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