Sudad H. Al-Obaidi, Meil Hofmann
Mining University (Russia)
Ivan P. Kamensky
Scientific Research Centre, SPB (Russia)
https://doi.org/10.53656/nat2024-5-6.03
Abstract. The exploration of undersaturated oil-bearing, layer-by-layer heterogeneous oil reservoirs has become increasingly important due to the overall depletion of oil reserves. It is associated with non-standard changes in well production and increased values of water cut when these hard-to-recover oil reserves are developed. In its classical understanding, an undersaturated deposit is a conventionally large transitional water-oil zone of the reservoir.
The initial water cut is generally expected to correspond to the high initial water saturation of the formation. However, in some instances, this may not be the case. Predicting the trajectory of water cut during the initial stages of oil field development presents a considerable challenge, ascertaining whether it will increase, stabilize, or decrease. Hence, the primary objective of this study is to identify the key parameter and analyze the range of its variation using statistical methods. This analysis will enable us to make highly accurate predictions regarding the anticipated variations in water cut during the feasibility assessment of new well drilling projects.
In this study, the graphical dependence of the deviation of water cut during the early stages of well operation on the layer-by-layer heterogeneity of the formation was found for the conditions of the selected object, the Vatyogan oil field. The study’s findings strongly support the development of innovative technologies for selectively isolating reservoirs. These technologies would enable the reversible restriction of permeability in the low-permeability, low-saturated part of the reservoir. This is a significant advancement considering that current technologies primarily target selective isolation of highly permeable and water-saturated interlayers.
Keywords: permeability heterogeneity, water cut, undersaturated oil formation, water oil zone, OWC
