The evaluation of the efficiency of horizontal wells

Abstract

The number of fields that have reached stage IV of development is increasing every year. Due to the high level of water cut, it becomes difficult to develop residual recoverable reserves. Also, due to the increase in the share of high-viscosity oils in Kazakhstan, the task of their effective development becomes more complicated. The development of terrigenous reservoirs, which have a complex structure and contain high-viscosity oil, is usually characterized by low production rates and oil recovery factors. Currently, technologies that ensure high efficiency in the development of such deposits are very expensive.
 In this regard, the development of oil fields through the commissioning of horizontal wells is becoming more in demand, capable of increasing the efficiency of developing oil reserves. Drilling of horizontal wells is considered for:
 
 floating reservoirs with low reservoir production coverage due to high water cut. High levels of water cut are due to breakthroughs of bottom water and degraded technical condition of wells (annular flows, wear and leakage of the string, depressurization of previously isolated intervals and poor quality of cement adhesion);
 thin layers, not involved in the production. Basically, thin layers are not involved in the production due to the low performance of vertical wells;
 on horizons with high-viscosity oil. In highly viscous horizons, the injected water breaks through to the bottom of production wells along the base of the reservoir when the horizon is not developed.
 
 Also in the Atyrau region, fields with hard-to-recover reserves (fields with high oil viscosity and low permeability of the productive horizon) are being developed. It is in such fields that horizontal wells have already been drilled and will be drilled in the future.
 The presented article discusses the results of the analysis of the drilled horizontal wells in the North Volga and Aknur oil fields.