Optimization of horizontal well drilling in carbonate reservoirs of Eastern Siberia: results from the application of seismic-geological analysis

UDK: 622.243.24

DOI: 10.24887/0028-2448-2025-5-94-98

Key words: abnormally low reservoir pressure, horizontal well drilling, managed pressure drilling (MPD), drilling fluid, seismic-geological analysis (SGA)

Authors: A.V. Pivovar (IGIRGI JSC, RF, Moscow); N.N. Pleshko (IGIRGI JSC, RF, Moscow); V.P. Filatova (IGIRGI JSC, RF, Moscow); D.O. Kryuchkov (IGIRGI JSC, RF, Moscow)

The article addresses the challenges of drilling horizontal wells in carbonate reservoirs of Eastern Siberia, characterized by fractured-vuggy structures, abnormally low reservoir pressure, and extensive tectonic fault networks. The study focuses on mitigating geological risks through the integration of seismic-geological analysis (SGA) and managed pressure drilling (MPD). The SGA methodology combines retrospective analysis of historical drilling data, pre-drill trajectory optimization for cluster pads, well-specific risk assessment, real-time operational monitoring, and post-drill verification of geological forecasts. The implementation of this integrated approach led to notable improvements in key performance indicators: enhanced drilling efficiency per bottom-hole assembly run, reduced time required to complete horizontal sections, and decreased frequency of drilling fluid losses. MPD technology enabled dynamic adjustments of downhole pressure in high-risk zones identified via seismic attributes such as Ant-Tracking, ensuring safer and more controlled operations. The study also highlights emerging challenges encountered in paleo-incision zones of the Vanavar Formation, including uncertainties in boundary delineation and instability in clay-rich intervals. To address these issues, the authors propose refining geological criteria for risk identification and optimizing horizontal section lengths. The research underscores that the synergy between SGA and MPD not only enhances operational reliability but also provides a robust framework for sustainable development of complex reservoirs under challenging geological conditions.

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