Field Monitoring and Identification Method for Overflow of Fractured-Vuggy Carbonate Reservoir

Abstract

Since carbonate reservoirs develop pores and fractures and have a complex formation pressure system, overflow and even blowout seriously threaten the exploration and development of these kinds of reservoirs. According to the overflow characteristics of fractured-vuggy carbonate reservoirs, a field monitoring and identification method for overflow has been developed. This method is based on the top-down logic framework for early overflow identification, combined with optimized monitoring parameters. The DBSCAN clustering algorithm is used to identify abnormal logging parameters, and thus, a probability weight coefficient of overflow (K) indicated by the abnormal engineering parameters of a gas well can be calculated. K is divided into four early warning response levels of overflow, and the overflow control operation can be made according to the different levels of early warning response. Based on this method, an integrated software system for field monitoring and identification of early overflow is designed. This software system integrates the functions of data collection and management, overflow risk parameter calculation, overflow early warning, and overflow simulation analysis. Finally, according to a case analysis of overflow prediction for a fractured-vuggy carbonate reservoir in Well XX, this method’s prediction stability and accuracy are demonstrated, indicating that it can be used for the overflow early warning in engineering practice.

Numerical well test model of oil-water two-phase flow in fractured and vuggy carbonate reservoir

“…These patterns encompass a highly dispersed and diverse network of connectivity, giving rise to a multitude of distinct flow configurations (Jiao, 2019;Tian et al, 2019;Huang et al, 2021). Furthermore, significant variations in both the permeability and the porosity levels can be observed within different media systems, contributing to a pronounced degree of reservoir heterogeneity (Lu et al, 2020;Zhang et al, 2023). The investigation of reservoir flow mechanisms constitutes fundamental research in the realm of oilfield development, which maintains a close and intrinsic relationship with well test studies aimed at enhancing comprehension of these complex reservoir flow mechanisms.…”