Temperature Transient Analysis for Characterization of Multilayer Reservoirs with Crossflow

Abstract

Multilayer systems are widely encountered in underground hydrocarbon reservoirs. To obtain accurate multilayer properties and understand the flow behavior in a multilayer system, many testing and analysis procedures have been evolved. Recent developments on downhole temperature monitoring systems open new alternatives contributing to multilayer reservoir characterization. The progressing technique, temperature transient analysis, is developed to use the temperature data, which are unique for each layer in a multilayer reservoir.In this work, we present an analytical solution to determine the individual layer temperature signal associated with constant rate production of slightly compressible fluid from a fully penetrating vertical well in a multilayer reservoir. The analytical solution development process involves identifying the late time individual layer production rates and applying the single layer transient temperature behavior, the results of which are benchmarked with those from the numerical simulation. The temperature signals are presented at the bottom-hole location and further into the reservoir for two-layered and multi-layered systems, for which each layer may be damaged or undamaged. The temperature profiles obtained from analytical solution shows excellent agreement with those from numerical simulation and are sensitive to layer permeability, porosity, and damaged zone properties. In addition, we provide semi-log temperature interpretation techniques to characterize the layer permeability and porosity, and damaged zone radius and permeability considering the availability of adequate data. The simplified characterization methods are also developed in the case of insufficient or inaccurate data to obtain permeability and production rate ratios between layers which helps to identify the layers contributing the most to well production.

An Analytical Model for Multilayer Well Production Evaluation to Overcome Cross-Flow Problem

“…The properties allow the fluid to cross each layer reservoir. The study of formation crossflow could be evaluated by using flow well testing interpretation (Park, 1989;Happy et al, 2014) and temperature analysis of well (Mao and Zeidouni, 2017). Wellbore crossflow could happen once the production line is commingle and impermeable layer appears between the producing layers.…”

Pressure and Temperature Transiente Response in a Coupled Stratified Wellbore-Reservoir Model

“…Mao and Zeidouni (2017) [39] presented an analytical solution to determine the individual layer temperature signal associated with constant rate production of slightly compressible fluid from a fully penetrating vertical well in a multilayered reservoir. They provide semi-log temperature interpretation techniques to characterize the layer permeability and porosity, and damage zone radius considering the availability of adequate data.…”