Investigation of the Applicability of Thermal Well Test Analysis in Steam Injection Wells for Athabasca Heavy Oil

Abstract

Thermal well testing of steam injection wells offers an inexpensive quick method to estimate flow capacity and swept volume in thermal recovery processes. Pressure falloff tests are commonly used for this purpose. Estimation of steam zone properties and swept volume from falloff test data in this study is based on the theory assuming a composite reservoir with two regions of highly contrasting fluid mobilities and the interface as an impermeable boundary. Consequently, the swept zone acts as a bounded reservoir for a short duration, during which the pressure response is characterized by pseudo steady state behavior. The purpose of this study is to evaluate the applicability and accuracy of thermal well test analysis method and effects of different parameters on results. Pressure falloff testing is simulated using a numerical thermal simulator. The generated pressure falloff data are then analyzed to calculate swept volume and reservoir parameters. Different gridblock models are considered. Viscosity of Athabasca heavy crude sample was measured in the lab using a rotational viscometer up to 300°C. Bitumen sample molar mass was measured by cryoscopy. Density at standard conditions was measured by a density measuring cell. These data were used as input for numerical simulation purposes. Results of this work show that the swept volume, swept zone permeability and skin factor can reasonably be estimated from pressure falloff tests. The effects of gravity, dip, permeability anisotropy and irregular shapes of swept zones are studied. It can be seen that these factors do not greatly affect the estimated results. Results of 3D models show that the estimation of permeability and steam swept volume depends on the vertical positions where pressure data are measured. It is also found that real gas analysis does not substantially improve the calculation accuracy and the pressure analysis technique suffices for all practical purposes.

A Multi-Layer Commingled Composite Reservoir Model for Thermal Well Test Analysis

“…MATHEMATICAL MODEL Unlike the traditional composite model assumption, in reality and in most of the cases studied in [23]- [25], three zones are formed: steam zone, hot water zone and the cold oil zone. A three-region model is introduced in this section.…”

“…The application of thermal well testing method to different cases was investigated in some initial simulation studies to consider some fundamental concepts and to evaluate the applicability and accuracy of thermal well test analysis method and the effects of several parameters on the results ( [23]- [25]). Errors in some cases are reported significant and there are trends on the pressure plots which cannot be explained correctly using the existing models.…”

The Impact of Autonomous Inflow Control Valve on Enhanced Oil Recovery in SAGD Application

“…Non-conventional oil is categorized as extra heavy oil and bitumen. The mobility of bitumen is quite poor since the viscosity can be as high as 10 6 cP (Ghahfarokhi et al, 2012). In reservoirs with extra heavy oil and bitumen, thermal methods such as steam assisted gravity drainage (SAGD) are used to reduce the oil viscosity and make the bitumen mobile and extractable.…”

Effect of Oil Mass Flow Rate on Temperature Profile in Oil Wells

“…The main factors in process design and production management are mathematical prediction models of temperature distribution across porous media during thermal flood processes [2]. Several models are proposed for the distribution of temperature in specific geothermal and natural reservoirs and for the thermal injection model well-tested [3,4]. Lawal and Vesovic [5] developed a one-dimensional heat transfer model to predict the distribution of temperatures for various conditions.…”