Development and Verification of an Enhanced Equation of State in TOUGH2

2021 ◽  
Author(s):  
Cheng An ◽  
Yanhui Han ◽  
Hui-Hai Liu ◽  
Zhuang Sun
Keyword(s):  
Equation Of State ◽  
Reservoir Simulation ◽  
Fluid Pressure ◽  
Saturation Temperature ◽  
Production Performance ◽  
Communication Process ◽  
Coupled Simulation ◽  
Simulation Code ◽  
Multiphase Fluid Flow ◽  
Multiphase Fluid

Abstract A reservoir-geomechanics coupled simulation tool is required to interpret and predict stimulation and production performance in unconventional reservoirs in a physically rigorous manner. This work presents a simulation platform by integrating a multiphase fluid flow and heat transport code (TOUGH2) with a geomechanics code (FLAC3D) using an iteratively coupled method. In the communication between the two codes during coupled simulation, the fluid pressure, saturation, temperature and capillary pressure are transferred from the reservoir simulation code to the geomechanics code, which feedbacks updated variables, such as stresses, strains, porosity and permeability, to the reservoir simulation code in return. To optimize the communication process, a generic mesh generator was developed and added to the platform so that two identical computational meshes will be used in both reservoir and geomechanics models in a coupled simulation. The equation of state was significantly enhanced for modeling gas reservoir more appropriately. The development was verified and validated using four well-defined problems that are related to fluid diffusion, thermal conduction, thermal fluid conduction and convection, and fluid-geomechanics interaction, respectively. The first three problems were verified with analytical solutions and the fourth one was validated with laboratory measurements.

Improved Compaction Modeling in Reservoir Simulation and Coupled Rock Mechanics—Flow Simulation, With Examples From the Valhall Field

2009 ◽  
Vol 12 (02) ◽  
pp. 329-340 ◽  
Author(s):  
Øystein Pettersen ◽  
Tron Golder Kristiansen
Keyword(s):  
Rock Mechanics ◽  
Reservoir Simulation ◽  
Pore Volume ◽  
Traditional Approach ◽  
Fluid Pressure ◽  
Flow Simulation ◽  
Maximum Efficiency ◽  
Coupled Simulation ◽  
Processor Time ◽  
Flow Simulator

Summary In traditional flow simulation, compaction is modeled as a function of fluid pressure, whereas in reality, it is dependent on effective stress (e.g., mean effective and shear stress). Therefore, although compaction computed by a flow simulator may be correct on a regional average basis, the true variation throughout the reservoir (both spatial and temporal) cannot be accounted for by a traditional approach. A stress simulator (i.e., geomechanics model) honoring material properties, rock mechanical boundary conditions, and material-to-material interaction is needed to achieve this compaction. Especially for sands, chalk, and other weak materials, which in general, have a compaction-dependent permeability, the spatial variation of compaction may have a significant impact on the flow pattern. The industry standard approach for computing true compaction is by either doing a fully coupled simulation or by using partial coupling with pore-volume iterations, both typically being expensive in terms of computer processor time. For this reason, the simplified compaction calculations are often used in practice thus disregarding actual physics in the reservoir simulation. In this paper, we describe a procedure whereby a modified (pseudo) material definition is constructed and used to improve compaction calculations by the flow simulator. The construction is based on results from a simplified, coupled flow-stress simulation, typically consisting of three to six explicit stress steps. The resulting compaction field is comparable to the true one and represents a significant improvement over the traditional approach. This compaction state is the optimal input to the stress simulator in a coupled scheme and, therefore, assures the rock mechanics calculations can be performed with maximum efficiency. By using our suggested procedure, the pore-volume iterations in a coupled scheme are eliminated or significantly reduced, and the simulated reservoir state is accurate at all times--not only when stress simulations are performed. Our main goal is to reduce the total computer time in iterative-coupled simulations without loss of accuracy, especially focusing on two mechanistic models from the Valhall field, which is a highly compacting chalk reservoir in the North Sea. We also demonstrate benefits of using the procedure in a simplified form to increase accuracy in reservoir simulation for reservoirs in which coupled simulation is traditionally not seen as needed because of either a perceived lack of complexity or the computing costs. In this paper, we demonstrate that the developed construction methodology is general in use. Further, the maximum permitted difference between flow-simulator calculated compaction and true compaction (i.e., computed from strain using a geomechanics simulator) is user-controlled, such that by proper definition of this parameter, the coupled simulation in most cases can be guaranteed to converge at the first pore-volume iteration.

scholarly journals Integrating geophysical monitoring data into multiphase fluid flow reservoir simulation

2018 ◽  
Vol 2018 (1) ◽  
pp. 1-5
Author(s):  
Trevor P. Irons ◽  
Brian J.O.L. McPhserson ◽  
Nathan Moodie ◽  
Rich Krahenbuhl ◽  
Yaoguo Li
Keyword(s):  
Fluid Flow ◽  
Reservoir Simulation ◽  
Monitoring Data ◽  
Geophysical Monitoring ◽  
Multiphase Fluid Flow ◽  
Multiphase Fluid

Analysis of Single- and Two-Phase Flows in Turbopump Inducers

1967 ◽  
Vol 89 (4) ◽  
pp. 577-586 ◽  
Author(s):  
P. Cooper
Keyword(s):  
Equation Of State ◽  
Flow Field ◽  
Thermal Effects ◽  
Single Phase ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Recent Theory ◽  
Two Phase ◽  
Overall Efficiency

A model is developed for analytically determining pump inducer performance in both the single-phase and cavitating flow regimes. An equation of state for vaporizing flow is used in an approximate, three-dimensional analysis of the flow field. The method accounts for losses and yields internal distributions of fluid pressure, velocity, and density together with the resulting overall efficiency and pressure rise. The results of calculated performance of two sample inducers are presented. Comparison with recent theory for fluid thermal effects on suction head requirements is made with the aid of a resulting dimensionless vaporization parameter.

Gravity Drainage System: Investigation and Field Development Using Geological Modelling and Reservoir Simulation

2021 ◽  
Author(s):  
Obinna Somadina Ezeaneche ◽  
Robinson Osita Madu ◽  
Ishioma Bridget Oshilike ◽  
Orrelo Jerry Athoja ◽  
Mike Obi Onyekonwu
Keyword(s):  
Reservoir Simulation ◽  
Structural Control ◽  
History Matching ◽  
Drainage System ◽  
Production Performance ◽  
Gravity Drainage ◽  
Base Case ◽  
Proper Understanding ◽  
Field Development ◽  
Reservoir Performance

Abstract Proper understanding of reservoir producing mechanism forms a backbone for optimal fluid recovery in any reservoir. Such an understanding is usually fostered by a detailed petrophysical evaluation, structural interpretation, geological description and modelling as well as production performance assessment prior to history matching and reservoir simulation. In this study, gravity drainage mechanism was identified as the primary force for production in reservoir X located in Niger Delta province and this required proper model calibration using variation of vertical anisotropic ratio based on identified facies as against a single value method which does not capture heterogeneity properly. Using structural maps generated from interpretation of seismic data, and other petrophysical parameters from available well logs and core data such as porosity, permeability and facies description based on environment of deposition, a geological model capturing the structural dips, facies distribution and well locations was built. Dynamic modeling was conducted on the base case model and also on the low and high case conceptual models to capture different structural dips of the reservoir. The result from history matching of the base case model reveals that variation of vertical anisotropic ratio (i.e. kv/kh) based on identified facies across the system is more effective in capturing heterogeneity than using a deterministic value that is more popular. In addition, gas segregated fastest in the high case model with the steepest dip compared to the base and low case models. An improved dynamic model saturation match was achieved in line with the geological description and the observed reservoir performance. Quick wins scenarios were identified and this led to an additional reserve yield of over 1MMSTB. Therefore, structural control, facies type, reservoir thickness and nature of oil volatility are key forces driving the gravity drainage mechanism.

Physics of the Interaction of Ultrasonic Excitation With Nucleate Boiling

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Sreenath Krishnan ◽  
Sarit K. Das ◽  
Dhiman Chatterjee
Keyword(s):  
Mechanistic Model ◽  
Interactive Effect ◽  
Nucleate Boiling ◽  
Ultrasonic Frequency ◽  
Pressure Amplitude ◽  
Surface Parameter ◽  
Site Density ◽  
Multiphase Fluid Flow ◽  
Ultrasound Assisted ◽  
Multiphase Fluid

Physics of ultrasound-assisted augmentation of saturated nucleate boiling through the interaction of multiphase fluid flow is revealed in the present work. Different regimes of influence of ultrasound, ranging from augmentation to deterioration and even no effect, as reported in literature in a contradictory fashion, have been observed. However unlike the previous studies, here it has been clearly demonstrated that this apparent anomaly lies in the different natures of interactions between the influencing parameters like heat flux, ultrasonic frequency, and pressure amplitude. The present results clearly bring out an interactive effect of these operating parameters with surface parameter like surface roughness. A mechanistic model unifying all these parameters has been presented to explain quantitatively the physics of the interaction. The model-based predictions match experimental results quite well suggesting the validity of the hypothesis on liquid–vapor-surface interaction through the process of nucleation and its site density, on which the model is built, and thus revealing the underlying physics.

Sign in / Sign up

Export Citation Format

Share Document