Mathematical Modeling of Fluid Flow to Unconventional Oil Wells With Radial Fractures and Its Testing With Field Data

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Xuejun Hou ◽  
Xiaohui Zhang ◽  
Boyun Guo
Keyword(s):  
Fluid Flow ◽  
Case Studies ◽  
High Energy ◽  
Well Performance ◽  
Productivity Improvement ◽  
Fracture Angle ◽  
Well Stimulation ◽  
Second Fracture ◽  
Lower Permeability ◽  
Transient Data

Radial fractures are created in unconventional gas and oil reservoirs in modern well stimulation operations such as hydraulic refracturing (HRF), explosive fracturing (EF), and high energy gas fracturing (HEGF). This paper presents a mathematical model to describe fluid flow from reservoir through radial fractures to wellbore. The model can be applied to analyzing angles between radial fractures. Field case studies were carried out with the model using pressure transient data from three typical HRF wells in a lower-permeability reservoir. The studies show a good correlation between observed well performance and model-interpreted fracture angle. The well with the highest productivity improvement by the HRF corresponds to the interpreted perpendicular fractures, while the well with the lowest productivity improvement corresponds to the interpreted conditions where the second fracture is much shorter than the first one or where there created two merged/parallel fractures. Result of the case studies of a tight sand reservoir supports the analytical model.

Thermal Performance Comparison between Single and Double Storey Terrace Houses in Melaka, Malaysia

2016 ◽  
Vol 835 ◽  
pp. 416-422
Author(s):  
Fahanim Abdul Rashid ◽  
Asrul Mahjuddin Ressang Aminuddin ◽  
Norafida Ab. Ghaffar
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Case Studies ◽  
Thermal Performance ◽  
High Energy ◽  
Performance Comparison ◽  
Building Envelope ◽  
The Difference ◽  
Economic Developments ◽  
Housing Typology

Over the past decade many studies were conducted to investigate the thermal performance of terraced houses in Malaysia. It was found that this housing typology failed to address the need for thermal comfort and alternatives to the narrow frontage with deep plan have been proposed with simulated good thermal performance. Although this is good progress for new generation of terraced houses, millions of units of terraced houses are still in use and new units with the outdated existing plans continued to get built due to consistently very high demand due to progressive urbanisation and rapid economic developments. Therefore, it is imperative that the thermal comfort issue for existing terraced houses is dealt with and through this paper a comparison between single and double storey terraced houses is made through analysis of indoor environmental monitoring (ambient temperature, relative humidity and air velocity) of two (2) selected case studies in Merlimau, Melaka. Contrary to popular belief, it is found that there is no statistical difference between both sets of indoor temperature and relative humidity between the case studies. This finding is indicative of the consistent and stable temporal temperature highs and lows in a 24 hour cycle despite the difference in indoor volume and distance between the ground floor and the roof cavity. Much of the reason is due to the materiality of the terraced houses construction and unsealed and uninsulated building envelope. Therefore, further research into improving the thermal performance of existing terraced houses of any typology have to be conducted to allow thermal comfort and to reduce reliance on high energy consuming air-conditioning.

scholarly journals Self-Potential Studies in Volcanic Environments: A Cheap and Efficient Method for Multiscale Fluid-Flow Investigations

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
N. Grobbe ◽  
S. Barde-Cabusson
Keyword(s):  
Electrical Resistivity ◽  
Fluid Flow ◽  
Case Studies ◽  
Potential Method ◽  
Hydrothermal Systems ◽  
Geochemical Data ◽  
Data Types ◽  
Spatial And Temporal Scales ◽  
Cooling Behavior ◽  
Self Potential

We demonstrate the value of using the self-potential method to study volcanic environments, and particularly fluid flow in those environments. We showcase the fact that self-potential measurements are a highly efficient way to map large areas of volcanic systems under challenging terrain conditions, where other geophysical techniques may be challenging or expensive to deploy. Using case studies of a variety of volcano types, including tuff cones, shield volcanoes, stratovolcanoes, and monogenetic fields, we emphasize the fact that self-potential signals enable us to study fluid flow in volcanic settings on multiple spatial and temporal scales. We categorize the examples into the following three multiscale fluid-flow processes: (1) deep hydrothermal systems, (2) shallow hydrothermal systems, and (3) groundwater. These examples highlight the different hydrological, hydrothermal, and structural inferences that can be made from self-potential signals, such as insight into shallow and deep hydrothermal systems, cooling behavior of lava flows, different hydrogeological domains, upwelling, infiltration, and lateral groundwater and hydrothermal fluid flow paths and velocities, elevation of the groundwater level, crater limits, regional faults, rift zones, incipient collapse limits, structural domains, and buried calderas. The case studies presented in this paper clearly demonstrate that the measured SP signals are a result of the coplay between microscale processes (e.g., electrokinetic, thermoelectric) and macroscale structural and environmental features. We discuss potential challenges and their causes when trying to uniquely interpret self-potential signals. Through integration with different geophysical and geochemical data types such as subsurface electrical resistivity distributions obtained from, e.g., electrical resistivity tomography or magnetotellurics, soil CO2 flux, and soil temperature, it is demonstrated that the hydrogeological interpretations obtained from SP measurements can be better constrained and/or validated.

scholarly journals Assessing the Needs to Incorporate Completion Details in a Petroleum Reservoir Simulation Model

2015 ◽  
Vol 8 (1) ◽  
pp. 16-28 ◽  
Author(s):  
Liang-Biao Ouyang
Keyword(s):  
Fluid Flow ◽  
Simulation Model ◽  
Simulation Study ◽  
Reservoir Simulation ◽  
High Rate ◽  
Petroleum Reservoir ◽  
Well Performance ◽  
Well Completion ◽  
Reservoir Permeability ◽  
Reservoir Simulation Model

Most of the current research and commercial reservoir simulators lack the capability to handle complex completion details like perforation tunnels in a simulation study. In most common applications, the simplified handling of completion complexity in reservoir simulations is not expected to introduce significant error in simulation results. However, it has been found that under certain circumstances, especially in high rate wells that have become more and more common in deepwater oil and profilic gas development, exclusion of the complex completion details in a reservoir simulation model would lead to nontrivial errors. New equations have been proposed to assess the needs to incorporate completion details in a reservoir simulation study based on the understanding of the fluid flow in a formation, the fluid flow along a wellbore and the fluid flow through perforation tunnels if exist. A series of sensitivity studies with different completion options under different flow and reservoir environments has been conducted to provide some guidance to improve well performance prediction through reservoir simulation. Impacts of key parameters like perforation density, perforation diameter, perforation length, wellbore length, borehole diameter, well completion configuration, well placement, reservoir permeability, reservoir heterogeneity, pressure drawdown, etc, have also been investigated.

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