Browsing by Subject "SIMULATION"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Empirical modeling and simulation of edgewater cusping and coning(Texas A&M University, 2008-10-10) Ayeni, Kolawole BabajideIn many cases, it is important to predict water production performance of oil wells early in, or maybe before, their production life. In as much as oil field water is important for pressure maintenance purposes and displacement of oil towards the perforation of the producing well, excessive water production leads to increased cost. In the case when no provision is made, it represents a significant liability. The case considered here is a well producing from a monocline with an edge-water aquifer. Although such problems can be computed with reservoir simulation, the objective of this work was to develop an empirical method of making water production predictions. The reservoir model was described as a single well producing from the top of a monocline drainage block with water drive from an infinite-acting aquifer. During the reservoir simulation runs, water would cusp and cone into the well, increasing water production and decreasing oil production. A number of simulation runs were made, varying eleven model variables. Typical model variables include dip angle, formation thickness and production rate. For each run a modified Addington-style plot was made. The relationship between each model parameter and three graphical variables was used to develop the set of empirical correlations. The empirical correlations developed were integrated with some derived equations that relate important reservoir parameters and incorporated into a computer program. The developed correlations and program can be used to carry out sensitivity analysis to evaluate various scenarios at the early planning stages when available reservoir data are limited. This gives a quick and easy method for forecasting production performance with an active edge-water drive. Furthermore, the approach developed in the research can be applied to other water production problems in other fields/reservoirs. The developed program was validated and used to evaluate synthetic and field cases. Overall, a good match was achieved.Item Simulation of fracture fluid cleanup and its effect on long-term recovery in tight gas reservoirs(2009-05-15) Wang, YilinIn the coming decades, the world will require additional supplies of natural gas to meet the demand for energy. Tight gas reservoirs can be defined as reservoirs where the formation permeability is so low (< 0.1 md) that advanced stimulation technologies, such as large volume fracture treatments, are required before a reasonable profit can be made. Hydraulic fracturing is one of the best methods to stimulate a tight gas well. Most fracture treatments result in 3-6 fold increases in the productivity index. However, if one computes the effective fracture length of most wells, we usually find that the effective length is less than the designed propped fracture length. The ?propped length? is the distance down the fracture from the wellbore where proppants have been placed at a high enough concentration to ?prop open? the fracture. The ?effective length? is the portion of the propped fracture that cleans up and allows gas flow from the reservoir into the fracture then down the fracture to the wellbore. Whenever the effective length is much shorter than the designed propped length, several reasons must be evaluated to determine what might have occurred. For example, the difference could be caused by one or more of the following issues: insufficient fracture fluid cleanup, proppant settling, proppant embedment, proppant crushing, or poor reservoir continuity. Although all these causes are possible, we believe that fracture fluid cleanup issues may be the most common reason the industry fails to achieve the designed propped fracture length in most cases. In this research, we have investigated fracture fluid cleanup problems and developed a better understanding of the issues involved which hopefully will lead to ways to improve cleanup. Fracture fluid cleanup is a complex problem, that can be influenced by many parameters such as the fluid system used, treatment design, flowback procedures, production strategy, and reservoir conditions. Residual polymer in the fracture can reduce the effective fracture permeability and porosity, reduce the effective fracture half-length, and limit the well productivity. Our ability to mathematically model the fundamental physical processes governing fluid recovery in hydraulic fractures in the past has been limited. In this research, fracture fluid damage mechanisms have been investigated, and mathematical models and computer codes have been developed to better characterize the cleanup process. The codes have been linked to a 3D, 3-phase simulator to model and quantify the fracture fluid cleanup process and its effect on long-term gas production performances. Then, a comprehensive systematic simulation study has been carried out by varying formation permeability, reservoir pressure, fracture length, fracture conductivity, yield stress, and pressure drawdown. On the basis of simulation results and analyses, new ways to improve fracture fluid cleanup have been provided. This new progress help engineers better understand fracture fluid cleanup, improve fracture treatment design, and increase gas recovery from tight sand reservoirs, which can be extremely important as more tight gas reservoirs are developed around the world.Item Simulation study of areal sweep efficiency versus a function of mobility ratio and aspect ratio for staggered line-drive waterflood pattern(Texas A&M University, 2008-10-10) Guliyev, RuslanPattern geometry plays a major role in determining oil recovery during waterflooding and enhanced oil recovery operations. Although simulation is an important tool for design and evaluation, the first step often involves rough calculations based upon areal sweep efficiencies of displacements in homogeneous, two-dimensional, scaled, physical models. These results are available as a function of the displacement pattern and the mobility ratio M. In this research I studied the effect of mobility ratios on five-spot and staggered waterflood patterns behavior for areal (2D) displacement in a reservoir that is homogeneous and isotropic containing no initial gas saturation. Simulation was performed using Eclipse 100 simulator. Simulation results are presented as graphs of areal sweep efficiency at breakthrough versus Craig mobility ratio for various staggered line drive aspect ratios. The main results of the study are presented in the form of a graph of areal sweep efficiency at breakthrough as a function of staggered line drive aspect ratio. This should enable engineers to utilize the results in a convenient manner.Item The Creation of a Courtyard Microclimate Thermal Model for the Analysis of Courtyard Houses(2009-05-15) Bagneid, AmrThis research is an effort to revive the use of courtyard housing clusters in a modern context, which were traditionally known for their distinctive passive cooling performance. The goal is to promote energy efficient design in hot-arid climates and temperate climates by reviving the use of courtyard housing clusters. The objective is to introduce a simplified thermal model that simulates the courtyard microclimate, which has been tested with actual field data from a case study house. The case study house was an indigenous courtyard house in Cairo, Egypt that was built around 1400 AD, having an area of about 5000 sq. ft. (i.e., comparable to the size of a single-family house) with heavy thermal mass. To accomplish this, a finite difference thermal network model was created for simulating the case study courtyard microclimate. The finite difference (FD) model showed validity as it calibrated very well against field data. This model allowed running parametric sensitivity studies on the courtyard thermal simulation factors: air change rates, thermal mass, solar absorption, wall and floor emissivity, ground temperature, cloud cover, and ambient air temperature. The results of the parametric analysis showed that the model was sensitive to variations in the air change rates, solar absorptivity, and ambient air (rooftop) temperatures. The courtyard microclimate model was then used in combination with thermal simulation software (DOE-2) to analyze the thermal performance of the case study house, which was also validated with measured field data. The DOE-2 program showed limitations when applied to the case study, non-conditioned building, and showed a convergence deficiency when simulating high thermal mass buildings. The DOE-2 program did not perform well in simulating the impact of changes in thermal mass as compared to previous published field measurements. The proposed combinations of the FD microclimate/DOE-2 simulation did not perform as well as the FD microclimate simulation. The FD courtyard microclimate simulation model with onsite data for calibration is advantageous in introducing for the first time the ability to perform computer simulations on any number of proposed courtyard design alternatives for reaching optimum thermal performance.Item The use of large plot rainfall simulation to investigate(Texas A&M University, 2006-04-12) Sorenson, Joshua RussellIn this study, large scale rainfall simulation was used to evaluate runoff generation from canopy and intercanopy areas within an ashe juniper woodland of the Edwards Plateau. One 3 x 12 m site was established beneath the canopy of mature ashe juniper trees and two sites were established in intercanopy areas. At the base of each plot a trench was constructed for capturing and monitoring shallow subsurface flow. Rainfall simulations on the juniper site produced little surface runoff even though rainfall intensity exceeded 145mm/hour on some occasions. A total of 82.6% of the water applied to the juniper dominated site was accounted for as shallow subsurface flow. The dynamic nature of shallow subsurface flow indicate this process is driven chiefly by macropore flow. On the intercanopy site, 12.67% of the water left the site as surface runoff and ≤3% left as shallow subsurface flow. Large root channels and conduits, which were not present on the intercanopy site, within the soil may promote shallow subsurface flow beneath the juniper canopy. This study is the first to document and suggest shallow subsurface flow occurs on Texas rangelands. The results of this experiment indicate shallow subsurface flow is an important mode of runoff generation on the Edwards Plateau.