Generalized empirical correlations have been developed to predict, (1) critical oil rate, and (2) water breakthrough time in vertical and horizontal wells. Water coning is a serious problem in many producer wells, which increases the cost of producing operations, and reduces the efficiency of the depletion mechanism and the overall recovery. A numerical simulation was used to analyze the most relevant fluid and reservoir parameters that affect water coning using a 3-D radial vertical well model and a 3-D Cartesian horizontal well model. The method of determining the average oil column height below perforations at breakthrough (hwb), was developed from a stepwise procedure. First, a number of simulation runs was made to investigate the coning performance at different reservoir and fluid properties for both vertical and horizontal wells. Then, for each simulation run, water oil ratio (WOR) was plotted against of average oil column height below perforations (hbp), on a semi-log scale, from which (hwb) was determined. Once the (hwb) data was obtained for all the simulation runs, regression analysis was then used to define the relationship between (hwb) and various reservoir and fluid properties. An extensive parametric sensitivity analysis of water coning was made to provide data for developing a predictive correlation of calculating breakthrough time and breakthrough height as a function of various reservoir and fluid properties. The simulation outputs are used to develop empirical water coning correlations to predict critical oil rate, and water breakthrough time for vertical and horizontal wells. The parameters were grouped together based on the basic flow equations and the grouping was confirmed by regression analysis. Several field examples from CTH1 area of Hassi R'mel field in Algeria will be discussed. Introduction Water and gas coning are serious problems in many oil field applications, where the production of water and gas from a thin oil reservoir is a common occurrence, which increases the cost of producing operations, and reduces the efficiency of the depletion mechanism and the overall recovery. We will deal with one cause of this production namely, coning. One of the main reasons for coning is pressure drawdown. A vertical well exhibits a large pressure drawdown near the wellbore, whereas horizontal well exhibits minimum pressure drawdown, thus horizontal wells provide option whereby pressure drawdown can be minimized, coning tendencies can be minimized, and high oil production rates can be achieved. Two forces control the mechanism of water coning:dynamic flow force (applied force), andgravity force. In water-coning systems, the upward dynamic force due to wellbore drawdown causes water at the bottom of the oil zone to rise to a certain height at which the dynamic force is balanced by the weight of water beneath this point. As the radial distance from the wellbore increases, pressure drawdown and upward dynamic force caused by it decrease, and the height of the balance-point decreases along the radial direction. Therefore, the locus of the balance point is a stable cone-shaped water oil interface. Oil flows above the interface, while water remains stationary below the interface. As the production rate is increased, the height of the cone above the original oil-water contact also increases, until at a certain production rate, the cone becomes unstable and water is produced into the well.
Generalized empirical correlations have been developed to predict (1) critical oil rate and (2) water breakthrough time in vertical and horizontal wells. Water coning is a serious problem in many producing oil wells, which increases the cost of producing operations and reduces the overall oil recovery. A numerical simulator was used to analyze the most relevant fluid properties and reservoir parameters that affect water coning using a 3-D radial vertical well model and a 3-D Cartesian horizontal well model.A stepwise procedure was developed to determine the average oil column height below perforations at breakthrough (hwb) for various water oil ratio, fluid properties, and reservoir parameters. Several simulation runs were performed to determine the effect of the various parameters on water coning. Regression analysis was used to develop relationship between (hwb) and the various variables. Results of the simulation runs showed that coning tendency is more severe in heavy oil reservoirs and less severe in reservoirs with low water-oil mobility ratios. Furthermore, results showed that the use of horizontal wells can significantly reduce water coning, improve ultimate oil recovery, and increase water breakthrough time compared to vertical wells.An extensive parametric sensitivity analysis was performed to provide input data for developing a predictive correlation needed to calculate breakthrough time and height as function of fluid properties and reservoir parameters. The simulation outputs were used to develop empirical water coning correlations to predict critical oil rate and water breakthrough time for vertical and horizontal wells. The parameters were grouped based on the regression analysis. The developed empirical correlations are illustrated with several field examples from Hassi R'Mel oil field in Algeria
A considerable number of studies have been conducted to optimize the perforated completions for horizontal wells, but very few of them took into account the effect of reservoir heterogeneity and coning problems in the completion design. One of the most relevant work directly related to this topic is the one developed by Goode and Wilkinson7. They have presented an analytical solution for the performance of partially completed horizontal well. Their model, however, has two major limitations:it considers the reservoir as homogeneous and ignores heterogeneity, andit does not take into account the water and gas coning effects. In this study, a numerical solution has been developed to optimize the perforated completions for horizontal wells in a heterogeneous reservoir laying between a large gas cap and an active aquifer (double coning problem). Another objective of this study was to examine the performance of various perforation schemes for horizontal wells in Hassi R'mel oil Rim using reservoir simulation. Since the capability of the numerical simulators to model a horizontal well performance is largely controlled by the quality of the geological description of the reservoir, therefore, a reservoir characterization based on geological (sedimentary) units was performed on the A-Sand reservoir of Hassi R'mel oil Rim. The simulation modeling in this study was undertaken in two large parts. First, a sensitivity analysis was conducted to investigate the effects of the most relevant reservoir parameters on the horizontal well performance for different perforation schemes. This allowed us to examine the effect of the perforation length and its distribution and to find the optimum perforation scheme for horizontal wells in Hassi R'mel oil Rim. Second, the simulation modeling was involved in a real case where the performance of the well HRZ-09 was a concern. The reason for taking this well as a case study is that it was completed non-conventionally using the Inverted High Angle technique. This completion led us to investigate the possibility of perforating the slanted section of the well, in addition to the horizontal section (Double perforation scheme). As a result of this study, correlation curves have been generated to optimize the perforated completions for horizontal wells in Hassi R'mel oil Rim. It has also been found that the optimum perforation scheme for horizontal wells in Hassi R'mel oil Rim corresponds to the case of 60% uniformly distributed perforation. From the case study, it was found that there is no extra-recovery to be expected from the double perforation of the well HRZ-09. Moreover, such perforation scheme yields much higher gas-oil ratio in comparison to the actual perforation case. This result was confirmed by an economic analysis performed on three proposed perforation schemes. Introduction Horizontal wells are one of the most important strategic tools in petroleum exploitation. As a result of the advances in drilling and completion technologies in the last two decades, the efficiency and economy of horizontal well have significantly increased. Today, horizontal well technology is applied more often and in many different types of formations. The state of art applications of the horizontal well technology require better completion designs to optimize production, long-term economics, and ultimate recoverable reserves. Perforating is a common method of well completion. The performance of perforated completion generally depends on the perforation length and its distribution along the horizontal well, perforation density (shots per foot), phasing (angular separation between neighboring perforations), depth of penetration, and diameter of the individual perforations. The numerical simulation provides a powerful tool to investigate the performance of perforated completions.
TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe purpose of this work is to develop a new method suitable for hand calculation. Simulation is shown to be a cumbersome process to investigate and predict optimum oil rate based on maximizing economic recovery, and breakthrough time for both vertical and horizontal wells.Since the early days, several experiments and mathematical analyses were conducted to solve coning problems, since the production of water and gas increase the cost of producing operations, reduce the efficiency of the depletion mechanism, and the overall recovery. One of the basic conclusions of many analyses was if oil is produced at a sufficiently low rate, coning of water and gas can be avoided, and only oil is produced. This low rate is called critical oil rate.These different theoretical correlations are conflicting and give different answers, probably due to the different assumptions each of them involves, and many times the critical rates are too low, and for economic reasons, a well is frequently produced in field operations at a rate above critical rate. This results in production of water, gas as well as oil, which could results in a low economic recovery.To overcome this problem, an extensive parametric sensitivity analysis of the various reservoir and fluid properties on water and gas coning was investigated and performed using numerical simulation to provide input data for developing a new predictive correlation needed to calculate breakthrough time and optimum oil rate based on maximizing economic recovery for both vertical and horizontal wells. The parameters were grouped based on the regression analysis.The new method is more robust, where the developed empirical correlations were tested and found to be reliable and closely accurate in estimating optimum oil rate to be used for a well in field operations. These correlations are illustrated with several field examples from Hassi R'mel field, Algeria, where calculated and observed, show satisfactory agreement of correlations with production data.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.