scholarly journals A novel approach in extracting predictive information from water-oil ratio for enhanced water production mechanism diagnosis

2010 ◽  
Vol 50 (1) ◽  
pp. 567 ◽  
Author(s):  
Minou Rabiei ◽  
Ritu Gupta ◽  
Yaw Peng Cheong ◽  
Gerardo A. Sanchez Soto

Despite the advances in water shutoff technologies, the lack of an efficient diagnostic technique to identify excess water production mechanisms in oil wells is preventing these technologies being applied to deliver the desired results, which costs oil companies a lot of time and money. This paper presents a novel integrated approach for diagnosing water production mechanisms by extracting hidden predictive information from water-oil ratio (WOR) graphs and integrating it with static reservoir parameters. Two common types of excess water production mechanism (coning and channelling) were simulated where a wide range of cases were generated by varying a number of reservoir parameters. Plots of WOR against oil recovery factor were used to extract the key features of the WOR data. Tree-based ensemble classifiers were then applied to integrate these features with the reservoir parameters and build classification models for predicting the water production mechanism. Our results show high rates of prediction accuracy for the range of WOR variables and reservoir parameters explored, which demonstrate the efficiency of the proposed ensemble classifiers. Proactive water control procedures based on proper diagnosis obtained by the proposed technique would greatly optimise oil productivity and reduce the environmental impacts of the unwanted water.

SPE Journal ◽  
2020 ◽  
pp. 1-15
Author(s):  
Gang Li ◽  
Lifeng Chen ◽  
Meilong Fu ◽  
Lei Wang ◽  
Yadong Chen ◽  
...  

Summary Horizontal wells that are completed with slotted liners often suffer from a severe water-production problem, which is detrimental to oil recovery. It is because the annulus between the slotted liners and wellbore cannot be fully filled with common hydrogels with poor thixotropy, which determines the ultimate hydrogel filling shape in the annulus. This paper presents a novel hydrogel with high thixotropy to effectively control water production in horizontal wells. This study is aimed at evaluating the thixotropic performance, gelation time, plugging performance, and degradation performance. The thixotropic performance of the new hydrogel was also investigated by measuring its rheological properties and examining its microstructures. It was found that the new hydrogel thickened rapidly after shearing. Its thixotropic recovery coefficient was 1.747, which was much higher than those of traditional hydrogels. The gelation time can be controlled in the range of 2 to 8 hours by properly adjusting the concentrations of the framework material, crosslinker, and initiator. The hydrogel could be customized for mature oil reservoirs, at which it was stable for more than 90 days. A series of laboratory physical modeling tests showed that the breakthrough pressure gradient and the plugging ratio of the hydrogel in sandpacks were higher than 9.5 MPa/m and 99%, respectively. At the same time, it was found that the hydrogel has good degradation properties; the viscosity of the hydrogel breaking solution was 4.22 mPa·s. Freeze-etching scanning-electron-microscopy examinations indicated that the hydrogel had a uniform grid structure, which can be broken easily by shear and restored quickly. This led to the remarkable thixotropic performance. The formation of a metastable structure caused by the electrostatic interaction and coordination effect was considered to be the primary reason for the high thixotropy. The successful development of the new thixotropic hydrogel not only helps to control water production from the horizontal wells, but also furthers the thixotropic theory of hydrogel. This study also provides technical guidelines for further increasing the thixotropies of drilling fluids, fracturing fluids, and other enhanced-oil-recovery polymers that are commonly used in the petroleum industry.


Author(s):  
Gulnaz Zh. Moldabayeva ◽  
Raikhan T. Suleimenova ◽  
Sairanbek M. Akhmetov ◽  
Zhanar B. Shayakhmetova ◽  
Gabit E. Suyungariyev

This paper discusses topical problems of further effective development of depleted oil fields (DOF) to increase their final oil recovery on the example of the oil field in Western Kazakhstan. Further exploitation of fields using waterflooding becomes unprofitable. At the same time, on average at these facilities, at least 50% of the reserves will remain unrecovered. Most of the oil fields in the Republic of Kazakhstan are at the late and final stages of development, which is characterised by an increase in the share of hard-to-recover oil reserves, a decrease in annual oil withdrawals, and a high water cut of the produced oil. Therefore, the problems of improving the technology aimed at reducing the volume of associated water production and increasing oil recovery from partially flooded deposits is very urgent. With an increase in the well density, the degree of field drilling and aging of the well stock, the work with the current declining well stock remains a very topical issue. Improving the efficiency of diagnostics and the systematic selection of wells for repair and isolation works is an important element for rationalising field development in the current conditions of profit variance in the oil and gas industry. The methods of bottomhole zone treatment also implement a deflecting effect on filtration flows. Therefore, this method includes a wide range of geological and technical measures: down-spacing; water production restraining; conformance control of injectivity profiles; forced production; all types of mechanical, thermochemical and thermal technologies. Consider a number of geological and technical measures that perform the tasks of occupational safety rules. Geological and statistical models are proposed for diagnosing wells for a premature increase of water production using factor analysis calculations for base production and Hall plots. Results. The degree of temperature influence of the primary components of the compounds on the rheology, filtration characteristics, and stability of inverted emulsions was determined. The classification of oil loss factors was carried out based on the results of downhole analysis and oil production losses were determined. Geological and statistical models for well diagnostics for premature increase in water production were built using factor analysis calculations for base production and Hall plots.


2021 ◽  
Vol 5 (1) ◽  
pp. 1-12
Author(s):  
Shabibi M

Excess water production is one of the limiting factors in oil recycling, which reduces production efficiency and leaves a lot of costs. In this paper, water control methods were investigated in order to find the best way to control excess water production. For this propos first, a real model was made using the history match of one of Iran's oil fields that produced excess water because of canalization and different simulation scenarios for gel treatment have been investigated. In the study of more scenarios, comparing the water production in the early times and later injecting the gel, the percentage of water production for injection in the early times has been further reduced. When the gel is injected for a fixed period of 6 months in the production and injection wells The best results for lowering the rate of production water are obtained when the gel is injected simultaneously into the injection and production well, which reduces the water production rate by 12,000 barrels, and the best oil production efficiency for when simultaneous injection is performed in the production and injection well. The best treatment method is injection of high concentration gel in the early stages of water production and it's better to inject gel in deeper wells.


2011 ◽  
Vol 51 (1) ◽  
pp. 577
Author(s):  
Fadi Ali ◽  
Hassan Bahrami ◽  
Po Chu Byfield ◽  
Jijin Mathew

Water breakthrough and the flow of water towards the perforations of a producing well increase production operation costs and influence overall recovery efficiency. To control water production, a downhole water sink can be used in which a well is completed in both oil and water zones. Water is produced from an interval in water zone, which can result in the same pressure drop below water oil contact (WOC) as the pressure drop created by oil or gas production. This system can reduce water production through oil zone perforations. Water produced from water zone perforations can then be injected in deeper aquifers intervals. This technology can also be implemented in horizontal and multi-lateral wells to further increase hydrocarbon recovery with fewer water problems. This study examines the use of horizontal downhole water sink technology to increase oil recovery. Numerical simulation is performed to optimise oil production and water control in a multi-layered oil reservoir, by optimising the direction of drilling and the downhole water sink method. Different scenarios of drilling direction and horizontal down-hole water sink method are examined to identify the option that provides maximum oil recovery. The simulation results showed that drilling horizontal wells in a north–south direction resulted in higher well productivity, and that wells with significantly more water production problems can be controlled using a horizontal downhole water sink.


Author(s):  
A. A. Kazakov ◽  
V. V. Chelepov ◽  
R. G. Ramazanov

The features of evaluation of the effectiveness of flow deflection technologies of enhanced oil recovery methods. It is shown that the effect of zeroing component intensification of fluid withdrawal leads to an overestimation of the effect of flow deflection technology (PRP). Used in oil companies practice PRP efficiency calculation, which consists in calculating the effect on each production well responsive to subsequent summation effects, leads to the selective taking into account only the positive components of PRP effect. Negative constituents — not taken into account and it brings overestimate over to overstating of efficiency. On actual examples the groundless overstating and understating of efficiency is shown overestimate at calculations on applied in petroleum companies by a calculation.


2018 ◽  
Vol 55 (3) ◽  
pp. 252-257 ◽  
Author(s):  
Derong Xu ◽  
Wanli Kang ◽  
Liming Zhang ◽  
Jiatong Jiang ◽  
Zhe Li ◽  
...  

2004 ◽  
Vol 4 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
A.R. Costa ◽  
M.N. de Pinho

Membrane fouling by natural organic matter (NOM), namely by humic substances (HS), is a major problem in water treatment for drinking water production using membrane processes. Membrane fouling is dependent on membrane morphology like pore size and on water characteristics namely NOM nature. This work addresses the evaluation of the efficiency of ultrafiltration (UF) and Coagulation/Flocculation/UF performance in terms of permeation fluxes and HS removal, of the water from Tagus River (Valada). The operation of coagulation with chitosan was evaluated as a pretreatment for minimization of membrane fouling. UF experiments were carried out in flat cells of 13.2×10−4 m2 of membrane surface area and at transmembrane pressures from 1 to 4 bar. Five cellulose acetate membranes were laboratory made to cover a wide range of molecular weight cut-off (MWCO): 2,300, 11,000, 28,000, 60,000 and 75,000 Da. Severe fouling is observed for the membranes with the highest cut-off. In the permeation experiments of raw water, coagulation prior to membrane filtration led to a significant improvement of the permeation performance of the membranes with the highest MWCO due to the particles and colloidal matter removal.


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