Effect of salinity and temperature on water cut determination in oil reservoirs

2003 ◽  
Vol 40 (3-4) ◽  
pp. 177-188 ◽  
Author(s):  
Abdel-Mohsen O. Mohamed ◽  
Maisa El Gamal ◽  
Abdulrazag Y. Zekri
Keyword(s):  
Oil Reservoirs ◽  
Water Cut

scholarly journals A New Method of Plugging the Fracture to Enhance Oil Production for Fractured Oil Reservoir using Gel Particles and the HPAM/Cr3+ System

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 446 ◽  
Author(s):  
Lei Zhang ◽  
Nasir Khan ◽  
Chunsheng Pu
Keyword(s):  
Oil Recovery ◽  
Oil Production ◽  
Oil Reservoirs ◽  
New Method ◽  
Water Flooding ◽  
Whole Process ◽  
Gel Particles ◽  
The Matrix ◽  
Water Cut ◽  
Enhance Oil Recovery

Due to the strong heterogeneity between the fracture and the matrix in fractured oil reservoirs, injected water is mainly moved forward along the fracture, which results in poor water flooding. Therefore, it is necessary to reduce the water cut and increase oil production by using the conformance control technology. So far, gel particles and partially hydrolyzed polyacrylamide (HPAM)/Cr3+ gel are the most common applications due to their better suitability and low price. However, either of the two alone can only reduce the conductivity of the fracture to a certain extent, which leads to a poor effect. Therefore, to efficiently plug the fracture to enhance oil recovery, a combination of gel particles and the HPAM/Cr3+ system is used by laboratory tests according to their respective advantages. The first step is that the gel particles can compactly and uniformly cover the entire fracture and then the fracture channel is transformed into the gel particles media. This process can enhance the oil recovery to 18.5%. The second step is that a suitable HPAM/Cr3+ system based on the permeability of the gel particles media is injected in the fractured core. Thus, the fracture can be completely plugged and the oil in the matrix of the fractured core can be displaced by water flooding. This process can enhance oil recovery to 10.5%. During the whole process, the oil recovery is increased to 29% by this method. The results show that this principle can provide a new method for the sustainable and efficient development of fractured oil reservoirs.

scholarly journals Simulation of High Water-Cut in Tight Oil Reservoirs during Cyclic Gas Injection

2019 ◽  
Author(s):  
Chi Zhang ◽  
Ye Tian ◽  
Yizi Shen ◽  
Bowen Yao ◽  
Yu-Shu Wu
Keyword(s):  
Gas Injection ◽  
High Water ◽  
Oil Reservoirs ◽  
Tight Oil ◽  
Tight Oil Reservoirs ◽  
High Water Cut ◽  
Water Cut

A Study on a Copolymer Gelant With High Temperature Resistance for Conformance Control

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Lei Zhang ◽  
Cheng Jing ◽  
Jing Liu ◽  
Khan Nasir
Keyword(s):  
High Temperature ◽  
Oil Recovery ◽  
Oil Reservoirs ◽  
Conformance Control ◽  
Temperature Resistance ◽  
High Temperature Resistance ◽  
Long Time ◽  
Stable Performance ◽  
Water Cut ◽  
Hydrolyzed Polyacrylamide

Due to the limited temperature resistance, the deep conformance control technology of using the conventional hydrolyzed polyacrylamide (HPAM) gel failed to enhance oil recovery in high-temperature heterogeneous oil reservoirs. Therefore, it is necessary to develop a gelant with high temperature resistance to meet the demands of increasing oil production and decreasing water cut in high-temperature heterogeneous oil reservoirs. In this paper, a copolymer is first synthesized by the method of inverse emulsion polymerization using 2-acrylamide-2-tetradecyl ethyl sulfonic acid (AMC16S), acrylamide (AM), and acrylic acid (AA). The developed copolymer has a highly branching skeleton and can resist temperature up to 100 °C. And then, a gelant with high temperature resistance and good shear resistance can be formed by mixing a certain proportion of the developed copolymer and polyethyleneimine (PEI). After the controllable gelation, a copolymer gel is formed and the formed gel can maintain the stable performance for a long time in the high-temperature environment. Experimental results show that the developed gelant can be applied in the conformance control of high-temperature heterogeneous oil reservoir.

Pressure Maintenance and Improving Oil Recovery by Means of Immiscible Water-Alternating-CO2 Processes in Thin Heavy-Oil Reservoirs

2013 ◽  
Vol 16 (01) ◽  
pp. 60-71 ◽  
Author(s):  
Sixu Zheng ◽  
Daoyong Yang
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
Oil Production ◽  
Horizontal Wells ◽  
Operating Conditions ◽  
Oil Reservoirs ◽  
Oil Saturation ◽  
Water Alternating Gas ◽  
Heavy Oil Reservoirs ◽  
Water Cut

Summary Techniques have been developed to experimentally and numerically evaluate performance of water-alternating-CO2 processes in thin heavy-oil reservoirs for pressure maintenance and improving oil recovery. Experimentally, a 3D physical model consisting of three horizontal wells and five vertical wells is used to evaluate the performance of water-alternating-CO2 processes. Two well configurations have been designed to examine their effects on heavy-oil recovery. The corresponding initial oil saturation, oil-production rate, water cut, oil recovery, and residual-oil-saturation (ROS) distribution are examined under various operating conditions. Subsequently, numerical simulation is performed to match the experimental measurements and optimize the operating parameters (e.g., slug size and water/CO2 ratio). The incremental oil recoveries of 12.4 and 8.9% through three water-alternating-CO2 cycles are experimentally achieved for the aforementioned two well configurations, respectively. The excellent agreement between the measured and simulated cumulative oil production indicates that the displacement mechanisms governing water-alternating-CO2 processes have been numerically simulated and matched. It has been shown that water-alternating-CO2 processes implemented with horizontal wells can be optimized to significantly improve performance of pressure maintenance and oil recovery in thin heavy-oil reservoirs. Although well configuration imposes a dominant impact on oil recovery, the water-alternating-gas (WAG) ratios of 0.75 and 1.00 are found to be the optimum values for Scenarios 1 and 2, respectively.

scholarly journals Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in Kazakhstan

2020 ◽  
Vol 12 (1) ◽  
pp. 1736-1749
Author(s):  
Jincai Wang ◽  
Zifei Fan ◽  
Lun Zhao ◽  
Li Chen ◽  
Jun Ni ◽  
...  
Keyword(s):  
High Water ◽  
High Viscosity ◽  
Oil Wells ◽  
Oil Reservoirs ◽  
Low Viscosity ◽  
Well Pattern ◽  
Remaining Oil ◽  
Oil Water ◽  
High Water Cut ◽  
Water Cut

Abstract After a sandstone oilfield enters the high water-cut period, the viscosity of crude oil has an important influence on remaining oil distribution and waterflooding characteristics under the same factors of, e.g., reservoir quality and development methods. Based on a comprehensive interpretation of the waterflooded layers in new oil wells, physical simulation experiments, and reservoir numerical simulations, we analyzed the waterflooding laws of a high water-cut sandstone reservoir with different oil viscosities in Kazakhstan under the same oil production speed, and we clarified the remaining oil potential of reservoirs with different viscosities and proposed corresponding development measures. The results show that low-viscosity oil reservoirs (1 mPa s) have uniform waterflooding, thick streamlines, small waterflooding areas, and low overall waterflooding degrees because of their homogeneous oil–water viscosities. However, within waterflooded areas, the reservoirs have high oil displacement efficiencies and high waterflooding degrees, and the remaining oil is mainly concentrated in the unwaterflooded areas; therefore, the initial production and water cut in new oil wells vary significantly. High-viscosity oil reservoirs (200 mPa s) have severe waterflooding fingering, large waterflooding areas, and high overall waterflooded degrees because of their high oil–water mobility ratios. However, within waterflooded areas, the reservoirs have low oil displacement efficiencies and low waterflooding degrees, and the remaining oil is mainly concentrated in both the waterflooded areas and the unwaterflooded areas; therefore, the differences in the initial production and water cut of new oil wells are small. Moderate-viscosity oil reservoirs (20 mPa s) are characterized by remaining oil distributions that are somewhere in between those of the former two reservoirs. Therefore, in the high water-cut period, as the viscosity of crude oil increases, the efficiency of waterflooding gradually deteriorates and the remaining oil potential increases. In the later development, it is suggested to implement the local well pattern thickening in the remaining oil enrichment area for reservoirs with low viscosity, whereas a gradual overall well pattern thickening strategy is recommended for whole reservoirs with moderate and high viscosity. The findings of this study can aid better understanding of waterflooding law and the remaining oil potential of reservoirs with different viscosities and proposed corresponding development measures. The research results have important guidance and reference significance for the secondary development of high water-cut sandstone oilfields.

Estimating the effect of permeability variability of undersaturated oil reservoirs on the change in the start water-cut of well production

2020 ◽  
pp. 69-81
Author(s):  
I. M. Sagitova ◽  
D. K. Sagitov ◽  
Yu. V. Zeigman
Keyword(s):  
New Technologies ◽  
Water Saturation ◽  
Initial Period ◽  
Oil Reservoirs ◽  
Selective Isolation ◽  
Oil Saturation ◽  
Object A ◽  
Oil Reserves ◽  
Well Production ◽  
Water Cut

The development of undersaturated oil layered heterogeneous oil reservoirs against the background of a general depletion of oil reserves is becoming increasingly interesting. The development of these hard-to-recover oil reserves is associated with non-standard changes and increased water-cut in wells. An undersaturated (unformed, young) reservoir is a conditionally large transitional water-oil zone of the reservoir, in its classical sense. It is assumed that, since the initial oil saturation of the formation is low, and the water saturation is correspondingly high, the starting water cut should correspond to this ratio, but this is not so in some cases. At the same time, it is difficult to say in advance whether water-cut will increase, stabilize or fall in the first months. The study is aimed at identifying the determining parameter and the ranges of its change by statistical methods, based on which it will be possible to predict with high probability the nature of the change in water cut during the feasibility study for drilling new wells. For the conditions of the selected object, a graphical dependence of the water cut deviation in the initial period of well operation from layered heterogeneity of the reservoir is found. The results of the study are the rationale for creating new technologies for the selective isolation of oil-layers. It should to allow reversibly limiting the permeability of the low-permeability low-saturated part of the reservoir. Most of the existing technologies are aimed at the selective isolation of high-permeability and watered layers.

Autonomous Inflow Control Valve Multiphase Flow Performance for Light Oil

2021 ◽  
Author(s):  
Soheila Taghavi ◽  
Einar Gisholt ◽  
Haavard Aakre ◽  
Stian Håland ◽  
Kåre Langaas
Keyword(s):  
Multiphase Flow ◽  
Single Phase ◽  
Control Valve ◽  
Oil Reservoirs ◽  
Test Results ◽  
Gas Oil ◽  
Flow Loop ◽  
Light Oil ◽  
Water Cut ◽  
Oil Rim

Abstract Early water and/or gas breakthrough is one of the main challenges in oil production which results in inefficient oil recovery. Existing mature wells must stop the production and shut down due to high gas oil ratio (GOR) and/or water cut (WC) although considerable amounts of oil still present along the reservoir. It is important to develop technologies that can increase oil production and recovery for marginal, mature, and challenging oil reservoirs. In most fields the drainage mechanism is pressure support from gas and/or water and the multiphase flow performance is particularly important. Autonomous Inflow Control Valve (AICV) can delay the onset of breakthrough by balancing the inflow along the horizontal section and control or shut off completely the unwanted fluid production when the breakthrough occurs. The AICV was tested in a world-leading full-scale multiphase flow loop located in Porsgrunn, Norway. Tests were performed with realistic reservoir conditions, i.e. reservoir pressure and temperature, crude oil, formation water and hydrocarbon gas at various gas oil ratio and water cut in addition to single phase performances. A summary of the flow loop, test conditions, the operating procedures, and test results are presented. In addition, how to represent the well with AICVs in a standard reservoir simulation model are discussed. The AICV flow performance curves for both single phase and multiphase flow are presented, discussed, and compared to conventional Inflow Control Device (ICD) performance. The test results demonstrate that the AICV flow performance is significantly better than conventional ICD. The AICV impact on a simplified model of a thin oil rim reservoir is shown and modelling limitations are discussed. The simulation results along with the experimental results demonstrated considerable benefit of deploying AICV in this thin oil rim reservoir. Furthermore, this paper describes a novel approach towards the application of testing the AICV for use within light oil completion designs and how the AICV flow performance results can be utilized in marginal, mature, and other challenging oil reservoirs.

A New Model for Predicting Water Cut in Oil Reservoirs

2011 ◽  
Author(s):  
Kewen Li ◽  
Xianghai Ren ◽  
Li Li ◽  
Xiaodong Fan
Keyword(s):  
Oil Reservoirs ◽  
New Model ◽  
Water Cut

Effects of Bottom Aquifer on the Productivity of Chemical Flooding Applied to Multi-Layered Heterogeneous Reservoirs

2013 ◽  
Vol 316-317 ◽  
pp. 791-794
Author(s):  
Byung In Choi ◽  
Moon Sik Jeong ◽  
Kun Sang Lee
Keyword(s):  
Bottom Water ◽  
High Water ◽  
Oil Reservoirs ◽  
Chemical Flooding ◽  
Accurate Assessment ◽  
Heterogeneous Reservoirs ◽  
High Water Cut ◽  
Water Cut ◽  
Reservoir Simulator ◽  
Unfavorable Condition

Complex geological properties of oil reservoirs affect productivity of chemical flooding. Presence of bottom-water aquifer combined with heterogeneous reservoirs has been regarded as a problem which brings out reduction of recovery factor and high water-cut. A numerical reservoir simulator is used to investigate effects of aquifer on the performance of chemical flooding. By including the effects of bottom-water aquifer, productivity decreases significantly compared with that from non-aquifer case. Results from this study emphasize the importance of an accurate assessment of performance before implementing chemical flooding, especially in unfavorable condition such as bottom-water aquifer.

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