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

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.

scholarly journals Optimization of triple-alternating-gas (TAG) injection technique for enhanced oil recovery in tight oil reservoirs

2021 ◽  
Author(s):  
Mvomo Ndzinga Edouard ◽  
Pingchuan Dong ◽  
Chinedu J. Okere ◽  
Luc Y. Nkok ◽  
Abakar Y. Adoum ◽  
...  
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Gas Injection ◽  
Oil Reservoirs ◽  
Recovery Factor ◽  
Injection Technique ◽  
Tight Oil ◽  
Compositional Model ◽  
Injection Scheme ◽  
Tight Oil Reservoirs

AbstractAfter single-gas (SG) injection operations in tight oil reservoirs, a significant amount of oil is still unrecovered. To increase productivity, several sequencing gas injection techniques have been utilized. Given the scarcity of research on multiple-gas alternating injection schemes, this study propose an optimized triple-alternating-gas (TAG) injection for improved oil recovery. The performance of the TAG process was demonstrated through numerical simulations and comparative analysis. First, a reservoir compositional model is developed to establish the properties and composition of the tight oil reservoir; then, a suitable combination for the SG, double alternating gas (DAG), and TAG was selected via a comparative simulation process. Second, the TAG process was optimized and the best case parameters were derived. Finally, based on the oil recovery factors and sweep efficiencies, a comparative simulation for SG, DAG, and TAG was performed and the mechanisms explained. The following findings were made: (1) The DAG and TAG provided a higher recovery factor than the SG injection and based on recovery factor and economic advantages, CO2 + CH4 + H2S was the best choice for the TAG process. (2) The results of the sensitivity analysis showed that the critical optimization factors for a TAG injection scheme are the injection and the production pressures. (3) After optimization, the recovery factor and sweep efficiency of the TAG injection scheme were the best. This study promotes the understanding of multiple-gas injection enhanced oil recovery (EOR) and serves as a guide to field design of gas EOR techniques.

scholarly journals Experimental Study on EOR Performance of Natural Gas Injection in Tight Oil Reservoirs

2019 ◽  
Vol 252 (5) ◽  
pp. 052021
Author(s):  
Haiyang Yu ◽  
Zhewei Chen ◽  
Xin Lu ◽  
Shiqing Cheng ◽  
Youan He ◽  
...  
Keyword(s):  
Experimental Study ◽  
Natural Gas ◽  
Gas Injection ◽  
Oil Reservoirs ◽  
Tight Oil ◽  
Tight Oil Reservoirs

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.

scholarly journals A novel method for improving recovery of heavy oil reservoirs with high water cut based on polymer gel-assisted CO2 huff and puff

2021 ◽  
Author(s):  
Haiwei Lu ◽  
Zhenyuan Wang ◽  
Tong Peng ◽  
Jiapeng Zheng ◽  
Xiaoliang Yang ◽  
...  
Keyword(s):  
Heavy Oil ◽  
Apparent Viscosity ◽  
Retention Rate ◽  
High Water ◽  
Salt Resistance ◽  
Oil Reservoirs ◽  
Polymer Gel ◽  
Heavy Oil Reservoirs ◽  
High Water Cut ◽  
Water Cut

AbstractA novel enhanced oil recovery (EOR) method based on polymer gel-assisted carbon dioxide (CO2) huff and puff was developed aiming to improve the development effect of heavy oil reservoirs with high water cut. The polymer gel prepared using partially hydrolyzed polyacrylamide (HPAM), hexamethylenetetramine, phenol, resorcinol, oxalic acid, and thiocarbamide as raw materials had a special network structure to overcome the challenge of significant heterogeneity in heavy oil reservoirs. The strength of polymer gel reached the maximum value 20,000 mPa·s within 22 h. The temperature resistance and salt resistance of polymer gel directly determined the plugging effect. The polymer gel was placed for 190 days at 85 ℃, and its apparent viscosity retention rate was 66.4%. The salt resistance experiments showed that the apparent viscosity retention rate of this polymer gel at 1.8 wt % NaCl, 0.045 wt % CaCl2, 0.045 wt % MgCl2 was 71.3%, 78.5%, 71.4%, respectively. Huff and puff experiments confirmed that this method could be used to increase the sweep volume and improve the oil displacement efficiency of heavy oil reservoirs with high water cut. Furthermore, the EOR of this method was better than that of water huff and puff, polymer gel huff and puff or CO2 huff and puff.

D-optimal design for Rapid Assessment Model of CO2 flooding in high water cut oil reservoirs

2014 ◽  
Vol 21 ◽  
pp. 764-771 ◽  
Author(s):  
Zhaojie Song ◽  
Zhiping Li ◽  
Chunsheng Yu ◽  
Jirui Hou ◽  
Mingzhen Wei ◽  
...  
Keyword(s):  
Optimal Design ◽  
Rapid Assessment ◽  
High Water ◽  
Assessment Model ◽  
Oil Reservoirs ◽  
Co2 Flooding ◽  
High Water Cut ◽  
Water Cut
Sign in / Sign up

Export Citation Format

Share Document