scholarly journals Controlling factors of remaining oil distribution after water flooding and enhanced oil recovery methods for fracture-cavity carbonate reservoirs in Tahe Oilfield

2019 ◽  
Vol 46 (4) ◽  
pp. 786-795 ◽  
Author(s):  
Songqing ZHENG ◽  
Min YANG ◽  
Zhijiang KANG ◽  
Zhongchun LIU ◽  
Xibin LONG ◽  
...  
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Controlling Factors ◽  
Carbonate Reservoirs ◽  
Water Flooding ◽  
Tahe Oilfield ◽  
Oil Distribution ◽  
Remaining Oil ◽  
Remaining Oil Distribution ◽  
Recovery Methods

scholarly journals Optimization Design of Injection Strategy for Surfactant-Polymer Flooding Process in Heterogeneous Reservoir under Low Oil Prices

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3789 ◽  
Author(s):  
He ◽  
Chen ◽  
Yu ◽  
Wen ◽  
Liu
Keyword(s):  
Oil Recovery ◽  
Oil Prices ◽  
Water Flooding ◽  
Fractional Flow ◽  
Simultaneous Injection ◽  
Oil Distribution ◽  
Remaining Oil ◽  
Remaining Oil Distribution ◽  
Incremental Oil Recovery ◽  
Injection Strategies

Surfactant–polymer (SP) flooding has significant potential to enhance oil recovery after water flooding in mature reservoirs. However, the economic benefit of the SP flooding process is unsatisfactory under low oil prices. Thus, it is necessary to reduce the chemical costs and improve SP flooding efficiency to make SP flooding more profitable. Our goal was to maximize the incremental oil recovery of the SP flooding process after water flooding by using the equal chemical consumption cost to ensure the economic viability of the SP flooding process. Thus, a systematic study was carried out to investigate the SP flooding process under different injection strategies by conducting parallel sand pack flooding experiments to optimize the SP flooding design. Then, the comparison of the remaining oil distribution after water flooding and SP flooding under different injection strategies was studied. The results demonstrate that the EOR efficiency of the SP flooding process under the alternating injection of polymer and surfactant–polymer (PASP) is higher than that of conventional simultaneous injection of surfactant and polymer. Moreover, as the alternating cycle increases, the incremental oil recovery increases. Based on the analysis of fractional flow, incremental oil recovery, and remaining oil distribution when compared with the conventional simultaneous injection of surfactant and polymer, the alternating injection of polymer and surfactant–polymer (PASP) showed better sweep efficiency improvement and recovered more remaining oil trapped in the low permeability zone. Thus, these findings could provide insights into designing the SP flooding process under low oil prices.

scholarly journals Prediction of Intraformational Remaining Oil Distribution Based on Reservoir Heterogeneity: Application to the J-Field

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jie Zhang ◽  
Feifei Fang ◽  
Jie Wang ◽  
Yajie Tian ◽  
Fei Mo ◽  
...  
Keyword(s):  
Pore Structure ◽  
Oil Recovery ◽  
Composite Index ◽  
Water Flooding ◽  
Research Approach ◽  
Reservoir Heterogeneity ◽  
Oil Distribution ◽  
Remaining Oil ◽  
Remaining Oil Distribution ◽  
Water Cut

At high water cut stage, the study of remaining oil distribution in water-flooding reservoir is the basis of implementing potential-tapping measures and enhancing oil recovery. At present, most of the oilfields in China have entered the stage of ultrahigh water cut. The reserves of the oilfields are highly developed, the situation of water flooding is extremely complex, and it is difficult to predict the distribution of the remaining oil, which seriously restricts the adjustment of the production measures, tapping the potential and improving the ultimate recovery rate. In view of aforementioned difficulties, this study puts forward a research approach to predict remaining oil distribution based on reservoir heterogeneity, which can quantitatively characterize reservoir heterogeneity. In order to avoid the drawback that a single parameter cannot fully describe the characteristics of pore structure, the composite index of pore structure (SQRT(K/Φ)) is introduced to study the pore microstructure. The composite index of pore structure is used to predict the distribution of remaining oil in the formation, and the results are basically consistent with those calculated by numerical simulation. It is concluded that the larger the fractal dimension of the composite index of pore structure is, the stronger the heterogeneity of reservoir is; the smaller the composite index of pore structure is, the smaller the recovery degree is. The composite index of pore structure is used to analyze and predict the distribution of remaining oil in the layer, which provides a new direction for the prediction method of remaining oil.

Heavy Oil Distribution and its Influence on Remaining Oil Distribution of G6 Block in Jinhu Depression

2014 ◽  
Vol 556-562 ◽  
pp. 937-939
Author(s):  
Xue Li ◽  
Jing Rui Xu ◽  
Jin Liang Zhang
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
Water Flooding ◽  
Dynamic Resistance ◽  
Reservoir Properties ◽  
Oil Distribution ◽  
Geological Conditions ◽  
Remaining Oil ◽  
Remaining Oil Distribution ◽  
The Impact

Heavy oil, with the characteristics of high viscosity and large density, is the most important component of petroleum hydrocarbon energy. In reservoir exploration, its dynamic resistance not only reduces driven efficiency, but also brings much more exploration difficulty, so it is not feasible to exploit heavy oil with conventional methods. Previous studies have carried heavy oil research , but few have attempted to examine the impact of heavy oil on reservoir properties .In this paper, a detailed analysis of heavy oil distribution and remaining oil distribution of G6 block is performed. The conclusion are drawn: the local water flooding and local remaining oil selectively accumulation are caused by heavy oil through reducing water flooding efficiency; As to heavy oil recovery, appropriate exploration should be selected to reduce viscosity of heavy oil according to different geological conditions.

The Remaining Oil Distribution and Main Controlling Factor Analysis of Inefficient Reserves in Complex Fault Block

2014 ◽  
Vol 915-916 ◽  
pp. 1128-1131
Author(s):  
Yu Sheng Ding ◽  
Shuang Yan Chen ◽  
Jun Xie ◽  
Ju Biao Zhou ◽  
Li Yao Li
Keyword(s):  
Development Process ◽  
Oil Field ◽  
Water Flooding ◽  
Field Development ◽  
Fault Block ◽  
Oil Distribution ◽  
Complex Fault ◽  
Distribution Rule ◽  
Remaining Oil ◽  
Remaining Oil Distribution

Inefficient reserves in fault block belongs to low permeability thin interbed, thus water flooding development process has exposed many contradictions which are serious heterogeneity, large difference of suction of interlayer. Entering the water injection development, the injected water which rapidly advance along the high permeability channel causes water channeling and water flooding, which intenses development contradictions between layers. The reservoir numerical simulation technology on computer can reappear the movement of water and gas in the underground reservoir development process and describes the underground remaining oil distribution of inefficient reserves in complex fault block, which summarizes the remaining oil distribution rule of the water flooding development for complex fault block of inefficient reserves and provides basis for the establishment of oil field development adjustment scheme.

The Research of Flood Pattern Completeness in the Thin and Poor Oil Layers of South West II Area

2012 ◽  
Vol 594-597 ◽  
pp. 2541-2544
Author(s):  
Xiao Hui Wu ◽  
Kao Ping Song ◽  
Chi Dong ◽  
Ji Cheng Zhang ◽  
Jing Fu Deng
Keyword(s):  
Oil Recovery ◽  
Water Flooding ◽  
South West ◽  
Oil Distribution ◽  
Well Pattern ◽  
Remaining Oil ◽  
Tertiary Oil Recovery ◽  
Well Pattern Optimization ◽  
Numerical Simulation Technique

As line well pattern is the main development technique in the thin and poor oil layers of Daqing Oilfield South West Ⅱ PⅠ group, the layers have been idle and the degree of reserve recovery is far less than the region level. In response to these problems, we analyzed the balanced flood performance of various layers and the remaining oil distribution through numerical simulation technique. It shows that, the main remaining oil type of intended layers is caused by voidage-injection imperfection. Considering the needs of the follow-up infill well pattern and tertiary oil recovery, we decided to keep the well network independent and integrated without disturbing the pattern configuration and main mining object of various sets of well pattern. Finally we confirmed to perforate-adding the first infill wells of intended layers to consummate the water flooding regime. Through analyzing the production target of different well pattern optimization programs relatively, it shows that the best program has regular well pattern and large drilled thickness.

scholarly journals Microscopic Determination of Remaining Oil Distribution in Sandstones With Different Permeability Scales Using Computed Tomography Scanning

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Yongfei Yang ◽  
Haiyuan Yang ◽  
Liu Tao ◽  
Jun Yao ◽  
Wendong Wang ◽  
...  
Keyword(s):  
Distribution Pattern ◽  
Oil Recovery ◽  
Distribution Patterns ◽  
High Water ◽  
Water Flooding ◽  
Oil Distribution ◽  
Computed Tomography Scanning ◽  
Remaining Oil ◽  
High Water Cut ◽  
Water Cut

To investigate the characteristics of oil distribution in porous media systems during a high water cut stage, sandstones with different permeability scales of 53.63 × 10−3 μm2 and 108.11 × 10−3 μm2 were imaged under a resolution of 4.12 μm during a water flooding process using X-ray tomography. Based on the cluster-size distribution of oil segmented from the tomography images and through classification using the shape factor and Euler number, the transformation of the oil distribution pattern in different injection stages was studied for samples with different pore structures. In general, the distribution patterns of an oil cluster continuously change during water injection. Large connected oil clusters break off into smaller segments. The sandstone with a higher permeability (108.11 × 10−3 μm2) shows the larger change in distribution pattern, and the remaining oil is trapped in the pores with a radius of approximately 7–12 μm. Meanwhile, some disconnected clusters merge together and lead to a re-connection during the high water cut period. However, the pore structure becomes compact and complex, the residual nonwetting phase becomes static and is difficult to move; and thus, all distribution patterns coexist during the entire displacement process and mainly distribute in pores with a radius of 8–12 μm. For the pore-scale entrapment characteristics of the oil phase during a high water cut period, different enhance oil recovery (EOR) methods should be considered in sandstones correspondent to each permeability scale.

Successful in the Lab, Not as Effective in the Field? Uncertainties in the Field Observations of Low Salinity Water Flooding in Sandstone and Carbonate Reservoirs-A Critical Analysis

2021 ◽  
Author(s):  
Navpreet Singh ◽  
Hemanta Kumar Sarma
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Experimental Studies ◽  
Carbonate Reservoirs ◽  
Water Flooding ◽  
Water Salinity ◽  
Field Scale ◽  
Low Salinity ◽  
Low Salinity Water ◽  
Salinity Water

Abstract Low salinity waterflooding has been an area of great interest for researchers for almost over three decades for its perceived "simplicity," cost-effectiveness, and the potential benefits it offers over the other enhanced oil recovery (EOR) techniques. There have been numerous laboratory studies to study the effect of injection water salinity on oil recovery, but there are only a few cases reported worldwide where low salinity water flooding (LSW) has been implemented on a field scale. In this paper, we have summarized the results of our analyses for some of those successful field cases for both sandstone and carbonate reservoirs. Most field cases of LSW worldwide are in sandstone reservoirs. Although there have been a lot of experimental studies on the effect of water salinity on recovery in carbonate reservoirs, only a few cases of field-scale implementation have been reported for the LSW in carbonate reservoirs. The incremental improvement expected from the LSW depends on various factors like the brine composition (injection and formation water), oil composition, pressure, temperature, and rock mineralogy. Therefore, all these factors should be considered, together with some specially designed fit-for-purpose experimental studies need to be performed before implementing the LSW on a field scale. The evidence of the positive effect of LSW at the field scale has mostly been observed from near well-bore well tests and inter-well tests. However, there are a few cases such Powder River Basin in the USA and Bastrykskoye field in Russia, where the operators had unintentionally injected less saline water in the past and were pleasantly surprised when the analyses of the historical data seemed to attribute the enhanced oil recovery due to the lower salinity of the injected water. We have critically analyzed all the major field cases of LSW. Our paper highlights some of the key factors that worked well in the field, which showed a positive impact of LSW and a comparative assessment of the incremental recovery realized from the reservoir visa-a-vis the expectations generated from the laboratory-based experimental studies. It is envisaged that such a comparison could be more meaningful and reliable. Also, it identifies the likely uncertainties (and their sources) associated during the field implementation of LSW.

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