The Influence of Microscopic Pore Structure on Microscopic Residual Oil in Sandstone Reservoir

2013 ◽  
Vol 787 ◽  
pp. 721-725 ◽  
Author(s):  
Yan Zhang ◽  
Xin Li
Keyword(s):  
Pore Structure ◽  
Water Flooding ◽  
Structure Effect ◽  
Residual Oil ◽  
Thin Sections ◽  
Unresolved Problem ◽  
Oil Distribution ◽  
Cluster Type ◽  
Sandstone Reservoir ◽  
Different Origin

The distribution of microscopic residual oil varied according to the character of rock pore structure. How pore structure effect residual oil distribution is still an unresolved problem. In this paper, different origin samples were collected, then the characters of microscopic pore structure was analyzed with mercury injection curves, casting thin sections and SEM. The character of microscopic residual oil was observed with fluorescence thin sections. The study showed that after strong water flooding, the microscopic residual oil was mainly composed of intergranular type and cluster type residual oil, but the proportion of different type of residual oil varied according to different microscope pore structure. the smaller the radius of pore structure is, the higher the proportion of intergranular type and cluster type remaining oil is, but the lower the proportion of corner type, membranous type and throat type is.

scholarly journals Differences of microscopic seepage mechanisms of water flooding and polymer flooding and prediction models of final oil recovery for conglomerate reservoir

2019 ◽  
Vol 74 ◽  
pp. 13
Author(s):  
Fengqi Tan ◽  
Changfu Xu ◽  
Yuliang Zhang ◽  
Gang Luo ◽  
Yukun Chen ◽  
...  
Keyword(s):  
Pore Structure ◽  
Polymer Solution ◽  
Oil Recovery ◽  
Particle Surface ◽  
Polymer Flooding ◽  
Water Flooding ◽  
Residual Oil ◽  
Displacement Efficiency ◽  
Oil Saturation ◽  
Oil Displacement Efficiency

The special sedimentary environments of conglomerate reservoir lead to pore structure characteristics of complex modal, and the reservoir seepage system is mainly in the “sparse reticular-non reticular” flow pattern. As a result, the study on microscopic seepage mechanism of water flooding and polymer flooding and their differences becomes the complex part and key to enhance oil recovery. In this paper, the actual core samples from conglomerate reservoir in Karamay oilfield are selected as research objects to explore microscopic seepage mechanisms of water flooding and polymer flooding for hydrophilic rock as well as lipophilic rock by applying the Computed Tomography (CT) scanning technology. After that, the final oil recovery models of conglomerate reservoir are established in two displacement methods based on the influence analysis of oil displacement efficiency. Experimental results show that the seepage mechanisms of water flooding and polymer flooding for hydrophilic rock are all mainly “crawling” displacement along the rock surface while the weak lipophilic rocks are all mainly “inrushing” displacement along pore central. Due to the different seepage mechanisms among the water flooding and the polymer flooding, the residual oil remains in hydrophilic rock after water flooding process is mainly distributed in fine throats and pore interchange. These residual oil are cut into small droplets under the influence of polymer solution with stronger shearing drag effect. Then, those small droplets pass well through narrow throats and move forward along with the polymer solution flow, which makes enhancing oil recovery to be possible. The residual oil in weak lipophilic rock after water flooding mainly distributed on the rock particle surface and formed oil film and fine pore-throat. The polymer solution with stronger shear stress makes these oil films to carry away from particle surface in two ways such as bridge connection and forming oil silk. Because of the essential attributes differences between polymer solution and injection water solution, the impact of Complex Modal Pore Structure (CMPS) on the polymer solution displacement and seepage is much smaller than on water flooding solution. Therefore, for the two types of conglomerate rocks with different wettability, the pore structure is the main controlling factor of water flooding efficiency, while reservoir properties oil saturation, and other factors have smaller influence on flooding efficiency although the polymer flooding efficiency has a good correlation with remaining oil saturation after water flooding. Based on the analysis on oil displacement efficiency factors, the parameters of water flooding index and remaining oil saturation after water flooding are used to establish respectively calculation models of oil recovery in water flooding stage and polymer flooding stage for conglomerate reservoir. These models are able to calculate the oil recovery values of this area controlled by single well control, and further to determine the oil recovery of whole reservoir in different displacement stages by leveraging interpolation simulation methods, thereby providing more accurate geological parameters for the fine design of displacement oil program.

Residual Oil Distribution Law and Controlling Factors of Chang 6 Reservoir in Liutai Area

2014 ◽  
Vol 1010-1012 ◽  
pp. 1735-1739
Author(s):  
Feng Run Zhang ◽  
Ai Hua Guo ◽  
Huai En Cai
Keyword(s):  
Sedimentary Facies ◽  
Geological Structure ◽  
Controlling Factors ◽  
Water Flooding ◽  
Residual Oil ◽  
Distribution Law ◽  
Total Recovery ◽  
Main Layer ◽  
Oil Distribution ◽  
Distribution Laws

Because of the high heterogeneity, late water flooding and irregular well network, the distribution law of residual oil reserve in Chang 6 reservoir becomes much complicated. Combining the geology with dynamics of the reservoir, volumetric and formation coefficient methods are adapted to calculated the residual reserves, and then the distribution laws and controlling factors are analyzed. The results indicate that: there are still large amounts of residual reserve in main layer Chang 622; the residual reserve can be classified into three kinds, Class I and class II are distributed concentrative in main layer; the controlling factors include property, sedimentary facies, heterogeneity, well network controlling and geological structure and so on. Finally, according to the distribution laws and controlling factors, targeted measures are proposed. The studying results provide well foundations for improving recovery of residual oil reserves and the total recovery of the reservoir.

scholarly journals Quantitative Study of Residual Oil Distribution during Water Flooding through Digital Core Analysis

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Xuechao Liu ◽  
Dazhong Ren ◽  
Fengjuan Dong ◽  
Junxiang Nan ◽  
Ran Zhou
Keyword(s):  
Ct Scanning ◽  
Water Flooding ◽  
Fluid Distribution ◽  
Core Analysis ◽  
Residual Oil ◽  
Tight Sandstone ◽  
Oil Storage ◽  
Oil Distribution ◽  
Distribution Features ◽  
Digital Core

The character of residual oil formed during water flooding, one important technique to enhance oil recovery, is helpful to further study permeability and recovery in tight sandstone oil reservoirs. In this paper, we take a tight sandstone reservoir in Ordos Basin as the research object and use in situ displacement X-CT scanning technology to analyze the dynamic characteristics of oil during water flooding. Firstly, core pore radius and oil storage space radius were measured from digital cores which are acquired in different water flooding stages by X-CT scanning technology. Secondly, analytical and evaluation methods were established to describe fluid distribution in the pore space of the core in different water flooding stages based on curve similarity. Finally, by numerical results, we analyzed the oil distribution features in the process of water flooding for core samples. In this paper, the oil distribution characteristics during water flooding are revealed based on digital core analysis. Also, a quantitative evaluation method is given to provide theoretical guidance.

Research on Residual Oil Distribution Regular with the Application of Facies Controlled Modeling and Reservoir Numerical Simulation

2012 ◽  
Vol 616-618 ◽  
pp. 126-132 ◽  
Author(s):  
Hua Bin Wei ◽  
Shang Ming Shi ◽  
Pan Zhao ◽  
Dong Kai Huo ◽  
Wan Zhen Zhu
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Simulation Method ◽  
Structural Features ◽  
Development Stage ◽  
Water Flooding ◽  
Residual Oil ◽  
Distribution Law ◽  
North West ◽  
Oil Distribution

The high water cut stage on the residual oil distribution regularity in late development stage of oilfield is difficult in Daqing oilfield, North West Water Flooding fine demonstration zone development time is long, well under the complicated characteristic, adopts phase control of three-dimensional geological modeling and the method of reservoir numerical simulation in the demonstration zone, structural features and sedimentary characteristics of based on the establishment of demonstration zone, three-dimensional geological model. Through the application of fine reservoir numerical simulation method for the numerical simulation of remaining oil, and a summary of the demonstration zone of residual oil distribution law and cause of formation, provides reliable basis for the next step of oilfield development adjustment.

scholarly journals Micropore structure and water driving characteristics of tight sandstone reservoirs in Ordos Basin

2021 ◽  
Author(s):  
Shuxun Zhou ◽  
Yan Zhou ◽  
Jian Shi ◽  
Yujie Zhu ◽  
Wulin Xiao ◽  
...  
Keyword(s):  
Ordos Basin ◽  
Residual Oil ◽  
Key Factors ◽  
Tight Sandstone ◽  
Micropore Structure ◽  
Oil Distribution ◽  
Sandstone Reservoir ◽  
Thin Section Analysis ◽  
Major Target ◽  
Section Analysis

AbstractIn order to explore the influence of the micropore structure of the tight sandstone reservoir in the water driving characteristics, the studies on the Chang 6 tight sandstone reservoir of the middle-western part of Ordos Basin are carried out by various experiments such as cast-thin section analysis, scanning electron microscopy, high-pressure mercury injection and micro-water driving. The result shows that the permeability contribution curves of samples shift to the left as the sample permeability decreases, indicating that the greater the permeability, the greater the proportion of large pores. The permeability is mostly dominated by pores with the radius larger than R50–R60. There are big differences in the water driving type, oil-driven efficiency and residual oil distribution characteristics between reservoirs of different types. The type II reservoir is the major target of subsequent exploration and development, where water driving types consist of mesh and finger, leaving the residual oil mainly locked by water or isolated as oil drops. The size and distribution feature of pores are the key factors dominating the oil-driven efficiency.

scholarly journals Pore structure and its control on reservoir quality in tight sandstones: a case study of the Chang 6 member of the Upper Triassic Yanchang Formation in the Jingbian oilfield in the Ordos Basin, China

2020 ◽  
Author(s):  
Yubin Bai ◽  
Jingzhou Zhao ◽  
Delin Zhao ◽  
Hai Zhang ◽  
Yong Fu
Keyword(s):  
Physical Properties ◽  
Pore Structure ◽  
Clay Minerals ◽  
Mercury Porosimetry ◽  
Ordos Basin ◽  
Reservoir Quality ◽  
Overburden Pressure ◽  
Thin Sections ◽  
The Ordos Basin ◽  
Sandstone Reservoir

AbstractThis study applied vacuum-impregnated casting thin sections, fluorescence slices, scanning electron microscopy (SEM), pressure-controlled mercury porosimetry (PCP), rate-controlled mercury porosimetry (RCP), X-ray diffraction of clay minerals, overburden pressure, and conventional physical property strategies to determine the microscopic characteristics of the Chang 6 member, a typical tight sandstone reservoir in the Jingbian oilfield in the Ordos Basin, China. We also analyzed the controlling effects of pore structure on reservoir quality and oiliness. The results showed that the pore types of the Chang 6 sandstone reservoir can be divided into four categories: residual intergranular pores, dissolution pores, intercrystalline pores between clay minerals, and microfractures. The pore size of the Chang 6 sandstone reservoir ranged from 20 to 50 μm. We employed PCP and RCP strategies to characterize the pore structure of the Chang 6 reservoir. The pore radius was less than 2 μm, and on average, the throat radius was less than 0.3 μm. The reservoir physical properties were affected by diagenesis, particularly compaction, and the average porosity failure rate was 56.3%. Cementation made the reservoir more compact, dissolution improved the physical properties of the reservoir locally, and fracturing effectively improved the reservoir seepage ability; however, its influence on porosity was limited. The pore structure controlled the quality of the reservoir. The physical properties of the reservoir were closely related to the oil-bearing properties. The lower limits of porosity and permeability of industrial oil flow in the reservoir were 7.5% and 0.15 mD, respectively. These results provide an additional resource for the exploration and development of tight oil in the Ordos Basin.

scholarly journals Determination of Residual Oil Distribution after Water Flooding and Polymer Flooding

2013 ◽  
Vol 5 (8) ◽  
pp. 2642-2647
Author(s):  
Yining Wang ◽  
Xiaodong Wu ◽  
Fengpeng Lai ◽  
Zhaopeng Yang ◽  
Man Teng
Keyword(s):  
Polymer Flooding ◽  
Water Flooding ◽  
Residual Oil ◽  
Oil Distribution

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.

Sign in / Sign up

Export Citation Format

Share Document