Reasons for Formation Damage and Preparation for Disentanglement Agent in Low Permeability Oilfield

2013 ◽  
Vol 457-458 ◽  
pp. 1597-1600
Author(s):  
Jing Ping Cao ◽  
Fu Lei Zhao ◽  
Kun Zhang

For the characteristics of serious formation damage and insufficient injecting in injection wells in the water flooding development process in low permeability oilfield, it carries the analysis of reasons for forming low efficient injection wells and the development of acidizing disentanglement agent. Through core damage experiment of wellhead sewage in S oilfield, formation damage is mainly caused by excessive levels of suspended matters and the multiple of exceeding standards is 45.3. Based on the result of core damage experiment and actual oilfield production data, the variation of apparent injectivity index in low efficient injection wells is researched. The research result indicates that formation damage radius of pollution wells is about 20m in this oilfield. Based on formation damage condition of this oilfield, compound acid is developed, which has the properties of strong penetration, retarding reaction velocity and strong-chelating. Plug removal experiment indicates that the recovery rate of core permeability is about 100% using developed compound acid.

2014 ◽  
Vol 694 ◽  
pp. 340-345
Author(s):  
Ke Liang Wang ◽  
Jin Yu Li ◽  
Lei Lei Zhang ◽  
Xue Li ◽  
Guo Qiang Fu ◽  
...  

Profile control and flooding technique is an effective way to enhance the oil recovery of low permeability reservoir.Analyzing the relation between oil and water interface and determining injection volume under different concentration is the key to success in profile controlling and flooding in low permeability reservoir .The research is about SJT-B collosol of physicochemical property under normal pressure and temperature.We also carry on the study on measuring SJT-B collosol interfacial tension for a long time under different concentration.Besides, we conduct the plugging degree experiment by injecting SJT-B collosol with the concentration of 0.8% in different permeability core.The lower the core permeability, the higher the plugging degree. By optimizing the injection pattern we conduct the three-tube parallel profile control and flooding experiment in the low permeability heterogeneous core.It indicates that SJT-B collosol mainly access to high permeability layer and have an effective plugging effect .The absorbed liquid rate of medium permeability layer is increased apparently ,while low permeability layer is increased slightly.The SJT-B collosol of injection method has efficient effect on enhancing the oil recovery of low permeability reservoir in late water flooding.


Author(s):  
Yazhou Zhou ◽  
Wenbin Yang ◽  
Daiyin Yin

AbstractWater injection is an effective method for developing low permeability sandstone reservoirs. In the process of water flooding, reservoir damage can occur due to clay mineral content changes and it will significantly affect oil production. There are few investigations on the changes in clay mineral content and the degree of reservoir damage after injecting the water into low permeability sandstone reservoirs with different permeabilities and lithologies. In this study, low permeability natural cores from different lithological strata were collected from 4 wells in the Daqing sandstone reservoir, and clay mineral components and contents were measured through X-ray diffraction. Changes in the clay mineral content were determined after water injection. The reservoir damage mechanism by clay mineral migration was determined by analyzing scanning electron microscopy (SEM) images after water injection. Meanwhile, the porosity and permeability of the cores were tested after water injection, and the degree of reservoir damage in different lithological strata was determined. The clay mineral content ranges from 6.78 to 14.14% in low permeability sandstone cores and declines by 49.73% after water flooding. Illite, chlorite and illite/smectite mostly decrease, and kaolinite decreases the least. Due to the large particle size of kaolinite, kaolinite migration will block the pore-throats and cause formation damage after water flooding. In argillaceous siltstone and siltstone, kaolinite particles blocking pore-throats are very serious, and the permeability decreases greatly by 21.87–36.89% after water injection. With increasing permeability, the permeability decreases greatly after water injection. The findings of this study can help to better understand the mechanisms of formation damage after injecting water into low permeability sandstone reservoirs.


2012 ◽  
Vol 524-527 ◽  
pp. 1203-1208
Author(s):  
Xiao Liang Huang ◽  
Zhi Lin Qi ◽  
Deng Sheng Lei ◽  
Zhi Jun Li

Abstract. Low permeability water-flooding gas reservoir easy to cause the well bottom effusion in the middle of development,Effusion was often can't take out.Then with the function of capillary forces,the effusion will be absorbed in pore of rocks around the bottom well,and the Porous Medium part was block, The gas phase circulation pore canal becomes small,finally gas-phase effective permeability will be influence in the rocks,reduced pore channel permeability,made the productivity decline。The paper,the base of special experiment,analysis relation between the rate of damage about core permeability and imbibitions water saturation,and Introducing the correlation coefficient to the capacity formula of reverse imbibitions gas reservoir ,then get the capacity formula of the water flooding gas reservoir for realize the similar gas reservoir reverse imbibitions damage degree provides the basis.


2011 ◽  
Vol 361-363 ◽  
pp. 520-525
Author(s):  
Jun Feng Yang ◽  
Han Qiao Jiang ◽  
Han Dong Rui ◽  
Xiao Qing Xie

Physical simulation experiments were made to research on the stress sensitivity on physical property of low permeability reservoir rocks. The experimental results shown that effective pressure had good exponential relationship with reservoir permeability. Combining with materaial balance method, reservoir engineering and rational deducation was made to reserach on water-flooding timing of low permeability reservoir development. Several production targets were obtained by these method, such as formation pressure, water and oil production, water cut and so on. The results shown that advanced water-flooding was very important in low permeability reservoir development to reduce the bad impact of stress sensitivity on formation permeability and maintain formation pressure.


2021 ◽  
pp. 014459872110052
Author(s):  
Xizhe Li ◽  
Zhengming Yang ◽  
Shujun Li ◽  
Wei Huang ◽  
Jianfei Zhan ◽  
...  

Low-permeability to ultralow-permeability reservoirs of the China National Petroleum Corporation are crucial to increase the reserve volumes and the production of crude oil in the present and future times. This study aimed to address the two major technical bottlenecks faced by the low-permeability to ultralow-permeability reservoirs by a comprehensive use of technologies and methods such as rate-controlled mercury injection, nuclear magnetic resonance, conventional logging, physical simulation, numerical simulation, and field practices. The reservoir characteristics of low-permeability to ultralow-permeability reservoirs were first analyzed. The water flooding development adjustment mode in the middle and high water-cut stages for the low-permeability to ultralow-permeability reservoirs, where water is injected along the fracture zone and lateral displacement were established. The formation mechanism and distribution principles of dynamic fractures, residual oil description, and expanding sweep volume were studied. The development mode for Type II ultralow-permeability reservoirs with a combination of horizontal well and volume fracturing was determined; this led to a significant improvement in the initial stages of single-well production. The volume fracturing core theory and optimization design, horizontal well trajectory optimization adjustment, horizontal well injection-production well pattern optimization, and horizontal well staged fracturing suitable for reservoirs with different characteristics were developed. This understanding of the reservoir characteristics and the breakthrough of key technologies for effective development will substantially support the oil-gas valent weight of the Changqing Oilfield to exceed 50 million tons per year, the stable production of the Daqing Oilfield with 40 million tons per year (oil-gas valent weight), and the realization of 20 million tons per year (oil-gas valent weight) in the Xinjiang Oilfield.


2018 ◽  
Vol 54 (4) ◽  
pp. 457-466
Author(s):  
P. A. Gushchinu ◽  
A. N. Cheremisin ◽  
N. G. Glavnov ◽  
P. M. Zobort ◽  
N. A. Svarovskaya ◽  
...  

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Chengli Zhang ◽  
Guodong Qu ◽  
Guoliang Song

For the large pores and cracks of reservoirs with low temperatures, high salinity, and low permeability, a new type of high strength gel ABP system is developed in this paper. The defects of conventional gels such as weak gel strength, no gelling, and easy dehydration are overcome under the conditions of low temperature and high salinity. The temperature and salt resistance, plugging characteristics, and EOR of the gel system are studied. Under the condition of 32°C and 29500 mg/L salinity, the ABP system formulation is for 0.3% crosslinking agent A + 0.09% coagulant B + 3500 mg/L polymer solution P. The results show that when the temperature was increased, the delayed crosslinking time of the system was shortened and the gel strength was increased. The good plugging characteristics of the ABP system were reached, and the plugging rate was greater than 99% in cores with different permeability. A good profile control performance was achieved, and the recovery rate was improved by 19.27% on the basis of water flooding. In the practical application of the gel system, the salinity of formation water and the permeability of fractures are necessary to determine the appropriate formulation.


2014 ◽  
Vol 915-916 ◽  
pp. 1128-1131
Author(s):  
Yu Sheng Ding ◽  
Shuang Yan Chen ◽  
Jun Xie ◽  
Ju Biao Zhou ◽  
Li Yao Li

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.


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