Experimental Study on a New Type of Water Shutoff Agent Used in Fractured Low Permeability Reservoir

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Lei Zhang ◽  
Chunsheng Pu ◽  
Shuxia Cui ◽  
Khan Nasir ◽  
Yang Liu
Keyword(s):  
Mathematical Model ◽  
High Water ◽  
Low Permeability ◽  
Low Permeability Reservoir ◽  
Water Shutoff ◽  
Viscous Modulus ◽  
Starch Gel ◽  
New Type ◽  
High Water Cut ◽  
Water Cut

In order to effectively plug the fracture channeling-path in the high water cut fractured low permeability reservoir, a new type of water shutoff agent is developed by bottle tests and its injectivity and plugging performance in fractures are systematically studied by rheology and fractured core displacement experiment. The gelant consists of modified starch, dimethyl diallyl ammonium chloride, N,N′-methylene diacrylamide, and potassium persulfate, which behaves as a Newtonian with a good flowing capacity that allows its accurate positioning in the fractures. After gelatinization, the gel has high elastic modulus and viscous modulus. During the gelant injection into the fractured core, the filtration from fracture into matrix of the gelant leads to a difference between the injection volume of the gelant and the plugged fracture volume. Thus, a mathematical model for calculating filtration volume is established and applied in plugging experiment very well. After plugging, the two block cores can be tightly cemented together by the starch gel. The experiments show that the water shutoff agent and the mathematical model of filtration can be used to effectively plug the fracture channeling-path in the high water cut fractured low permeability reservoir.

scholarly journals New prediction method for transient productivity of fractured five-spot patterns in low permeability reservoirs at high water cut stages

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 499-508
Author(s):  
Chuanzhi Cui ◽  
Zhongwei Wu ◽  
Zhen Wang ◽  
Jingwei Yang ◽  
Yingfei Sui
Keyword(s):  
Prediction Method ◽  
Mass Conservation ◽  
High Water ◽  
Low Permeability ◽  
Element Analysis ◽  
Fracture Length ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut ◽  
Low Permeability Reservoirs

AbstractPredicting the productivity of fractured five-spot patterns in low permeability reservoirs at high water cut stages has an important significance for the development and optimization of reservoirs. Taking the reservoir heterogeneity and uneven distribution of the remaining oil into consideration, a novel method for predicting the transient productivity of fractured five-spot patterns in low permeability reservoirs at high water cut stages is proposed by using element analysis, the flow tube integration method, and the mass conservation principle. This new method is validated by comparing with actual production data from the field and the results of a numerical simulation. Also, the effects of related parameters on transient productivity are analyzed. The results show that increasing fracture length, pressure difference and reservoir permeability correspond to an increasing productivity. The research provides theoretical support for the development and optimization of fractured five-spot patterns at the high water cut stage.

scholarly journals Characteristics and causes of Mesozoic reservoirs with extra-low permeability and high water cut in northern Shaanxi

2011 ◽  
Vol 38 (5) ◽  
pp. 583-588 ◽  
Author(s):  
Jianmin Wang ◽  
Shengfu Liu ◽  
Jun Li ◽  
Yongfu Zhang ◽  
Ling Gao
Keyword(s):  
High Water ◽  
Low Permeability ◽  
Northern Shaanxi ◽  
High Water Cut ◽  
Water Cut

scholarly journals Analytical Solution and Simulation of Oil Deliverability Analysis for Reorientation Hydraulic Fracture in Low-Permeability Reservoirs

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xinyu Qiu ◽  
Botao Kang ◽  
Pengcheng Liu ◽  
Shengye Hao ◽  
Yanglei Zhou ◽  
...  
Keyword(s):  
Analytical Solution ◽  
Principal Stress ◽  
High Water ◽  
Maximum Principal Stress ◽  
Low Permeability ◽  
Minimum Principal Stress ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut ◽  
Low Permeability Reservoirs

The hydraulic refracturing operations are often used to improve oil deliverability in the low-permeability reservoir. When the development of oilfields has entered a high water cut stage, oil deliverability can be promoted by refracturing reservoirs. The orientation of the new fracture formed by refracturing will be changed. The new formed fracture is called reorientation fracture. To calculate the oil deliverability of the refracture wells, a three-section fracture which includes reorientation fracture was established. The multiwell pressure drop superposition theory is used to derive the analytical solution of the refracture wells which includes the reorientation fracture. The numerical simulation was conducted to validate the results of the analytical solution. Comparing the refracture well deliverability of reorientation and nonreorientation, permeability, deflection angle, and the length of reorientation fracture will jointly control the productivity of refracture well. When the permeability in the direction of maximum principal stress is greater than the permeability in the direction of minimum principal stress, the capacity of reorientation fractures is relatively large. The deflection angles and the length of the reorientation fracture will directly affect the drainage area of the fracture, thus affecting productivity. The reorientation fractures generated by repeated fracturing have great potential for improving oil deliverability in the anisotropic low-permeability reservoirs.

A Successful Application of Continuous Pack-Off Technology to Water Shutoff Recompletion for High-WCT Gravel-Packed Horizontal Well

2021 ◽  
Author(s):  
An Jiang ◽  
Yunpeng Li ◽  
Xing Liu ◽  
Fengli Zhang ◽  
Tianhui Wang ◽  
...  
Keyword(s):  
Horizontal Well ◽  
Axial Flow ◽  
High Water ◽  
Bohai Bay ◽  
Horizontal Section ◽  
Well Completion ◽  
Water Shutoff ◽  
Sand Control ◽  
High Water Cut ◽  
Water Cut

Abstract Objectives/Scope Controlling the excessive water production from the high water cut gravel packing horizontal well is a challenge. The approach which uses regular packers or packers with ICD screens to control the unwanted water does not function well. This is mainly because of the length limitation of packers which will make the axial flow resistance insufficient. Methods, Procedures, Process In this paper, a successful case that unwanted water is shutoff by using continuous pack-off particles with ICD screens (CPI) in the whole horizontal section in an offshore oilfield of Bohai bay is presented. The reservoir of this case is the bottom-water high viscosity reservoir. The process is to run 2 3/8" ICD screen string into the 4" screen string originally in place, then to pump the pack-off particles into the annulus between the two screens, and finally form the 360m tightly compacted continuous pack-off particle ring. Results, Observations, Conclusions The methodology behind the process is that the 2-3/8" ICD screens limit the flow rate into the pipes as well as the continuous pack-off particle ring together with the gravel ring outside the original 4" screens to prevent the water channeling into the oil zone along the horizontal section. This is the first time this process is applied in a high water cut gravel packed horizontal well. After the treatment, the water rate decreased from 6856BPD to 836.6BPD, the oil rate increased from 44BPD to 276.8BPD. In addition, the duration of this performance continued a half year until March 21, 2020. Novel/Additive Information The key of this technology is to control the unwanted water by using the continuous pack-off particles instead of the parkers, which will bring 5 advantages, a) higher efficiency in utilizing the production interval; b) no need to find the water source and then fix it; c) the better ability to limit the axial flow; d) effective to multi-WBT (water break though) points and potential WBT points; e) more flexible for further workover. The technology of this successful water preventing case can be reference to other similar high water cut gravel packed wells. Also, it has been proved that the well completion approach of using CPI can have good water shutoff and oil incremental result. Considering the experiences of historical applications, CPI which features good sand control, water shutoff and anti-clogging is a big progress compared to the current completion technologies.

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