scholarly journals Study on the response characteristics of oil wells after deep profile control in low permeability fractured reservoirs

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 832-838 ◽  
Author(s):  
Lijun Lin ◽  
Wei Lin
Keyword(s):  
Fractured Reservoirs ◽  
Oil Production ◽  
Oil Wells ◽  
Low Permeability ◽  
Response Characteristics ◽  
Well Pattern ◽  
Profile Control ◽  
Deep Profile ◽  
Low Permeability Reservoirs ◽  
Oilfield Development

AbstractThe rhombus inverted nine-spot well pattern is often adopted in low permeability oilfield development, which has the advantage of high oil production rate and flexible adjustment. Due to the strong heterogeneity of the low permeability reservoirs, the oil wells along the fracture direction are heavily water-flooded and the water cut rises quickly, and the oil wells on both sides of fractures have no response to water injection. Hence, deep profile control is an effective way to solve this kind of plane contradiction, and is widely applied in the low permeability oilfield development. However, because of the asymmetry of the rhombus inverted nine-spot well pattern and the heterogeneity of the low permeability reservoirs, there are differences in the response characteristics of oil wells at different locations after deep profile control. In this paper, combined with physical experiments and numerical simulations, we analyzed oil increment, the distribution of streamlines and slugs of wells at different locations before and after deep profile control, and evaluated the response characteristics of oil wells of rhombus inverted nine-spot well pattern after deep profile control in low permeability fractured reservoirs. It is concluded that the effect of increasing oil production of the side wells is better than that of the angle wells after deep profile control, and the response sequence is side well, angle well in short axis, and angle well in long axis, which is also verified by the practical results of deep profile control in Daqing Oilfield.

scholarly journals The experimental investigation of the HPAM/phenolic resin deep profile system in fractured low-permeability reservoirs

2021 ◽  
Vol 252 ◽  
pp. 02078
Author(s):  
Wei Zhou ◽  
Daiyin Yin ◽  
Yazhou Zhou
Keyword(s):  
Control System ◽  
Control Systems ◽  
Phenolic Resin ◽  
Good Effect ◽  
Low Permeability ◽  
Low Permeability Reservoir ◽  
Shearing Rate ◽  
Profile Control ◽  
Deep Profile ◽  
Low Permeability Reservoirs

The problem of injected water channeling along fractures exists in the process of water injection in fractured low permeability reservoir, aimed at this problem, deep profile control technology applies to plug fractures to improve the recovery of low permeability reservoir. In this paper, partially hydrolyzed polyacrylamide (HPAM) is used as water-plugging/profile-modifying agent and phenolic resin as crosslinker agent. Several profile control systems are tested to find the one which is suitable for fractured low permeability reservoirs. The performances of profile control systems are evaluated, and effects of formation water salinity, that of shearing rate and that of temperature on the performance are studied. Finally, in order to study effects of this profile control system on displacing oil, flowability experiment and core displacement experiment are applied. It shows that with the increase of salinty of prepared water and the increase of the shearing rate, the viscosity of this system decreases. With the increase of temperature, the gelling time shortens, the viscosity increases, but the stability weekens. This kind of profile control system has a good effect on plugging fractures of low permeability cores. After water flooding, this kind of profile control system is injected into cores, the recovery ratio can increase 3.5%. So the profile control system composed of HPAM/ phenolic resin can apply to deep profile control in fractured low permeability reservoir to enhance oil recovery.

Best Practices in Development and Production Optimization of Offshore Low Permeability Reservoir

2021 ◽  
Author(s):  
Lijian Zhang ◽  
Panpan Tian ◽  
Chuanheng Xing ◽  
Ruiting Bai ◽  
Yanjun Yin ◽  
...  
Keyword(s):  
Water Injection ◽  
Liquid Extraction ◽  
Oil Wells ◽  
Production Optimization ◽  
Low Permeability ◽  
Electric Pump ◽  
Efficient Operation ◽  
Well Pattern ◽  
Geological Conditions ◽  
Low Permeability Reservoirs

Abstract The development effect of low permeability reservoirs of offshore Shahejie Formation in China is poor with fast formation pressure drop, rapid production decline and numerous abnormal wells due to the influence of low permeability, strong heterogeneity, ultra-high reservoir temperature and pressure and high wax and asphaltene content. To overcome these difficulties, this paper takes geological conditions, reservoir potential, stimulation technology and actual wells situation into consideration on the basis of the reservoir performance research, and gives full play to the integration of reservoir and mechanical recovery. A set of production enhancement and efficiency improvement technologies has been formed, including moderate periodic water injection based on pressure fluctuation theory, liquid extraction optimization for low permeability fields, modified compound plugging removal technology, small flowrate and broad width electric pump selection technology, and pump stuck early warning technique to achieve the efficient development of offshore low-permeability oilfields. Moderate periodic water injection not only makes full use of the imbibition effect to achieve the equilibrium displacement, but also avoids the water channeling in fracture area; eight main controlling factors are used to classify and evaluate the liquid extraction potential and select the well group at level-1 for the workover with the effect of daily oil increase of 42 m3; modified compound plugging removal technique completely removes the pollution and plugging of the formation and the wellbore to release the potential of the oil wells to the greatest extent and cumulative oil increase of 6 well times is expected to be 12.44×104 m3; small flowrate and broad width electric pump selection technology applied for more than 30 well times improves the adaptability of the pumps substantially and extends the pump inspection cycle to 857 days; real-time pump stuck warning technique through the dual pattern of analyzing both conventional and high-frequency data guarantees the efficient operation of oil wells. The technologies in this paper have been applied in the target low-permeability field with daily oil production of 429 m3, oil recovery rate of 1.1%, natural decline rate drop year by year and the expected recovery factor of 20.9% under current well pattern. The key technologies in this paper have improved the target reservoir development effect significantly and provided important reference significance for other offshore low-permeability reservoirs development.

Application of the Imitation Horizontal well Technique in the Development of Low Permeability Reservoirs

2013 ◽  
Vol 734-737 ◽  
pp. 1350-1353
Author(s):  
Yan Dong ◽  
An Zhu Xu
Keyword(s):  
Horizontal Well ◽  
Influence Factors ◽  
Oil Production ◽  
Low Permeability ◽  
Daily Production ◽  
Drainage Radius ◽  
Well Pattern ◽  
Single Well ◽  
Lower Permeability ◽  
Low Permeability Reservoirs

The fluid flowing resistance increase and the water absorbing capacity reduce due to the threshold pressure gradient and media deformation of the low permeability reservoirs in the course of development. The oil production of vertical wells may decrease fastly and the controlled reservers are hard to recover. The development effects are not satisfied. Through great fracturing measurements create many fractures, and fractures extended along the direction of well line, the long fracture channels were formed like horizontal well segments. This kind of long fracture was called as horizontal segment of imitation horizontal well. It can broad drainage radius in production well and increase controlled reserves and daily oil production of single well. In this paper, the influence factors of the low permeablity reservoirs development by imitation horizontal wells were analysised. Through well pattern, well distance, line distance, injector and producer parameters and fracturing parameters of imitation horizontal well optimization, drainage radius in lower permeability reservoirs can be reached to 200 meters, the daily production in single well can increase two times of that before, and the production result was improved greatly in lower permeability reservoirs development.

scholarly journals Profile control performance and field application of preformed particle gel in low-permeability fractured reservoir

2020 ◽  
Author(s):  
Bin Xu ◽  
Yan Wang
Keyword(s):  
Fractured Reservoirs ◽  
Field Tests ◽  
Field Application ◽  
Low Permeability ◽  
Fractured Reservoir ◽  
Synthesis Conditions ◽  
Preformed Particle Gel ◽  
Profile Control ◽  
Deep Profile ◽  
Preformed Particle Gels

AbstractWater well profile control is the main way to control water channeling in low-permeability fractured reservoirs, and preformed particle gels (PPGs) are commonly used. A preformed particle gel was prepared and the synthesis conditions were optimized. The temperature and salt resistant performance, plugging performance were investigated and the field application was tested. The results showed PPGs exhibited good temperature and salt resistant performance. PPGs with larger particle size showed greater plugging strength but shorter valid period. Field tests suggested that multiple rounds of profile control should be employed using PPGs with different particle sizes to achieve deep profile control.

Compatibility evaluation of in-depth profile control agents in dominant channels of low-permeability reservoirs

2020 ◽  
Vol 194 ◽  
pp. 107529 ◽  
Author(s):  
Junjian Li ◽  
Ze Wang ◽  
Hanxu Yang ◽  
Hai'en Yang ◽  
Tianjiang Wu ◽  
...  
Keyword(s):  
Depth Profile ◽  
Low Permeability ◽  
Profile Control ◽  
Low Permeability Reservoirs

scholarly journals Experimental Research on the Optimization and Evaluation of the Polymer/Chromium-Ion Deep Profile Control System for the Fractured Low-Permeability Reservoirs

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1021
Author(s):  
Daiyin Yin ◽  
Shuang Song ◽  
Qi Xu ◽  
Kai Liu
Keyword(s):  
Molecular Weight ◽  
Control System ◽  
High Molecular Weight ◽  
Low Molecular Weight ◽  
Low Permeability ◽  
Chromium Ion ◽  
Oil Displacement ◽  
Profile Control ◽  
Deep Profile ◽  
Plugging Performance

The matrix/fracture conductivity of a fractured low-permeability reservoir is variable, and its heterogeneity is serious. When carrying out deep profile control measures, it is difficult to inject under the premise of ensuring the plugging effect. According to the characteristics of the fractured low-permeability reservoir in Chaoyanggou Oilfield, the polymer/chromium ion deep profile control system was optimized via a viscosity evaluation experiment, liquidity experiment and oil displacement experiment. The experimental results show that the high molecular weight main agent/low concentration system and low molecular weight main agent/high concentration system can meet the gel strength requirement. The evaluation results of the injection ability and plugging performance of the fractured low-permeability core show that a high molecular weight profile control system is difficult to inject, while a low molecular weight profile control system has a poor plugging performance and high cost after simulated shear. Therefore, the formulation of the profile control system was determined to be a polymer with a molecular weight of 16 million g·mol−1 as the main agent with a concentration of 1000–1500 mg·L−1. As assisting agents, the concentrations of thiourea, NaCl and NaHCO3 were 900 mg·L−1, 800 mg·L−1 and 700 mg·L−1, respectively. The plugging rate of the system was 87.6%, and the resistance coefficient was 19.2. Finally, a fractured low-permeability core model with parallel long cores was designed, and the optimal profile control system was used for the core oil-displacement experiment. Compared with the water-flooding experiment, the plugging rate can be increased by 6.9–8.0%.

scholarly journals Analysis of Controlling Factors at Separate Imbibition Stages for Ultra-Low-Permeability Reservoirs

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7093
Author(s):  
Hailong Dang ◽  
Hanqiao Jiang ◽  
Binchi Hou ◽  
Xiaofeng Wang ◽  
Tao Gao ◽  
...  
Keyword(s):  
Fractured Reservoirs ◽  
Influential Factors ◽  
Controlling Factors ◽  
Spontaneous Imbibition ◽  
Low Permeability ◽  
Relative Importance ◽  
Oil Viscosity ◽  
Oil Saturation ◽  
Low Permeability Reservoirs ◽  
Interfacial Characteristics

Spontaneous imbibition is an important mechanism in naturally fractured reservoirs. In our previous studies on the effect of imbibition efficiency of ultra-low permeability reservoirs, we mostly focused on the relationship between macroscopic core recovery rate and influential factors. Additionally, we also mainly focused on the factors that control the final imbibition recovery for ultra-low permeability reservoirs. Through a large number of experiments, it was found that the factors affecting imbibition are different in separate stages. However, the relative importance of those factors in different imbibition stages was hardly studied. In this work, we tested six key factors, i.e., the core length, RQI, salinity, interfacial characteristics, initial oil saturation, and oil viscosity, in natural sandstone samples from Chang 6 in the Zichang area. Based on experimental results, we divided the imbibition process into three stages (i.e., the early stage, the middle stage, and the late stage) to quantify the effects of the controlling factors. The results show that the relative importance of the controlling factors is changing during the imbibition process. The weight of importance is obtained for those factors at each stage. In addition, a comparative model is established for the dual-porosity media from Chang 6 formation. The results show that the increase of the rock size can extend the imbibition period for the early and middle stages. Moreover, the weight of importance for the initial oil saturation, interfacial characteristics, and salinity are also analyzed in three imbibition stages. This study provides theoretical support to guide water injection in ultra-low-permeability reservoirs and to understand the formation of energy supplements and oil recovery during the imbibition process.

Sign in / Sign up

Export Citation Format

Share Document