Reasonably Water Injection Time about Abnormal Pressure of Low Permeability Reservoir

2012 ◽  
Vol 601 ◽  
pp. 134-138
Author(s):  
Xiao Liang Huang
Keyword(s):  
Pore Space ◽  
Water Injection ◽  
Stress Sensitivity ◽  
Reservoir Rock ◽  
Low Permeability ◽  
Injection Timing ◽  
Injection Time ◽  
Low Permeability Reservoir ◽  
Abnormal Pressure ◽  
Low Permeability Reservoirs

Abnormal pressure of low permeability reservoirs is a special reservoir, which have some characteristic : low permeability, strong stress sensitivity, complex pore structure, abnormal pressure. with the pressure decreasing about bottom-hole and reservoir, the formation of the rock pore space and permeability will decrease, and reservoir stress-sensitive phenomenon of serious. All these have brought greater difficulty for developing. in order to reasonable development of those reservoirs, maintain the formation energy is important, choose the reasonable injection timing is an important aspect. In this paper, taking abnormal pressure of low permeability reservoir as an example, studies variation law of abnormally pressure reservoir rock compressibility, porosity, stress sensitivity by experimental, Associated with the nature of the reservoir to determine a reasonable water injection time, and demonstrated by numerical simulation, finally proposed reasonable water injection timing about abnormal pressure of low-permeability reservoirs.

A Study of Influential Factors of Advance Water Injection in Extra-Low Permeability Reservoir

2014 ◽  
Vol 487 ◽  
pp. 255-258
Author(s):  
Jin Gang He ◽  
Kao Ping Song ◽  
Jing Yang ◽  
Bao Gang Sun ◽  
Si Chen ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Early Stage ◽  
Retention Rate ◽  
Water Injection ◽  
Stress Sensitivity ◽  
Influential Factors ◽  
Low Permeability ◽  
Formation Pressure ◽  
Low Permeability Reservoir ◽  
Start Up

This paper study on the permeability, start-up pressure gradient and stress sensitivity of advance water injection in extra-low permeability reservoir in Fuyu Oil layer of Daqing Oilfield. Experimental results show that the reasonable formation pressure level should be at about 120% in the advance water injection experiment, advanced water injection in the the early stage have higher oil production, the water breakthrough, earlier than synchronous water injection has certain inhibitory effect of water cut rise; Under the premise of advance water injection can overcome the start-up pressure, the lower the level of the reservoir permeability, the higher improve recovery efficiency of the proportion; permeability retention rate increase by about 22% with 5×10-3μm2 core and effectively overcome the stress sensitivity of low permeability reservoir damage; Advanced water injection can overcome stress sensitivity and restoring formation pressure, all that influence the start-up pressure gradient, which significantly reduce the start-up pressure gradient.

scholarly journals Effect evaluation and influencing factors of stratified water injection in low permeability reservoir

2021 ◽  
Vol 292 ◽  
pp. 01014
Author(s):  
Xin Bai ◽  
Shiyan Hao ◽  
Chunfen Guo ◽  
Shenglin Yao
Keyword(s):  
Influencing Factors ◽  
Oil Recovery ◽  
High Efficiency ◽  
Water Injection ◽  
Low Permeability ◽  
Injection Timing ◽  
Effect Evaluation ◽  
Low Permeability Reservoir ◽  
Drive Control ◽  
Injection Effect

The main production layers in Danba oil area of Yanchang oilfield are Chang 4 + 5 and Chang 6 oil layers, which are the main development areas for increasing reserves and production. In view of the unclear influencing factors of water injection effect and the disunity of effect evaluation in the study area, the stratified water injection effect evaluation and influencing factors of low permeability reservoir are studied by means of production data statistical analysis and numerical simulation. The results show that the effect of water injection in the study area is affected by five factors: intraformational heterogeneity, interlayer heterogeneity, interlayer pressure difference, fracture and water injection timing, the results show that the water injection effect is obvious in the study area by using the five indexes of water drive reserves producing degree, water storage rate, water drive index, oil recovery rate and water drive control degree. The research results provide ideas for the study of high-efficiency separate layer water injection in low permeability reservoir, and provide guidance for the next step of potential mining.

Optimized Cyclic Water Injection Strategy for Oil Recovery in Low-Permeability Reservoirs

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Xiaofei Sun* ◽  
Yanyu Zhang ◽  
Jie Wu ◽  
Mengke Xie ◽  
Hang Hu
Keyword(s):  
Oil Recovery ◽  
Water Injection ◽  
Tracer Tests ◽  
Oil Prices ◽  
Fuzzy Comprehensive Evaluation ◽  
Low Permeability ◽  
Operational Parameters ◽  
Recovery Method ◽  
Low Permeability Reservoir ◽  
Low Permeability Reservoirs

With the worldwide decline in conventional oil production, tremendous unconventional resources, such as low-permeability reservoirs, are becoming increasingly important. Cyclic water injection (CWI) as an oil recovery method has attracted increasing attention in the present environment of low oil prices. However, the optimal CWI strategy is difficult to determine for a mature oilfield due to the involvement of multiple wells with multiple operational parameters. Thus, our main focus in this paper is to present a novel and systematic approach to optimize CWI strategies by studying a typical low-permeability, namely, reservoir G21. To this end, a comprehensive method that combines the advantages of streamline simulation and fuzzy comprehensive evaluation (FCE) was proposed to identify water channeling in the reservoir. Second, the reliability of the method was verified using tracer tests. Finally, a new hybrid optimization algorithm, the simulated annealing-genetic algorithm (SAGA), coupled with a reservoir simulator was developed to determine an optimal CWI strategy for the low-permeability reservoir. The results show that the CWI technique is viable as a primary means in the present environment of low oil prices to improve the waterflood performance in low-permeability reservoirs. The oil recovery of the most efficient strategy increases by 6.8% compared to conventional waterflooding. The asymmetric CWI scheme is more efficient than the symmetric CWI scheme for the low-permeability reservoir.

A Study of Seepage Characteristics of Unsteady Waterflooding Development for Fractured Ultra-Low-Permeability Reservoir

2021 ◽  
Author(s):  
Qing Liu ◽  
Xiangfang Li ◽  
Jian Yang ◽  
Sen Feng ◽  
Minxia He ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Water Injection ◽  
Injection Rate ◽  
Low Permeability ◽  
Tensor Model ◽  
Capillary Imbibition ◽  
Low Permeability Reservoir ◽  
Water Cut ◽  
Low Permeability Reservoirs

Abstract Unconventional fractured ultra-low-permeability reservoirs play an important role in continental sedimentary basins in China, and their formation characteristics and seepage laws are greatly different from that of traditional reservoirs. In this paper, the influence of microfractures and unsteady waterflooding on the productivity of fractured ultra-low permeability reservoirs are studied deeply. The reservoir parameters used in the study are from an actual fractured ultra-low-permeability reservoir in Ordos Basin, where microfractures are developed but macroscopic fractures are not. The microfractures have a small opening and are widely distributed in the reservoir, so the reservoir numerical simulation model adopts the equivalent continuous matrix model to simulate waterflooding. On one hand, the physical model of micro-fractured reservoir and the permeability tensor model of the equivalent continuous matrix are established. The results show that the existence of microfractures can increase the permeability of matrix by 1.4 times. On the other hand, an ideal heterogeneous numerical simulation model composed of pure matrix and equivalent continuous matrix considering microfracture is established according to actual geological parameters of the fractured ultra-low-permeability reservoir. To simulate and compare the unsteady waterflooding and continuous waterflooding development in 10-year development under the condition of constant annual injection rate, the results indicate that unsteady waterflooding development make higher productivity and lower water cut and lower formation water saturation than that of continuous waterflooding. By conducting unsteady waterflooding development simulation for sensitivity analysis, the results demonstrate that the greater the capillary force, the better the role of capillary imbibition in a certain range, meanwhile, the unsteady waterflooding has the best exploitation effect when the value of water injection cycle time is 100 days and the fluctuation amplitude of water injection rate is 1. At the above situation, the displacement and capillary imbibition and pressure disturbance achieve the desired effect of reducing water cut and increasing oil production.

Analysis of the channeling of water injection in low permeability reservoirs with interlayer considering the seepage–stress coupling

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ji Youjun ◽  
K. Vafai ◽  
Huijin Xu ◽  
Liu Jianjun
Keyword(s):  
Water Injection ◽  
Simulation Method ◽  
Stress Sensitivity ◽  
Injection Rate ◽  
Water Flooding ◽  
Low Permeability ◽  
Content Type ◽  
Main Injection ◽  
Low Permeability Reservoirs ◽  
The Impact

Purpose This paper aims to establish a mathematical model for water-flooding considering the impact of fluid–solid coupling to describe the process of development for a low-permeability reservoir. The numerical simulation method was used to analyze the process of injected water channeling into the interlayer. Design/methodology/approach Some typical cores including the sandstone and the mudstone were selected to test the permeability and the stress sensitivity, and some curves of the permeability varying with the stress for the cores were obtained to demonstrate the sensitivity of the formation. Based on the experimental results and the software Eclipse and Abaqus, the main injection parameters to reduce the amount of the injected water in flowing into the interlayer were simulated. Findings The results indicate that the permeability of the mudstone is more sensitive to the stress than sandstone. The injection rate can be as high as possible on the condition that no crack is activated or a new fracture is created in the development. For the B82 block of Daqing oilfield, the suggested pressure of the production pressure should be around 1–3MPa, this pressure must be gradually reached to get a higher efficiency of water injection and avoid damaging the casing. Originality/value This work is beneficial to ensure stable production and provide technical support to the production of low permeability reservoirs containing an interlayer.

Advance Water-Flooding to Reduce the Stress Sensitivity Affect on Low Permeability Reservoir Development

2011 ◽  
Vol 361-363 ◽  
pp. 520-525
Author(s):  
Jun Feng Yang ◽  
Han Qiao Jiang ◽  
Han Dong Rui ◽  
Xiao Qing Xie
Keyword(s):  
Physical Simulation ◽  
Physical Property ◽  
Stress Sensitivity ◽  
Water Flooding ◽  
Low Permeability ◽  
Formation Pressure ◽  
Exponential Relationship ◽  
Low Permeability Reservoir ◽  
Reservoir Development ◽  
Water Cut

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.

The Research and Evaluation of Finely Layered Water Injection Standard in Low-Permeability Reservoirs - A Case from Block A in one Low-Permeability Reservoir

2014 ◽  
Vol 1073-1076 ◽  
pp. 2310-2315 ◽  
Author(s):  
Ming Xian Wang ◽  
Wan Jing Luo ◽  
Jie Ding
Keyword(s):  
Oil Recovery ◽  
Water Injection ◽  
Injection Pressure ◽  
Injection Rate ◽  
Low Permeability ◽  
Reservoir Permeability ◽  
Engineering Parameters ◽  
The Common ◽  
Common Problems ◽  
Low Permeability Reservoirs

Due to the common problems of waterflood in low-permeability reservoirs, the reasearch of finely layered water injection is carried out. This paper established the finely layered water injection standard in low-permeability reservoirs and analysed the sensitivity of engineering parameters as well as evaluated the effect of the finely layered water injection standard in Block A with the semi-quantitative to quantitative method. The results show that: according to the finely layered water injection standard, it can be divided into three types: layered water injection between the layers, layered water injection in inner layer, layered water injection between fracture segment and no-fracture segment. Under the guidance of the standard, it sloved the problem of uneven absorption profile in Block A in some degree and could improve the oil recovery by 3.5%. The sensitivity analysis shows that good performance of finely layered water injection in Block A requires the reservoir permeability ratio should be less than 10, the perforation thickness should not exceed 10 m, the amount of layered injection layers should be less than 3, the surface injection pressure should be below 14 MPa and the injection rate shuold be controlled at about 35 m3/d.

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