EFFICIENCY EVALUATION OF WATERFLOODING OF LOW-PERMEABILITY RESERVOIRS BY HORIZONTAL WELLS WITH WATER-INJECTION INDUCED FRACTURES

2020 ◽  
pp. 52-60
Author(s):  
I.Sh. Bazyrov ◽  
E.V Shel ◽  
M.M. Khasanov
Keyword(s):  
Flow Rate ◽  
Water Injection ◽  
Horizontal Wells ◽  
Low Permeability ◽  
Equilibrium Pressure ◽  
Critical Fracture ◽  
Induced Fractures ◽  
Low Permeability Reservoirs ◽  
Fracture Growth ◽  
Half Length

In this paper, semi-analytical model of waterflooding by parallel horizontal wells with transverse water-injection induced fractures has been reviewed for low-permeability reservoirs. The numerical experiments can be divided in following stages: equilibrium pressure of stable water-injection induced fracture existence estimation; evaluation of the critical equilibrium pressure of the injection-induced fractures and estimation of the conditions for the stable fracture growth; evaluation of the critical injection fluid rate for the stable fracture growth; prognosis of the fracture growth dynamics. The main idea of the proposed work is to obtain the conditions of the stable fracture existence. This situation is possible in the late stages of field development, when oil production is compensated by fluid injection, and the pressure distribution does not depend on time. Numerical modeling shows the existence of the critical fracture half-length and pressure, after which the equilibrium of injection-induced fractures becomes unstable. Before this critical fracture length is exceeded, the fracture growth can be controlled by bottomhole pressure and flow rate, since each subcritical length of the equilibrium existence of a fracture corresponds to its equilibrium pressure and flow rate. It is possible to control fracture growth before its unstable state, knowing this pressure and flow rate. The early fracture growth can be estimated by the analytical formula for the fracture half-length in the so-called Carter regime. These results were obtained for specific parameters of the development system, but can be scaled to another homothetic system. The developed model will help to understand the fundamentals of water-injection induced fracture initiation and poroelasticity, as well as develop methods that allow to control and regulate the growth of water-injection induced fractures.

Review and Outlook on Technologies for Developing PetroChina Low-Permeability Reservoirs

2013 ◽  
Vol 838-841 ◽  
pp. 1869-1872
Author(s):  
Xiu Juan Fu ◽  
Shu Hong Ji
Keyword(s):  
Water Injection ◽  
Horizontal Wells ◽  
Low Permeability ◽  
Future Technology ◽  
The Past ◽  
Low Permeability Reservoirs ◽  
Technology Trend

The technologies applied to develop PetroChina low-permeability reservoirs are summarized in the past more than 20 years. These technologies include water injection in advance, waterflood pattern optimization, fracturing and horizontal wells, etc. In addition, future technology trend is also forecasted.

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.

Research on Flow Units of Extra-Low Permeability Reservoirs in Fault Block Sheng554 of Shengping Oilfield

2013 ◽  
Vol 295-298 ◽  
pp. 3162-3165
Author(s):  
Lu Lu Zhou ◽  
Zi Nan Li ◽  
Jun Gang Liu ◽  
Yan Yun Zhang ◽  
Guang Qiang Shu
Keyword(s):  
Fluid Flow ◽  
Water Injection ◽  
Type A ◽  
Low Permeability ◽  
Type B ◽  
Flow Units ◽  
Fault Block ◽  
Remaining Oil ◽  
Type C ◽  
Low Permeability Reservoirs

Taking the example of the fourth member of the Lower Cretaceous Quantou formation reservoirs in fault block Sheng554 of Sanzhao sag, this article discusses the methodology of flow units in extra-low permeability reservoirs. The research on flow units in such reservoirs can be divided into two ranks, one is to determine the distribution of seepage barriers and inner connected sands， the other is to analyze the differentia of fluid flow in the inner connected sands so as to subdivide the flow units. The result shows that the pelitic barriers are rather developed in fault block Sheng554. Through the analysis of differentia of fluid flow, according to the value of flow zone index (FZI), the inner connected sands can be classified into three types of flow units, among which type A with FZI value greater than 1.0 has better permeable property and higher intensity of water injection, and the ability of permeability and water injection of type B with FZI value between 0.5 and 1.0 takes the second place, and type C is the worst flow unit with the worst permeable property and intensity of water injection with FZI value less than 0.5. Among the three types of flow units, type A poorly develops, while type B and type C develops well. The research on flow units can provide reliable geologic bases for forecasting the distribution of remaining oil in extra-low permeability reservoirs and for developing remaining oil in the study area.

scholarly journals Semi-analytical modeling of advanced water injection in low permeability reservoirs under non-Darcy-flow condition

2019 ◽  
Vol 11 (5) ◽  
pp. 168781401984676 ◽  
Author(s):  
Chengyong Li ◽  
Jing Yang ◽  
Jianwen Ye ◽  
Jun Zhou ◽  
Ran Zhang ◽  
...  
Keyword(s):  
Flow Condition ◽  
Analytical Modeling ◽  
Water Injection ◽  
Darcy Flow ◽  
Low Permeability ◽  
Low Permeability Reservoirs

scholarly journals Optimal Inflow Performance Relationship Equation for Horizontal and Deviated Wells in Low-Permeability Reservoirs

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Liqiang Wang ◽  
Zhengke Li ◽  
Mingji Shao ◽  
Yinghuai Cui ◽  
Wenbo Jing ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Superposition Principle ◽  
Horizontal Wells ◽  
Low Permeability ◽  
Flow Function ◽  
Low Permeability Reservoir ◽  
Inflow Performance ◽  
Low Permeability Reservoirs ◽  
Performance Equation ◽  
Deviated Wells

After Vogel proposed a dimensionless inflow performance equation, with the rise of the horizontal well production mode, a large number of inflow performance relationship (IPR) equations have emerged. In the productivity analysis of deviated and horizontal wells, the IPR equation proposed by Cheng is mainly used. However, it is still unclear whether these inflow performance models (such as the Cheng, Klins-Majcher, Bendakhlia-Aziz, and Wiggins-Russell-Jennings types) are suitable for productivity evaluations of horizontal and deviated wells in low-permeability reservoirs. In-depth comparisons and analyses have not been carried out, which hinders improvements in the accuracy of the productivity evaluations of horizontal wells in low-permeability reservoirs. In this study, exploratory work was conducted in two areas. First, the linear flow function relationship used in previous studies was improved. Based on the experimental pressure-volume-temperature results, a power exponential flow function model was established according to different intervals greater or less than the bubble point pressure, which was introduced into the subsequent derivation of the inflow performance equation. Second, given the particularity of low-permeability reservoir percolation, considering that the reservoir is a deformation medium, and because of the existence of a threshold pressure gradient in fluid flow, the relationship between permeability and pressure was changed. The starting pressure gradient was introduced into the subsequent establishment of the inflow performance equation. Based on the above two aspects of this work, the dimensionless IPR of single-phase and oil-gas two-phase horizontal wells in a deformed medium reservoir was established by using the equivalent seepage resistance method and complex potential superposition principle. Furthermore, through regression and error analyses of the standard inflow performance data, the correlation coefficients and error distributions of six types of IPR equations applicable to deviated and horizontal wells at different inclination angles were compared. The results show that the IPR equation established in this study features good stability and accuracy and that it can fully reflect the particularity of low-permeability reservoir seepage. It provides the best choice of the IPR between inclined wells and horizontal wells in low-permeability reservoirs. The other types of IPR equations are the Wiggins-Russell-Jennings, Klins-Majcher, Vogel, Fetkovich, Bendakhlia-Aziz, and Harrison equations, listed here in order from good to poor in accuracy.

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