A Solution for Mechanical Isolation Volume Refracturing in Ultra-Low Permeability Horizontal Wells: A Case Study in Ordos Basin

2021 ◽  
Author(s):  
Zhiguo Wang ◽  
Zhongneng Liu ◽  
Jie Gui ◽  
Hai'en Yang ◽  
Yong Ren ◽  
...  
Keyword(s):  
Large Volume ◽  
Ordos Basin ◽  
Field Tests ◽  
Horizontal Wells ◽  
Low Permeability ◽  
Effective Measure ◽  
Stable Production ◽  
Volume Fracturing ◽  
Mechanical Isolation ◽  
Reliable Solution

Abstract With the rise of volume fracturing concept and its application in new wells, it has been shown that increasing fracturing volume is an effective measure to improve production and achieve long-term stable production of ultra-low permeability reservoirs in Ordos Basin. However, refracturing requires running liner, which makes the flow passage smaller and can't reach the volume of new wells. The challenge is how to design the tubing combination and develop matching tools to further improve refracturing volume in 5.5″ casing. The objectives of this study are to design a combined mechanical isolation liner and carry out fine-staged large-volume refracturing with a rate of 8 m3/min in 5.5″ casing. In this study, researchers have designed the liner, optimized refracturing tools and wellhead equipment by comprehensively considering reservoir pressure, wellbore, available tubing combinations and friction of fracturing fluid. Downhole microseismic technology is used to monitor refracturing microseismic events, and high-precision 3D scanning technology is used to detect and analyze the wall wear of liners after refracturing. Field tests have been carried out in Ordos ultra-low permeability horizontal wells and achieved perfect effect. This research provides a reliable solution and technical reserve for volume refracturing of ultra-low permeability reservoir in horizontal wells, and verifies that large-volume plays an important role in improving refracturing effect in the test area.

scholarly journals An approach for determining the water injection pressure of low-permeability reservoirs

2018 ◽  
Vol 36 (5) ◽  
pp. 1210-1228 ◽  
Author(s):  
Wenya Lyu ◽  
Lianbo Zeng ◽  
Minzheng Chen ◽  
Dongsheng Qiao ◽  
Jianming Fan ◽  
...  
Keyword(s):  
Ordos Basin ◽  
Water Injection ◽  
Injection Pressure ◽  
Production Performance ◽  
Low Permeability ◽  
Bohai Bay ◽  
Natural Fractures ◽  
Effective Measure ◽  
Water Breakthrough ◽  
Low Permeability Reservoirs

Waterflooding is an important functional process for low-permeability reservoir development. However, production practice shows that water breakthrough and floods along natural fractures are ubiquitous in low-permeability reservoirs. Therefore, controlling the water injection pressure to prevent water breakthrough and floods along natural fractures is an effective measure for improving the waterflooding development effect. In this paper, an approach is proposed for determining the water injection pressure based on the opening pressure of natural fractures in fractured low-permeability reservoirs. The opening pressures of natural fractures calculated by the analytical method in the paper and the formation-parting pressures are compared based on the production performance in two different fault blocks F16 and Z3 of the Zhouqingzhuang Oilfield in the Bohai Bay Basin, China. The results show that the calculated opening pressures of the natural fractures in fault blocks F16 and Z3 are 31.4 and 42.9 MPa, respectively, and they are close to the opening pressures of natural fractures obtained from the step-rate tests in injection wells (28.6 and 41.1 MPa); whereas, the formation-parting pressures (44.5 and 47.6 MPa) are greater than the opening pressures of natural fractures. This suggests that the opening pressures of natural fractures can be used, instead of the formation-parting pressure, for the maximum threshold of the water injection pressure. Its effectiveness has been confirmed via comparison to the production performances of the other two wells in the Zhouqingzhuang Oilfield and several fractured low-permeability reservoirs in the Ordos Basin, China. This study will have beneficial applications in the design of waterflooding development in low-permeability reservoirs characterized by the presence of natural fractures.

WELL TESTING HORIZONTALGAS-CONDENSATE WELLS

2017 ◽  
pp. 56-61
Author(s):  
M. L. Karnaukhov ◽  
O. N. Pavelyeva
Keyword(s):  
Comparative Analysis ◽  
Skin Effect ◽  
Horizontal Wells ◽  
Gas Condensate ◽  
Low Permeability ◽  
Well Testing ◽  
Flow Capacity ◽  
Formation Zone ◽  
Horizontal Wellbore

The well testing of gas-condensate horizontal wells are discussed in the article and the comparative analysis of borehole flow capacity, depending on the mode of it’s operation is presented. Extra attention is focused on the issue of timely identification of the reasons for the reduction of fluid withdrawal from the reservoir. The presence of high skin effect is proved, which confirms the existence of low-permeability of bottomhole formation zone related to condensation in the immediate area of the horizontal wellbore.

scholarly journals Reservoir characteristics and effective development technology in typical low-permeability to ultralow-permeability reservoirs of China National Petroleum Corporation

2021 ◽  
pp. 014459872110052
Author(s):  
Xizhe Li ◽  
Zhengming Yang ◽  
Shujun Li ◽  
Wei Huang ◽  
Jianfei Zhan ◽  
...  
Keyword(s):  
Horizontal Well ◽  
Water Flooding ◽  
Low Permeability ◽  
Reservoir Characteristics ◽  
Well Pattern ◽  
China National Petroleum Corporation ◽  
Volume Fracturing ◽  
Effective Development ◽  
Oil Gas ◽  
Ultralow Permeability

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.

scholarly journals Volume fracturing of deep shale gas horizontal wells

2017 ◽  
Vol 4 (2) ◽  
pp. 127-133 ◽  
Author(s):  
Tingxue Jiang ◽  
Xiaobing Bian ◽  
Haitao Wang ◽  
Shuangming Li ◽  
Changgui Jia ◽  
...  
Keyword(s):  
Shale Gas ◽  
Horizontal Wells ◽  
Volume Fracturing

scholarly journals Improvement of oil production in low permeability deposits with a system of horizontal wells

2020 ◽  
Vol 11 (29) ◽  
pp. 205-216 ◽  
Author(s):  
N.R. Krivova
Keyword(s):  
Oil Production ◽  
Horizontal Wells ◽  
Low Permeability ◽  
Pilot Tests

The article describes an approach to the production of difficult to extract oil, confined to deposits with low poroperm properties, using a system of horizontal wells and hydraulic multistage fracturing. The main problems that arise during the development of the well are analyzed. A conclusion is reached on the possibility of continuing to apply the method based on the analysis of pilot tests.

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