Numerical investigation into effects of fracturing parameters on the productivity of multi-staged fractured horizontal wells in tight oil reservoirs

ABSTRACT

Although the development of stimulated reservoir volume (SRV) fracturing treatment promotes the exploitation of the tight oil reservoirs, the well production performance has not been modeled comprehensively with existing simulators. In this paper, a new dual-porosity and dual-permeability model considering threshold pressure gradient, stress-sensitive matrix permeability, and capillary pressure were established. Additionally, the artificial hydraulic fracture model and fracture conductivity failure model were developed. The model is solved numerically and validated by the commercial simulator Eclipse and field production data. Based on the novel model, the sensitivity analysis of parameters including cluster spacing, stage spacing, net fracture permeability, fracture conductivity, and fracture length were performed. The results indicate that even distribution of stages and clusters in the horizontal well results in higher production and there is no need to over increase the permeability of the fracture network. Further, the maintaining of the fracture conductivity is vital for the economic development of tight oil reservoir and the increase of the fracture length is beneficial for achieving higher productivity. This study provides a basis for long-term tight oil production analysis, oil/water flow simulation, and post-treatment productivity prediction of hydraulically fractured tight oil wells.

KEYWORDS:

• Tight oil reservoir
• SRV fracturing
• productivity performance
• fracturing parameter analysis
• numerical simulation

Acknowledgments

The authors gratefully acknowledge the sponsor of the Project supported by The National Science and Technology Major Project of China, No. 2017ZX05035.

Additional information

Notes on contributors

Linjing Xu

Linjing Xu is continuing her research work in the postdoctoral workstation of CNPC Great Wall Drilling Company. She received her PhD and MS in Petroleum Engineering from China University of Petroleum, Beijing. Her current research interests include the flow theory of tight oil reservoirs, numerical simulation of production in unconventional reservoirs.

Guoyong Wang

Guoyong Wang is a professorate senior engineer and the director of Energy Business Department in CNPC Great Wall Drilling Company. He mainly engages in the research and management of gas reservoir engineering, natural gas exploration and development. He presided and participated in a number of national and CNPC major scientific research projects, and achieved many innovative results.

Tianyu Liu

Tianyu Liu is an engineer of CNPC Research Institute of Petroleum Exploration and Development. She received her MS in Petroleum Engineering from China University of Petroleum, Beijing. Her current research interests include oilfield development technology in high water cut stage and numerical reservoir simulation.

Naizhen Liu

Naizhen Liu is a professorate senior engineer of CNPC Great Wall Drilling Company. He mainly engaged in the research and management of drilling engineering, well completion engineering and reservoir stimulation technology. He presided and participated in a number of national and CNPC major scientific research projects. Meanwhile, many results have successfully applied in the oilfield.

Shicheng Zhang

Shicheng Zhang is a Professor of Petroleum Engineering of China University of Petroleum, Beijing. He and his graduate students work in the areas of hydraulic fracturing technology in unconventional reservoirs and low-permeability reservoirs, production engineering theory and technology. His research efforts with his graduate students have produced more than 50 PhD and MS theses and more than 100 publications including three books.

Haiyan Jia

Haiyan Jia is a senior engineer of CNPC Great Wall Drilling Company. She received her MS in Petroleum Engineering from Southwest Petroleum University. Her current research interests include hydraulic fracturing technology in unconventional reservoirs and fracturing fluid flowback in hydraulically fractured shale gas reservoirs.