Abstract

Multi-component thermal fluid (MCTF) huff and puff technology is an innovative heavy oil development technology widely used in China offshore oilfields. MCTFs mainly include steam, N2 and CO2. Under high temperature and high pressure, the physical and chemical reactions between thermal fluids and rocks occur, damaging the reservoir permeability and production effect. In this paper, 16 groups of core comparison experiments were carried out by MCTF device, the influence of original permeability, temperature and component on reservoir damage was quantitatively studied, and a mathematical model was established. Finally, the influence of reservoir damage on heavy oil development was investigated through numerical simulation. The experimental study reveals that MCTF has an obvious damage effect on the reservoir, where temperature and PV dominate the damage degree; with the increase of MCTF injection volume (PV), the core permeability rapidly decreases initially and stabilizes later (>6 PV). The numerical simulation results show that reservoir damage could lead to a recovery drop by 6.9% during MCTF development; on the premise of considering reservoir damage, MCTF huff and puff will further improve oil recovery by 9.68% compared with pure steam. The research is of great significance for understanding the production law of MCTF huff and puff and helpful for promoting the development of offshore heavy oil reservoir.

Highlights

  • At present stage, the potential of conventional sandstone reservoirs has gradually declined, and heavy oil reservoirs have become one of the key areas to increase production in China (Jiang et al, 2020; Li, 2021; Yang, 2021)

  • To determine the key influencing factors, we study the influence of original permeability level, temperature and thermal fluid component proportion on reservoir damage degree

  • This paper quantitatively studies the influence of multiple factors on reservoir damage through core experiments

Read more

Summary

INTRODUCTION

The potential of conventional sandstone reservoirs has gradually declined, and heavy oil reservoirs have become one of the key areas to increase production in China (Jiang et al, 2020; Li, 2021; Yang, 2021). Offshore heavy oil development platform has been seeking a new thermal recovery method, where injection material is easy to obtain, transport and store, and the equipment is light and able to produce enough heat. These requirements coincide with the target of. The compaction and cementation of offshore heavy oil reservoir are usually poor Under such high temperature and pressure environment, complex physical and chemical reactions will occur between hot steam, CO2, N2, formation fluid and rock, which will cause continuous damage to the reservoir in the process of long-term huff and puff production, making it difficult to accurately predict, evaluate and adjust reservoir development. Simulation method to compare the development effect considering reservoir damage on oilfield scale

Experimental Equipment
Experimental Design
The Influence of Permeability on Damage Degree
The Influence of Temperature on Damage Degree
The Influence of Component Proportion on Damage Degree
The Influence of Stream Proportion on Damage Degree
The Influence of CO2 Proportion on Damage Degree
The Influence of N2 Proportion on Damage Degree
Comparison of Thermal Cavity Expansion
Comparison of Viscosity Reduction Effect Near Well Zone
Comparison of the Influence of Reservoir Damage on the Development Effect of MCTF
Comparison of Development Effects Between MCTF and Steam Huff and Puff
CONCLUSION
Findings
DATA AVAILABILITY STATEMENT

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.