Feasibility and Mechanism of Deep Heavy Oil Recovery by CO2-Energized Fracturing Following N2 Stimulation
Author:
Sun Shuaishuai1, Wu Yongbin2, Ma Xiaomei3, Liu Pengcheng1ORCID, Zhang Fujian1, Liu Peng2, Zhang Xiaokun1
Affiliation:
1. School of Energy Resources, China University of Geosciences, Beijing 100083, China 2. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China 3. Fengcheng Oil Plant, Xinjiang Oilfield Company, PetroChina, Keramay 834000, China
Abstract
There are large, heavy oil reserves in Block X of the Xinjiang oilfields, China. Due to its large burial depth (1300 m) and low permeability (26.0 mD), the traditional steam-injection technology cannot be used to obtain effective development benefits. This paper conducts experimental and simulation research on the feasibility and mechanism of CO2-energized fracturing of horizontal wells and N2 foam huff-n-puff in deep heavy oil reservoirs with low permeability in order to further explore the appropriate production technology. The foaming volume of the foaming agent at different concentrations and the oil displacement effect of N2 foam at different gas/liquid ratios were compared by the experiments. The results show that a high concentration of foaming agent mixed with crude oil is more conducive to increasing the foaming volume and extending the half-life, and the best foaming agent concentration is 3.0∼4.0%. The 2D micro-scale visualization experiment results show that N2 foam has a good selective blocking effect, which increases the sweep area. The number of bubbles per unit area increases as the gas/liquid ratio increases, with 3.0∼5.0 being the optimal gas/liquid ratio. Numerical simulation results show that, when CO2-energized fracturing technology takes into account the advantages of fracturing and crude oil viscosity reduction by CO2 dissolution, the phased oil recovery factor in the primary production period can reach approximately 13.7%. A solvent pre-slug with N2 foam huff-n-puff technology is applied to improve oil recovery factor following primary production for 5∼6 years, and the final oil recovery factor can reach approximately 35.0%. The methodology formulated in this study is particularly significant for the effective development of this oil reservoir with deeply buried depth and low permeability, and would also guide the recovery of similar oil deposits.
Funder
the National Natural Science Foundation of China
Subject
Energy (miscellaneous),Energy Engineering and Power Technology,Renewable Energy, Sustainability and the Environment,Electrical and Electronic Engineering,Control and Optimization,Engineering (miscellaneous),Building and Construction
Reference47 articles.
1. Experimental investigation into hydraulic fracture network propagation in gas shales using ct scanning technology;Yushi;Rock Mech. Rock Eng.,2016 2. Numerical investigation into the influence of bedding plane on hydraulic fracture network propagation in shale formations;Yushi;Rock Mech. Rock Eng.,2016 3. Kizaki, A., Tanaka, H., Ohashi, K., Sakaguchi, K., and Matsuki, K. (2012, January 15–19). Hydraulic fracturing in inada granite and ogino tuff with super critical carbon dioxide. Proceedings of the ISRM Regional Symposium-7th, Asian Rock Mechanics Symposium, Seoul, Republic of Korea. 4. Inui, S., Ishida, T., Nagaya, Y., Nara, Y., and Chen, Q. (2014, January 1–4). Ae monitoring of hydraulic fracturing experiments in granite blocks using supercritical CO2, water and viscous oil. Proceedings of the 48th U.S. Rock Mechanics/Geomechanics Symposium, Minneapolis, MI, USA. 5. Experimental study on the hydraulic fracture propagation in shale;Heng;Curr. Sci.,2018
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|