Screening and Evaluation of New Technologies in Developing Super-Heavy Oil or Oil Sands Projects
Authors: Liang Guangyue , Xie Qian , Liu Shangqi , Liu Yang , Xia Zhaohui , Bao Yu , Zhou Jiuning 
Published: May 2023

SAGD process has been widely applied in super-heavy oil and oil sands projects. Slow vertical steam chamber growth and non-uniform conformance tends to generate lower oil rate and higher steam to oil ratio in SAGD projects, which were mainly influenced by thin pay, shale interlayers and bottom transition zone. Therefore, this paper presents screening and evaluation results of many emerging technologies to develop super-heavy oil or oil sands projects.

15 kinds of new technologies were investigated by AER reports and numerous papers. 6 of them were evaluated by numerical simulation, including multilateral injector or producer, vertical slimholes assisted SAGD process, steam drive assisted gravity drainage, offset SAGD well pair, and bottom-up gravity-assisted pressure drive, etc. Besides, the experience of field practices related to many little-known emerging technologies was extensively and deeply analyzed including single vertical well SAGD process, fishbone wedge producer, liner or tubing deployed ICD/FCD, various dilation practices in preheating or SAGD phase, movable steam splitter, re-drill injector or producer with optimized location, steam drive assisted gravity drainage, etc. Moreover, the mechanisms, detailed pilots and challenges were further summarized.

For thin pay, single vertical well SAGD process aims to realize vertical multi-stage fracturing based on expansion pipe, accelerate steam chamber growth from top to the bottom, maximize the effect of gravity drainage to achieve earlier peak oil rate. For the reservoir impacted by shale laminae, steam drive assisted gravity drainage under different well spacing can be trialed. Steam circulation or stimulation, hydraulic fracturing and multilateral producer may be applied from 5m, 10m to 20-30m horizontal spacing while keep vertical spacing at 3-5m. Besides, enhancing vertical permeability, drilling vertical channels or enforcing horizontal driving force are possible solutions to overcome shale interlayers and bottom water. Dilation process assisted by waste water, polymer, chemical or low cost catalyzer in more than one hundred well pairs can reduce steam consumption in start-up process and achieve better early SAGD performance. Bottom-up gravity-assisted pressure drive process overwhelms SAGD process in terms of accelerated oil production and lower SOR in relatively low quality oil sands projects such as thin pay, shale interlayers, bottom transition zone, etc. Especially, the practices of wedge wells, multilateral injector or producer, steam drive assisted gravity drainage based on multilateral producer, and re-drill injector or producer successfully tapped the remaining oil, enhanced the peak oil rate or reduced SOR significantly.

This paper presents much novel information about research advancement and field practices of many new technologies. These technologies can be effectively applied to relatively low quality heavy oil projects such as thin pay, shale interlayers, bottom transition zone, etc.