Laboratory to field scale assessment for EOR applicability in tight oil reservoirs

Abstract

Tight oil reservoirs are contributing a major role to fulfill the overall crude oil needs, especially in the US. However, the dilemma is their ultra-tight permeability and an uneconomically short-lived primary recovery factor. Therefore, the application of EOR in the early reservoir development phase is considered effective for fast-paced and economical tight oil recovery. To achieve these objectives, it is imperative to determine the optimum EOR potential and the best-suited EOR application for every individual tight oil reservoir to maximize its ultimate recovery factor. Since most of the tight oil reservoirs are found in wide spatial source rock with complex and compacted pores and poor geophysical properties yet they hold high saturation of good quality oil and therefore, every single percent increase in oil recovery from such huge reservoirs potentially provide an additional million barrels of oil. Hence, the EOR application in such reservoirs is quite essential. However, the physical understanding of EOR applications in different circumstances from laboratory to field scale is the key to success and similarly, the fundamental physical concepts of fluid flow-dynamics under confinement conditions play an important role. This paper presents a detailed discussion on laboratory-based experimental achievements at micro-scale including fundamental concepts under confinement environment, physics-based numerical studies, and recent actual field piloting experiences based on the U.S. unconventional plays. The objective of this paper is to discuss all the critical reservoir rock and fluid properties and their contribution to reservoir development through massive multi-staged hydraulic fracture networks and the EOR applications. Especially the CO 2 and produced hydrocarbon gas injection through single well-based huff-n-puff operational constraints are discussed in detail both at micro and macro scale.