The Importance of Laminae for China Lacustrine Shale Oil Enrichment: A Review

Abstract

The laminar structure of shale system has an important influence on the evaluation of hydrocarbon source rock quality, reservoir quality, and engineering quality, and it is receiving increasing attention. A systematic study of the lamina structure is not only of great scientific significance but also of vital practical importance for shale oil production. In this paper, the identification and description classification of shale laminae are first reviewed. Multiple scales and types indicate that a combination of different probe techniques is the basis for an accurate evaluation of shale laminar characteristics. The influence of laminae on shale reservoir, oil-bearing, mobility, and fracability properties is discussed systematically. A comparative analysis shows that shale systems with well-developed lamination facilitate the development of bedding fractures, thus improving the shale storage space. The average pore size and pore connectivity are also enhanced. These factors synergistically control the superior retention and flow capacity of shale oil in laminated shales. In such conditions, the high production of shale oil wells can still be achieved even if complex networks of fracturing cracks are difficult to form in shale systems with well-developed lamination. This work is helpful to reveal the enrichment mechanism of shale oil and clarify the high-yield law of hydrocarbons, so as to guide the selection of sweet spots.

Novel Method for the Classification of Shale Oil Reservoirs Associated with Mobility: Inspiration from Gas Adsorption and Multiple Isothermal Stage Pyrolysis

“…Thus, we suggest that an application of CO 2 adsorption should be avoided in shale oil reservoir analysis in order to reduce expenses and analysis time. In reality, it is noteworthy that laminae play a prominent role in the process of shale oil storage, migration, and production. ,,, Accordingly, it is particularly important and urgent to establish a new full-scale characterization method that can comprehensively evaluate restricted pores, free pores, and even laminar structures for shale oil reservoirs.…”

Geophysical Interpretation of Horizontal Fractures in Shale Oil Reservoirs Using Rock Physical and Seismic Methods

“…Recent experiments and core and outcrop observations have indicated that the presence of horizontal fractures in the shale can cause substantial anisotropy variations with loading stresses [33][34][35]. Geological studies have also confirmed the importance of horizontal fractures for sweet spot predictions in shale reservoirs [36][37][38][39]. Accordingly, some efforts have been made to predict the VTI anisotropy of the shale based on rock physical modeling using logging data [40].…”