Multiple-stacked Hybrid Plays of lacustrine source rock intervals: Case studies from lacustrine basins in China

Abstract

Hydrocarbon-producing lacustrine basins are widely developed in the world, and China has a large number of lacustrine basins that have developed since the early Permian. The organic-rich shale-dominated heterogeneous source rock intervals in Chinese lacustrine basins generally contain frequent thin interbeds of stratigraphically associated sandstone, siltstone, marl, dolomite, and limestone. The concept of ''Hybrid Plays'' as put forth in this article recognizes this pattern of alternating organicrich shale and organic-lean interbeds and existence of mixed unconventional and conventional plays. Hybrid Plays in lacustrine source rock intervals present a unique closed petroleum system hosting continuous hydrocarbons. The interbedded organic-lean siliciclastic and/or carbonate plays are efficiently charged with hydrocarbons via short migration pathways from the adjacent organic-rich shale that is often also a self-sourced play. We assert ''Hybrid Plays'' provide the most realistic exploration model for targeting multiple-stacked and genetically related very tight shale, tight and conventional plays together in the entire source rock interval rather than individual plays only. The Hybrid Play model has been proven and works for a wide variety of lacustrine rift, sag and foreland basins in China.

Fourier-Transform Infrared Proxies for Oil Source and Maturity: Insights from the Early Permian Alkaline Lacustrine System, Junggar Basin (NW China)

“…In recent years, previous studies suggested that the lower Permian Fengcheng formation in the Mahu sag was deposited in an alkaline–saline lake. − Based on the general characteristics of alkaline–lacustrine deposition, ,, we infer that oil family 1, family 2, and family 3 were derived from alkaline, saline, and brackish–freshwater source rocks of the Fengcheng formation, respectively.…”

“…The lower Permian Fengcheng formation in the Mahu sag, northwestern Junggar Basin, Northwest China, was deposited in an alkaline–saline lake and is globally the first discovered in the late Paleozoic with giant petroleum accumulations. − The organic facies of such lacustrine source rocks show large spatial variations, resulting in a complex and heterogeneous oil distribution. − Therefore, classifying and identifying the origin(s) of alkaline lacustrine oils in this area is critical but challenging.…”

Optimization of shale gas reservoir evaluation and assessment of shale gas resources in the Oriente Basin in Ecuador

“…Deep and semi-deep seas are rich in organic matter, which is formed by bio-remain deposition and other sources that form black shales (Stow et al 2001). These carbonaceous shales that are rich in black organic matter can serve as good hydrocarbon source rocks (Jiang et al 2017). After hydrocarbon generation and expulsion, the deepwater environment of the ocean becomes a favorable shale gas enrichment area (Gross et al 2015;Misch et al 2016;Zou et al 2015).…”

Key factors controlling shale oil enrichment in saline lacustrine rift basin: implications from two shale oil wells in Dongpu Depression, Bohai Bay Basin

“…The organic matter in the shales shows large variations in contents and compositions dominated by type I and type II kerogens, which have low thermal maturity, low quartz mineral content and mainly generate waxy oil (Katz and Lin 2014;Chen et al 2015;Wang et al , 2015aWang et al , b, 2019Nie et al 2016). Clearly, lacustrine basins and marine basins have distinct differences in geological and geochemical characteristics (Jiang et al 2017;Wang et al 2019). It is difficult to arbitrarily apply the shale oil enrichment laws of productive shale oil plays in the USA to China.…”