The diversity of hydrocarbon habitat in Russia

Abstract

The setting of the petroleum basins of Russia varies from Precambrian cratons to Tertiary active margins. Four economically and strategically important basins illustrate this diversity. The North Sakhalin Basin is a Tertiary strike-slip basin supplied with Oligocene-Pliocene reservoir sands, and seal- and source-forming mudrocks by the palaeo-Amur delta. Miocene diatomites are additional source rocks. Plio-Pleistocene structuring was crucial to hydrocarbon entrapment. The West Siberia Basin contains identified oil reserves of 60 billion bbl and 1400 tcf gas, respectively 47% of the oil reserves of the CIS and 77% of its gas reserves. The world-class Upper Jurassic Bazhenov source rock and a high impedance entrapment style are the keys to the productivity of the basin. The Timan-Pechora Basin contains Ordovician-Triassic reservoirs and a major Late Devonian source rock. Hydrocarbon preservation is good despite the basin's complex history of subsidence and inversion. On the Siberian Platform in East Siberia 12 billion BOE reserves are sourced, reservoired and sealed by Upper Precambrian-Cambrian rocks. Protracted preservation times there reflect a stable geological setting.

The limited suitability of silica diagenetic boundaries as isothermal markers: Insights from seismic reflection imaging, Offshore Sakhalin, Russian Far East

“…1). The sea is an area where biogenic siliceous sediments accumulated during the Miocene, which were buried by deltaic sediments in the Pliocene (Tull, 1997).…”

“…There was a change in tectonic regime from subduction to strike-slip in the Palaeogene that generated a series of basins to the east of Sakhalin. Early Cenozoic transtension provided the accommodation space for deltaic progradation from the palaeo-Amur and its distributaries, with very high sedimentation rates of up to 500-800 m Ma À1 (Tull, 1997). An episode of lateral compression during the Late Miocene resulted in erosion and the development of an unconformity on top of which the Pliocene deltaic sediments were deposited (Lindquist, …”

“…Sakhalin had become an island by 3 Ma (Early Pliocene) as a result of the propagation of the strike-slip fault system northwards; this resulted in the deflection of the Amur delta to the north (Brettle and Bessa, 2006). Late Pliocene tectonism and orogenic inversion resulted in significant geologically recent folding and thrusting, in modification and rupturing of pre-existing structures (Tull, 1997) in the NSB.…”

“…It is within these rocks that the silica conversions are most likely to occur. Pliocene lithologies consist of deltaic sandstones and some mudstones with limited biosiliceous content (Tull, 1997;Lindquist, 2000). Diatomaceous mudrocks and siltstones are common in the basins of the Sea of Okhotsk, because the marginal sea represents a clastic-poor, sediment starved area, with much of the runoff towards the Arctic due to Eocene uplift of the areas around the sea (Karlo and Gebhard, 2006).…”

“…The seismic stratigraphy (Fig. 3) consists of a Cretaceous basement overlain by Oligocene, Miocene and Pliocene successions (Tull, 1997;Lindquist, 2000).…”