Earth Science Frontiers ›› 2023, Vol. 30 ›› Issue (4): 100-111.DOI: 10.13745/j.esf.sf.2022.10.24

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Volcanic reservoir characteristics and hydrocarbon accumulation control factors of rift depressions in southern Songliao Basin

LI Ruilei1(), YANG Liying2,*(), ZHU Jianfeng1, LIU Yuhu1, XU Wen1, LI Zhongbo1, FAN Xuepei1, LENG Qinglei1, ZHANG Tingting1   

  1. 1. Sinopec Northeast Oil and Gas Branch, Changchun 130062, China
    2. Applied Technology College, Jilin University, Changchun 130061, China
  • Received:2022-08-16 Revised:2022-09-21 Online:2023-07-25 Published:2023-07-07

Abstract:

Intermediate-basic volcanic rocks of the Huoshiling Formation are widely developed in rift depressions in southern Songliao Basin. In this present study we investigated the volcanic rock distribution, lithology and lithofacies, volcanic structure types, reservoir space characteristics and gas accumulation characteristics through comprehensive multi-scale analysis, and then discussed the formation mechanism of effective reservoir space and the main controlling factors of hydrocarbon accumulation. We found that (1) intermediate-basic volcanic rocks are widely distributed in the basin mainly as multi-stage superimposed, connected low-amplitude mounds. The rock develops 3 types of lithofacies and 7 types of subfacies as well as a composite pore-fracture network-type reservoir space. (2) Volcanic structures control the lithology and lithofacies distribution, and determine the formation and distribution of primary pores; while tectonic movements and rock dissolution are conducive to the formation of structural fractures and secondary dissolution pores and fractures, and they are the key factors controlling the formation of high-quality reservoirs. (3) The reservoir control mechanism can be described by a quaternary model: The paleostructural setting during the accumulation period determines the direction of hydrocarbon accumulation; the favorable hydrocarbon generation center of the deep depression provides the material basis for the hydrocarbon accumulation and dynamic conditions; the multi-type, multi-scale pore-fracture development zones control the distribution of favorable reservoirs and determine the degree of oil and gas enrichment; and stable mudstone and late-stage weak tectonic activities provide better preservation conditions for the development of petroleum reservoirs.

Key words: Songliao Basin, faulted layer, volcanic rock, effective reservoir, main controlling factors of accumulation

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