摘要
本区石炭、二叠系埋深1500—4600m,主要残留在断陷构造及古向斜中,分布面积3万多平方公里,总厚达1000m 以上。上石炭统太原组及下二叠统山西组为煤系,有机质丰度高,已成熟,是较好的油气源岩。石炭、二叠系可自成生储盖组合,又可从上覆下第三系中获得油气。从构造运动及热演化条件分析,主要生油气期为喜山期,次为燕山期。文安斜坡的油气远景较好,廊坊地区次之;冀南地区应以找气为主。
Abstract
The Carboniferous and Permian Systems in central and south Hebei Pro-vince,remained primarily in some fault-depressed basins and paleosynclines,distri-but within an area of more than 3000km with buried depth of 1500-4600m anda total thickness of more than 1000m,In the Permian System,the Shiqianfeng Formation,the Upper and Lower Shihezi Formations are mainly terrestrial clas-tic sediments formed in oxidizing environment,the Shanxi Formation is coal-bearing strata;the Benxi and Taiyuan Formations of the Middle and Upper carbo-niferous are transitional facies of terrestrial and marine sediments in which theTaiyuan Formation consists of coal measure.The Shanxi Formation contains 4-12 coal beds with a total thickness of 8.5-27m;the Taiyuan Formation contains 2-11 coal beds,with a total thick-ness of 2.5-33.5 m.Much carbonaceous and dark mudstones can be found incoal measures.The content of chloroform bitumen“A”is more than 0.2% inthe coal beds,the content of residual organic carbon is generally 0.5-1.0% andchloroform bitumen“A”is 0.048-0.115% in the dark mudstones.Vitrinite reflec-tance of them is greater than 0.5%.These indices show that they are favour-able source rocks.To analyze the hydrocarbon generation of the basin in accordance with tec-togenesis and the conditions of thermoevolution,the Himalayan phase is consi-dered to be an important period,and then the Yanshan phase.The Carboniterous and Permian Systems here have composed a great source-reservoir-cap rock assemblage,which can receive oil and gas from the overlying Eogene too.Thus the assemblage has double oil sources.The trap type on thewhole is considred to be fault-block type.The authors suggest that Wen'an Slop is the most favourable area in oiland gas prospects,and then Shenxian and Langfang ranges;as for the south ofHebei,it is better to seek coal-formed gas.
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