燕辽裂陷带辽西拗陷中元古界高于庄组生物标志化合物特征及意义

燕辽裂陷带辽西拗陷多口钻井钻遇油气显示，使得该地区中-新元古界的古老海相地层再次成为油气勘探及研究的焦点.采用气相色谱、气相色谱-质谱技术，对辽凌地1井中元古界高于庄组岩心样品开展烃源岩生物标志化合物研究，据此分析了其生源信息、沉积环境及生烃潜力.综合分析认为，辽凌地1井高于庄组属于差-中等烃源岩，有机质类型II₁型，整体处于成熟-高成熟阶段，已大量生排烃.高于庄组烃源岩饱和烃的正构烷烃碳数分布呈前单峰型，主峰碳多为nC₁₇，具有C₂₇规则甾烷优势，指示其母质输入以低等生物为主.综合萜烷类化合物分布特征，推测高于庄组生源主要为低等菌藻类.另外，较高的伽马蜡烷含量、较低的Pr/Ph比值，反映出高于庄组烃源岩主体形成于咸水还原环境，个别层位可能为强还原环境.

BIOMARKER CHARACTERISTICS AND IMPLICATION OF THE MESOPROTEROZOIC GAOYUZHUANG FORMATION IN LIAOXI DEPRESSION OF YANLIAO RIFT ZONE

The oil-gas shows found in several bore wells in Liaoxi Depression of Yanliao Rift Zone bring the Meso-Neoproterozoic marine strata in the area once again into the focus of oil-gas exploration and research. Both gas chromatography and gas chromatography-mass spectrometry are used to study the biomarkers of source rocks from Mesoproterozoic Gaoyuzhuang Formation in LLD1 well, and analyze the organic matter source, sedimentary environment, and hydrocarbon generation potential. Through comprehensive analysis, it is considered that Gaoyuzhuang Formation belongs to poor-medium grade source rocks, as organic type of II₁, generally in mature-high mature stage with mass generation and expulsion of hydrocarbon. The carbon number distribution of n-alkanes in saturated hydrocarbon is pre-unimodal. The main peak carbon is mostly nC₁₇, with the advantage of C₂₇ regular sterane, indicating that the parent material input is dominated by lower organism. Combined with the distribution characteristics of terpanes, it is inferred that the main organic source is low bacteria algae. Moreover, the high gammacerane content and low Pr/Ph ratio reflect the main source rocks of Gaoyuzhuang Formation were formed in salt water reduction environment, with certain layers possibly in strongly reduced environment.