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为了研究歧口凹陷滨海地区高温高压条件下烃源岩生排烃特征,本文在对歧口凹陷烃源岩进行综合评价的基础上,研究了滨海地区古近系生排烃特征及主控因素。结果表明,滨海地区古近系烃源岩厚度大、分布范围广,有机质丰度高,类型丰富,富烃源岩发育,演化程度较高,具备较大的生烃潜力,烃源岩的成熟门限偏深,有效生油井段长,与一般的烃源岩相比生油下限明显向深部偏移,大量生气门限较深,有效生气期作用时间短,具有“持续生油、集中生气”的特点;同时,烃源岩在4300m开始进入排烃门限,排烃效率高,厚层泥岩也能有效排烃。除受沉积相的影响因素外,滨海地区高温高压条件对古近系烃源岩生排烃演化特征具有明显的控制作用。
In order to study the characteristics of hydrocarbon generation and expulsion in source rocks under high temperature and high pressure in the coastal area of Qikou Sag, this paper studied the characteristics of Paleogene hydrocarbon generation and expulsion and their controlling factors in the coastal area based on the comprehensive evaluation of source rocks in Qikou Sag. The results show that the Paleogene source rocks in the coastal area are of large thickness, wide distribution, high abundance of organic matter, rich types, rich source rocks, high evolutionary potential, high hydrocarbon generation potential and maturity of source rocks The threshold is deeper and the length of active oil well is longer. Compared with the general source rocks, the lower limit of oil generation obviously shifts to the deep, with a large number of thresholds for deep gas generation and a short effective period of active gas generation period, with "sustained oil generation, concentrated gas generation At the same time, the hydrocarbon source rocks begin to enter the hydrocarbon expulsion threshold at 4300m, the hydrocarbon expulsion efficiency is high, and the thick mudstone can effectively drain hydrocarbons. In addition to the influence factors of sedimentary facies, the conditions of high temperature and high pressure in the coastal area have significant control over the evolution characteristics of hydrocarbon generation and expulsion in the Paleogene source rocks.