东濮凹陷前梨园洼陷深层天然气成藏模式与主控因素

发布时间：2019-05-18 01:11

【摘要】：本文综合运用地质、地球物理、地球化学等资料,研究了前梨园洼陷深层天然气成因类型、来源,重点解剖了文203-58断块区和杜寨地区的深层天然气藏,总结了前梨园洼陷深层天然气成藏的主控因素及成藏模式。利用地球化学资料,分别按母质来源和相态变化,对前梨园洼陷深层天然气进行分类、判识,结果表明,深层干气以晚期干酪根裂解气为主,含有少量原油裂解气,分布于洼陷中心;无油环凝析气以干酪根裂解气和原油裂解气混合为主,分布于斜坡带;有油环的凝析气为原油裂解气和原油混合相,主要分布于中央隆起带等构造高部位。从宏观和微观两个角度研究了深层天然气的充注路径,明确了深层天然气藏主要形成于生烃中心及其邻近上倾部位。从静态地质特征、天然气特征、充注过程三个方面解剖典型深层天然气藏,结果表明,文203-58断块区油气充注期分别为东营沉积末及明化镇组沉积期至今,东营沉积末期主要充注石油,含有少量原油裂解气;明化镇期至今前梨园洼陷再次沉降,温压升高,原油大量裂解生气,并有少量晚期干酪根裂解气充注于文203-59断块圈闭边缘。杜寨地区同样存在两期油气充注,东营沉积末期,油气为原油与原油裂解气和干酪根裂解气混合相;明化镇组期,杜寨地区附近的烃源岩发生二次生烃,生成晚期干酪根裂解气充注到圈闭中,并驱替原有的混合相油气。通过综合研究,前梨园洼陷深层天然气成藏主控因素可以概括为:烃源岩热演化及原油裂解控制不同成因类型天然气的生成与分布、微构造控制深层天然气的聚集。前梨园洼陷深层天然气存在两种成藏模式:单源早油相晚气相运聚成藏模式和单源早混相晚气相运聚成藏模式,分别发育于斜坡带和洼陷带。前者烃源岩热演化程度较低,早期生油,晚期生成干酪根裂解气和原油裂解气混合的凝析气,排替古油相,经短距离的二次运移,在斜坡带的构造-岩性圈闭中成藏;后者烃源岩热演化程度较高,早期生凝析气与原油的混相,晚期生干气,经初次运移,在洼陷带的岩性圈闭中就近成藏。
[Abstract]:Based on geological, geophysical and geochemical data, the genetic types and sources of deep natural gas in Qianliyuan sag are studied in this paper, and the deep natural gas reservoirs in Wen20358 fault block area and Duzhai area are dissected. The main controlling factors and reservoir forming model of deep natural gas accumulation in Qianliyuan sag are summarized. Based on the geochemical data, the deep natural gas in Qianliyuan sag is classified and identified according to the source and phase change of parent material, respectively. the results show that the deep dry gas is dominated by late kerogen cracking gas and contains a small amount of crude oil cracking gas. Distributed in the center of the sag; The condensate gas without oil ring is mainly composed of kerogen cracking gas and crude oil cracking gas, which is distributed in the slope zone, and the condensate gas with oil ring is the mixed phase of crude oil cracking gas and crude oil, which is mainly distributed in the high tectonic parts such as the central uplift zone. The filling path of deep natural gas is studied from the macro and micro point of view, and it is clear that the deep natural gas reservoir is mainly formed in the hydrocarbon generation center and its adjacent updip position. The typical deep natural gas reservoirs are dissected from three aspects: static geological characteristics, natural gas characteristics and filling process. The results show that the filling period of oil and gas in the fault block area of Wen 203 / 58 is the sedimentary period at the end of Dongying deposition and Minghuazhen formation, respectively. At the end of Dongying deposition, it was mainly filled with oil and contained a small amount of crude oil cracking gas. From the Minghua town period to the present, the Liyuan sag settled again, the temperature and pressure increased, and a large amount of crude oil cracked gas, and a small amount of late kerogen cracking gas was filled into the trap edge of Wen 203 / 59 fault block. There are also two stages of oil and gas filling in Duzhai area. At the end of Dongying deposition, the oil and gas is a mixture of crude oil and crude oil pyrolysis gas and kerogen cracking gas. During the Minghuazhen formation, the source rocks near Duzhai area produced secondary hydrocarbon generation, formed late kerogen cracking gas and filled into the trap, and displaced the original mixed phase oil and gas. Through comprehensive study, the main controlling factors of deep natural gas accumulation in Qianliyuan sag can be summarized as follows: thermal evolution of source rocks and crude oil cracking control the generation and distribution of different genetic types of natural gas, and microstructure controls the accumulation of deep natural gas. There are two reservoir forming models for deep natural gas in Qianliyuan sag: single source early oil phase late gas migration accumulation model and single source early miscible phase late gas migration accumulation model, which are developed in slope zone and sag zone, respectively. The former source rock has a low degree of thermal evolution, the early generation of oil, the late formation of kerogen cracking gas and crude oil cracking gas mixture condensate gas, the displacement of ancient oil phase, through short distance secondary migration, in the slope zone of the structure-lithologic trap to form a reservoir; The latter source rocks have a high degree of thermal evolution, the mixing of early condensate gas and crude oil, and the late generation of dry gas, after primary migration, are close to the reservoir in the lithologic trap of the sag zone.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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