裂陷湖盆深层烃类赋存相态极限的动力学过程分析——以渤海湾盆地歧口凹陷为例

发布时间：2018-07-01 21:32

本文选题：深层 + 烃类相态　；参考：《天然气地球科学》2017年05期

【摘要】：为适应东部盆地向深层—超深层勘探的需求,通过歧口凹陷沙河街组典型原油的裂解生气模拟实验,采用原油裂解生烃动力学特征研究深层烃类流体相态变化规律。结果表明:原油裂解气生烃动力学可以方便地研究地质条件下原油裂解程度,进而判断地下油气相态的理论深度极限。在固定频率因子A=10~(14)S~(-1)前提下,渤海湾盆地歧口凹陷沙河街组原油裂解成C_1—C_5的活化能分布在250~270kJ/mol之间,平均活化能E_0=255.47kJ/mol,高于海相原油的245kJ/mol(59kCal/mol)。在同等升温速率条件下,其裂解生气路径与西部海相原油存在明显差异。以歧口凹陷地层沉积埋藏史确定的热史路径进行动力计算结果显示,歧口凹陷深层单一液相原油存在的理论深度极限为5 700m,凝析油气存在的理论深度极限为6 700m。结合歧北次凹和滨海具体地质条件进行油气藏相态演变过程分析,结果表明:在实际地质条件下,干酪根的裂解生气和更深部气源的充注气侵,使得原有油藏提前达到极高的气油比,纯液相原油提前消失。油气运移到浅部过程中受温—压条件的变化,导致了油气的分异和相态转换。温度和时间决定的生烃效应是深层油气相态的内因,在具体分析单个油藏相态时,不仅要考虑油气来源、组成、油气成藏过程,尤其还要注意后期构造活动造成的油气调整改造,这些是后期油气相态分异转化的外因。
[Abstract]:In order to meet the demand of deep to ultra deep exploration in the eastern basin, through the typical crude oil pyrolysis gas simulation experiment of Shahejie formation in Qikou sag, the dynamic characteristics of hydrocarbon generation of crude oil pyrolysis were used to study the variation law of deep hydrocarbon fluid phase state. The results show that the hydrocarbon generation kinetics of cracking gas of crude oil can conveniently study the degree of cracking of crude oil under geological conditions and then judge the theoretical depth limit of the phase state of underground oil and gas. On the premise of a fixed frequency factor of 10 ~ (14) S ~ (-1), the activation energy of crude oil of Shahejie formation in Qikou depression of Bohai Bay basin is distributed between 250 ~ 270 KJ / mol and 250 ~ 270 KJ / mol, which is higher than that of marine crude oil at 245 kJ / r / mol (59 kCal/ mol). At the same heating rate, the pyrolysis gas path is obviously different from that of western marine crude oil. The thermal history path determined by stratigraphic burial history in Qikou sag shows that the theoretical depth limit of single liquid oil in deep layer of Qikou sag is 5 700 m and that of condensate oil and gas is 6 700 m. Based on the geological conditions of Qibei subdepression and Binhai, the phase evolution process of oil and gas reservoirs is analyzed. The results show that under the actual geological conditions, the pyrolysis gas generation of kerogen and the filling gas invasion of deeper gas sources can be obtained. It makes the original reservoir advance to the extremely high gas / oil ratio, and the pure liquid crude oil disappears ahead of time. The variation of temperature-pressure conditions in the process of oil and gas migration to shallow leads to the differentiation and phase transition of oil and gas. The effect of hydrocarbon generation determined by temperature and time is the internal cause of the phase state of deep oil and gas. When analyzing the phase behavior of a single reservoir, we should not only consider the source and composition of oil and gas, but also the process of oil and gas accumulation. In particular, attention should be paid to the oil and gas adjustment and transformation caused by late tectonic activities, which are the external causes of the late phase differentiation and transformation of oil and gas.
【作者单位】：长江大学录井技术与工程研究院;中国石油大港油田公司勘探开发研究院;油气资源与探测国家重点实验室中国石油大学(北京);中国石油大港油田公司;中国石油勘探开发研究院廊坊分院;
【基金】：国家自然科学基金(编号:41503034;41472095) 油气资源与探测国家重点实验室开放课题(编号:PRP/open-1509)联合资助
【分类号】：P618.13

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