塔里木盆地寒武系深层油气赋存相态研究

塔里木盆地寒武系深层烃类相态是地球化学家和石油勘探家密切关注的科学问题。应用封闭体系黄金管热模拟方法,对塔里木盆地塔河油田稠油、正常原油、高蜡原油进行热模拟实验。在频率因子为1.78×10¹⁴s^-1的前提下,塔河油田奥陶系井稠油具有最宽的C₁-C₅质量生成的活化能分布,分布范围为56~66 kcal/mol,主频活化能最低,为59 kcal/mol。根据原油转化率,使用Kinetic软件计算表明原油作为油相可以存在于178~205℃的储层中。依据塔里木盆地塔北、塔中、塔东、巴楚4个古隆起典型钻井寒武系古地温演化,建立了4个古隆起寒武系古油藏裂解动力学模型。模型表明塔北隆起塔深1井寒武系建隆Ⅰ顶部的古油藏至今可以保持独立油相状态,建隆Ⅰ底部的古油藏能保持凝析油状态。巴楚、塔中、塔东地区典型寒武系钻井模拟表明,寒武系中的烃类可能以天然气、凝析油为主要相态类型。

Hydrocarbon phase in the deep Cambrian of the Tarim Basin

The hydrocarbon phase of the deep Cambrian in the Tarim Basin is a scientific focus of geochemists and explorationists. Thermal simulations of heavy oil, normal oil and waxy-oil from the Tahe Oilfield in the Tarim Basin were carried out using a gold-tube confined system. For a frequency factor (A) of 1.78×1014s-1, the activation energy range of C₁-C₅ gas yield of heavy oil is the widest, ranging from 56 to 66 kcal/mol, and the dominant potential is at 59 kcal/mol. In view of the ratio of oil conversion to gas, oil can be a separate phase at temperatures of 178-205℃. According to the paleo-temperatures of the Cambrian wells from the Tabei, Tazhong, Tadong and Machu uplifts, four dynamic models of the Cambrian reservoir cracking were established. The paleo-oil reservoir of well Tashen1 in the Tabei Uplift can be as a separate oil phase above Builtup Ⅰ in the Cambrian at present, whereas only condensate oil phase existsat the bottom of the UpliftⅠ. The models of the Cambrian paleo-oil reservoirs of typical wells from the Bachu Uplift, Tazhong Uplift and Tadong Uplift suggest that the hydrocarbon phase of the above areas may be dominated by gas and condensate phases.