【摘要】 论文以原油裂解气的动力学实验数据为基础,热力学模拟中提出油气藏多阶段模拟和流体超压泄漏与静水压力平衡再封闭的理论模型,应用PVTsim软件模拟计算了普光气藏不同地质历史阶段的流体压力变化曲线,及其对油气藏散失和保存的影响。模拟计算结果表明:在175~157 Ma油藏阶段的压力为25.2~49.8 MPa;在154~142 Ma油气藏阶段的压力为54.6~150.64 MPa,并在后期压力系数大于2.4时,发生流体泄漏,泄漏流体约为当时油气藏总量的22.89%时,达到与静水压力平衡再封闭的压力为62.13 MPa;在141~132 Ma主要为湿气裂解阶段,压力由68.2 MPa增加到170.9 MPa时,压力系数大于2.4,发生第二次超压泄漏,泄漏流体约为32.7%,达到与静水压力平衡再封闭的压力为70.1 MPa;在130~96 Ma为气藏进一步埋深阶段,裂解气增加很少,压力主要受温度增加而增加到86.62 MPa;由90 Ma抬升至当前,气藏压力因温度降低而降低到56.9~61.0 MPa;油裂解气藏在以上超压泄漏中的总散失率约为50.33%,总保存率约为49.67%。论文中PVTsim模拟油裂解气产生的超压现象,已由储层样品中发现捕获压力达155~165 MPa的高密度超临界甲烷包裹体所证实;模拟地质历史中油裂解气藏压力演变的最终结果也与当前普光气藏的PVT资料比较相似。更多还原

【Abstract】 Based on data from kinetic experiment of oil-cracked gas,we designed the multi-interval simulation of hydrocarbon accumulation and setup the thermodynamic model for overpressure-induced fluid leakage and hydrostatic pressure balance and re-seal in this paper.By means of PVTsim software,we simulated fluid pressure curves of Puguang gas pool at different geological stages and discussed influence of fluid pressure on loss and storage of hydrocarbon reservoir.The simulation and calculation results inferred as follows: fluid pressure in oil pool was 25.2-49.8 MPa at 175-157Ma,and 54.6-150.64 MPa at 154-142 Ma in gas and oil pool;then when pressure coefficient was more than 2.4,fluid was leaked about 22.89% volume of hydrocarbon reservoir as far as equilibrium pressure for hydrostatic pressure and re-seal arrived at 62.13 MPa.At wet gas cracking stage(about 41-132 Ma),fluid pressure increased from 68.2 MPa to 170.9 MPa and pressure coefficient was more than 2.4,fluid was leaked again about 32.7% until equilibrium pressure for hydrostatic pressure and re-seal became 70.1 MPa.At 130-96 Ma,the gas pool was buried further,the temperature increased,associated with few amount of crude-cracked gas,the fluid pressure was increased to 86.62 MPa.The pressure for gas reservoir decreased to 56.9-61.0 MPa,due to basin uplift and temperature decrease since 90 Ma to present.The accumulative leakage of fluid was about 50.33% and storage was about 49.67% due to overpressure as mentioned above.The result of overpressure fluid simulated by PVTsim software has been proved by discovery of high density methane inclusions showing trapping pressure up to 155-165 MPa in reservoir samples.The simulation of pressure evolution in oil-cracked gas pool was also similar to the measured PVT data for Puguang gas reservoir.更多还原