塔里木盆地顺南1井和顺南4井油气相态演化的数值模拟与预测

Numerical simulation and prediction of hydrocarbon phase evolution of wells Shunnan 1 and 4， Tarim Basin

黄越义 廖玉宏 陈承声 史树勇 王云鹏 彭平安

Yueyi HUANG Yuhong LIAO Chengsheng CHEN Shuyong SHI Yunpeng WANG Ping’an PENG

塔里木盆地顺南1井和顺南4井位置相近且地质背景相似，埋藏史、热演化史和压力史也基本相似，显示两井的原油都曾遭受过严重的热裂解，但油气相态差异显著，顺南1井为凝析气藏伴生凝析油，顺南4井为典型干气藏。顺南1井和顺南4井的油气相态演化过程以及导致这种相态差异的原因尚待解析。结合原油的黄金管封闭体系热模拟实验数据与实际地质背景资料，利用PetroMod软件和PVTsim软件完成了塔里木盆地顺南1井和顺南4井油气相态演化的数值模拟和预测，并与现今烃流体的组成和相态进行了比较。研究结果表明：顺南1井鹰山组油气藏在34 Ma由液相进入凝析气相，直到现今仍保持凝析气相，其凝析油正构烷烃摩尔浓度与碳数成非常好的线性关系，指示其未曾受气侵、蒸发分馏或多期充注等的影响；而顺南4井鹰山组油气藏在49 Ma由液相进入凝析气相，并很可能在22～10 Ma（中新世）遭受了来自寒武系烃源岩的过成熟干气的气侵作用；气侵通道应该为顺南地区发育的多条北东向断裂，气侵强度由东向西逐渐减弱，到顺南1井所在区域时已无明显气侵作用，这是顺南1井和顺南4井在组分和相态上存在明显差异的主要原因。

The wells Shunnan 1 and 4 in the Tarim Basin are located close to each other and have similar geological backgrounds. The reservoirs therein are similar in burial history， thermal history and pressure history， with their crude oils having undergone severe thermal cracking. However， the two wells are significantly different in hydrocarbon phase： the reservoir in well Shunnan 1 is of gas condensate type， while that in the well Shunnan 4 is typical of dry gas type. The hydrocarbon phase evolution processes of the two wells and the reasons for the phase difference between the two wells are yet to disclose. In this study， the thermal simulation data from the gold tube closed system experiment of crude oils in combination with the actual geological setting information are applied to the numerical simulation and prediction of hydrocarbon phase evolution of wells Shunnan 1 and 4 in the Tarim Basin via PetroMod and PVTsim， and the simulation results are compared with the composition and phase of present hydrocarbon fluids. The results show that the hydrocarbon reservoir in the Yingshan Formation in well Shunnan 1 varied from liquid phase to gas condensate phase at 34 Ma and remains in gas condensate phase till now. The molar concentration of -alkane in the gas condensates has a very good linear relationship with the carbon number， indicating that it was not affected by gas invasion， evaporative fractionation or multi-stage charging. The hydrocarbon reservoir in the Yingshan Formation in well Shunnan 4 transformed from liquid phase to gas condensate phase at 49 Ma， and probably suffered gas invasion in the Miocene （22?10 Ma） by over-mature dry gas from the Cambrian source rocks through channels of multiple NE-striking faults developed in Shunnan area. The gas invasion got weakened from east to west and disappeared in well Shunnan 1. This is the main reason for the marked difference in composition and phase between wells Shunnan 1 and 4.

10.11743/ogg20230111