油气藏潮汐重力的初步研究

Preliminary study in tidal gravity of oil and gas reservoir

(1.吉林大学地球探测科学与技术学院，吉林长春130026；2.浙江大学理学院，浙江杭州310027)

College of Geoexploration Science and Technology, Jilin University, Changchun 130026, China

在月亮和太阳等天体万有引力的作用下，地球上的岩体、海洋、湖泊及地下水都会产生潮汐现象，含油气的流体在含油气圈闭内由于天体的作用也会产生潮汐现象。潮汐作用使得流体在岩石孔隙中流动，使得油气藏密度随时间发生变化，进而会引起地表重力场的微弱变化。当天体处于不同极值位置时这种变化最大。在已知的构造边界上，通过观测天体在各个极值时段的重力场，然后应用特定的方法计算潮汐重力变化就能初步确定构造内部是否含有油气，并初步确定油气藏的规模。介绍了油气藏潮汐重力模型的设计、潮汐重力异常的观测、数据处理及资料解释，并通过某地实测潮汐重力异常处理后的结果验证了方法的有效性。

By the action of the universal gravitations between the sun and the moon, the tide phenomenon occurs on the rocks, sea, lakes and groundwater on the earth, and also on the liquids comprising hydrocarbon-bearing traps. Tide force makes the liquid flow in the cracked rock, making the density of the cracked rock change with time, which further causes the tiny changes of the surface gravity. The change will achieve the maximum when the heavenly bodies are on different extreme positions. By observing the gravity on the extreme position of the heavenly bodies with the known geological structure boundary and adopting a certain approach to calculate the changes of the tidal gravity, we can preliminarily determine whether the internal structure contain oil and gas or not and also the scale of reservoirs. For this purpose, we introduced the design of tidal gravity model for gas and oil reservoir, the observation of tidal gravity abnormally, the data processing and interpretation. The method is proved to be effective through actual observation and data processing of tidal gravity anomaly in a certain place.