地层温度对油气运、聚影响的系统分析

地层温、压是油气成藏环境的能量参数，影响着油气从生成、运聚、调整，直至逸散的整个过程。前人研究多注重温度对油气生成、压力对油气运移的控制作用，对温度在油气运移、聚集中的作用还没有系统的研究。作者通过对油气运移、聚集过程中所发生的物理、化学及物理化学作用分析，明确了地层温度在其中所起的作用。对油气运移，一方面，地层温度非均匀变化引起的热应力，可以直接为油气运移提供驱动力；另一方面，地层温度通过改变分子粘度、表面张力、溶解度等物性参数影响油气运移能力。对于油气聚集，地层温度(和地层压力等)不仅影响和制约油气的分布位置，还通过控制有机质演化进程、影响烃类流体相态分异，来影响油气的聚集特征。最后还对地层温度控藏中存在的问题进行了探讨，认为地层温度与地层压力、构造应力等因素存在一定内在联系并共同控制油气成藏，在分析地层温度对各成藏阶段的影响时应恢复相应时期的地温场。

Systematic Analysis of Geotemperature Influencing on Migration and Accumulation of Oil-Gas Fluids

As pool-forming energy parameters,geo-temperature and pressure influence the whole process from oil-gas generating,migrating and accumulating to dissipating.The controlling mechanisms of geo-temperature on oil-gas generated and geo-pressure on migrating have been investigated,while influences of geo-temperature on oil-gas migrating and accumulating have not been considered sufficiently.In order to uncover geo-temperature influence on migrating and accumulating of oil and gas,physical,chemical and physical chemical mechanisms during oil-gas migrating and accumulating have been investigated systemically.After these investigating and analyzing,a conclusion that each reservoiring processes of oil and gas are influenced by geo-temperature has been gained.There are two types of influencing mechanisms of geo-temperature on oil-gas migrating.Proving dynamic and driving oil and gas directly is the first mechanism.Inhomogeneous distribution of geo-temperature could provide heat-stress which drives oil and gas migrating directly.According to the heat stress theory,if temperature differences exist among different parties of a same body,heat stress would appear immediately.As giant geological bodies,stratums not for a moment have homogeneous temperature.Those eternal temperature differences imply timeless heat stress which has been and will be driving oil and gas migrating from higher temperature area to lower temperature area.The inference that temperature could drive oil and gas has been testified by Qiu Nansheng’s experiment,in which the phenomenon of oil migrating from the higher temperature end of tube to the lower end was observed.In oil-gas migrating process,geo-heat could not only provide power for oil-gas migrating,but also control migrating efficiency by changing some physical parameters,such as sorption,diffusivity and solubility.According to present relative achievements about accumulation of oil and gas,geo-temperature not only partly influences accumulating location of oil and gas,but also mainly controls oil and gas’s accumulating phases.Where oil and gas will accumulate in is determined by many factors,such as source rock,reservoir,capping,migrating process,preserved process,etc.However,these factors are more or less influenced by geo-temperature.Based on phase of reservoired oil and gas,reservoirs could be classified into heavy oil reservoir,normal oil reservoir,condense oil reservoir,oil-gas reservoir and gas reservoir.Phase of reservoired oil and gas is determined by their primordial phase and subsequent change.Geo-temperature is one of the two primary factors that determine primordial phase of oil and gas(another factor is the organic materials type of source rock).According to present data gain from experiments and experiences,reflection of vitrinite(Ro %),the directly decisive parameter of primordial phase of oil and gas,is a function of geo-temperature.In Zhanhua sag,when geo-temperature is under 100℃(Ro<0.5%),the source rock in Es3x generates biogas only.From 100℃ to 175℃(Ro is from 0.5% to 1.35%),routine oil is the main produce.When geo-temperature increase to 175℃(Ro>1.35%),produce of the source rock is condensable oil containing with wet gas.When geo-temperature is above 200℃(Ro>2.0%),produce of the source rock will be dry gas only.In summary,in accumulating,distributing situation and accumulating phase of oil and gas are influenced by geo-temperature(associating with pressure).Two facts are noteworthy,the first one is that geo-temperature is not only,but one of many factors which control reservoiring processes of oil and gas.According to the authors,geo-temperature has inherent relationships with geo-pressure and tectonic stress,and the three factors always control oil and gas migrating and accumulating cooperatively.Another one is that the oil and gas reservoirs we are looking for all reservoired during geological time.It is the paleo-geo-temperature that influenced oil and gas’s migrating and accumulating process.So paleo-geo-temperature should be estimated before analyzing influences of geo-temperature on oil-gas migrating and accumulating.