东营凹陷中央隆起带地温场建立及地热系统发育模式

针对断陷盆地中央隆起带地热能开发地温场建立难度大的实际,采用井筒测温法、SiO2地热温标、钾镁地热温标、钠钾地热温标等建立地温场,研究地温场分布的控制因素,建立地温场发育模式。结果表明,东营凹陷中央隆起带沙二段—第四系可以划分为地表变温带、第一增温带、第一保温带、第二增温带、第二保温带、第三增温带和第三保温带共7个温度带。采用SiO2、钾镁、钠钾地热温标等方法求取了地温。综合研究区内地层对比、构造、储层、测井等地质研究成果,利用测温及化验资料,垂向上划分了6个砂组,建立了地温场的地质模型。地温梯度变化主要受中央隆起带底部塑性物质、主断裂分布、岩性、地层层位、砂地比控制。根据中央隆起带的地热成因及发育特征、温度及产水量,建立了该区的地热系统发育模式,划分为热扩张带、高温裂隙带、高温致密带、中温致密带、中温热水带、低温热水带和封盖带7层结构,从热源、盖层、热储层、热流通道、封闭性几方面分析了地热系统发育成因。

Establishment of geothermal field and development model of geothermal system in central uplift belt of Dongying Sag

It is difficult to establish a geothermal field for geothermal energy development in the central uplift belt of a gra?ben basin.In this paper,the geothermal field is established through wellbore thermometry as well as SiO2,K-Mg,and Na-K geothermometers to identify the controlling factors of its distribution and clarify its development model.The results show that Es2-Q in the central uplift belt of Dongying Sag can be divided into the surface variable temperature zone,the first ther?mal warming and thermal insulation zone,the second thermal warming and thermal insulation zone,the third thermal warm?ing and thermal insulation zone.Geotemperature is calculated with SiO2,K-Mg,and Na-K geothermometers.Based on the geological research in stratigraphic correlation,structure,reservoirs and well logging in the study area,six sand formations are divided vertically and the geological model of the temperature field is established with the temperature measurements and laboratory data.It is found that the geothermal gradient is dominated by the plastic materials at the bottom of the cen?tral uplift belt,the patterns of main faults,lithology,stratigraphic horizon and thickness ratios of sand/mud.A geothermal system development model of the central uplift belt that consist with a thermal expansion zone,a high temperature fracture zone,a high temperature compact zone,a medium temperature compact zone,a medium temperature hot-water zone,a low temperature hot-water zone and a seal zone is introduced according to the geothermal genesis and development characteris?tics,temperature,and water yield.Besides,the genesis of geothermal system is analyzed from heat sources,cap rocks,ther?mal reservoirs,heat flow channels,and sealing.