雄安新区地层及主要热储空间结构特征与地热水资源潜力

Spatial distribution characteristics of strata and main thermal reservoirs and geothermal water resource potential in Xiong'an New Area

雄安新区中深层白云岩热储地热资源丰富,为了提高对该区主要热储白云岩热储特征及地热水资源潜力的认识程度,指导新区中深层白云岩热储地热水资源的规模化开发,基于钻井、地震、地质等资料,研究了该区白云岩热储的地层空间分布、构造特征、储集空间特征和主建设区白云岩热储地热水资源潜力。研究表明:雄安新区主要热储雾迷山组、高于庄组除在断裂面部分地区外基本全区分布;雾迷山组埋深在容城凸起、牛驼镇凸起相对较浅,在高阳低凸起相对较深;高于庄组有类似的分布特征,总体埋深更深,温度更高;其它地层除第四系、新近系明化镇组外分布都比较局限;区内发育众多以NNE向为主的正断层,与少数其它方向断裂交会,将深部地热通过流体传输到浅部,并造就断裂两侧大量的裂缝和控制岩溶发育方向及规模,形成众多溶蚀孔洞;同时构造演化中雾迷山组古地貌中高地貌部分,在喜山期大多剥蚀与新生界形成不整合面,共同构成本区重要的输导通道和储集空间,岩溶孔洞和裂缝结合型复合空间是本区雾迷山组主要热储空间,单独的裂缝、孔洞是次要热储空间,大型溶洞一旦发育往往是主力产水层;新区主建设区顶面在5000 m(底部埋深可达6000 m)及以浅的白云岩岩溶裂缝热储地热水资源,按100年采用总热水储量的50%及500 m井距“三采两灌”原则单井产量110 m^(3)/h计,最适宜生产井布井数目233口,主建设区现阶段可满足每年4787×10^(4)m^(2)的供暖面积,占实际需求的30.1%。结论认为:雾迷山组埋深较浅,在当前经济技术条件下是主力热储,高于庄组埋深较深是最重要的备用热储,今后20年内会被大规模开发利用,但即便现在同时开发它们也不能满足雄安新区主建设区的清洁能源需求,需要发展“多能互补”系统,域外的过剩地热资源能否向域内目标区集输受经济成本和环境成本风险制约。在当下和未来发展与应用节能保温技术既重要也必要。

It is rich that geothermal resources in mid-deep dolomite thermal reservoir in Xiong'an New Area.In order to improve the understanding of dolomite thermal reservoir characteristics and geothermal water resource potential,and guide the large-scale development of mid-deep dolomite thermal reservoir geothermal resources in Xiong'an,based on drilling,seismic,geological and other data,the strata spatial distribution characteristics,reservoir characteristics of dolomite thermal reservoir in this area and the geothermal water resource potential of dolomite thermal reservoir in the main construction area of Xiong'an are studied.The research shows that:The main thermal reservoirs in Xiong'an New Area are Wumishan Formation and Gaoyuzhuang Formation,which are distributed in the whole area except in some faults surface areas.Buried depth of Wumishan Formation is relatively shallow in Rongcheng Rise and Niutuozhen Rise,and relatively deep in Gaoyang low rise.Gaoyuzhuang Formation has similar distribution characteristics,with deeper burial depth and higher temperature.The distribution of other strata are limited except the Minghuazhen Formation of Neogene and Quaternary.Many normal faults mainly in NNE extension direction are developed in the area,which intersect with a few faults in other directions,communicating groundwater flow and heat flow,creating a large number of fractures on both sides of the faults,controlling the direction and scale of karst development,and forming a large number of dissolution holes.At the same time,the highlands of paleogeomorphology of the Wumishan Formation in the tectonic evolution,was mostly denuded in the Himalayanian,forming an unconformity with the Cenozoic,which together constitute an important transport channel and reservoir space in the area,The compound space of karst pores and fractures is the main thermal reservoir space of Wumishan Formation in this area,and the separate fractures and pores are the secondary thermal reservoir space.Once large karst caves are developed,they are often the main water producing layer.Geothermal water resources in dolomite reservoir with roof buried no more than 5000 m(the bottom depth can reach 6000 m)in the main construction area in Xiong'an New Area,using 50%of the total hot water reserves in 100 years and the single well output of 110 m^(3)/h based on the principle of"three production and two injection",is considered to be the most suitable number of production wells is 233.At present,the main construction area can meet the annual demand of 4787×10^(4) m^(2) of heating area,accounting for 30.1%of the actual demand.It is concluded that the Wumishan Formation is shallowly buried,which is currently the main thermal reservoir under the current economic and technological conditions.Gaoyuzhuang Formation with the deeper burial depth is the most important backup thermal reservoir,which will be developed and utilized on a large scale in the next 20 years.However,even if they are developed at the same time now,they could not meet the clean energy demand of the main construction area of Xiong'an New Area,and it is necessary to develop a"multi energy complementary"system.Whether the excess geothermal resources outside the region can be gathered and transmitted to the target areas within the region is subject to economic cost and environmental risks.