Baselines of acceptability and generational change on the Mactaquac hydroelectric dam headpond (New Brunswick,Canada)

Hydroelectricity is an old yet reliable form of renewable energy, with acknowledged social and ecological impacts. A tension currently exists between such concerns and energy needs, with dam construction and removal ongoing around the world. It is critical to better understand the implications of both on local citizens. We performed map elicitation interviews with 20 locals around the prematurely-aging Mactaquac Dam and headpond, in New Brunswick, Canada, to understand if and how they came to accept the dam landscape, and what they want for its future. A Baselines of Acceptability conceptual framework was developed to guide the interpretation. Respondents demonstrated attachment to the dam-in-place landscape, even those initially disadvantaged by its construction, and a preference for keeping the headpond intact. Despite this demonstrated adaptability, the paper calls for improved transparency, scope and justice in energy landscape decision-making, as well as further testing of the framework with different demographics, infrastructure case studies and over time.     

基于动库容曲线的水库调洪高水位查算方法研究

河道型水库因动库容特性显著,传统的静库容调洪方法难以适用,研究动库容调洪方法是亟待解决的问题。当坝前水位爬升到最高点时,库区内的洪水演进到达一种临界状态,库区内的水文、水力条件相对稳定,在出库流量和入库流量一定的情况下,可望获得最高坝前水位与同时刻库容之间良好的对应关系。依托三峡库区水文水动力耦合预报模型,建立了一组以出库流量、入库流量为参数的动库容曲线,以供调洪时快速查算最高坝前水位。采用2009年以来三峡水库16场场次洪水资料,检验所建动库容曲线的合理性。结果表明,各场洪水的最高库水位查算值与实况平均偏差仅0.20m,证明建立的基于动库容曲线的三峡水库最高库水位查算方法具有较好的实践价值。     

涪陵气田焦石坝区块页岩气储层储集空间特征及其定量评价

四川盆地涪陵气田焦石坝区块上奥陶统五峰组—下志留统龙马溪组一段海相页岩气储层是由孔隙和裂隙组成的双孔隙岩层。为确定储层的含气量和产出能力,应用页岩气测井评价技术对储层的孔隙度和渗透率进行了定性认识,并提出了定量评价方法。认为用"经验统计法"可以有效计算出页岩气储层的孔隙度,但由目前的测井评价技术所得到的渗透率仅能反映储层渗透率的变化趋势。     

四川盆地中部龙王庙组滩相储层特征及形成机制

依据岩心、常规薄片及铸体薄片、物性分析、压汞等资料的研究,四川盆地中部下寒武统龙王庙组滩相储层为发育良好的中低孔、低渗的孔隙型储层及裂缝—孔隙型储层。储集岩主要为砂屑白云岩、鲕粒白云岩与具残余颗粒结构的粉—细晶白云岩,储集空间主要包括粒间溶孔、粒内溶孔、晶间溶孔、铸模孔、残余粒间孔、裂缝及溶洞,孔喉配置关系好。储层形成机制研究表明,滩核和滩翼微相有利于储层发育,滩相储层在沉积早期具有典型的宏观非均质性,这为储层的形成与演化提供了物质基础。同生岩溶作用控制了早期储层的孔隙演化,表生岩溶作用决定了储层分布的基本特征,埋藏岩溶作用有利于先期孔渗层的优化改造。提出滩相储层的演化主要经历三个阶段,其中沉积—同生成岩阶段是早期优质储层形成的关键时期,表生岩溶改造阶段是滩相储层大规模增孔时期,埋藏成岩阶段为滩相储层孔隙调整和稳定时期。     

渤海典型低孔低渗油藏储层预测及效果——以渤海A油田沙河街组二段为例

综合利用地震、钻井、测井等资料,从渤海A油田古近系沙河街组二段的地层发育特征入手,以砂体发育特征与地震资料响应的匹配关系为研究思路,探究古地貌分析、地震属性分析等手段对研究区沙二段储层预测的适用性。通过开展最大振幅之和的地震属性计算、已钻井砂体厚度趋势约束、古地貌联合校正的储层预测,表明在沙二段沉积时期研究区主要为沟谷与洼地被两凸起分隔的古地貌格局,有利储层主要发育在西南及东北古地貌低洼处,东北部是后期开发调整的潜力区。基于该储层预测方法的合理性得到了5口设计井实钻结果的检验,证实了该成果不仅有助于油田下步调整方案的制定和实施,而且储层预测的思路和方法也可供海上类似中深层油田借鉴。     

Risks for poisoning of coastal and inland population due to asteroid impacts in Southern regions of Black Sea

The hydrogen sulfide rich waters of the Black Sea pose a potential danger for the surrounding land regions. The impact of an asteroid exceeding tens of meters in size may cause both a tsunami wave and a catastrophic poisonous gas release in the atmosphere. Some effects of this last phenomenon on the Southern Black Sea coastal regions are evaluated in this paper. The initial surface area of the poisonous cloud depends on asteroid size. The initial thickness of the cloud depends, in addition, on sea depth at impact location. The wind speed plays an important role in H₂S cloud dynamics. At 10 m/s wind speed, the cloud margins reach 185 km from the impact location in about 3 h. The maximum distance traveled by the hydrogen sulfide cloud increases by increasing the asteroid size and wind speed. The influence of the impact position on the distance traveled by hydrogen sulfide clouds is rather weak, as long as the seawater depth does not change significantly. The land surface area covered by the H₂S cloud generated by a 1,000 m size asteroid ranges between about 6,400 and 12,000 km². This may affect up to 3,000,000 people. When a 250 m size asteroid is considered, the covered land surface area ranges between about 1,400 and 2,100 km² and up to 120,000 people may be affected. In case of a 70 m size asteroid, the cloud covers up to 280 km² of land. This may affect up to about 70,000 people. These evaluations do not include the population of the towns on or near the seashore. A simple methodology to estimate the environmental risks of the potential asteroid impact was proposed. Sites less than 160 km from the impact place are at risk.     

Mid-Holocene variability in the marine C reservoir age for northern coastal Papua New Guinea

Changes in oceanic radiocarbon (¹⁴C) reservoir ages through the deglaciation and Holocene can provide important information on ocean circulation as Earth's climate warmed. Here, we present reservoir ages for the western tropical Pacific that span the mid-Holocene transition from less to more frequent El Niño events. Reservoir ages were calculated using paired U–Th and conventional ¹⁴C dating of eight individual fossil coral samples from Koil and Muschu Islands, northern coastal Papua New Guinea (PNG). AMS ¹⁴C and MC-ICPMS U–Th dating of additional samples from six of the fossil corals were used to confirm the TIMS U–Th and conventional ¹⁴C ages. The combined results show average reservoir ages of 185±30 ¹⁴C yr (n=4) for 7220–5850 yr BP compared to 420 ¹⁴C yr for a modern coral from Muschu Island. From 5850 to 5420 yr BP reservoir ages increase to modern values. The relatively young reservoir ages from 7220 to 5850 yr BP are best explained by greater influx of well-equilibrated sub-tropical water from the southern branch of the South Equatorial Current (SEC). This is consistent with strengthening trade winds (facilitating air–sea exchange) and a more northerly position of the Intertropical Convergence Zone thought to have occurred at this time. The transition to more modern-like reservoir ages from 5850 to 5420 yr BP suggests modern oceanic circulation patterns were established during this interval. The onset of modern El Niño activity around this time would have served to enhance the intrusion of ¹⁴C-depleted equatorial waters via the south equatorial branch of the SEC. Overall, the changes in reservoir age presented here for the western tropical Pacific suggest that Holocene changes in the El Niño–Southern Oscillation state of the tropical Pacific resulted in reorganisation of oceanic circulation in this region.     

加卸载响应比与应变能加速释放的临界现象讨论

对发生在中国大陆地区的8次地震, 用不同的区域半径分别进行应变能释放的幂率拟合和加卸载响应比计算, 发现最佳幂率拟合的区域半径与加卸载响应比最大值所对应的区域半径的对数与地震的震级呈线性关系, 且两者具有很好的一致性, 因而认为两者之间可能具有相同的物理机制, 是孕震系统进入临界状态的不同表现形式。     

柯坪地区下志留统储层性质及控制因素

野外露头浅钻取样分析发现,柯坪地区志留系下统柯坪塔格组的储层性质与塔北及塔中地区差别较大。柯坪地区的砂岩储层以粉细粒岩屑砂岩为主,处于晚成岩A2期,孔隙度主要为2%~6%,平均4.47%,渗透率主要为(0.01~0.1)×10-3μm2,平均0.06×10-3μm2,属于特低孔特低渗储层,而塔北及塔中地区以低孔低渗和中孔中渗为主。研究表明柯坪地区成岩压实、石英次生加大是储层物性的主控因素,储层经历长期深埋藏和短期浅埋藏,使成岩压实减孔率达30.4%;胶结作用所减少的孔隙量一般为1.5%~8%,致密胶结段可达10%~11%,石英次生加大所减少的孔隙量一般2%~4%,致密胶结段可达6%~8%;溶蚀作用及次生裂缝对储层物性改善不大,一般增孔量4%左右;成岩中后期强烈挤压构造运动对储层性质有重要影响。储层演化史表明晚二叠世、晚白垩世—早第三纪是油气聚集成藏期,随后遭后期构造运动破坏,油气逸散或发生氧化作用,柯坪塔格组含沥青砂岩即是这一过程的产物。     

国外海相油气田勘探实例(之一)挪威埃科菲斯克油田

介绍了挪威埃科菲斯克油田的基本概况及油田勘探历史,描述了该盆地的演化、油气系统、区域地层及沉积相。该油田的构造类型为盐丘构造,主要的储集层为麦斯特里希特统(K2)—下古新统(丹麦阶)托尔组和埃科菲斯克组。埃科菲斯克组以构造裂隙为主,托尔组主要发育与缝合线有关的裂隙。白垩地层主要为生物成因,其成分为分解的贝壳或浮游的Cocccophorid藻颗石、浮游类和海底有孔虫类。