绳索取心钻进技术在松散盐岩地层中的应用探讨

地质岩心钻探中,岩心采取率一直是地质找矿、地学科研工作者重点关注的对象,也是岩心钻探重要的考核指标。传统的钻探取心方法在松散、软弱、含盐地层,特别是含易溶盐地层的取心质量不佳;绳索取心钻探在完整地层取心效果较为理想,同时可大大提高劳动生产率、降低劳动强度,而对于松散、软弱地层,其取心难度比起传统钻探有时更为复杂。通过柴达木盆地达布逊干盐湖科学钻探工程,对钻遇的地表层、松散地层如何采取技术方法提高岩心采取率进行了探索和研究。实践证明,通过改善冲洗液性能、改进取心卡簧特性及钻头出水方式3个方面技术措施,可大大提高绳索取心钻进在松散、软弱、弱固结、含盐地层的岩心采取率,由改进前的平均30%提高为平均96%。     

断层输导下储集层排驱压力对油气成藏影响作用

利用油气成藏物理模拟方法,从排驱压力角度研究了断层输导下的油气藏形成过程。研究表明,储集层排驱压力控制与断层侧向配置不同储盖组合的成藏次序,即排驱压力小的储盖组合优先成藏,排驱压力较大的储盖组合次之,这种控制作用与储盖组合的空间相对位置无关;排驱压力影响不同储盖组合的含油或含气饱和度,排驱压力越小,含油或含气饱和度越高,这种影响作用会因储集层空间相对位置的不同而有所差异;断层与储集层的对接与否是储盖组合成藏的先决条件,与断层对接具备成藏的可能性,而未与断层对接则难以成藏。研究结论可用于勘探实践中对断层输导下多套储盖组合试油层位进行评价优选。     

塔河油田于奇地区奥陶系碳酸盐岩岩溶作用研究

塔河油田北部于奇地区经多期构造运动,岩溶储层发育不均。从岩心观察、薄片鉴定、钻井和录井资料及测井、地震资料等方面进行分析解释,论述于奇地区奥陶系碳酸盐岩多期岩溶作用的存在依据和发育特征,总结同生、表生期大气水裸露风化壳型岩溶作用和侵蚀埋藏岩溶作用模式。结果表明:研究区西南部岩溶斜坡集中发育岩溶缝孔洞和洞穴,北部岩溶高地溶蚀作用不强,岩溶缝孔洞相对较少。于奇地区主要经历了加里东中晚期表生大气水岩溶作用、海西早期同生岩溶作用及海西期埋藏岩溶作用。     

塔里木盆地柯坪-巴楚地区奥陶系层序界面特征及成因分析

通过综合分析塔里木盆地柯坪-巴楚地区露头剖面的宏观组合和微观结构,总结出奥陶系不同级别层序界面的表现特征、成因机制,指导盆地内层序界面的研究。柯坪-巴楚地区奥陶系主要有3个级别的层序界面:一级层序界面发育在构造变革期,如受到造山运动或区域构造隆升作用等影响,表现为角度不整合面、平行不整合等特征;二级层序界面发育在沉积环境重大转换阶段,主要受到全球海平面变化的影响或局部构造运动影响,表现为平行不整合、淹没不整合等特征;三级层序界面与局部构造运动有关,表现为局部平行不整合。层序界面的表现形式包括古土壤层、喀斯特化、地层削截、地层超覆、岩性岩相突变等。通过总结不同层序界面的性质和成因,分析不整合面的规模和发育部位,预测有利岩溶储层发育的区带。     

Ore-forming Fluid Characteristics of the Saishitang Cu-polymetallic Deposit in Qinghai Province, China

Saishitang Cu-polymetallic deposit is located in the southeast section of Late Paleozoic arcfold in the southeastern margin of Qaidam platform. Accoring to the geological process of the deposit,four mineralization episodes were identified: melt/fluid coexisting period(O),skarn period(A),first sulfide period(B) and second sulfide period(C),and 10 stages were finally subdivided. Three types of inclusions were classified in seven stages,namely crystal bearing inclusions(type I),aqueous inclusions(type II) and pure liquid inclusions(type III). Type I and II inclusions were observed in stage O1,having homogenization temperature from 252 to 431°C,and salinities ranging from 24.3% to 48.0%. Type I inclusion was present in stage A1,having homogenization temperature from 506 to 548°C,and salinities ranging from 39.4% to 44.6%. In stage B1,type II and III inclusions were observed,with homogenization temperature concentrating between 300–400°C,and salinities from 0.4% to 4.3%. Type II inclusions were present in stage B2,with homogenization temperature varying from 403 to 550°C. In stage C1,type I and II inclusion commonly coexisted,and constituted a boiling inclusion group,having homogenization temperatures at 187–463°C,and salinities in a range of 29.4%–46.8% and 2.2%–11.0%. Type II and III inclusions were developed in stage C2,having homogenization temperature at 124–350°C,and salinities ranging between 1.6% and 15.4%. In stage C3,type II and III inclusions were presented,with a homogenization temperature range of 164–360°C,and salinities varying from 4.0% to 11.0%. The results of micro-thermal analysis show that fluids are characterized by high temperature and high salinity in stage O1 and A1,and experienced slight decrease in temperature and dramatic decrease in salinity in stage B1 and B2. In stage C1,the salinity of fluid increased greatly and a further decrease of temperature and salinity occurred in stage C2 and C3. Fluids boiled in stage C1. With calculated pressure of 22 MPa from the trapping temperature of 284–289°C,a mineralization depth of 2.2 km was inferred. Results of Laser Raman Spectroscopy show high density of H2 O,CH4 and CO2 were found as gas composition. H-O isotope study indicates the oreforming fluids were the mixture of magmatic water and meteoric water. Physicochemical parameters of fluids show oxygen and sulfur fugacity experienced a decrease,and redox state is weakly reducing. Along with fluid evolution,oxidation has increased slightly. Comprehensive analysis shows that melt exsolution occurred during the formation of quartz diorite and that metal elements existed and migrated in the form of chlorine complex. Immiscible fluid separation and boiling widely occurred after addition of new fluids,bringing about dissociation of chlorine-complex,resulting in a great deal of copper precipitation. In conclusion,Saishitang deposit,controlled by regional tectonics,is formed by metasomatism between highly fractionated mineralization rock body and wall rock,and belongs to banded skarn Cu-polymetallic deposit.     

渤海湾西岸全新世海面变化

在讨论海面标志点基本定义的基础上,从渤海湾西岸534个原始数据中获得了136个指示高水位、潮间带或低水位的海面变化标志点,并重建了它们的相对海平面时空分布,进而获得了渤海湾西岸全新世相对海平面变化带.约10cal.ka B.P.时,相对海平面变化带达到-25m,以约6m/1000a(即约6mm/a)的平均速率上升,在6cal.ka B.P.前后达到现代海面的高度;6cal.ka B.P.至今,变化带的高度介于+1m～-2m之间,未发现中全新世相对高海面.再搬运海相贝类和陆相泥炭类样品的14C年龄,分别存在约600年和660年的驻留时间.经过驻留时间校正的新海面变化年代学序列,将渤海湾相对海平面达到现代高度的时间点确定为约6cal.ka B.P.,从而与全球海面变化的对比更为准确.渤海湾盆地的长期稳定下沉和沉积自重压实的共同作用,可能抵消了冰川均衡调整(GIA)引起的中全新世数米高的相对高海面.     

新疆吐鲁番胜金店墓地小麦遗存加工处理方式初探

脱粒是谷物加工处理的重要环节之一.本文选择新疆吐鲁番胜金店墓地M9墓葬出土大量保存完好的小麦遗存进行原始脱粒方式分析,并尝试结合现代小麦原始脱粒方式模拟实验,将现代模拟实验结果与古代材料进行对比分析,从而初步探讨新疆吐鲁番地区先民的小麦脱粒方式.本文首先对胜金店墓地M9墓葬出土的小麦遗存进行初步分类,将不同的小麦脱粒产品与副产品(麦秆、花序轴、小穗轴等)进行分析和统计;其次设计并完成现代小麦脱粒模拟实验,包括手搓、徒手摔打、木棍击打等3种相对原始的小麦脱粒方式,统计不同脱粒方式所产生的小麦加工产品与副产品的组合比例;将现代模拟实验所得结果与M9墓葬出土小麦遗存进行进一步对比分析.研究结果表明,在距今约2000多年前,新疆吐鲁番胜金店先民可能使用木棍击打方式对小麦进行脱粒.     

南冲绳海槽沉积物中淡水硅藻的发现及1000年以来台风降雨的重建

利用主成分分析法对冲绳海槽南部MD05-2908孔近1000年来沉积物硅藻数据进行研究发现,MD05-2908孔各样品在主成分一上的得分情况与该于孔淡水硅藻含量、夏季海水表层盐度变化以及台湾近1000年来的降水异常有良好的相关性,因此,各样品在主成分一上的得分可作为台湾东北部台风降雨指标,用来指示台风强降雨事件对南冲绳海槽海洋环境的影响情况.近1000年来台湾东北部台风强降雨事件波动增加,在1500～1800A.D.期间达到峰值;此外,5次典型的强台风降雨记录,分别发生于1040A.D.、1310A.D.、1530A.D.、1690A.D.和1900A.D.,其平均重现周期为215年(160～270年).利用MD05-2908孔各样品在主成分一上的得分重建的台风记录与广东、台湾等地已有的台风记录有较好的对应关系,进一步验证了硅藻作为研究工具重建古台风记录的可行性.