Geochemical characteristics of Sr isotopes in the LS33 drill core from the Qiongdongnan Basin, South China Sea, and their response to the uplift of the Tibetan Plateau

Making full use of modern analytical and testing techniques to explore and establish new indexes or methods for extracting paleoseawater geochemical information from sediments will help to reconstruct the sedimentary paleoenvironment in different research areas.The connection between the subsidence of the South China Sea basin and the uplift of the Tibetan Plateau has been a scientific concern in recent decades.To explore the information on the sedimentary paleoenvironment,provenance changes and uplift of Tibetan Plateau contained in core sediments(debris),we selected core samples from Well LS33 in the Qiongdongnan Basin,South China Sea,and analyzed the contents of typical elements(Al,Th,and rare earth elements)that can indicate changes in provenance and the Sr isotopic compositions,which can reveal the geochemical characteristics of the paleoseawater depending on the type of material(authigenic carbonate and terrigenous detritus).The results show the following:(1)during the late Miocene,the Red River transported a large amount of detrital sediments from the ancient continental block(South China)to the Qiongdongnan Basin.(2)The authigenic carbonates accurately record changes in the 87Sr/86Sr ratios in the South China Sea since the Oligocene.These ratios reflect the semi-closed marginal sea environment of the South China Sea(relative to the ocean)and the sedimentary paleoenvironment evolution process of the deep-water area of the Qiongdongnan Basin from continental to transitional and then to bathyal.(3)Since the Neogene,the variations in the 87Sr/86Sr ratio in the authigenic carbonates have been consistent with the variations in the uplift rate of the Tibetan Plateau and the sediment accumulation rate in the Qiongdongnan Basin.These consistent changes indicate the complex geological process of the change in the rock weathering intensity and terrigenous Sr flux caused by changes in the uplift rate of the Tibetan Plateau,which influence the Sr isotope composition of seawater.

Relationship between rock uniaxial compressive strength and digital core drilling parameters and its forecast method

The rock uniaxial compressive strength(UCS)is the basic parameter for support designs in underground engineering.In particular,the rock UCS should be obtained rapidly for underground engineering with complex geological conditions,such as soft rock,fracture areas,and high stress,to adjust the excavation and support plan and ensure construction safety.To solve the problem of obtaining real-time rock UCS at engineering sites,a rock UCS forecast idea is proposed using digital core drilling.The digital core drilling tests and uniaxial compression tests are performed based on the developed rock mass digital drilling system.The results indicate that the drilling parameters are highly responsive to the rock UCS.Based on the cutting and fracture characteristics of the rock digital core drilling,the mechanical analysis of rock cutting provides the digital core drilling strength,and a quantitative relationship model(CDP-UCS model)for the digital core drilling parameters and rock UCS is established.Thus,the digital core drilling-based rock UCS forecast method is proposed to provide a theoretical basis for continuous and quick testing of the surrounding rock UCS.

Estimating rock properties using sound signal dominant frequencies during diamond core drilling operations

In many engineering applications such as mining,geotechnical and petroleum industries,drilling operation is widely used.The drilling operation produces sound by-product,which could be helpful for preliminary estimation of the rock properties.Nevertheless,determination of rock properties is very difficult by the conventional methods in terms of high accuracy,and thus it is expensive and timeconsuming.In this context,a new technique was developed based on the estimation of rock properties using dominant frequencies from sound pressure level generated during diamond core drilling operations.First,sound pressure level was recorded and sound signals of these sound frequencies were analyzed using fast Fourier transform (FFT).Rock drilling experiments were performed on five different types of rock samples using computer numerical control (CNC) drilling machine BMV 45 T20.Using simple linear regression analysis,mathematical equations were developed for various rock properties,i.e.uniaxial compressive strength,Brazilian tensile strength,density,and dominant frequencies of sound pressure level.The developed models can be utilized at early stage of design to predict rock properties.

钻孔联合地质剖面探测施工中若干问题探讨

基于《活动断层探测》GB/T 36072—2018、《活动断层探查钻探》DB/T 92—2022等现行规范规程,对跨隐伏活动断层的钻孔联合地质剖面探测施工的基本要求和存在的主要问题进行了探讨,认为现行技术标准存在的问题有:(1)对岩芯采取率的要求偏低;(2)对横跨隐伏逆断层的钻孔深度和钻孔之间距离的要求偏低.提出了下列改进措施:(1)各类岩土的岩芯采取率应大于现行技术标准要求的数值;其中,黏土的岩芯采取率应不小于99%;(2)对横跨隐伏逆断层的钻孔深度应大于现行技术标准要求的孔深;在第四系厚度较薄时,在逆断层上断点附近,位于逆断层上盘的钻孔在钻遇上盘的前第四系后,还应继续钻进,钻孔深度应达到能够揭露逆断层下盘的前第四系的深度;(3)当隐伏逆断层在第四系中的断距较小时,逆断层上断点两侧的2个相邻钻孔间距就需要1~3 m甚至更小的数值.补充了钻孔联合地质剖面探测中的钻孔布设方式、隐伏断层产状的求取方法.分析了在钻孔联合地质剖面探测的断层识别中存在的一些不确定性因素,并提出了相应对策.指出钻孔联合地质剖面探测施工是基于动态设计的信息化施工,现场技术负责人及其施工现场技术管理在钻孔联合地质剖面探测工作中起着重要作用.

Development of a Drilling and Coring Test-bed for Lunar Subsurface Exploration and Preliminary Experiments

Drill sampling has been widely employed as an effective way to acquire deep samples in extraterrestrial exploration. A novel sampling method, namely, flexible-tube coring, was adopted for the Chang＇e mission to acquire drilling cores without damaging stratification information. Since the extraterrestrial environment is uncertain and different from the terrestrial environment, automated drill sampling missions are at risk of failure. The principles of drilling and coring for the lunar subsurface should be fully tested and verified on earth before launch. This paper proposes a test-bed for conducting the aforementioned experiments on earth. The test-bed comprises a rotary-percussive drilling mechanism, penetrating mechanism, drilling medium container, and signal acquisition and control system. For granular soil, coring experiments indicate that the sampling method has a high coring rate greater than 80%. For hard rock, drilling experiments indicate that the percussive frequency greatly affects the drilling efficiency. A multi-layered simulant composed of granular soil and hard rock is built to test the adaptability of drilling and coring. To tackle complex drilling media, an intelligent drilling strategy based on online recognition is proposed to improve the adaptability of the sampling drill. The primary features of this research are the proposal of a scheme for drilling and coring a test-bed for validation on earth and the execution of drilling experiments in complex media.

Investigation of active vibration drilling using acoustic emission and cutting size analysis

This paper describes an investigation of active bit vibration on the penetration mechanisms and bit-rock interaction for drilling with a diamond impregnated coring bit. A series of drill-off tests(DOTs) were conducted where the drilling rate-of-penetration(ROP) was measured at a series of step-wise increasing static bit thrusts or weight-on-bits(WOBs). Two active DOTs were conducted by applying 60 Hz axial vibration at the bit-rock interface using an electromagnetic vibrating table mounted underneath the drilling samples, and a passive DOT was conducted where the bit was allowed to vibrate naturally with lower amplitude due to the compliance of the drilling sample mountings. During drilling, an acoustic emission(AE) system was used to record the AE signals generated by the diamond cutter penetration and the cuttings were collected for grain size analysis. The instrumented drilling system recorded the dynamic motions of the bit-rock interface using a laser displacement sensor, a load cell, and an LVDT(linear variable differential transformer) recorded the dynamic WOB and the ROP, respectively. Calibration with the drilling system showed that rotary speed was approximately the same at any given WOB, facilitating comparison of the results at the same WOB. Analysis of the experimental results shows that the ROP of the bit at any given WOB increased with higher amplitude of axial bit-rock vibration, and the drill cuttings increased in size with a higher ROP. Spectral analysis of the AEs indicated that the higher ROP and larger cutting size were correlated with a higher AE energy and a lower AE frequency. This indicated that larger fractures were being created to generate larger cutting size. Overall, these results indicate that a greater magnitude of axial bit-rock vibration produces larger fractures and generates larger cuttings which, at the same rotary speed, results in a higher ROP.

EXPLORING THE ASIAN MONSOON THROUGH DRILLING IN THE SOUTH CHINA SEA

Both evolution of the Asian monsoon system and the Cenozoic global cooling are thought to be closely linked to the Himalayan—Tibetan orogen. The South China Sea (SCS) with its high sedimentation rates of carbonate\|rich hemipelagic sediments offers a unique opportunity to study the variability of the East Asian monsoon, the erosion and weathering of tectonic orogens as well as its possible impact on global and regional climate.Leg 184, the first deep\|sea drilling leg to the seas off China, cored 17 holes at 6 sites in the northern and southern parts of the SCS and recovered 5463m of sediment. The drilling of hemipelagic sediments was exceptionally successful, with core recovery averaging 83%～101%. The 32Ma sequence of deep\|sea sediments recovered during Leg 184 covers almost the entire environmental history of the SCS since its opening. The abnormally high sediment accumulation rates in the Oligocene section are correlative with the incipient sea floor spreading. The bathyal nature of the Oligocenefauna implies that rifting occurred in the Eocene or earlier. Faunal changesfrom the early to late Oligocene are indicative of basin deepening, a trend thatis even more evident in the Miocene section. Sediment deformation, abruptlithologic changes, and a hiatus occur near the Oligocene/Miocene boundary,representing one of the most significant events in the tectonic andenvironmental history of the SCS.

Modeling and experimental investigation of drilling into lunar soils

Dry drilling only with the assistance of an auger is a reliable and realistic approach to remove abundant soils from the side of a bit in the harsh, dry conditions on the Moon. Based on an elementary analysis, using Janssen's model to reflect the coupling effect among the different components of the stress, the present paper models the conveying dynamics along the helical groove and the sampling mechanism in the centering hole of the stem for an auger drilling into lunar soil simulant. Combining the two parts as well as a simple cutting model for the bit, a whole drilling model is established to investigate the complicated relation among the conveying ability of the auger, the coring rate, and drilling parameters such as the penetration and rotation speeds. The relation is revealed by the complicated transition between different sub-models with the help of the physical transition conditions. A series of experiments with constant penetration and rotation speeds are conducted to verify the model. Three aspects of characteristics of the drilling dynamics are manifested,(i) the loads on the bit are almost independent of penetration;(ii) three obvious drilling stages with respect to cut per revolution are grouped;(iii) a linear relationship is found between the coring rate and the revolution per penetration.

柴达木盆地卤水钾盐迁聚规律与找矿新突破

钾盐是我国大宗紧缺战略性“粮食”矿产,对保障国家粮食安全具有重要意义。我国钾盐资源具有需求量大、对外依存度高等特点,寻找新的钾盐矿床、形成新的大型钾盐资源基地刻不容缓。2023年,中国地质调查局组织开展青海柴达木盆地钾盐“增储保供”地质调查工作,在前期对柴达木盆地成盐聚钾规律性认识的基础上,于柴西北大浪滩—黑北凹地部署实施了“探采一体化”柴钾1井,钻获1021.95 m(井深111.54~1133.49 m)巨厚松散砂砾储卤层,全井段抽卤试验获日稳定涌水量8586 m^(3)/d、水位降深11.3 m、单位涌水量759.89 m^(3)/d·m、氯化钾平均含量为0.54%的高产工业品位“砂砾型”卤水钾矿,取得了柴达木盆地陆相深层卤水钾盐找矿新突破,为形成中国新的亿吨级大型钾盐基地夯实了资源基础。

Analysis of sedimentary environment of core AB-67 at Barrow

A total of 48 samples from the core AB 67 at Barrow are analyzed for 25 grain size items and 44 geochemical items. Q mode factor analysis applied to these data yielded 4 factors. Mapping of there factor showed their close affinity to sedimentary environment; these core sedimentary rate, precipitation, sea level change, annual temperature. Paleoenvironmentary transfer functions were defined to estimate mean annual temperature and annual precipitation from corelationship between 5 samples at core top and observation record from Barrow Meteorology Observatory. Sedimentary rate was determinated from dating by 210 Pb and several environment events, and sea level from changes of sedimentary phase. The reconstructed temperature and precipitation curves show that Barrow climate is colder and drier in the 16th and the 17th century, temperature rose up and precipitation fluctuated sharply in the 18th and the 19th century, these two changes are greater in the 20th century. The reconstructed temperature curves agree with the variation of assemblages of micropaleontology.

A NEW METHOD FOR CLASSIFICATION OF ROCK DRILLABILITY

A New method of rock drillability classification for impregnated diamond drilling is recommended. The essence of the method is comparing the area of the slots cut respectively on a standard synthetic rock sample and the rock sample being classified by one diamond saw to determine the rock drillability in diamond core drilling. This method has the advantages of good in simulation and stable in comparison standard.

Repacking practice for G-3 engineering driller power unit with drive shaft of dual channel reverse circulation

In order to satisfy operating requirements for constant core drilling technology in reverse circulation with hollow-through DTH,the power unit of G-3 engineering driller was ameliorated. The new one with dual channel drive shaft, achieved the perfect assemble with transmission structure of the original power unit. It could interconvert according to need by using two sets of drive shafts with direct and reverse circulation. The repacked G-3 engineering driller carried on experiment in the field test in Luanchuan molybdenum mine of Henan, whose effect was very good.

龙门山双复杂区表层结构调查方法研究

龙门山山前带地表地质条件复杂,浅表层速度及厚度差异大,给激发、接收和静校正等工作带来较大困难。表层调查工作直接影响到地下介质成像效果。为使该地区进行的地震勘探攻关能够获取准确的静校正量数据,给井深设计提供依据,研究适合该区域的表层调查方法,结合地质剖面、浅震、小层析、地面微测井、钻井取心、高密度电法、三分量共振表层调查方法的工作原理,分别应用不同方法做比对,分析了不同调查方法的应用效果。通过不同表层调查的比对,分析了不同方法的适用范围,为该区选择合适的表层调查方法及方法参数选取提供依据,同时为其他地表复杂区域进行表层调查提供参考。

钻井利器的故事之“全液压岩心钻机”

钻机作为钻探工程中最重要的地面设备,是当之无愧的钻井利器。全液压岩心钻机是岩心钻机的主要发展方向。本文从科普的角度,介绍了岩心钻机在破岩过程中提供压力和旋转运动的主要作用,类比杠杆分析液压传动的工作原理,回顾了立轴式手把钻机、立轴式油压钻机到全液压岩心钻机的发展历程,阐述模块化轻便岩心钻机的特点及适合绿色勘查要求的优越性,并指出全液压岩心钻机的智能化、高效化、绿色化的发展方向。

钻井利器的故事之“液动潜孔锤”

在各种钻探方法中,液动冲击回转钻进具有效率高、质量好、回次长、事故少、成本低等优点,而液动潜孔锤又是液动冲击回转钻进的技术核心。本文梳理了各种液动潜孔锤的结构特点及其与绳索取心钻具、孔底动力钻具相结合衍生的各种钻具,简要介绍了这一技术的典型应用案例,总结归纳了其下一步发展方向和技术难点,以期普及液动锤的应用,促进液动冲击回转钻进技术的进步。

Automatic Data Reduction and Quantification of X-Ray Computed Tomography Images of Sedimentary Cores: Method and Illustration

This paper presents a procedure from which information contained in 3-Dimensional single energy X-ray computed tomography (XR-CT) images of sedimentary rocks is converted into sub-mm scale resolution core scalar and core image logs. This new data provide a quantitative and compact (data volume reduction of ~90%) description of the XR-CT images. Density-related outputs are calibrated through automatic integration with continuous digital visual core description (VCD) and discrete moisture and density (MAD) property index measurements of selected samples. After lithology-based calibration of the X-ray attenuation coefficients into density values, quantitative displays include: 1) histogram of the distribution of density values and its related statistical parameters, 2) radial and angular distributions of core density values, 3) volume, average density and mass contributions of three core fractions defined by density thresholds corresponding to voids or vugs (VV, density ≤ ~1 g•cm−3), and a break in the histogram of distribution of the density values showing the limit between the damaged (DM) and non-damaged (ND) fractions of the core material, and so, 4) providing a sub-mm scale bulk density core log free of any drilling disturbance. The procedure is illustrated on data from the 365 m deep Hole C9001C drilled off-shore Shimokita (northeast coast of Honshu, Japan). Usage of the outputs include: 1) derivation of sub-mm scale porosity core log, 2) correction of volume sensitive measurements in case of poor core quality and partially filled core liner, and 3) seismic modeling and well ties.

岩心钻探振动拔管器的研制及在卡埋钻处理中的应用

卡埋钻事故是矿产资源勘查岩心钻探最难处理的事故,传统的强拉、强顶、强扭、反丝钻杆反取等处理方式,处理成功率均极低,且程序繁琐,耗时、耗力、耗成本。为解决卡埋钻事故处理难题,研制了振动拔管器。使用时,将该机具安装在孔口钻杆上,通电即产生高频高压振动,然后用钻机主卷扬向上提拉振动拔管器+钻杆连合体,通过提拔+振动联合作用,实现解除卡阻。振动拔管器坚固耐用、操作方便、成本低廉,在钻探现场应用处理卡埋钻事故数十次,成功率达90%以上,具有极大的推广应用价值。

中空螺杆马达井底动力绳索取心钻具的研制与试验

针对大洋钻探硬岩取心钻具钻进效率低、取心效率低等问题,本文介绍了中国地质科学院勘探技术研究所研制的Ø185 mm规格中空螺杆马达井底动力绳索取心钻具的基本研制情况及陆地试验情况。研制过程中,通过理论计算和Ansys Workbench有限元仿真模拟,对中空式螺杆马达螺旋线型的结构进行了优化设计及动力学分析,并对万向节进行了受力安全分析,优选了材质,钻具攻克了多头小偏移量短节距中空转子和柔性中空万向节等关键技术,通过在陆地开展花岗岩块取心试验,验证了该取心钻具原理样机工作性能的可行性,为该钻具的工程应用提供了工作参数指导及匹配钻头的优选,也可为我国大洋钻探及深地科学钻探提供硬岩取心技术支持。

雪峰弧构造带钻孔轨迹控制关键技术研究

随着近年来矿产资源勘查要求的提高,岩心钻孔的深度及地层复杂性也不断加大,为能精准的钻遇靶区矿体以实现地质目的,对钻孔轨迹控制的要求越来越高。雪峰弧构造带部分工作区地层倾角大、软硬交替频繁、地层破碎,实际施工中地层造斜情况严重,随着孔深增加导致终孔轨迹与靶区矿体偏差较大,影响矿产资源勘查的精度和质量。通过对该工作区地层造斜情况的深入分析,在ZK1001钻孔绳索取心钻进施工中采用初级定向孔技术和满眼钻具工艺,大幅度提高了钻孔孔身质量,较好地实现钻孔轨迹控制。并通过试验不同的岩心钻具组合,提出了满眼钻具组合的优化意见和建议,为工作区岩心钻孔轨迹控制提供技术参考。

共和盆地东北部花岗岩型干热岩井下裂缝系统及其构造成因

花岗岩型干热岩中的先存天然裂缝系统是影响地热能开发的重要因素之一,其识别对于地热资源的有效利用至关重要。由于花岗岩类具有高强度和低孔隙度,裂缝系统往往成为干热岩地热开采中热流体的主要渗流通道及储集空间,储层裂缝系统的表征一直是干热岩有效开发利用的关键,也是共和盆地干热岩勘查开采示范工程遇到的难题。本文采用构造地质学和地球物理学等多学科方法,以共和盆地东北部DR3和DR8全井段连续取心井、GR1和GR2分段取心井的岩心为研究对象,开展了先存裂缝系统的观察识别和测井、地震资料响应研究,明确了深部埋藏区花岗岩型干热岩天然裂缝系统发育特征,探讨了构造作用对裂缝系统的控制作用。通过对岩心裂缝类型和空间展布特征的详细解剖,发现研究区井下裂缝系统主要由单缝、网状缝和破碎带组成。单缝大多为剪切缝,少量拉张缝,单缝的产状受临近断层和裂隙的控制;网状缝多伴随破碎带;破碎带明显受断裂及较大规模隐伏裂隙控制。岩石岩性对裂缝发育程度有一定影响,在相同背景下,抗剪强度较低的正长花岗岩、二长花岗岩较花岗岩、花岗闪长岩和闪长岩更易产生破碎带及网状缝。通过连续取心与多种常规测井方法对比分析,声波测井对于花岗岩类裂缝响应较为明显,不同深度裂缝发育带声波时差值随着深度及破裂程度不同而发生变化。干热岩裂缝系统的形成与研究区多期区域构造活动有关,大量不同角度剪切缝的存在也反映了多期裂缝形成应力场的最大主应力方向发生过多次偏转。多尺度、多方法花岗岩型干热岩的先存裂缝系统识别,可为后续的储层改造及规模化地热能开发提供重要依据。