测井信号小波变换在层序地层划分中的应用——以南海北部莺歌海盆地D14井黄流组为例

本文介绍了小波变换的基本原理和步骤,探讨了测井信号小波变换在层序地层划分中的方法和地质意义。对南海北部莺歌海盆地D14井黄流组自然伽马（GR）测井信号利用Daubechies小波系db5小波进行了一维连续小波变换和一维离散小波变换。根据其时频色谱图特征和高频离散系数曲线特征,将黄流组一段划分出1个长期旋回、3个中期旋回和9个短期旋回。显示出小波变换在测井层序地层划分中较高的分辨率、在识别地质作用中的隐蔽旋回特征的优势。实践证明,将一维连续小波变换和一维离散小波变换进行综合分析,更有利于不同级次的层序旋回识别。     

Geochemistry and provenance of a multiple-stage fan in the Upper Miocene to the Pliocene in the Yinggehai and Qiongdongnan basins,offshore South China Sea

The Yinggehai and Qiongdongnan basins in the northwestern South China Sea preserve a large volume of Cenozoic sediments. However, their sources are still remain controversial and need a further research. This paper uses discriminant diagrams and bivariate plots of major, trace and rare earth elements, combined with heavy mineral data and detrital zircon U-Pb ages to determine the provenance, source area weathering and tectonic setting of the Upper Miocene to Pliocene sediments in the Yinggehai and Qiongdongnan basins, offshore South China Sea. The sandstone samples used in this study are characterized by four features: (i) The studied sandstones are first-cycle deposits, no recycling processes are recorded in these sediments, and there is a low degree of weathering conditions in the source areas. (ii) The sandstones from the DF fan, LD fan and Central Canyon System may have a similar source, being derived from an old upper continental crust mainly composed of felsic igneous source rocks. (iii) Detrital zircon U-Pb ages suggest that Central Vietnam is likely to be the dominant source of the DF fan, LD fan and Central Canyon System. (iv) The tectonic setting of the sandstones in the DF fan, LD fan and Central Canyon System belongs to the continental island arc (CIA) or the active continental margin (ACM) fields.     

莺歌海盆地D1-1底辟区天然气成藏过程与分布差异

通过对莺歌海盆地D1-1底辟区中深层高温超压带与浅层正常压力带、压力过渡带天然气的组成、碳同位素特征差异的对比分析,结合底辟活动特征,研究了天然气藏的形成过程和天然气组分的分布规律。研究结果表明：(1)D1-1底辟核部区和底辟波及区中深层天然气成藏过程有差异,主要受底辟活动影响程度的控制。底辟核部区中深层气藏的形成过程为早期成藏、后期破坏并再次充注;底辟波及区中深层气藏的形成则为早期成藏,后期改造较弱,成熟煤型原生气藏保存较好。(2)D1-1底辟核部区和底辟波及区中深层天然气组分、碳同位素分布有明显规律;随距底辟核部距离的增大,其甲烷含量升高,二氧化碳含量降低,甲烷碳同位素变轻(成熟度降低),二氧化碳碳同位素也变轻,底辟核部区富集无机成因CO₂,至底辟波及区则以有机成因CO₂为主。     

莺歌海盆地沉积格架和充填演化分析

位于南海西北部海域的莺歌海盆地,由于其大地构造位置的特殊性,沉积格架和充填演化也具有非常独特的特点。盆地古近纪和新近纪上下两部分沉积特征完全不同,古近系显示出走滑盆地对称沉积的特征,受断裂控制较明显,沉积活动范围局限;新近纪基本上脱离断裂活动的控制,其沉积活动到新近纪中晚期逐渐显示出形似被动大陆边缘的沉积特征。盆地沉积中心的变迁独树一帜,主要经历了3个阶段,由西北-东南、东南-西北、西北-东南方向有规律地变化。沉积充填过程历经了由陆相到海相、多次大规模海进和海退沉积序列,形成了多套厚度较大的互层砂泥岩组合,具有良好油气远景。     

莺歌海盆地地层各向异性多波地震判别技术研究

充分利用中国在海上采集到的多波地震资料:PZ分量(P波)时间偏移剖面、X分量(P-SV波)时间偏移剖面和Y分量(P-SH波)时间偏移剖面,对莺歌海盆地3个构造(A构造、B构造、C构造)和D砂体的地下岩石介质的各向异性特征进行了研究,Y分量(P-SH波)、X分量(P-SV波)的旅行时间闭合差、准各向异性系数和泊松比结果表明A构造、B构造、C构造等存在不同程度的各向异性,且A构造的各向异性最强.实践证明,在海洋石油勘探中,多波地震资料用于地下岩石介质各向异性的判别是可行的.     

Sequence Stratigraphic Modeling of Sedimentary Basin: Conceptual Model and Application to Erlian and Yinggehai Basins, China

INTRODUCTIONQuantitativebasinmodelinghasbecomeoneofthefrontiersinsedimentarybasinanalySis.Alargevarietyofnumericalmodelsconcerningbasinformation,basinfillingprocess,thermalhistory,hydrocarbongenerationandaCCUmulationhavebeenformulatedoverthelastdecadetondAnctheprocessesandevollltionofsedimentarybasins(Mckenzie,1978,signeretal.,1990;Ungereretal.,1990).Thebasinmodeling,utilizingcomputersimulationtechnique,isapowerfultoolforbasinanalySisandhasincreasinglybeenintegratedintoconventionalbasi…     

The Red River sediment budget in the Yinggehai and Qiongdongnan basins,northwestern South China Sea,and its tectonic implications

ABSTRACT

The rapid uplift of the Tibetan plateau, the intense movement of the Ailao Shan-Red River Shear Zone (ARSZ), and the related climate change during the Cenozoic Indo-Asian collision have been widely studied; however, their timings varied considerably due to different data and methods used. As these events have been documented in the Red River sediment that came from the eastern Tibetan plateau and the Red River region and eventually deposited in the offshore Yinggehai and Qiongdongnan basins, here these events can be explored by calculating and analysing the Red River sediment budget, especially in the Qiongdongnan basin based on dense seismic profiles and wells. Results show that the Red River sediment mainly accumulated in the Yinggehai basin and the west part of the Qiongdongnan basin, and there are three sedimentary accumulation peaks in the Red River sediment budget during ~29.5–21, ~15.5–10.5, and ~5.5–0 Ma. By further comparing with previous studies on the timings of these events, it is inferred that the first sedimentary peak, prior to the onset of the monsoon intensification (~22 Ma), was probably driven by an intense left-lateral movement of the ARSZ in ~29.5–21 Ma. The second peak (~15.5–10.5 Ma), however, reflects a rapid uplift of the Tibetan plateau after the cessation of the left-lateral strike slip of the ARSZ. The third peak (~5.5–0 Ma) is most likely linked with a right-lateral movement of the ARSZ and the related climate change. Overall, the Red River sediment budget from the offshore Yinggehai and Qiongdongnan basins provides an important constraint on the timings of these tectonic events as well as the related climate change during the Cenozoic Indo-Asian collision.     

Structural Effects of Overpressure Fluid Activities in Yinggehai Basin

The characteristics and distribution of faults in Yinggehai basin discussed in this paper reveal the structural effects of the overpressure fluid expulsion. The rapid subsidence and mud-rich intervals of the marine rocks dominate the formation of the overpressure systems and the enormous volumes of the overpressure fluids in the basin. Triggered by some faults, the overpressure fluids were expulsed rapidly from the overpressure compartments to form a series of diapirs in the basin, resulting in the dense fractures or faults and folds in the limbs of diapirs. These fractures and faults provided the migration pathway for the vertical flow of hydrocarbons, so that the gas fields arising from this process might migrate upwards to the sandstone reservoir. Therefore, the hydrocarbon accumulations are usually located in the upper parts of diapiric structures.     

Observation of Catastrophic Degassing from Mantle-Crust in Yinggehai Basin, South China Sea

Previousworkshavenotonlywellestablishedtheiso topiccriteriaforrecognizingdifferentsourcesofnoblegases(ref.PintiandMarty ,2 0 0 0 ;Sardaetal.,1985 ) ,butalsoadvocatedtheintegrationofC/ 3Heratioswithstableisotoperatiostoprovideaninsightintotheoriginsofmantle derivedCO2 (Ballentineetal.,2 0 0 1,2 0 0 0 ;Lollaretal.,1997;Pedronietal.,1996 ;Trulletal.,1993;MartyandJam bon ,1987;DesMarais ,1985 ) .Inmanycases,however,thenoble gassignatureandC/3Heratiocannotbesimplyusedtoindicatetheoriginsofsuc…     

莺歌海盆地底辟带热流体突破的地层水化学证据

地层水化学特征往往反映出盆地流体的成因和演化信息。莺歌海盆地地层水样品分析表明地层水矿化度可划分3个带,即非底辟带、底辟带上方常压段和超压段。非底辟带地层水矿化度接近于正常海水,而超压带为具有较低矿化度的NaHCO_3型水,底辟带上方常压段地层水矿化度变化极大,与垂向断裂距离有关,越靠近垂向断裂的井往往具有更低的矿化度和更高的 HCO_3~-和 CO_3~(2-)离子浓度。在远离垂向断裂的底辟带侧翼或较浅地层(<1200m)孔隙水接近正常海水,以 MgCl_2型地层水为主:而在毗邻于垂向断裂的浅部储层具有明显低的矿化度,与超压带流体相似,也具有较高的 HCO_3~-和 CO_3~(2-)离子浓度这些观察结果反映垂向断裂为深部超压热流体突破的主通道,底辟带上方成为地层原生孔隙水(海水)与超压带内低矿化度热流体混合场所,地层水矿化度越低,说明来自深部超压热流体所占比例越大。不同压力地层中的水化学特征可以很好地用来识别流体运移路径和可能的水-岩反应。