Kinetic Model of Gaseous Alkanes Formed from Coal in a Confined System and Its Application to Gas Filling History in Kuqa Depression,Tarim Basin,Northwest China

Based on the pyrolysis products for the Jurassic low-mature coal under programmed temperature,and chemical and carbon isotopic compositions of natural gas from the Kuqa Depression, the genetic origin of natural gas was determined,and then a gas filling model was established,in combination with the geological background of the Kuqa Depression.The active energy of CH_4,C_2H_6 and C_3H_8 was gotten after the data of pyrolysis gas products under different heating rates（2℃/h and 20℃/h）were fitted by the Gas Oil Ratio（GOR）Isotope Model soft.When the frequency factor（Af）was chosen as 1×10^（14）,the active energy of CH_4,C_2H_6 and C_3H_8 was 58 kcal/mol,57 kcal/mol and 54 kcal/ mol,respectively.The distributive ranges of theδ^（13）C_1,δ^（13）C_2 andδ^（13）C_3 values for the pyrolysis gas products are-35.9‰to-30.7‰,-26.2‰to-21.3‰and-26.4‰to-22.7‰,respectively.All of the natural gases from the Kuqa Depression are dominated by hydrocarbon gases,with the high gas dryness（C_1/C_（1-4））at the middle and northern parts of the depression and the low values at both east and west sides and the southern part.The carbon isotopes of methane and its homologs as a typical coal-type gas are enriched in ^（13）C,and the distributive range of theδ^（13）C_1,δ^（13）C_2 andδ^（13）C_3 value is-32‰to -38‰,-22‰to-24‰and-20‰to-22‰,respectively,with the carbon isotopes of gaseous alkanes being less negative with the carbon number.With the ethane being enriched in ^（13）C the increasing tendency of the geological reserve of natural gas in the Kuqa Depression is observed.This observed change is consistent with the results of pyrolysate gas yield of coal as a potential gas source in the Kuqa Depression,suggesting natural gas was thermally derived from the humic organic matters and the carbon isotopes of gaseous alkanes would coarsely predict the geological reserve of gas in the Kuqa Depression.Through the simulation of kinetic processes of gas generation for the Jurassic coal in the Kuqa Depression,the gas in the Kela 2 gas field would get the threshold of gas expulsion after 27 Ma,be expelled out of source rocks as＂pulse action＂,and then filled in the gas reservoir.The peak gas-filling history took place during the past 2 Ma.

Study on Basin-Filling and Reservoir Sedimentology of Zhu Ⅲ Depression of Pearl River Mouth Basin,South China Sea

Through basin-filling analysis, one coarsening-upward and two fining-upward sequences have been identified in Zhu Ⅲ depression. In accondance with the general model proposed by Ravnas and Steel (1998), the basin-filling has two large cycles—rift (sediment-balanced and -overfilled) and postrift (sedimentunderfilled and starved). During the rifting process, the rifted lake developed through three stages: early, climax and late. The sedimentary characteristics of reservoir rocks show that barrier bar, lagoon and tidal channel facies well developed in Zhuhai Formation; offshore, tidal and barrier bar well developed in Zhujiang Formation. Neighborly, Shenhu, Wenchang and Enping formations deposited in rifted lakes during Paleogene time; Zhujiang Formation deposited in bay, lagoon and shoreface in late Paleogene. Zhujiang and other formations deposited in offshore and open shallow sea to shelf.

Alkyl Naphthalenes and Phenanthrenes:Molecular Markers for Tracing Filling Pathways of Light Oil and Condensate Reservoirs

Condensates and light oils are generally characterized by high maturity, low concentration of sterane and terpane biomarkers and low content of non-hydrocarbon fraction. As a result, some commonly-used sterane, terpane and carbazole migration parameters in conventional oil reservoirs may have a certain limitation in condensate and light oil reservoirs for their poor signal-noise ratios in the gas chromatography-mass spectrometry （GC-MS）. Naphthalene, phenanthrene and their methylated substituents, however, are present in significant concentrations in condensates and light oils. Taking the Fushan depression （in the Beibuwan Basin, Northern South China Sea） as an example, this paper attempts for the first time to use polycyclic aromatic hydrocarbon （PAH）-related parameters to trace migration directions and filling pathways for condensate and light oil reservoirs. The result shows that TMNr （i.e. 1, 3, 7-TMN/（1, 3, 7-TMN ＋ 1, 2, 5-TMN）, TMN： trimethylnaphthalene））, MPI-1 （i.e. 1.5×（2-MP ＋ 3-MP）/（P ＋ 1-MP ＋ 9-MP）, P： phenanthrene MP： methyiphenanthrene）, MN/DMN （∑methylnaphthalene/∑dimethylnaphthalene, %） and MN/TMN （∑nethylnaphthalene/∑trimethylna- phthalene, %） can be used to trace the filling pathways of condensate and light oil reservoirs. These parameters, together with geological consideration and other bulk oil properties （e.g. the gas to oil ratio and density）, suggest that the condensates and light oils in the Huachang oil and gas field are mainly sourced from the Bailian sag that is located to the northeast of the Huachang uplift in the Fushan depression.

自体脂肪颗粒联合PRF移植填充矫治面部凹陷的效果及PRF对移植脂肪成活率的影响

目的:研究自体脂肪颗粒联合富血小板纤维蛋白(Platelet-rich fibrin,PRF)移植填充矫治面部凹陷的效果及PRF对移植脂肪成活率的影响。方法:选取2019年3月-2021年12月在笔者医院择期行脂肪颗粒移植填充手术的120例面部凹陷女性就医者,按照随机分组原则分为观察组和对照组,每组60例。两组均采取脂肪颗粒移植手术,观察组在移植自体脂肪颗手术基础上联合富血小板纤维蛋白治疗。术后6个月,比较两组移植脂肪的成活率及治疗效果。结果:观察组移植成活率显著高于对照组(P<0.05),且观察组治疗效果显著优于对照组(P<0.05);两组血肿情况、局部感染情况、坏死、脂肪液化、破溃、纤维囊肿发生情况比较,差异无统计学意义(P>0.05)。结论:自体脂肪颗粒移植联合PRF在面部凹陷填充中疗效确切,不仅提升了脂肪移植成活率,而且改善了面部凹陷情况,值得临床推广应用。

富血小板血浆联合自体脂肪颗粒移植修复颞部凹陷

目的:探究富血小板血浆联合脂肪颗粒移植对颞部凹陷患者的填充效果。方法:选择2019年9月-2022年3月笔者医院收治的100例颞部凹陷患者为研究对象,按随机数字表法分为对照组(50例,给予自体脂肪颗粒移植治疗)和观察组(50例,给予富血小板血浆联合自体脂肪颗粒移植治疗),比较两组患者手术效果、手术指标、满意度以及并发症发生情况。结果:治疗后,观察组治疗总优良率为92.00%,高于对照组的76.00%(P<0.05);治疗后,观察组脂肪厚度高于对照组,且观察组平均手术次数及脂肪移植总量低于对照组(P<0.05);观察组并发症总发生率低于对照组(P<0.05);观察组患者评价及医生评价满意率高于对照组(P<0.05)。结论:富血小板血浆联合自体脂肪颗粒移植能提高自体脂肪移植存活率,降低移植次数,填充效果显著。

Total alkyl dibenzothiophenes content tracing the filling pathway of condensate reservoir in the Fushan Depression,South China Sea

The condensates are generally characterized by high maturity,low concentration of steranes and ter-panes biomarkers and low content of non-hydrocarbon fraction. In this case commonly used steranes,terpanes and carbazoles parameters cannot be effectively applied in the reservoir-filling tracing. The hydrogen bond formed by sulfur atom in the dibenzothiophenes (DBTs) results in molecule adsorption and fractionation during oil migration in reservoir. Like carbazoles,total DBTs content decreases with the increasing of oil migration distance. Therefore,a new parameter——total DBTs content is proposed to be used to trace the oil migration orientation and filling pathway. In present study,total DBTs con-tents of condensates and light oils are obtained by adding internal standard——eight deuterium atoms substituted DBT during Gas Chromatography-Mass Spectrometry analysis of aromatic fraction. Except for a few samples with much lower content of non-hydrocarbon fraction,the total DBTs content shows a fine positive correlation with that of carbazoles. Large errors can be caused in the process of pyrrolic nitrogen compounds separation. The application of this new parameter in the Fushan Depression of Beibu Gulf Basin,South China Sea indicates that this parameter is a reliable one to trace filling pathway in condensate reservoirs. Combined with other DBTs-related parameters,such as 4-/1-methydibenzo-thiophene and 2,4-/1,4-dimethyldibenzothiophene,oil migration orientation and filling pathway of the Fushan Depression was determined. The accumulations of Huachang oil field in the Fushan Depres-sion are mainly migrated and charged from northeast to southeast along the Huachang uplift. It can be predicated that the light oil and condensates in the Huachang oil field should be sourced from the source kitchen at the Bailian Sag. It shows that total DBTs content is an effective parameter to tracing oil migration orientation and filling pathway.

Depositional sequence architecture and filling response model of the Cretaceous in the Kuqa depression,the Tarim basin

The Cretaceous system of the Kuqa depression is a regional scale (second order) depositional sequence defined by parallel unconformities or minor angular unconformities. It can be divided into four third-order sequence sets, eleven third-order sequences and tens of fourth- and fifth-order sequences. It consists generally of a regional depositional cycle from transgres-sion to regression and is composed of three sets of facies associations: alluvial-fluvial, braided river-deltaic and lacustrine-deltaic facies associations. They represent the lowstand, transgres-sive and highstand facies tracts within the second-order sequence. The tectonic subsidence curve reconstructed by backstripping technique revealed that the Cretaceous Kuqa depression underwent a subsidence history from early accelerated subsidence, middle rapid subsidence and final slower subsidence phases during the Cretaceous time, with the correspondent tectonic subsidence rates being 3035 m/Ma, 4045 m/Ma and 510 m/Ma obtained from northern foredeep. This is likely attributed to the foreland dynamic process from early thrust flexural sub-sidence to late stress relaxation and erosion rebound uplift. The entire sedimentary history and the development of the three facies tracts are a response to the basin subsidence process. The slower subsidence foreland gentle slope was a favorable setting for the formation of braided flu-vial deltaic systems during the late period of the Cretaceous, which comprise the important sandstone reservoirs in the depression. Sediment records of impermanent marine transgression were discovered in the Cretaceous and the major marine horizons are correctable to the high-stands of the global sea level during the period.

Organic Geochemical and Fluid Inclusion Evidence for Filling Stages of Natural Gas and Bitumen in Volcanic Reservoir of Changling Faulted Depression,Southeastern Songliao Basin

Recently,volcanic gas reservoirs in Yaoyingtai （腰英台） and Daerhan （达尔罕） tectonic belts in Changling （长岭） faulted depression of southeastern Songliao （松辽） basin have been discovered.Based on the compositions and isotopic values,the natural gas is characterized by high content of methane,low content of C2＋,and C1/C1-5 beyond 0.95.Also,the natural gas contains nonhydrocarbons including carbon dioxide with the content from 20% to 40% and minor amount of N2.Combined with the isotopic values,the natural gas is generated by humic kerogen and coal-derived type,but in Daerhan,the natural gas is probably mixed by oil type gas.From the measurement of lithology and fluid inclusions in volcanic rocks,the bitumen,liquid hydrocarbon,and gas hydrocarbon inclusions are present.Through the analysis of the single gas inclusion in volcanic reservoir,the content of carbon dioxide is low,so the carbon dioxide and hydrocarbon gas of the reservoirs are not accumulated at the same time.In addition,minor amount of bitumen in the reservoirs is formed by thermal evolution of the crude oils sourced from the Yingcheng （营城） Formation mudstones through the characterizations of the biomarkers.The distribution of homogenization temperatures presents two peaks,one with the liquid hydrocarbon filling stage,and the other with gas filling stage.However,in Daerhan tectonic belt,the second peak is gas and carbon dioxide mixed filling period probably.Combined with the homogenization temperatures of salt water inclusions,the oil and gas filling period is from Qingshankou （青山口） Formation to Nenjiang （嫩江） Formation in the research area.During the charging period,minor amount of inorganic carbon dioxide filled into the trap,but plenty of inorganic carbon dioxide from the end of Sifangtai （四方台） to Eogene periods was related with the structural movement.

经眉上入路自体颗粒脂肪填充术矫正上睑凹陷

目的:探讨经眉上入路自体颗粒脂肪填充术对上睑凹陷就医者的修复效果。方法:选择2022年4月-2023年4月在笔者医院行经眉上入路自体颗粒脂肪填充术的23例(46眼)上睑凹陷就医者为研究对象,回顾性分析临床疗效、美学效果(画框面积)、上睑凹陷分级、就医者满意度以及并发症。结果:就医者总有效率为95.65%(22/23)。治疗后的画框面积[(2.40±0.69)cm^(2)vs(4.36±1.57)cm^(2)]明显小于治疗前(P<0.05)。治疗前的上睑凹陷分级为1级11例(47.83%),2级9例(39.13%),3级3例(13.04%);治疗后的上睑凹陷分级为1级19例(82.61%),2级4例(17.39%),3级0例,治疗后的上睑凹陷分级明显优于治疗前(P<0.05)。就医者满意度为95.65%(22/23)。23例就医者均无感染、血肿、脂肪液化、一过性上睑下垂、硬结等并发症。结论:经眉上入路自体颗粒脂肪填充术对上睑凹陷就医者的修复效果显著,美学效果好,能明显改善上睑凹陷程度,安全性高。

真皮脂肪组织游离移植在颌面部缺损凹陷矫治中的应用研究

目的:研究真皮脂肪组织游离移植美容方案的构建及其在颌面部缺损凹陷患者中应用。方法:选取2018年1月-2022年1月在笔者医院就诊的颌面部缺损凹陷的患者90例,按照随机数字表法分为观察组和对照组,每组45例。对照组患者采用颗粒脂肪填充术;观察组给予真皮脂肪组织游离移植。比较两组患者术后1 d、术后1周、术后4周及术后12周的有效率;比较两组患者治疗6个月后的瘢痕情况。比较两组患者满意度情况、不良反应发生率及需要二次手术率。结果:观察组术后1 d及术后1周有效率比较差异无统计学意义(P>0.05)。术后4周及术后12周,观察组有效率高于对照组(P<0.05)。治疗前,两组患者温哥华瘢痕量表(Vancouver scar scale,VSS)及石溪瘢痕评估量表(Stony brook scar evaluation scale,SBSES)比较差异无统计学意义(P>0.05)。治疗后6个月,观察组VSS评分低于对照组(P<0.05),SBSES评分高于对照组(P<0.05)。治疗后3个月,观察组患者VAS评分高于对照组(P<0.05)。治疗期间,两组患者不良反应发生率比较差异无统计学意义(P>0.05)。治疗后3个月,观察组患者二次手术率低于对照组(P<0.05)。结论:真皮脂肪组织游离移植治疗颌面部缺损具有良好的临床疗效,且患者满意度高,术后不良反应少。

Efficient Priority-Flood depression filling in raster digital elevation models

Depressions in raster digital elevation models(DEM)present a challenge for extracting hydrological networks.They are commonly filled before subsequent algorithms are further applied.Among existing algorithms for filling depressions,the Priority-Flood algorithm runs the fastest.In this study,we propose an improved variant over the fastest existing sequential variant of the Priority-Flood algorithm for filling depressions in floating-point DEMs.The proposed variant introduces a series of improvements and greatly reduces the number of cells that need to be processed by the priority queue(PQ),the key data structure used in the algorithm.The proposed variant is evaluated based on statistics from 30 experiments.On average,our proposed variant reduces the number of cells processed by the PQ by around 70%.The speed-up ratios of our proposed variant over the existing fastest variant of the Priority-Flood algorithm range from 31%to 52%,with an average of 45%.The proposed variant can be used to fill depressions in large DEMs in much less time and in the parallel implementation of the Priority-Flood algorithm to further reduce the running time for processing huge DEMs that cannot be dealt with easily on single computers.

印制电路板电镀填盲孔的影响因素

以某公司电镀填盲孔的电镀液体系为研究对象,在500 m L哈林槽中模拟电镀线,系统地考察了电镀液配方(硫酸铜、硫酸、湿润剂、光亮剂、整平剂和氯离子的浓度以及添加剂相互作用)、电镀参数(电流密度和电镀时间)以及盲孔几何尺寸(深径比0.6∶1和1.07∶1)等化学和物理因素对FR-4基材盲孔电镀填孔的影响。以盲孔填孔率、凹陷度、表层镀铜厚度等指标综合评价盲孔填孔效果并用金相显微镜观察孔的横截面。结果表明,在适宜的电镀条件下,该电镀液体系对印制电路板盲孔的填孔效果良好。但是,适宜的电镀参数和电镀液配方与盲孔几何尺寸显著相关。

塔里木盆地古近系层序地层研究

运用露头、钻井岩心及测井层序地层学的有关理论方法,对塔里木盆地周边露头及盆地内钻井剖面的古近系进行了详细的沉积学和层序地层学研究,共识别出6个三级层序界面,把塔里木盆地古近系划分为5个三级层序。其中,古新世—始新世早期(库姆格列木群沉积期)发育3个层序,从下到上为S1,S2和S3。S1大致相当于库姆格列木群底部的砾岩段、膏泥岩段到白云岩段,在塔西南地区相当于土依洛克组。S2和S3大致相当于库车坳陷库姆格列木群上部两套膏盐岩段以及塔西南坳陷阿尔塔什组-齐姆根组及卡拉塔尔组-乌拉根组的两套膏盐岩段。始新世晚期—渐新世(苏维依组沉积期)发育1～2个三级层序,即S4和S5。S4相当于库车坳陷的苏维依组和塔西南坳陷巴什布拉克组的主体,S5仅在部分钻井中见到,以苏维依组顶部局部发育的扇三角洲相砂砾岩为代表。在这些层序中,低位体系域往往以发育扇三角洲分流河道及辫状河道相砂砾岩以及咸化潟湖或蒸发台地相厚层膏盐岩为特征,而水进体系域多以滨浅湖相泥岩和粉砂岩为主,高位体系域则主要为碳酸盐岩及富泥质的沉积序列。

济阳坳陷岩性油气藏充满度大小及分布特征

济阳坳陷岩性油气藏充满度统计结果表明 :1不同凹陷岩性油气藏充满度大小及分布特征不同 ,东营凹陷岩性油气藏充满度从 6 .8%至 94 .1%均有分布 ,平均为 4 6 .5 % ,沾化凹陷的分布范围为 7.4 %～ 78% ,平均充满度为 4 6 .6 % ,而车镇凹陷岩性油藏充满度为 5 %～ 6 0 % ,平均仅为 19%。岩性油气藏主要分布在沙二段和沙三段 ,其中沙三段的岩性油气藏平均充满度高 ,另外不同构造带和不同沉积体系岩性油气藏充满度大小不同。2不同类型岩性油气藏充满度大小及分布特征亦存在着差异 ,其中孤立砂岩体油藏的充满度绝大部分在 4 0 %以上 。

松辽盆地王府凹陷的沉积充填及生储盖组合

通过岩芯观察、测井分析 ,研究了王府凹陷沉积环境及充填层序 .结果表明 ,王府凹陷中生代经历了裂陷期和凹陷期两个充填阶段 ,裂陷期包括 2个充填层序 ,主要发育冲积扇、扇三角洲、湖泊沉积组合 ;凹陷期包括 3个充填层序 ,以河流和湖泊沉积为主 .王府凹陷发育良好的生储盖组合 ,青山口组、嫩江组半深湖 -深湖相暗色泥岩丰富 ,构成主要烃源岩 ;储集层以泉头组河道砂体和营城组扇三角洲砂体为主 ,烃源岩及储层发育和展布受沉积环境及充填层序控制 .

冀中坳陷古近系沉积层序特征及其沉积体系的演化

冀中坳陷古近系是由平行、微角度或角度不整合面所限定的一个区域性(二级)的沉积层序,其内可划分出3个二级层序、13个三级层序和数十个四级、五级的层序单元。整体上显示为三套从水进到水退的沉积旋回,可识别出冲积扇—河流、湖泊—湖泊三角洲以及河流等三套沉积相组合。构造、气候、物源供给及湖平面的变化等各地质要素之间严格控制着坳陷内部层序的构成及其充填响应模式。构造沉降过程等分析过程揭示了沉积坳陷经历了两次沉积速率变化的演化旋回,即两个不同的沉降阶段。第一阶段为古近纪古新世的缓慢加速沉降、始新世早中期的快速沉降和始新世晚期的缓慢沉降;第二阶段为始新世末期的缓慢加速沉降、渐新世早期的快速沉降和渐新世中晚期的缓慢加速沉降。这两个阶段的演化过程沉降速率分别为100～110m·Ma-1、205～220m·Ma-1、40～50m·Ma-1、30～40m·Ma-1、135～142m·Ma-1和10～20m·Ma-1。古近纪扭动作用揭示了坳陷左旋运动使其雁列构造在沙四末和东营末为北北东或北东方向展布;右旋运动使其雁列构造在左旋交替过程中产生,但其产生的构造的规模要比左旋构造小得多,一般表现为北西—北北西向构造。这种扭动作用的表现形式是南北对扭,并最终造就了坳陷东西向两凹夹一隆的构造格局。

适用于大尺度水文气候模式的DEM洼地填充和平坦区处理的新方法

针对传统的DEM(Digital Elevation Model)洼地和平坦区处理方法存在的速度慢等问题,提出了新的DEM处理方法。新方法由两个新算法组成:其一为DEM快速分位数分类算法,此算法先利用DEM的统计特征计算出分位数,然后分类,其时间复杂度仅为O(N),速度远大于传统分类方法的O(NlogN);其二为对分类后洼地和平坦区处理的新算法,此算法从高程最小的一类开始逐类处理,直到处理结束。用90m DEM对不同方法进行评价的结果表明:新方法在保证结果准确性前提下显著提高了DEM洼地和平坦区的处理效率。而且,新方法除了可将洼地填平之外,还可对洼地增加微小高程,生成无平坦区的DEM。新方法已成功地应用到地形指数的计算及TOPMODEL水文模拟,还适用于基于DEM的大尺度水文气候模拟与分析。

断陷湖盆层序地层格架中的油气聚集规律——以松辽盆地为例

松辽盆地早期断陷湖盆样式研究表明 ,松辽盆地存在二型四式构造样式 :即有补偿断层和无补偿断层的单断型断陷盆地 ,有补偿断层和无补偿断层的复合型断陷盆地。一个完整的断陷湖盆层序形成一套区域生储盖组合 ,其中 ,发育在TST和HST之间的最大密集段为主力生油层 ,也是良好的盖层 ;而LST、TST底部、HST顶部及RST通常发育有利储层。它们的规律性配置可构成上生下储、下生上储、侧生侧储和自生自储四种有利的生储盖层组合类型。每个体系域中都有岩性油气藏 ,构造油气藏是HST的主要类型 ,RST中可以找到不整合油气藏。

东营凹陷旋回式深湖相烃源岩研究

对东营凹陷沙河街组烃源岩的研究发现 :在灰褐色泥岩、纹层状褐色泥岩、钙质泥岩和油页岩中常常夹有泥质粉砂岩和少量浊积砂岩 ;对牛 38井密集采样分析则指示有机碳含量等多项地球化学参数呈现出“波峰”、“波谷”状变化特征 ,沉积界面也清晰地记录了湖平面的旋回式 (升降 )变换过程。本文探讨了盆地的充填过程 ,建立了旋回式深湖相沉积的地层模式———平衡充填 ,并深入分析了该套烃源岩的地质地球化学特征和有机质的赋存状态 ,指出旋回式深湖相烃源岩与浊积砂和前三角洲砂体主要以交互式或包裹式构成最佳生储配置关系 ,有利于隐蔽油气藏的形成。

同沉积构造组合模式下的沉积层序特征及其演化——以东蒙古塔贝尔凹陷为例

塔贝尔凹陷是塔木察格盆地的次级构造单元,位于蒙古国东部,向北延伸进入中国境内,与中国的海拉尔盆地同属一个构造单元。塔贝尔凹陷是塔木察格盆地早白垩世由高角度不整合面所限定的一个区域性(二级)的沉积层序构造单元,其内可划分出4个三级层序和数个四级、五级的层序单元。整体上显示为四套从水进到水退的沉积旋回,可识别出扇三角洲、湖泊—扇三角洲—近岸水下扇及湖泊—三角洲等三套沉积相组合。构造、气候、古地貌、物源供给及湖平面的变化等各地质要素之间配合严格控制着凹陷内部层序的构成及其充填响应模式。不同的同生断裂组合模式及其构造参量的变化明显对内部砂体的富集起到再分配、再沉积作用,特别是"人"字型、"之"字型类断裂组合系统,其形成的局部"断角式"富砂模式,易形成良好的圈闭,是有利的勘探方向。构造沉降过程等分析揭示了沉积凹陷经历了三次沉积速率变化的演化旋回,即三个不同的沉降阶段。分别为早白垩世早期的缓慢加速沉降阶段、早白垩世中期的快速沉降阶段和早白垩世晚期的快速—缓慢沉降阶段,这三个阶段的平均沉降速率分别为160m/Ma、205m/Ma和120m/Ma。规模不等的构造沉降严格控制着砂体分散体系在四维空间的展布。