Synthesis, Characterization and Formation Mechanism of Friedel's Salt(FS:3CaO·A1_2O_3·CaCl_2·10H_2O) by the Reaction of Calcium Chloride with Sodium Aluminate

The synthesis of Friedel＇s salt （FS： 3CaO·Al2O3·CaCl2·10H2O） by the reaction of calcium chloride with sodium aluminate was investigated. Factors affecting the preparation of Friedel＇s salt, such as reaction temperature, initial concentration, titration speed, aging time and molar Ca/Al ratio were studied in detail. XRD, SEM images and particle size distribution show that the reaction temperature, aging time and molar Ca/Al ratio have significant effect on the composition, crystal morphology, and average particle size of the obtained samples. In addition, the initial CaCl2 concentration and NaAlO2 titration speed do not significantly influence the morphology and particle size distribution of Friedel＇s salt. With the optimization of the operating conditions, the crystals can grow up to a average size of about 28 μm, showing flat hexagonal （or pseudo- hexagonal） crystal morphology. Moreover, two potential mechanisms of Friedel＇s salt formation including adsorption mechanism and anion-exchange mechanism were discussed. In the adsorption mechanism, Friedel＇s salt forms due to the adsorption of the bulk C1- ions present in the solution into the interlayers of the principal layers, [Ca2Al（OH-）6·2H2O]＋, in order to balance the charge. In the anion-exchange mechanism, the freechloride ions bind with the AFro （a family of hydrated compounds found in cement） hydrates to form Friedel＇s salt by anion-exchange with the ions present in the interlayers of the principal layer, [Ca2Al（OH-）6. 2H2O]＋- OH-.

Reservoir Characterization of the Early Cretaceous Sarmord and Garagu Formations from Atrush-1 and Mangesh-1 Wells, Kurdistan Region, Iraq

Petrophysical properties of the Early Cretaceous Sarmord and Garagu formations from the Atrush and Sarsang Blocks in the Kurdistan Region are studied. These formations are generally composed of limestones and dolomitic limestones interbedded with thin to medium layers of yellowish-gray marl (calcareous mudstone). The current study shows that the average shale volume in the Sarmord and Garage formations is between 16% and 20%. In Atrush-1 Well, the average porosity ratio of the Sarmord and Garagu formations is fair to good (15% and 11%, respectively). However, in Mangesh-1 Well, the porosity value is poor;it is around 4% on average. Generally, most of the hydrocarbons that have been observed within the pore spaces are residual oil type in Atrush-1 Well and movable hydrocarbon type in Mangesh-1 Well. In Atrush-1 Well, out of 362 m thickness of both formations, only 180 m is considered to be a pay zone;whereas, the pay zone is just around 8.0 m thick out of 347 m of the total thickness. According to the calculated porosity values, the Garagu and Sarmord formations are not considered as good reservoirs in the studied wells, with the exception of Atrush-1 Well where the Sarmord Formation has fair potential reservoir characteristics.

Geochemical Characterization of the Paleocene Ewekoro Limestone Formation, SW Nigeria: Implications for Provenance, Diagenesis and Depositional Environment

The usefulness of limestone as an industrial raw material is dependent on the level of its purity, largely controlled by diagenesis and the depositional setting. Limestone samples (83) obtained from the Ewekoro Formation exposed in quarry sections at Shagamu were analyzed using X-Ray Fluorescence spectrometry (XRF). A geochemical characterization of result was done to evaluate the purity levels and the implications on provenance, diagenesis, and depositional setting of the limestone. Five limestone beds from quarry sections (15 locations) were logged. Beds “E”, “D”, “C”, “B”, and “A” comprised sandy algal in sparry calcite cement, sandy biomicrite, algal biomicrite, sandy algal biomicrite, and the intra-sparite facies respectively. Results of major elements che- mistry indicated concentrations (in wt%) as follows: CaO (33.71 - 59.99), MgO (0.39 - 3.15), Al2O3 (0.47 - 3.23), Fe2O3 (0.51 - 3.43), SiO2 (0.47 - 45.98), SO3 (0.10 - 2.27), K2O (0.02 - 0.28), Na2O (0.00 - 10.0), TiO2 (0.00 - 0.27), P2O5 (0.02 - 0.92), MnO (0.01 - 0.06) and Loss on ignition (17.64 - 45.20). Geochemical result showed that the samples are enriched in CaO, while SiO2 varies widely, likely due to hinterland input. Plots of SiO2 versus CaO concentrations depicted a negative correlation attributable to chemical diagenetic processes. Diagenesis of the carbonate in form of reversible replacement of SiO2 with CaO and vice versa occurred under a shallow marine condition. This negative correlation between these oxides (CaO and SiO2) dictates zones of high purity limestones that are of desirable industrial applications. Relatively high silica content in the northwestern part is possible indication of outlets to the continental or inland areas where clastic sediment source may have been prominent. Ratios of Ca/Mg and Mg/Ca indicated a relatively low rate of evaporation of sea water and palaeo-salinity conditions marked by precipitation of limestone. Intermittent increase in palaeo-salinity and sea water evaporation level gave rise to the magnesian limestone.

鄂尔多斯盆地西南缘浅埋藏储层致密化成因

鄂尔多斯盆地西南缘镇原地区三叠系延长组8段细粒砂岩在较浅的埋藏条件下便发生了致密化。综合利用岩心分析、铸体薄片、扫描电镜与图像分析等技术,对其孔喉及成岩特征进行分析。结果表明:储层的成分及结构成熟度较低,孔隙结构以细孔—微细喉型为主,压实作用强烈,并且具有多期胶结与多期溶解的特征。以储层的“埋藏史-油气充注史-成岩演化序列-孔隙结构”为约束条件对储层的致密化定量表征发现,长8段在稳定的构造背景与辫状河三角洲环境的控制下,形成了细粒、富含塑性颗粒且高杂基含量的沉积,配合其后的快速埋深造成了强烈压实,其对储层致密化的贡献值为85%。成岩环境的多期变化造成了富集不同盐类的孔隙流体对储层的强烈胶结作用,对储层致密化贡献值为40.8%。早期绿泥石膜对颗粒的保护、稳定的构造背景及顶底板围岩处的硅质与钙质胶结层对孔隙流体活动的限制、过早的低渗和远离盆地生烃中心造成的缺乏酸性流体持续性注入等导致了溶蚀作用较弱,对储层致密化的抑制值仅为26.1%,且形成的次生孔喉易被后期胶结物充填。构造、沉积、成岩作用及其与油气充注在时空的耦合关系造成了长8段储层在浅埋藏条件下的致密化。

下扬子地区荷塘组细粒沉积岩岩相划分及微观孔隙发育特征

下扬子地区下寒武统荷塘组细粒沉积岩岩相微观孔隙发育特征不清楚制约了页岩气的勘探开发。基于普通薄片观察、氩离子抛光扫描电镜(SEM)分析、物性测试、X射线衍射全岩矿物及黏土矿物含量分析、N_(2)及CO_(2)等温吸附实验、聚焦离子束扫描电镜(FIBSEM)分析等实验资料,建立了荷塘组细粒沉积岩岩相划分方案,分析了不同岩相的微观孔隙结构特征。研究表明:①荷塘组细粒沉积岩主要发育块状硅质泥岩相、纹层状硅质页岩相、块状含黏土硅质泥岩相、块状硅/灰混合质泥岩相和块状混合灰质泥岩相5种岩相类型。②荷塘组不同细粒沉积岩岩相孔隙度和渗透率差异较大。孔隙类型主要为粒间孔、晶间孔、粒内孔、有机质孔和微裂缝,以微米-纳米级孔隙为主。介孔孔径为2.0~10.0 nm,微孔孔径为0.4~0.9 nm。③块状硅/灰混合质泥岩相有机质和脆性矿物含量高,粒间孔与微裂缝发育,孔隙度和渗透率较大、孔隙连通性较好、比表面积较大,为荷塘组最有利的页岩气勘探开发细粒沉积岩岩相。块状含黏土硅质泥岩相孔隙比表面积和孔体积较高,脆性指数、孔隙度和渗透率低于块状硅/灰混合质泥岩相,为次要的有利岩相。

金属半固态浆料非枝晶微观组织形成机制与表征

半固态技术自20世纪70年代由麻省理工学院开发以来,因其独特的优势而在全球范围内得到了广泛的研究。非枝晶组织的形成机理是半固态成形技术的基石,它决定了在特定条件下应采用哪些工艺来获得优质的半固态组织,对开发新工艺具有重要的指导作用。经过近半个世纪的发展,半固态浆料制备过程中非枝晶结构的形成机理已经发展出许多不同的观点。由此衍生了丰富的半固态浆料制备技术,大大促进了半固态领域的发展。为了进一步理解凝固过程中球晶的形成机制,对各种非枝晶组织的形成机制进行了梳理,基于制备原理将半固态制浆技术分为搅拌制备技术类和低过热度制备技术类,并对常见的几种技术的原理和应用进行了总结。半固态产品的性能在很大程度上取决于其微观组织结构,但半固态形态复杂,传统的二维表征手段对材料内部空间结构的理解可能存在误差。对半固态浆料的二维微观组织和三维显微组织表征技术进行总结分析,为理解金属半固态浆料的微观结构演变和微观组织与性能之间的关系提供了理论基础。

准噶尔盆地永进地区齐古组深埋砂岩成岩作用对储集层质量影响的定量表征

永进地区侏罗系齐古组是准噶尔盆地腹部一套重要的深埋含油层系,现今埋深5400~6100 m,其储集层质量控制了油气储量和产量。运用铸体薄片、阴极发光、扫描电镜、物性、XRD全岩和黏土矿物分析等资料对齐古组深埋砂岩储集层成岩演化过程开展研究,建立成岩演化序列,定量表征不同成岩作用对储集层质量的影响,结合区域埋藏史、油气充注史,最终明确储集层成岩演化过程。永进地区齐古组储集层岩性主要为长石质岩屑砂岩和岩屑砂岩,杂基含量低,胶结物类型主要为碳酸盐矿物、硅质和黏土矿物,具成分成熟度低而结构成熟度高的特征;储集空间类型以剩余原生粒间孔和粒间溶孔为主;整体处于中成岩A期阶段,储集层孔隙度变化主要受压实、胶结、溶蚀作用控制,压实作用和胶结作用是造成储集层减孔的主要成岩因素,分别造成原生孔隙损失率为65.98%和21.80%,溶蚀作用增加了5.25%的孔隙度,起到了有效改善储集层物性的作用。综合研究认为,永进地区齐古组储集层成岩演化主要受沉积环境、成岩作用、埋藏史、油气充注4大因素共同控制,成岩作用起到改造储集层物性的作用,是导致储集层非均质性较为明显的决定性因素。

四川盆地元坝地区二叠系茅口组相控岩溶刻画及预测

通过岩溶古地貌恢复、倾角约束增强相干、相控岩溶地震反演和非线性伽马模拟等技术,对四川盆地元坝地区二叠系茅口组相控岩溶异常及有效储层分布进行了研究。研究结果表明:①四川盆地元坝地区二叠系茅口组在纵向上可划分为表层风化壳、垂直渗流带、水平潜流带3个岩溶作用带,茅三段相控岩溶储层受浅滩相带和岩溶作用共同控制,储层类型分为孔隙-孔洞型和半充填溶洞型。②岩溶残丘地貌相对较高,为岩溶作用供水区域,是相控岩溶发育的有利位置;溶丘平原地貌相对较低,为岩溶作用汇水区域。③倾角约束的增强相干技术可定性描述岩溶残丘内相控岩溶发育的有利带,研究区的该类储层主要分布于古地貌高部位,并呈北西向展布。④相控岩溶储层预测方法可以相对准确地预测有效岩溶储层的分布范围,研究区垄脊带、峰丛带岩溶储层最为发育,最大厚度为28m。

Integrated Mineralogical Characterisation of Banded Iron Ores of Orissa and Its Implications on Beneficiation

Iron is a primary raw material for steel industry. Increase in demand for steel puts pressure on iron resources of India in respect of its grade and reserve. With increase in demand for good grade of ore vis-a-vis its limited reserve, the utilization of low to medium grade iron ores is the order of the day with adoption of advanced beneficiation techniques. In order to find out the effective way of utilization, an in depth mineralogical study is essential as it throws light on the mineralogical peculiarities associated with the ores which affect the resultant beneficiation technique as well as the final product. In order to have a detail insight into the different mineralogical attributes, various characterisation studies megascopic, microscopic (both optical & electron), XRD, mossbauer and VSM are undertaken on the iron ores from different iron ore formations of Orissa. Importance of integrated mineralogical characterisation in beneficiation of iron ores is discussed.

基于多分量地震资料的河道砂体刻画及含气性预测技术——以QL地区沙溪庙组为例

四川盆地中部地区中侏罗统沙溪庙组为三角洲前缘沉积,水下分流河道砂体发育,是新一轮非常规天然气勘探开发的新领域。但依靠现有纵波地震资料刻画出的河道砂体边界不清楚、部署的井位产能差异较大,难以满足致密气高效勘探开发的需求。针对勘探与开发的需求以及面临的河道砂体边界刻画不准确、储层含气性预测难等地质问题,利用2020年QL地区新采集的三维三分量地震勘探资料开展了研究,形成了基于多波地震资料融合的河道雕刻技术。该技术较单一纵波可更加清楚地刻画河道边界,补充中、高阻抗河道砂体的识别;形成了基于多波资料的含气预测技术,并利用河道砂体含气后纵波、转换波的地震振幅响应特征及相位特征的差异性,建立了高产气井的多波地震响应模式,从而获得含气性预测成果。该研究成果支撑了区内致密气开发井位部署,为致密气高效开发奠定了基础。

Characterization of the Upper Cretaceous Sediments in the Ikpankwu-Ihube Axis, Okigwe, Southeastern Nigeria

Detailed characterization of the outcropping sediments in the Ikpankwu and Ihube axis was undertaken to validate lithostratigraphic boundaries and nomenclatures which had stirred up debates amongst scholars in recent times. Stochastic method established dominant facies associations and preferred stacking patterns, which were used to interpret environments of deposition (EODs), while foraminiferal and palynological analyses fingerprinted both paleo depths and age of the sediments. The results established the dominance of similar lithofacies at the basal parts of both sections indicating mappable geological units and members of the same lithostratigraphic unit. The basal lithofacies are succeeded up section, however, by different lithological units in both the KM 75 and Ikpankwu sections. Interpretations of EODs using lithofacies successions predicted fluvial to tidally-influenced shallow marine deposits, which are environments in close affinity with each other. Interpretations using abundance and diversity of micro fauna supported non-marine (coastal-deltaic) to middle neritic paleo-water depths also, typical of marginal to shallow marine EODs. Recovered foraminiferal assemblages in the shale samples from the upper parts of both sections, however, depicted deposits of Nsukka Formation despite variations observed in lithofacies assemblages because the identified Haplophragmoides species that populate the upper units had been used to define the Late Maastrichtian-Paleocene age. Sediments at the basal parts with mappable lithological units at both sections were rather populated by species that connote the Campanian-Maastrichtian age when the Mamu Formation sediments were deposited. Palynomorphs recovered from both the basal and upper sections also suggested Campanian-Maastrichtian and Late Maastrichtian-Paleocene age, indicative of Mamu and Nsukka Formation sediments, respectively.

Factor Controlling Reservoir Properties and Flow Unit Determination in the Ilam Formation of Dezfol Embayment at Zagros Fold-Thrust Belt, Southwest of Iran

Dezfol embayment in the Southwest of Iran is located in the Zagros fold-thrust belt, which is one of the world’s largest petroleum provinces. Ilam Formation (Santonian-Companian) is one of the reservoir formations in this area that has been less studied. This paper focused on reservoir properties in this formation using petrography and petrophysics data. According to the petrography studies Ilam Formation composed of limestone as dominant lithology. Detailed petrographic analyses, have led to identification of 10 micro-facies which are represented as a carbonate ramp depositional model. Also petrographic analyses are revealed that cementation, dissolution, compaction and dolomitization are most important digenetic processes. Detailed petrographic analyses and petrophysics data showed that due to mud-supported nature of more facies (inherited low reservoir potential from their depositional settings), diagenetic process plays an important role in increasing of reservoir quality. However cementation and dissolution had negative and positive effects on Ilam reservoir formation, respectively. Finally at the end for better correlation and to create a flow unit, according to the petrography data and using petrophysics log, this reservoir is divided into 5 units (flow unite) by using Geolog software and then they have been correlated across the field.

Petrophysical Analysis and Flow Units Characterization for Abu Madi Pay Zones in the Nile Delta Reservoirs

Field development typically requires detailed petrophysical analysis and well defined hydraulic flow units for comprehensive formation evaluation and reservoir characterization. In the present study, pay zones petrophysics are studied using an assembly of well log data from 8 wells together with core plugs measurements. Petrophysical analysis showed a good reservoir quality with average water saturation increasing toward the East and Southeast of the study area. Using a multi-linear regression technique on well logs and core data, permeability is estimated at well locations for flow unit characterization and flow capacity calculation. Results showed that five hydraulic flow units are identified through the studied wells, with relatively good correlation. Such correlation indicated a good continuity in the net pay zone of Abu Madi Formation in the Nile Delta reservoirs. The developed hydraulic flow units (HFUs) are classified according to its hydraulic conductivity into two main categories: the first category comprises the units with low permeability (K 1270 mD). The reservoir flow capacity (RFC) of these units indicated the development of 4 distinct classes (~11, ~30, ~80, and greater than 130 D.ft). The wells within the Northwestern part of the study area showed three HFUs that relatively vary from those located at the Southeast where two HFUs are only developed. In addition, the Southeastern part of the reservoir is characterized by good RFC as indicated by the development of high order HFUs (3, 4, and 5) compared to the Northeastern part with predominated low order HFUs (1, 2, and 3). Such results are crucial for the efficient field development and profound reservoir management of oil and gas fields in the Nile Delta.

鄂尔多斯盆地中南部地区延长组砂岩溶蚀增孔模型的建立与应用

溶蚀作用作为一种建设性的成岩作用,对于砂岩储层储集空间的扩大以及储层性能的改善具有重要作用。由于现有研究更多的是从定性的角度出发表征溶蚀作用对于砂岩储层孔隙度的影响,对于溶蚀作用产生的孔隙度增加值有多少,对砂岩储层性能的改善效果有多大,目前暂不能定量表征。本文采用化学反应动力学基本原理,基于录井、测井数据,结合砂岩成岩序列、地层埋藏史和热史等资料,采用化学反应动力学基本原理,对鄂尔多斯盆地中南部地区延长组砂岩现今孔隙度特征及成因进行了分析,构建了砂岩溶蚀增孔定量模型,并用该模型对延长组砂岩孔隙度演化进行了模拟,取得以下主要认识:(1)研究区延长组现今砂岩孔隙度剖面总体上可分为正常趋势段和次生溶蚀增孔段两部分,依据次生孔隙形成的起始层位和形态特征,现今砂岩孔隙度剖面可划分为双峰Ⅰ型、双峰Ⅱ型、单峰Ⅰ型和单峰Ⅱ型4种类型;(2)延长组现今砂岩孔隙度主要经历了孔隙度减小和孔隙度增大两种变化效应。其中浅部地层孔隙度减小主要是缘于机械压实作用,深层孔隙度减小则是由于压实和胶结共同作用,而孔隙度增大主要由有机酸溶蚀长石等矿物形成的;(3)建立了砂岩溶蚀增孔定量表征模型,具体包括3个阶段:(1)地层进入酸化窗口之前,由于酸化溶蚀发生的条件不满足,砂岩溶蚀增孔量为0;(2)地层进入酸化窗口内,砂岩累计溶蚀增孔量是现今次生增孔量和时间的函数;(3)地层继续深埋超过酸化窗口后,溶蚀孔隙不再变化。表明砂岩溶蚀增孔模型是一个分段函数,具有明显的窗口效应;(4)运用砂岩溶蚀增孔模型对研究区延长组砂岩孔隙度演化进行了模拟,发现研究区南部镇泾地区红河1井长8砂岩、东部安塞地区丹40井长6砂岩及北部姬塬地区峰12井长4+5砂岩在酸化窗口内溶蚀作用产生的增孔量具有明显的阶段性演化特征,实现了溶蚀作用对于砂岩孔隙度增加值的定量表征。本文建立的砂岩溶蚀增孔模型可以定量计算酸化窗口内溶蚀作用形成的孔隙度增加值,首次实现了砂岩溶蚀增孔的定量模拟,在分析溶蚀作用和砂岩储层性能演化等方面具有比较重要的探索性意义。

柳江盆地二叠系山西组露头致密砂岩储层非均质性表征方法

为了深入研究致密砂岩露头储层的非均质性,解决致密砂岩储层非均质性影响因素多、综合定量表征储层非均质性难度大的问题,对柳江盆地二叠系山西组露头储层进行了系统化密集采样。利用地质统计分析、样品实验分析和显微镜薄片观察等方法,确定了致密砂岩储层各项性质及相关定量数据。同时基于洛伦兹曲线理论分析处理数据,运用层次分析法确定了渗透率、孔隙度、面孔率、填隙物含量和粒度等影响因素的权重,提出了综合定量表征致密砂岩储层非均质性的方法。研究表明,靶区山西组露头致密砂岩为强非均质性储层,区域垂直层面和平行层面的孔、渗特征近乎一致。孔隙度与渗透率之间的差相关性表明,基于突进系数、变异系数和级差等参数的传统非均质性评价方法不适用于致密砂岩储层。用新方法得到的结果比传统仅基于渗透率指标所构建的参数能更好地反映致密岩储层和非均质性。该方法也适用于其他类型非常规储层的非均质性评价。

地震沉积学在东海陆架盆地西湖凹陷河流-三角洲相储集层刻画中的应用

针对东海陆架盆地西湖凹陷渐新统花港组河流-三角洲相储集层横向变化快、常规切片属性形态差、储集层预测难度大、难以满足岩性油气藏的后续勘探开发的问题应用分频解释、反演-常规-90°相移联合构建地震岩性体、非线性切片、古地貌恢复、多属性融合等特色技术对传统地震沉积学方法进行优化。研究发现花港组发育辫状河、曲流河和浅水三角洲3类沉积体,垂向沉积演化受中期基准面旋回和古地貌联合控制。在中期基准面旋回上升阶段的早—中期以辫状河道沉积为主,发育垂向叠置型砂体;在上升半旋回晚期和下降半旋回的早期以曲流河沉积为主,发育孤立型砂体;在中期基准面下降半旋回的中—晚期以浅水三角洲沉积为主,发育迁移型中—厚层砂体。限定性古地貌对砂体展布具有控制作用,非限定性古地貌对砂体展布影响较小。在储集层刻画的基础上,提出断层封堵型和储集层上倾尖灭型构造岩性圈闭是西湖凹陷下一步滚动挖潜的主力方向。

北京大气中醛酮化合物污染特征与来源分析

为研究北京大气中醛酮化合物的污染特征,利用2,4-二硝基苯肼采样管采样-高效液相色谱仪分析的方法,于2020年1月—12月以及2020年5月26—29日对北京城区评价点(车公庄)大气中的13种醛酮化合物开展常规和加密监测分析,于2020年9月17—21日对北京城区评价点和北京东南边界点(永乐店)开展同步监测分析,并对醛酮化合物的来源进行了初步分析.结果表明:①2020年北京城区大气中醛酮化合物总浓度为(25.1±8.5)μg/m^(3),其中丙酮、甲醛和乙醛的贡献率分别为43.1%、30.7%和15.6%.臭氧生成潜势呈甲醛>乙醛>丙酮的特征,其中甲醛和乙醛对臭氧生成潜势的贡献率分别为66.5%和23.0%.②醛酮化合物总浓度呈夏季>春季>秋季>冬季的特征,甲醛和乙醛浓度日变化均呈“双峰”特征,均在12:00—15:00达第1个峰值,在17:00—19:00达第2个峰值.③同步监测期间,车公庄和永乐店的醛酮化合物总浓度分别为(24.4±7.8)(24.1±7.5)μg/m^(3),车公庄丙酮、甲醛的贡献率分别较永乐店高1.3%和1.6%,乙醛、正丁醛、甲基丙烯醛的贡献率分别较永乐店低0.7%、2.0%和2.0%.④春季、夏季、秋季、冬季北京城区大气中甲醛和乙醛浓度之比(C1/C2)分别为1.9、2.4、1.7和1.2,乙醛和丙醛浓度之比(C2/C3)分别为10.6、12.4、8.3和8.3;车公庄甲醛浓度与乙醛浓度以及甲醛浓度与2-丁酮浓度均呈显著相关,而丙酮浓度与各化合物浓度的相关性较弱,永乐店乙醛浓度与丙醛浓度、乙醛浓度与甲基丙烯醛浓度以及甲醛浓度与正丁醛浓度均显著相关.研究显示,车公庄醛酮化合物浓度主要受机动车、光化学反应和溶剂使用影响较大,永乐店同时还受工业排放和柴油车尾气影响.

玛北斜坡百口泉组致密砾岩水力压裂裂缝表征

水力压裂是致密砾岩油气开发的主要手段,主要通过物理实验和数值模拟研究水力压裂裂缝,由于缺少现场数据的验证,增产措施的设计存在较强的不确定性。为了描述致密砾岩压裂裂缝的形态,证实储集层有效改造,在玛湖凹陷北斜坡钻取了1口以获取压裂裂缝为目的的取心井。在致密砾岩岩心观察与分析的基础上,对比岩心、成像测井、CT扫描等资料,描述了压裂裂缝形态,表征了裂缝产状和密度。致密砾岩具有粒径大、分选差、颗粒支撑以及非均质性强的特征。从长度为323 m的岩心中识别了335条压裂裂缝,主裂缝扩展以与井筒垂直的方向为主,分支裂缝较少且与主裂缝近垂直,部分层段出现破碎带,是不对称的双翼缝。裂缝具有绕砾和穿砾2种扩展方式,分别在拉张和剪切作用下形成,因此,将其分为张性缝和剪切缝。张性缝和剪切缝产状一致,均为接近90.0°的高角度倾角,近南北向的倾向,剪切缝的密度整体上大于张性缝。

基于深度学习的露头地层剖面裂缝自动提取

目前我国油气勘探开发的主要目标在逐步转向碳酸盐岩油气资源和页岩油气资源,而碳酸盐岩储层以缝洞型为主,对野外露头地层剖面的裂缝提取能够为缝洞型储层研究提供直观、形象的结果。最常见的传统露头裂缝研究是耗时耗力的人工解译,为此提出基于深度学习的露头地层剖面裂缝智能化提取技术:在Mask R-CNN算法的基础上结合在线增广策略和注意力机制实现裂缝的自动化提取。为了证明Mask R-CNN改进算法对错误标签的容错能力,设计了含有不同程度错误标签的训练集对比实验,结果表明,当错误标签占比达到30%时模型精度下降较大;接着通过消融实验定量分析不同的改进算法对精度的提高程度;然后以人工提取结果为参照,与大津法(OTSU)、区域生长算法、UNet算法、DeepLabv3+算法等进行精度对比评价,结果表明,改进的Mask R-CNN裂缝识别方法提取的裂缝线性特征更准确完整,且正确率在97%以上,高于其它对比算法,验证了该方法的有效性;最后将改进的Mask R-CNN裂缝识别方法应用于四川盆地西南部峨边先锋地区野外露头地层剖面的裂缝提取,并对裂缝长度、密度、倾向和间距参数进行统计分析,定量分析裂缝分布特征,验证了该方法的可行性。本研究为加快石油勘探综合研究和目标精细评价,储层预测和露头地层剖面参数表征的自动化发展提供了依据。

基于碳酸盐岩储层裂缝表征与产能描述的开发技术对策——以川西北双鱼石区块栖霞组气藏为例

针对碳酸盐岩气藏试采期开发技术对策研究中存在的问题,在剖析裂缝表征方法和扩展气井产能概念的基础上,探索和揭示了不同类型储层裂缝特征相对应的气井产能变化规律,形成了碳酸盐岩储层裂缝表征与产能描述技术。文中研究明确了裂缝-孔洞型、裂缝-孔隙型和孔隙型3类储层酸压改造后形成的裂缝搭配模式与试井双对数曲线的对应关系;通过建立复合地层渗流方程,实现了对气井产能以及影响产能的动态储量、平均渗透率的描述,揭示了纯气井和气水同产井在早期、过渡期、平稳期和变化期4个阶段的产能变化规律,以此为依据提出了井位平面部署、靶体位置优化、钻井及储层改造工艺、生产井制度优化4个方面的对策建议。通过实施开发技术对策,取得了单井产量的突破,生产井水侵速度得到一定程度的控制。文中研究成果指导了气藏开发技术对策的制定,为同类型碳酸盐岩气藏的高效勘探开发提供了技术参考。