Fracture prediction approach for oil-bearing reservoirs based on AVAZ attributes in an orthorhombic medium

Fracture systems in nature are complicated. Normally vertical fractures develop in an isotropic background. However, the presence of horizontal fine layering or horizontal fractures in reservoirs makes the vertical fractures develop in a VTI（a transversely isotropic media with a vertical symmetry axis） background. In this case, reservoirs can be described better by using an orthorhombic medium instead of a traditional HTI（a transversely isotropic media with a horizontal symmetry axis） medium. In this paper, we focus on the fracture prediction study within an orthorhombic medium for oil-bearing reservoirs. Firstly, we simplify the reflection coefficient approximation in an orthorhombic medium. Secondly, the impact of horizontal fracturing on the reflection coefficient approximation is analyzed theoretically. Then based on that approximation, we compare and analyze the relative impact of vertical fracturing, horizontal fracturing and fluid indicative factor on traditional ellipse fitting results and the scaled B attributes. We find that scaled B attributes are more sensitive to vertical fractures, so scaled B attributes are proposed to predict vertical fractures. Finally, a test is developed to predict the fracture development intensity of an oil-bearing reservoir. The fracture development observed in cores is used to validate the study method. The findings of both theoretical analyses and practical application reveal that compared with traditional methods, this new approach has improved the prediction of fracture development intensity in oil-bearing reservoirs.

Origin and Distribution of Hydrogen Sulfide in Oil-Bearing Basins,China

The concentration of hydrogen sulfide gas （H2S） varies greatly in the oil-bearing basins of China, from zero to 90%. At present, oil and gas reservoirs with high H2S concentration have been discovered in three basins, viz. the Bohai Bay Basin, Sichuan Basin and the Tarim Basin, whereas natural gas with low H2S concentration has been found in the Ordos Basin, the Songliao Basin and the Junggar Basin. Studies suggest that in China H2S origin types are very complex. In the carbonate reservoir of the Sichuan Basin, the Ordos Basin and the Tarim Basin, as well as the carbonatedominated reservoir in the Luojia area of the Jiyang depression in the Bohai Bay Basin, Wumaying areas of the Huanghua depression, and Zhaolanzhuang areas of the Jizhong depression, the H2S is of Thermochemical Sulfate Reduction （TSR） origin. The H2S is of Bacterial Sulphate Reduction （BSR） origin deduced from the waterflooding operation in the Changheng Oilfield （placanticline oil fields） in the Songliao Basin. H2S originates from thermal decomposition of sulfur-bearing crude oil in the heavy oil area in the Junggar Basin and in the Liaohe heavy oil steam pilot area in the western depression of the Bohai Bay Basin. The origin types are most complex, including TSR and thermal decomposition of sulfcompounds among other combinations of causes. Various methods have been tried to identify the origin mechanism and to predict the distribution of H2S. The origin identification methods for H2S mainly comprise sulfur and carbon isotopes, reservoir petrology, particular biomarkers, and petroleum geology integrated technologies; using a combination of these applications can allow the accurate identification of the origins of H2S. The prediction technologies for primary and secondary origin of H2S have been set up separately.

Sedimentary facies and depositional model of shallow water delta dominated by fluvial for Chang 8 oil-bearing group of Yanchang Formation in southwestern Ordos Basin,China

A systematic analysis of southwestern Ordos Basin's sedimentary characteristics,internal architectural element association styles and depositional model was illustrated through core statistics,well logging data and outcrop observations in Chang 8 oil-bearing group.This analysis indicates that shallow water delta sediments dominated by a fluvial system is the primary sedimentary system of the Chang 8 oil-bearing group of the Yanchang Formation in southwestern Ordos Basin.Four microfacies with fine grain sizes are identified: distributary channels,sheet sandstone,mouth bar and interdistributary fines.According to the sandbody's spatial distribution and internal architecture,two types of sandbody architectural element associations are identified: amalgamated distributary channels and thin-layer lobate sandstone.In this sedimentary system,net-like distributary channels at the delta with a narrow ribbon shape compose the skeleton of the sandbody that extends further into the delta front and shades into contiguous lobate distribution sheet sandstone in the distal delta front.The mouth bar is largely absent in this system.By analyzing the palaeogeomorphology,the palaeostructure background,sedimentary characteristics,sedimentary facies types and spatial distribution of sedimentary facies during the Chang 8 period,a distinctive depositional model of the Chang 8 shallow water fluvial-dominated delta was established,which primarily consists of straight multi-phase amalgamated distributary channels in the delta plain,net-like distributary channels frequently diverting and converging in the proximal delta front,sheet sandstones with dispersing contiguous lobate shapes in the distal delta front,and prodelta or shallow lake mudstones.

Palaeotemperatures and Diagenetic Phases of the Upper Triassic Oil-bearing Sandstones in the Eastern Part of the Ordos Basin

The maximum palaeotemperature of oil-bearing sandstones in the UpperTriassic in the eastern Ordos basin has been determined by using many methods including thevitrinite reflectance, fluid inclusion, apatite fission track, illite crystallinity, chlorite polytypeand diagenetic change of authigenic minerals. The thermal gradient in the Late Mesozoic wasabout 2.9-3.0℃/100m. The Upper Triassic was in a mature stage of organic matter andhydrocarbon began to be generated and migrated during this period. The palaeotemperatures ofoil-bearing sandstones were in the range of 88-110℃; those for the generation and migrationof oil ranged from 112 to 122℃. The thickness of the denuded strata overlying the UpperTriassic was 2465-2750m. The present burial depth of oil-bearing sandstones is generally from400 to 1200m. At a depth of ca. 1900m, the temperature may reach 140℃. Below this depth,organic matter was supermature and mainly generated gas.

A Newly Discovered Oil-bearing Mesoproterozoic Erathem within the Niu D1 Well, Liaoxi Depression, Yanliao Faulted Depression Zone, NE China

Objective The Yanshan Fold Belt is located within the northern margin of the North China platform and contains welldeveloped and widespread Neoproterozoic and Mesoproterozoic sedimentary units with a total thickness of up to 9000 m.Previous studies identified many oil seedlings as well as asphalt and ancient hydrocarbon reservoirs in Northern Hebei depression and western Liaoning depression.This research indicates that the Mesoproterozoic and Neoproterozoic sedimentary units are ideally suited for the formation of significant oil and gas resources.The Niu D1 well was drilled by the China Geological Survey(CGS)in the Niuyingzi area and intercepted oil immersions and oil-and gas-bearing units within a limestone reservoir in the middle Proterozoic Gaoyuzhuang Formation(Fig.1).This study presents new biomarker compound and carbon isotope data that indicate that the oil within this formation was derived from hydrocarbon source rocks of the Hongshuizhuang Formation,part of the Mesoproterozoic Jixian Series,and the reservoir type is overthrust fault fractured anticline hydrocarbon reservoir.The oil reservoir within the Gaoyuzhuang Formation limestone might represent the oldest oil reservoir discovered to date within the Yanliao faulted depression zone.

Study of Oil-Bearing Drill Cuttings Cleaning and De-Oiling Treatment Method for Shale Gas Reservoirs

Due to its extensive use in shale gas exploration and development,oil-based drilling fluids generate large amounts of oil-bearing drill cuttings during the drilling process.The large amount of oil-bearing drill cuttings generated during the drilling process can lead to serious secondary contamination.In this study,a wetting agent FSC-6 with good hydrophobic and oleophobic properties was synthesized to construct an efficient oil removal system.For the first time,the mechanism of this system was analyzed by using the theory of adhesion function,interfacial tension and wettability.At the same time,a combined acoustic-chemical treatment process was applied to the wastewater and slag generated after the cleaning of the oil-bearing drill cuttings.The experimental results show that the application of this pollution-free technology can effectively solve the environmental pollution and resource recovery problems of oil-bearing drill cuttings.It meets the standard of drilling chips with oil content less than 2%in SY/T7422-2018“Oil-based drilling fluid drilling chips treatment system for oil and gas drilling equipment”.

A comparison analysis between developed and undeveloped depressions over the South China Sea

-- In this paper, by using two sets of composite data of developed and undeveloped depressions over the South China Sea, we analyze and compare the dynamic structures, the heating fields and the vorticity budget residuals of two different types of depressions. Our conclusions are as follows:The two types of depressions are similar in thermodynamical and dynamical structures. The main differ ences are : in the high layer of developed depression there is a divergence field, with a center near the zero line of vertical wind shear, and over undeveloped depression, the divergence field is weaker and the vertical wind at its center is greater than 5 m s-1. The thermodynamical field of the former is asymmetrical and that of the latter is quasi - symmetrical. As far as the dynamics structure is concerned, the convergence in the lower layer and the difference of divergence between the upper and lower layers of developed depression is three tmies larger than that of undeveloped depression. The upward motion and heating field at the center of developed depression is also stronger than that of undeveloped one.The vorticity budget of the two types of depressions is mainly determined by the divergence term, the vorticity advection term and the vertical transport term. The residual term is also important.The principal contribution comes from the divergence term . This is more significant for developed depression than for undeveloped depression.

胜利油田未动储量开发技术及实践

胜利油田未动储量规模大,是油田后续建产稳产的重要接替阵地。但多年的开发实践证实,这部分储量的整体动用存在很多问题,制约着油藏效益开发和建产。针对这部分油藏品位差、动用难度大和开发效果差的特点,系统梳理了胜利油田未动储量的类型及分布特征,明确了主要的未动储量类型和重点攻关目标。结合近年来在砂砾岩、滩坝砂和深层低渗透稠油等油藏类型方面的开发实践,分析了砂砾岩油藏大斜度井大规模压裂、低渗透滩坝砂油藏压驱和深层低渗透稠油油藏降黏复合压驱等3种主要的未动储量开发技术及实践。长井段大斜度井大规模压裂技术,通过地质工程一体化实现工程甜点与地质甜点的结合,在低品位砂砾岩油层中的应用大幅提高了油藏产能;压驱注水开发技术创新开发理念,实现了低渗透滩坝砂油藏补能增产的突破;降黏复合压驱开发技术通过转变开发思路,实现了深层低渗透稠油油藏效益开发的突破。这3种油藏类型从单井提产、油藏补能和低成本开发等方面实现了未动储量的有效动用,取得了良好的开发效果。开发技术的突破、开发理念的转变是未动储量有效开发的必由之路,对胜利油田其他未动储量的开发具有非常重要的示范和指导意义。

数字经济对欠发达地区城市经济高质量发展的影响机制——基于科技创新的中介作用分析

中国广大欠发达地区城市正在寻求一系列方案措施来激发数字经济带来经济增长的红利效应。为探讨数字经济发展对欠发达地区城市经济高质量发展的赋能作用及影响机制,根据数字经济和经济高质量发展内涵构建城市层面的数字经济及经济高质量发展评价指标体系,在熵值法测算相关指数的基础上,采用双向固定效应模型对2012—2021年广西14个地市面板数据进行分析,同时用个体与时间双向固定模型检验科技创新因素的中介效应。实证结果表明:欠发达地区城市数字经济与经济高质量发展水平稳步上升,但存在发展不平衡、不充分问题;数字经济显著促进欠发达地区城市经济高质量发展,同时政府干预程度、产业结构水平、高等教育水平及城镇化率提升能有效促进欠发达地区城市经济高质量发展;科技创新在数字经济促进欠发达地区城市经济高质量发展过程中起重要中介作用。基于结论,提出实施差异化数字发展战略、推动传统产业数字化转型升级等推动欠发达地区城市经济高质量发展的政策建议。

广州市珠江水系未开发江心岛土壤镉污染特征及生态风险评价

广州珠江水系中未开发的江心岛是广州市非常重要的城市湿地系统和自然景观资源,其土壤重金属镉污染不仅影响岛屿自身生态系统的发育与稳定,也是珠江水生生态系统安全与健康的重要影响因素。本研究调查与分析了广州市珠江水系5个流域的22个未开发江心岛的土壤镉含量及污染状态,并采用物种敏感性分布模型(SSD)评价了大洲岛和龙门沙这2座岛屿土壤镉对附近水域的水生生态风险。结果发现:22座江心岛共计67份土壤样品全镉含量范围为0.01~5.95 mg/kg,平均值为0.62 mg/kg,镉含量最高的为东江流域的大洲围,岛屿镉含量平均值达到2.35 mg/kg,其次是前后航道龙门沙、流溪河流域的大洲岛和南航道的屎船沙;根据《土壤环境质量农用地土壤污染风险管控标准(试行)》(GB 15618—2018),共有34份土壤样品镉含量超出风险筛选值。基于岛屿土壤样点镉地累积指数评价结果,22座江心岛中,仅有3座岛屿土壤镉处于无污染状态,其他19个存在不同程度的镉污染。土壤镉潜在生态风险分析结果表明,低风险岛屿9座,7座岛屿为中风险,6座岛屿为高风险,广州市珠江水系5个流域均有土壤镉呈现中、重度污染且存在中、高生态风险的江心岛。SSD曲线生态风险评价结果发现,大洲岛以及龙门沙2座岛屿的4份样品中仅大洲岛16号样品为中度生态风险,其余3份样品均为高风险,2座岛屿的土壤可能在丰水期淹没后成为镉释放源,对附近水生生态系统具有危害。因此,广州珠江水系江心岛土壤镉污染存在一定的生态风险,应该加以监控与修复。

An intelligent automatic correlation method of oilbearing strata based on pattern constraints:An example of accretionary stratigraphy of Shishen 100 block in Shinan Oilfield of Bohai Bay Basin,East China

Aiming at the problem that the data-driven automatic correlation methods which are difficult to adapt to the automatic correlation of oil-bearing strata with large changes in lateral sedimentary facies and strata thickness,an intelligent automatic correlation method of oil-bearing strata based on pattern constraints is formed.We propose to introduce knowledge-driven in automatic correlation of oil-bearing strata,constraining the correlation process by stratigraphic sedimentary patterns and improving the similarity measuring machine and conditional constraint dynamic time warping algorithm to automate the correlation of marker layers and the interfaces of each stratum.The application in Shishen 100 block in the Shinan Oilfield of the Bohai Bay Basin shows that the coincidence rate of the marker layers identified by this method is over 95.00%,and the average coincidence rate of identified oil-bearing strata reaches 90.02% compared to artificial correlation results,which is about 17 percentage points higher than that of the existing automatic correlation methods.The accuracy of the automatic correlation of oil-bearing strata has been effectively improved.

降低烷基化装置待生酸单元尾气氮氧化物的研究

待生酸单元是烷基化配套装置,尾气中氮氧化物一直偏高,通过优化攻关,对氮氧化物的浓度进行降低。研究结果表明,通过本文的优化措施,废气NOx中NO2与NO比例由1:1下降至1:2,NOx人工检测平均值为53.6 mg/m3,达到了绿色企业≤80 mg/m3的指标要求,比去年同期降低37%。

基于螺旋接触线的五轴侧铣刀具定位方法

针对五轴侧铣加工非可展直纹面时刀具与设计曲面相互干涉的问题,提出了一种基于螺旋接触线的刀具定位方法。首先,基于Z-buffer法建立单个刀位下的误差解析模型,以评估刀具定位方法的优劣。其次,根据非可展直纹面的扭转特性,构造刀轴矢量的数学模型,同时分析刀具-工件接触线的性质及参数表达式。再次,考虑实际加工中的非线性加工误差,通过运动学变换对全局刀位进行路径插补优化。最后,基于改进两点偏置法、最小二乘法及所提出的方法进行仿真分析并对比3种方法所产生的误差,同时基于后2种方法进行实验验证。仿真和实验结果表明,所提出的方法能够有效减小侧铣加工中的原理误差,可为非可展直纹面的五轴侧铣加工提供一定的参考依据。

块煤开采的工艺参数及工程应用研究

针对大硬度厚度以及裂隙不发育煤层开采时块煤率低以及能耗较大的问题,以23101工作面实践生产为例,对其基本地质条件分析的基础上,通过数值模拟仿真手段确定了适用于23101工作面的最佳压裂处理方式为双排孔压裂;根据现场条件和理论计算得出最佳开采工艺为双向割煤端头斜切进刀方式,对应开采工艺的块煤率指标从37%提升至75.8%。

不可展曲面近似展开的四边形网格等面积法

提出了以面积不变作为基本展开原则，对不可展曲面进行近似展开的数值方法—四边形网格等面积法。以飞机整体壁板为例，给出了确定定义于外形曲面的零件结构信息的方法。

探明未动用储量经济评价方法探讨

从石油储量管理的现状入手,通过石油地质学和技术经济学的有机结合,按照未动用储量的落实程度,在现有技术水平、财务政策、开发方式、经营管理体制条件下,按照未开发储量投入开发后预期的内部收益率,将未动用储量分为近期可开发储量、低效一类储量、低效二类储量和暂无效益储量四类。对近期可开发储量的经济评价通常采用常规经济评价;对于低效储量,首先估算出该块近期投入开发的概率分布,通过开发概念设计进行现金流量计算;对于暂无效益储量,主要进行商业开采的风险评价。通过Y1和Y2区块的实际资料验证,证实了研究结果的可行性,它对于科学地盘活地下存量,实现储量探明与开发的有机结合,树立效益第一的观念,具有重要的指导意义。

中国未开发石油储量分析和对策

中国探明而未开发的石油储量随时间推移而增加,但未开发率变化却不明显。截至2013年底,全国地质储量中的未开发量为85.11×108t,未开发率21.9%;可采储量中的未开发量为10.71×108t,未开发率12.5%。在分别做了未开发储量的盆地分布和公司分布、不同类型油田的未开发储量分析后,提出了以新思维、新技术来动用未开发石油储量的有关问题:1未开发石油储量是现实的增产领域;2重新认识探明储量的动态和现状;3适宜技术的应用是关键。在适宜技术的应用中包括:必须强调每块未开发储量的特殊性,进行新一轮的精细地震工作,适度引入致密储层油气的钻井和储层改造技术,大力推进稠油开发,以先进方式开发海上中小油田群,重视凝析油气田的开发等问题。最后提出中国三大国有石油公司要想在全方位发展过程中集中力量为石油增产做出更大贡献,可适当缩小已占有勘探区块面积,集中力量在已开发的油田上提高采收率,大力动用未开发储量,以取得更高的投资回报率和整体经济效益。

新区经济可采储量计算方法

为了计算新区钻加密调整井的经济界限,快速评估新区储量,根据影响单井经济可采储量的主要因素--地质条件和油价、成本、投资等经济条件之间的关系,利用资金的盈亏平衡原理,以原油采收率和井网密度的指数关系式为基础,通过确定钻新井必须满足的新增可采储量界限,建立了新区加密调整井的经济合理井网密度的新计算模型。经大量实例检验,该模型各项参数容易求取,计算方便灵活,不但能够满足钻调整井的前期评价需要,而且能够评估新区储量,是一种实用的计算方法。

固井二界面封隔能力评价方法研究

利用测井评价方法和界面胶结强度评价方法均难以获得固井二界面的实际封隔能力。基于固井二界面封隔失效机理,设计了固井二界面封隔能力仿真评价装置,建立了固井二界面封隔能力评价方法。该方法把固井二界面作为独立的测试对象,直接沿固井二界面来评价流体的窜通能力,并以固井二界面当量渗透率为指标,实现了固井二界面封隔能力的定量评价。同时,解决了固井二界面胶结强度评价方法无法模拟环空窜槽的问题。验证结果表明,该方法能比较客观地反映固井二界面的实际封隔能力,可为难采储层薄隔层压裂工艺的选择提供科学依据。

硝酸银对冰糖橙胚性愈伤组织诱导的影响

为了诱导冰糖橙的愈伤组织和建立胚性细胞系,以冰糖橙成熟果实中未发育胚珠为外植体,将乙烯合成抑制剂AgNO3应用于冰糖橙胚性细胞系的建立,AgNO3设有5,10,12mg/L等3个处理,以未加AgNO3的MT培养基为对照.结果表明,在诱导培养基中添加AgNO3不能促进胚性愈伤组织的形成,反而抑制了胚状体的发生.然而在继代培养基中添加5mg/L的AgNO3有利于小而弱的胚状体基部形成胚性愈伤组织,胚性愈伤组织发生率达28%.经过5次继代处理建立了冰糖橙的胚性细胞系.