地质雷达探测技术(Ground-penetrating Radar,简称GPR)是一种用于确定浅层地下介质分布的广谱勘探地球物理技术.以海拉尔曲流河现代沉积为目标,探讨了如何应用地质雷达探测技术开展河流相储层构型表征及建立原型地质模型.地质雷达探测技术及实施过程具体包括目标区地质雷达资料采集、数据处理及剖面综合解释等环节,以河流相储层构型及沉积模式为基础的地质雷达剖面分析和解释是研究工作的核心.通过海拉尔地区目标的探测,共识别出了河道充填构型(CH)、侧向增生体(LA)、废弃河道沉积(FFCH)、洪泛细粒沉积(FF)4种曲流河储层构型单元,总结了各自的地质雷达响应特征以及构型界面识别标志,结合探槽、钻孔等其他信息,建立了目标区曲流河沉积三维原型地质模型.

地质模型动态更新方法是一种基于正演模拟的随钻地质导向技术,模型质量制约方法应用效果.本文在建模范围、网格划分及模拟属性等方面改进提出了一种更适于随钻地质导向的地质建模和动态更新方法.方法应用于渤南中浅层油田水平井的实施过程,通过建立以自然伽马属性、砂体概率分布属性为主的先导地质模型,在随钻过程中动态加入随钻测井资料并更新地质模型,利用模型预测结果指导调整水平井钻井轨迹.A33H井实钻结果显示,应用地质模型动态更新方法有效降低了夹层钻遇风险,水平段油层钻遇比例超过80％.

海上油气田受平台规模约束,开发井距大,地质不确定性贯穿开发全寿命历程,对于油藏内部影响开发效果、但无法精确刻画的小尺度(厚度小于5 m、展布范围小于500 m)阻渗屏障体,等效表征是主要解决方案.本文以渤海A油田为例,探讨了小尺度阻渗屏障体的等效表征方法.具体为:首先,基于新近系浅水三角洲地质知识库,从储层构型角度入手,总结了构成潜在渗流屏障的地质界线,包括沙坝-沙坝、沙坝-河道、河道-河道三种界线类型;然后,通过简化界线几何形态模式,开展机理建模,包括两套模型:小尺度网格精细原型模型、大尺度网格粗化等效模型;最后,设定无水采油期、采收率(30年)、剩余油分布规模作为检验条件,开展数值模拟等效实验,落实最优网格方案及渗透性参数,并基于实验结果,建立了A油田典型单元的渗流屏障等效地质模型.

河流相储层内部夹杂着诸多影响地层渗流的不连续界限,研究其对剩余油分布的影响,优化布井策略,对此类油藏高效开发具有重要意义.结合复合砂体构型理论成果,建立了不同级别不连续界限的油藏数值模拟模型,模拟了在大井距开发条件下,不连续界限对剩余油分布的影响,建立了河流相储集层不连续界限控制的剩余油分布规律图版;根据不连续界限两侧砂体叠置关系,将河流相不连续界限归纳为3种接触模式,基于界限规模和连通能力认识,结合界限控制的剩余油分布,提出了水平井穿不连续界限的布井策略.选取渤海某河流相油田进行了成果应用,根据示踪剂产出分析结果和新钻调整井生产效果认为,本文研究具有较好地适用性,对油藏开发方案设计井位部署和剩余油挖潜具有指导作用.

综合运用岩心、测井、地震、野外露头及生产测试资料对渤中19-6太古界潜山储层地质模式进行了分析.研究发现,渤中19-6太古界潜山储层纵向分为风化带和内幕带.风化带受构造和风化淋滤作用双重控制,发育构造缝、风化缝、溶蚀孔隙等储集空间类型,裂缝整体发育呈网状,储层连通性好,呈"似层状"分布模式.内幕带主要受高角度断层控制,储集空间以构造缝为主,内幕带储层沿高角度断层呈"带状"分布模式.针对渤中19-6潜山高含凝析油、低地露压差以及低孔低渗的油气藏特征,提出采用周期注气的开发方式提高凝析油采收率;基于潜山地质模式,采取储层顶部注气、中下部采气的立体注采井网.为减缓气窜,增加注气波及面积,提高单井产量,结合数值模拟结果,井网部署采取井轨迹与裂缝斜交45°角、注采井主流线方向与裂缝走向呈一定夹角的布井原则.

油藏内部普遍存在阻碍或影响流体渗流的不连续界限,由于尺度小且难识别,不连续界限的等效表征是地质建模的主要技术手段.选取海上新近系河流相复合砂体,对其内部发育的接触型、切叠型、堆叠型3种不连续界限开展了等效表征方法研究.设计了机理模型和数值模拟基础方案,分别从连通网格数量、渗透率变化、传导率变化等3个方面开展了敏感性分析;在此基础上,对不同类型不连续界限等效表征方法的适用性进行了研究.结果 表明,基于连通网格数量的等效表征方法较适合于接触型界限,基于模型渗透率的方法较适合于切叠型界限,基于网格面传导能力的方法更适合于堆叠型界限.心滩坝的等效表征实验及海上油田复合砂体表征结果表明,本文方法可实现储层不连续界限的精细表征.

综合运用岩心、测井、地震、野外露头及生产测试资料对渤中19-6太古宇潜山储层发育特征及主控因素进行了分析.研究发现渤中19-6太古宇潜山储层主要受岩石类型、构造运动和风化淋滤等因素影响,储层纵向分为风化带和内幕带,其储层发育主控因素及储层空间分布模式差异明显.其中,风化带受构造和风化淋滤作用双重控制,发育构造缝、风化缝、溶蚀孔隙等储集空间类型,裂缝整体发育呈网状,储层连通性好.受宏观古地貌控制,风化带厚度从古构造高部位向构造低部位呈逐渐减薄的"似层状"分布模式.同时,受岩石类型、局部断层、沟-脊微地貌以及坡度等因素的影响,风化带厚度局部增厚或减薄.潜山内幕带主要受内幕高角度断层控制,基本不受风化作用影响,储集空间以构造缝为主.通过内幕高角度断层的识别和刻画,认为内幕带储层沿高角度断层带状、漏斗型分布.上述认识对于渤中19-6凝析气田开发方案的编制,特别是为潜山储量动用及注采井网部署奠定了重要基础.

渤中19-6凝析气田太古界潜山裂缝性储层物性差,表现为特低孔、特低渗特征.综合成像测井、岩心、薄片等资料对渤中19-6潜山裂缝特征及低孔、低渗原因进行了研究和分析.渤中19-6潜山主要储集空间类型为裂缝,受附近主要断层影响,裂缝走向与断层方向基本一致,以NE向、近EW向为主,裂缝倾角主要分布在30°～70°,以中—高角度裂缝为主.成像测井解释成果表明,渤中19-6潜山裂缝密度主要分布在1～5条/m,宏观裂缝开度100～400μm,宏观裂缝开度仅有蓬莱9-1、锦州25-1南等中高渗潜山裂缝开度的1/5～1/2.另外,宏观裂缝多被石英、碳酸盐岩矿物以及伊利石、绿泥石等黏土矿物充填,裂缝以充填、半充填裂缝为主,极少见未充填缝.镜下微观裂缝开度10～30μm,大多数被硅质、铁白云石以及黏土矿物充填,微观裂缝整体充填程度达到85％.分析认为,裂缝开度小和充填程度高造成裂缝网络有效通道数减少、单条裂缝通道局部堵塞,是造成储层低渗特征的主要因素.

渤海海域渤中凹陷深层具有大型天然气田形成的良好地质条件,B19气田是渤海湾盆地迄今发现的最大的天然气田,储量超千亿立方米,纵向上具有明显的分带特征.孔店组砂砾岩和太古界潜山变质岩储层的岩石类型和储集空间类型复杂,优质储层的识别难度大、空间分布规律复杂,直接影响优质储层评价及动用.通过利用大量岩心、铸体薄片、扫描电镜等资料,对B19气田太古界潜山岩石学特征和储层发育特征进行了系统分析,确定变质岩潜山岩石类型与储集空间之间的关系,以及储层分布特征,指导B19气田的开发,实现渤海海域天然气勘探的突破,对渤海湾盆地深层天然气勘探具有重要指导意义.

在现有的碎屑沉积地质体构型分级方案基础上,充分考虑自然界中河流沉积演化规律以及海上油田的资料基础与经济开发尺度等因素,遵循地质体分级原则与依据,建立了海上油田河流相复合砂体构型分级方案.从地质成因、主控因素、时空规模等方面系统阐述了河流相复合砂体13级构型单元的基本特征,并解析其与相关沉积地质体级次的关联性.与现有的储层构型分级的差异主要在于新增了"复合点坝"级次,复合点坝是多期残存点坝以复合体形式叠置而成的沉积单元,该级次是储层构型理论、海上油田资料分辨能力与经济开发尺度三者的契合点,是海上油田"地震导向、井震联合"构型研究思路的良好实践.河流相复合砂体构型分级对于指导海上油气开发具有一定的优势.

储层不连续界限是指由于沉积作用、成岩改造及构造运动等因素,在储层中形成的岩性尖灭、砂体叠置、物性变化及小断层等对流体流动产生影响的各类界限统称,它是影响油田开发效果的重要因素之一.基于河道砂体的叠置程度,建立了考虑“厚度、高程、叠置范围”的河流相储层结构“三参数”概念模型及6类储层结构类型敏感属性图版;在此基础上,分析了“尖灭型、接触型、切叠型和叠加型”4类储层不连续界限地震响应特征.其中,尖灭型界限,地震响应表现为砂、泥岩的岩性变化特征,界限为岩性尖灭线,储层基本不连通;接触型界限,地震响应表现为砂岩厚度的变化特征,界限为“强—弱 强”的振幅类属性变化特征,储层具有一定的连通性但相对较差;切叠型和叠加型储层界限,地震响应表现为两期砂体叠置厚度与高程差的变化,由振幅类与波形类属性表征,在无明显夹层的情况下,储层连通性较好.储层不连续界限地震响应影响因素研究表明,时间采样率越小、主频越高、道间距越小,地震响应特征越明显.进一步,提出了基于储层结构平面分区的不连续界限预测方法,通过砂、泥岩相的识别,可以实现尖灭型界限的提取;通过砂岩岩相内地震属性的梯度变化求取不连续界限,基于界限及两侧的属性“强—弱—强”的相对关系,可以实现接触型和切叠型界限的识别.

石臼坨凸起F油田沙一二段发育巨厚、低渗混积岩储层,岩性多样、孔隙结构复杂、纵向非均质性强,影响酸化层段选择.综合岩心、薄片、压汞曲线等资料,结合测井信息,对储层开展分类评价,分析储层可酸化改造的潜力并落实有利的酸化层段.结果 显示,沙一二段储层包括鲕粒白云岩、生物白云岩、白云质砂岩、凝灰质砂岩、砂岩和灰质砂岩等6类岩性;根据岩石类型、物性及孔隙结构参数将储层整体划分为I、II、III类,结合实际酸化作业效果,I类储层可改造性最强,II类次之,III类最差.

致密砂岩气藏储层物性差、含气饱和度低,合理评价气藏内有利含气储集体,对于优选动用单元、提高单井产能意义重大.以渤海湾盆地A气田为例,通过开展岩、电、震多尺度资料分析,总结了致密储层成因演化与气藏成藏过程的耦合关系,建立了"先成藏、后致密"的气藏成藏模式和分布规律;在模式指导下,开展致密砂岩储层综合评价,形成了以"致密系数(Tightness Index)"为核心的致密储层物性评价方法,大幅提高了致密砂岩物性解释精度;通过重构含气特征参数,利用基于神经网络的地震多属性拟合方法预测了气藏分布,验证了气藏模式,并通过可拓学方法定量评价优选出了有利目标.

双重介质油藏储层建模方法是表征潜山裂缝型储层的主要方法,影响建模质量的因素较多,需深入研究.以渤海湾变质岩潜山A油田为例,阐述了储层建模及质控方法.综合动静态资料分析储集空间、介质物性及渗流差异,判断储层内是否存在多重介质,这是双重介质建模方法应用的前提;分析风化作用、断裂活动对基质的改造作用,提出将基质系统细分为共同改造型、断裂改造型、未改造型,分类相模拟建立基质模型,有利于改善基质系统建模质量;考虑研究资料及其描述尺度开展裂缝分组,对不同尺度裂缝采用与之相适应的建模方法,共同构建裂缝网络模型;统计裂缝密度属性与裂缝形状因子σ的关系,对模型进行质控,若存在一致性说明模型质量较好.本文方法可推广应用于同类型潜山油藏,有利于改善双重介质油藏储层的建模质量.

The architecture theory and characterization method of fluvial reservoir, which were based on dense wells data of onshore oilfields, have become relatively mature after decades of research. Nevertheless, it is challenging to apply this theory and method to offshore oilfields, where only sparse wells drilled. Through years of exploration, our research team proposes a new architecture theory and character-ization method for fluvial reservoir of offshore oilfield by combining well data with seismic data and taking compound sand-body as major research target. Compared with previous study, this new approach employs technologies such as 3 D prototype model reconstruction, seismic architecture facies prediction and seismic driving deterministic geological reservoir modeling to detailedly study the 5 th, 6 thand 7 tharchitecture units of fluvial reservoir (compound channel belt, single channel belt and compound point bar) , which shows obvious advantages on substrata division and correlation and discontinuous permeation barriers prediction in development phase. At present, there are still challenges applying this theory and method to fine geological modeling and numerical simulation. It's important to make full use of seismic data and develop artificial intelligence ways to improve seismic interpretation.

In the preparation of oil field development plans,there is limited basic research data,especially exploration and evaluation well data for offshore oil fields.The understanding of oil field geological reserves based on limited data will inevitably have certain limi-tations and uncertainties,which will affect the rationality and flexibility of the development plan.Through research on geological re-serves in over 100 offshore oil fields,a three-step method for evaluating the quality of geological reserves has been proposed.Firstly,the distribution characteristics of geological reserves were analyzed based on the scale of geological reserves,fluid properties and reser-voir physical properties.Secondly,single factor and multi-factor analysis methods were used to classify the proved geological reserves and screen the high-quality proved geological reserves.The third was to classify the controlled geological reserves according to the calcu-lation method,analyze the reliability of the controlled geological reserves according to the understanding of the controlled geological re-serves and the distance from the evaluation well,and quantify the controlled geological reserves that can be developed and used.Taking oil field L of Bohai Sea as an example,this paper introduces the practical effect of geological reserve quality evaluation method,which shows that the reserves of oil field development can be determined by geological reserve quality evaluation,and the ability of oil field development plan to deal with risks can be effectively improved.

Considering large well spacing in offshore oilfields development,traditional fine reservoir research thoughts from onshore oilfield,which focuses on well-seismic combination and well-based study,is not applicable on offshore oilfields.Therefore,the concept of fluvial compound sandbody is proposed.In this concept,compound sandbody is defined as sandbodies composed of several spatially genetically associated subunits within certain geologic period.Compound sandbody is hierarchical inside,where each level is composed of lower level sandbody and its interbeds,and compound sandbody unit boundaries of different levels are constrained by interfaces.Based on this concept,this paper explored the fundamental methods and approaches of characterizing compound sandbody,put forward the characterization principle of "axis-variation delimitation,pattern-fixing and well-point fixing",and determined three-step method for characterizing complex superimposed channels based on seismic sensitive attributes.Taking Bohai Q oilfield as an example,the theory is applied on residual oil prediction and injection-production connectivity analysis,which achieved better effects on tapping the potential oil.It demonstrates that this compound sandbody theory can somehow solve development challenges in oilfield production and provide support for the efficient development of offshore oilfield.The results in this paper can provide references for reservoir subdivision and comparison,development layer division,development well location deployment and well types selection.

Considering the great heterogeneity in fluvial reservoir of offshore oilfield,reservoir architecture characterization is the core for reservoir fine description.Based on previous study and under the research concept of historical comparison,this paper conducted GPR detection on modern sediments of meandering rivers,namely Hailar River and Chaobai River.This paper,through prototype model reconstruction,reviewed and explored fluvial reservoir architectural units features,and concluded the following understandings:Firstly,due to the transformation of deposition dynamic mechanism and dominating factors,fluvial reservoir formation takes the 6th order interface as breaking point.As a whole,from lower order toward higher order,the sedimentation process of fluvial reservoir architecture tends to transfer from lateral to vertical,and the 6th and 7th orders are key interfaces.Secondly,under the influence of ancient valley landform,fluvial deposits present the characteristics of multi-stacked complex longitudinally,which is an indication of multi-stage valley terraces.Relatively continuous and stable sequence interfaces may be developed among different stages.Thirdly,individual point bars were mostly reserved in the form of remnant bodies.Generally,point bar complex,which is composed of several genetically related individual point bar remnants and takes abandoned channels as lateral boundary,may have favorable conditions to form isolated sedimentary units.Therefore,point bar complex is the most important unit for meandering river sand body architecture characterization.

基于前人扇三角洲储层构型研究成果,以贝尔凹陷苏德尔特油田兴安岭油层为例,探讨扇三角洲单期扇体的构型解剖方法及扇体组合样式.扇三角洲单期扇体的构型解剖需完成点、线、面3个层次的研究.首先,单井分析构建单期扇体与高分辨率层序构型单元的对应关系,厘定纵向研究尺度;然后,扇体连井对比搭建合适的层序地层格架,通过识别沉积旋回的横向变化刻画扇体主体和扇体侧缘部位;最后,通过地震属性手段刻画扇体的具体边界位置.通过对苏德尔特油田兴安岭油层扇三角洲沉积进行单期扇体精细解剖,总结单期扇体的3类组合样式,即孤立扇型、叠置扇型、接触扇型.其中,孤立扇型组合可进一步划分为同供给水道型、异供给水道型两种亚类;叠置扇型组合根据叠置方向的差异,可进一步划分为垂向叠置扇、侧向叠置扇两种亚类;接触扇型组合根据扇体的级次关系可进一步划分为主次接触扇、同级接触扇两种亚类.

辽东湾馆陶组储层为典型辫状河沉积,是渤海重要油气产层之一.根据测井响应特征分析结果,建立泥岩分类方案,探讨各类泥岩沉积成因,并以井间对比关系研究为基础,结合类比分析结果,预测各类泥岩平面展布规模.结果表明:渤海L油田辫状河泥岩包括洪泛泥、漫溢相泥和河道内泥3类;洪泛泥厚度多大于6m,平面分布稳定,预测平面展布范围大于1 500 m,连续性强,属于隔层;漫溢相泥单层厚度多大于2 m,在局部范围内展布较连续,预测平面展布范围一般大于300m,影响储量动用;河道内泥厚度多小于2 m,分布局限,预测平面展布范围小于200 m,平面连续性较差,影响了水平井斜穿层布井方式.上述成果有效规避了储量动用风险,对开发井型的合理选择和部署具有重要的指导意义.