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.

Classification and Denominationof Flow Units for Clastic Reservoirsof Continental Deposit

On the basis of other researchers' achievements and the authors' understanding of flow units, a proposal on classification and denomination of flow units for clastic reservoirs of continental deposit is put forward according to the practical need of oilfield development and relevant theories. The specific implications of development and geology are given to each type of flow units, which has provided a scientific basis for oil development.

An Integrated Method of Data Mining and Flow Unit Identification for Typical Low Permeability Reservoir Prediction

With the development of oilfield exploration and mining, the research on continental oil and gas reservoirs has been gradually refined, and the exploration target of offshore reservoir has also entered the hot studystage of small sand bodies, small fault blocks, complex structures, low permeability and various heterogeneous geological bodies. Thus, the marine oil and gas development will inevitably enter thecomplicated reservoir stage;meanwhile the corresponding assessment technologies, engineering measures andexploration method should be designed delicately. Studying on hydraulic flow unit of low permeability reservoir of offshore oilfield has practical significance for connectivity degree and remaining oil distribution. An integrated method which contains the data mining and flow unit identification part was used on the flow unit prediction of low permeability reservoir;the predicted results?were compared with mature commercial system results for verifying its application. This strategy is successfully applied to increase the accuracy by choosing the outstanding prediction result. Excellent computing system could provide more accurate geological information for reservoir characterization.

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.

An Integrated Rock Typing Approach for Unraveling the Reservoir Heterogeneity of Tight Sands in the Whicher Range Field of Perth Basin, Western Australia

Tight gas sands in Whicher Range Field of Perth Basin show large heterogeneity in reservoir characteristics and production behavior related to depositional and diagenetic features. Diagenetic events (compaction and cementation) have severely affected the pore system. In order to investigate the petrophysical characteristics, reservoir sandstone facies were correlated with core porosity and permeability and their equivalent well log responses to describe hydraulic flow units and electrofacies, respectively. Thus, very tight, tight, and sub-tight sands were differentiated. To reveal the relationship between pore system properties and depositional and diagenetic characteristics in each sand type, reservoir rock types were extracted. The identified reservoir rock types are in fact a reflection of internal reservoir heterogeneity related to pore system properties. All reservoir rock types are characterized by a compacted fabric and cemented framework. But distribution and dominance of diagenetic products in each of them depend on primary depositional composition and texture. The results show that reservoir rock typing based on three aspects of reservoir sandstones (depositional properties, diagenetic features and petrophysical characteristics) is a suitable technique for depiction of reservoir heterogeneity, recognition of reservoir units and identifying factors controlling reservoir quality of tight sandstones. This methodology can be used for the other tight reservoirs.

川西中坝致密砂岩气储层微观孔隙结构特征及分类评价

川西中坝地区致密砂岩储层经历复杂的沉积作用和成岩演化,导致其储层物性差、孔隙结构复杂且非均质性强,给储层有效性评价和“甜点”预测带来困难。针对这一问题,以中坝地区须家河组致密砂岩储层为例,基于气测孔渗、铸体薄片、高压压汞及扫描电镜等岩石物理实验,系统评价了储层微观孔隙结构特征,并结合流动单元理论及BP神经网络技术进行储层分类测井评价,明确优质储层发育及分布特征。结果表明:研究区目的储层物性差,储集空间主要为次生粒间孔和溶蚀孔,喉道类型以点状和缩颈状为主,孔径主要为纳米—亚微米级;基于流动单元对储层进行分类,将储层分为4类(Ⅰ—Ⅳ)。流动单元指数(FZI)可有效表征储层孔隙结构及渗流特征,研究区须二段主要发育Ⅱ、Ⅲ类储层,气藏中部ZB9-65-46井区域Ⅰ类储层发育;中坝主体构造储层厚度大,以Ⅱ类储层为主,老坪坝和构造鞍部发育储层多为薄层,以Ⅲ类储层为主;有效储层纵向上主要发育在须二段上部,其厚度占储层总厚度的73.60%。研究结果可为同类型致密砂岩气藏的储层评价及高效开发提供科学依据。

强非均质性储层构型表征与流动单元智能分类评价

为了评价珠江口盆地惠州A油田珠江组ZJ452强非均质性储层的储层质量及流体渗流规律,采用了储层构型分析与多层次自动聚类算法对强非均质性储层进行分类评价,筛选出孔隙度、渗透率、流动带指数(FZI)和储层质量参数作为判别参数。应用自组织映射神经网络和贝叶斯判别流动单元智能分类技术,将ZJ452储层定量划分出Ⅰ、Ⅱ、Ⅲ3类流动单元。通过流动单元判别公式进行体计算,建立三维流动单元模型,分析流动单元空间分布特征,得出ZJ452储层虽然空间上表现为强非均质性,但平面上Ⅰ类流动单元和Ⅱ类流动单元连片分布连通的结论。本研究为惠州A油田ZJ452强非均质性储层油藏挖潜指明了方向。

基于SSOM的流动单元划分方法及生产应用——以渤海湾盆地F油田古近系沙三中亚段湖底浊积水道为例

在储层构型级次划分的基础上,归纳总结了渤海湾盆地F油田古近系沙三中亚段湖底浊积水道各级渗流屏障与构型界面的关系,并采用监督模式下的自组织映射神经网络算法开展流动单元定量评价,明确了构型模式控制下的流动单元分布规律。研究结果表明:(1)渤海湾盆地F油田沙三中亚段储层可划分为Ⅰ、Ⅱ、Ⅲ、Ⅳ等4类流动单元。(2)基于SSOM算法的流动单元识别结果表现出较高的预测准确率,其中,256组训练样本的整体回判准确率为82.81%,110组测试样本的识别准确率为80.91%,能够满足地质油藏研究的需求。(3)垂向上,不同类型的单一水道内部发育的流动单元类型不同,造成流动单元垂向分布的差异性。Ⅰ类、Ⅱ类优质流动单元发育在浊积水道体系演化的中期,主要分布在二类单一水道;Ⅲ类、Ⅳ类流动单元发育在浊积水道体系演化的早期和晚期,其中,Ⅲ类流动单元分布广泛,在一类、二类、三类单一水道均有分布,Ⅳ类流动单元发育在一类、三类单一水道。侧向上,受水道体系不同沉积演化阶段的影响,流动单元的侧向分割方式不同。流动单元与非渗透层接触样式发育在浊积水道体系早期沉积旋回中,接触界面明显,属于一类水道沉积砂体;流动单元间的相互接触样式则发育在水道体系中晚期沉积旋回中,属于二类、三类水道沉积砂体。(4)平面上,受单一水道侧向迁移和垂向加积作用的影响,复合水道内部流动单元平面展布差异性明显。Ⅲ类流动单元在单砂体内部广泛发育,井间连续性好,在浊积主水道、浊积水道及水道漫溢沉积砂体处均有发育;渗流能力较好的Ⅰ类、Ⅱ类流动单元分布局限、连续性差,仅在浊积水道主流线方向及主水道砂体处有分布,呈不连续的点状或带状分布;Ⅳ类流动单元呈环带状分布在Ⅲ类流动单元的外缘,在浊积水道漫溢沉积砂体处发育。

基于神经网络模型的致密砂岩储层流动单元分类与评价——以鄂尔多斯盆地WQ北部长6油层组为例

为了明确鄂尔多斯盆地WQ北部地区致密砂岩储层流动单元对剩余油分布的影响,通过岩心观察、铸体薄片鉴定、X衍射分析、高压压汞测试等方法分析了研究区长6储层的基本特征,并结合测井和神经网络模型分析,明确了区内长6储层流动单元类型、特征、分布规律,及其与储层的关系。结果表明:研究区长6油层组为典型的低孔-特低渗储层,主要发育长石砂岩和长石岩屑砂岩,孔隙类型以残余粒间孔和长石溶孔为主,储层孔隙结构以细喉大孔型和细喉小孔型为主。共发育4类储层流动单元。其中,长6^(2-1)小层以Ⅲ、Ⅳ类单元为主,长6^(1-2)小层主要发育Ⅰ、Ⅱ类流动单元,长6^(1-1)小层仅见零星分布的Ⅰ类流动单元,有利储层主要分布在长61-2小层。

Estimation of reservoir and remaining oil prediction based on flow unit analysis

Through natural partition and clustering analysis,four kinds of flow units were distinguished in Pu53 block,Pucheng Oilfield. Taking the short-term cycle as studying unit,the two-dimensional distribution of each type of flow units was forecasted and the short-term cycle was classified into four types based on the two-dimensional characteristics of the flow units. The remaining oil was predicted by conceptual simulation,qualitative analysis and quantitative modeling. The results showed obvious control of the characteristics of reservoir flow units to the remaining oil. E and G units in type I and type II short-term cycles which are distributed continuously in large areas are mostly flooded,while the uncontrolled small isolated G flow unit in type III short-term cycles which were mainly made of F flow unit and F flow unit with continuous distribution become the accumulating place for remaining oil. Thus the development adjustment strategy should optimize the development of small-scale E and G units,strengthen the development of type III short-term cycles,and block out type I short-term cycles. This strategy improves the development of Pu53 block obviously.

基于流动单元的碳酸盐岩油藏剩余油分布规律

让纳若尔裂缝孔隙性碳酸盐岩油田Г北油藏储集层类型复杂多样,根据孔隙类型及其组合方式和不同孔隙组合的孔渗关系,将储集层划分为孔洞缝复合型、裂缝孔隙型、孔隙型和裂缝型4种类型,并实现了储集层类型的测井识别。孔洞缝复合型和裂缝型同类型储集层之间动用程度差异小,裂缝孔隙型和孔隙型同类型储集层之间动用程度差异较大,为了更准确地评价储集层动用的难易程度,优选了影响储集层动用程度的关键参数,裂缝孔隙型储集层为:储集层品质指数、饱和度中值喉道半径、总渗透率、裂缝渗透率与基质渗透率之比;孔隙型储集层为:储集层品质指数、饱和度中值喉道半径和基质渗透率。综合考虑基质和裂缝建立双重介质储集层流动单元划分方法,以关键参数作为聚类变量,利用神经网络聚类分析技术,将4种储集层类型划分为6类流动单元。建立流动单元三维地质模型和数值模拟模型,表征剩余油分布规律。根据剩余油研究结果,Г北油藏2013年投产8口井,初期日产油为周围老井的2.3倍。

应用储层流动单元研究高含水油田剩余油分布

高含水油田剩余油分布研究是一个世界性的难题。应用储层流动单元进行油气储层评价研究自 2 0世纪 80年代后期以来受到了石油工作者的广泛重视。文中以辽河油田欢 2 6断块为例 ,应用储层流动单元 ,在沉积微相分析的基础上研究高含水油田剩余油分布特征。密闭取心井岩芯分析资料表明剩余油饱和度与储层流动单元间存在良好的对应关系 ,在此基础上建立了利用流动单元流动带指标计算剩余油饱和度的方法。沉积微相内部对应着多个流动单元类型的组合 ,不同的沉积微相其流动单元组合形式也不同 ,表现出的渗流能力亦存在较大的差异性 ,从而为表征流体渗流的平面差异性和评价剩余油分布奠定了坚实的基础。研究结果表明 ,欢 2 6块剩余油平面上主要分布在中部和东部的构造较高部位。在本研究成果指导下 ,4口井 6个月累计增产原油 4 556t ,取得了良好的地质应用效果。

松辽盆地白垩系营城组埋藏火山机构岩相定量模型及储层流动单元特征

松辽盆地营城组火山机构类型划分为碎屑岩火山机构、熔岩火山机构和复合火山机构3种。碎屑岩火山机构中火山通道相占9.3%,爆发相占55.3%,喷溢相占29.2%,侵出相占1.4%,火山沉积相占4.8%;火山机构半径为0.5-1.5 km,高度为50-220 m。熔岩火山机构中火山通道相占8.1%,爆发相占23.4%,喷溢相占62.6%,侵出相占5.1%,火山沉积相占0.8%;火山机构半径为1-2 km,高度为200-300 m。复合火山机构中火山通道相占4.9%,爆发相占34.4%,喷溢相占56.8%,侵出相占2.6%,火山沉积相占1.3%;火山机构半径为2-4 km,厚度为300-450 m。亚相控制储层流动单元的规模,碎屑岩火山机构的储层流动单元范围为0.3-1.5 km,厚度小于60 m。熔岩火山机构的储层流动单元范围为1-2km,厚度小于80 m。复合火山机构的储层流动单元范围为1.5-3.0 km,厚度小于100 m。各类火山机构气藏开发时的井距和压裂方案均存在差异。

流动单元四维动态演化仿真模型研究

流动单元是油气储集最小宏观地质单元,应用室内岩心样品不同注入体积倍数驱替实验、不同开发阶段完钻井的测井参数评价及大量生产动态资料,研究分析了不同成因流动单元在水驱开发过程中储层宏观物性参数的演化规律,进而建立各类参数的数学演化模式,找出其相应物性参数的变化因子。并借助工作站三维地质建模软件Earthvision,在原始三维地质属性参数模型研究的基础上,加载物性参数变化因子,并经数据处理和结果提取,形成各类流动单元随开发过程的四维动态系列演化仿真模型,揭示和预测了不同开发阶段流动单元内部油水运动特点及剩余油分布状况。

碎屑岩储层流动单元模拟实验研究

根据流动单元渗流特征的定义,设计了层间非均质实验模型,研究了相同水动力条件下不同渗透率级差模型的水驱油渗流规律和水淹规律。实验结果表明,渗透率级差为2是流动单元划分的界限,渗透率级差小于2的非均质储层在合注时各个层位都能被注入水有效驱动的为一个流动单元。注入水自然流动形成的通道不完全是由绝对渗透率决定,而与层位之间渗透率相对大小有关。通过实验论证,提出了流动单元划分的渗透率差异指标。

低渗透油藏不同流动单元并联水驱油

为了描述低渗透油藏多层合注合采时,各层水驱效果差异、流体流动特征及分布规律,开展了不同流动单元并联水驱油实验及数值模拟研究。以新疆宝浪油田宝北区块低渗透储层为例,按流动层段指标由大到小将储层划分为五类流动单元,选取其中三类流动单元的9块天然岩心与1块人造岩心,组成4组并联模型,进行了水驱油实验及数值模拟研究。实验结果表明:不同流动单元岩心并联组合后,物性好的流动单元驱油效率比单独驱替时要高、物性差的流动单元驱油效率比单独驱替时要低;不同流动单元之间渗透率级差越大,流动单元之间相互影响越强烈,驱油效率相互差值越大。

濮城油田沙三上地层基准面旋回及储层流动单元

根据基准面旋回和可容纳空间变化原理 ,研究了东濮凹陷濮城油田沙三上亚段长期、中期、短期基准面旋回 ,划分出长期基准面旋回 1个、中期基准面旋回 10个、短期基准面旋回 5 0个 ,并对三种类型的短期基准面旋回结构特征及分布进行了详细描述。在高分辨率层序地层划分对比的基础上 ,建立了高精度层序地层格架。利用储层非均质性的层次性及流动单元层次性与基准面旋回级次性的相关性 ,对储层流动单元进行了划分 ,为精细储层研究提供了一种新的思路。

应用高分辨率层序地层学对储层流动单元层次性进行分析——以泌阳凹陷双河油田为例

储层流动单元被应用于油气田开发储层描述以来 ,对研究油气田开发过程中储层内油气水运动规律及剩余油气分布规律起着相当重要的作用。不同层次的储层流动单元研究 ,有助于指导油气开发不同阶段开发方案的制订、实施和完善。作者运用高分辨率层序地层学理论方法 ,以双河油田为例 ,重点分析解剖储层流动单元的层次性 ,探讨不同级次基准面旋回与储层流动单元层次性的关系 。

陆相储层流动单元研究的新思路

针对目前流动单元研究存在的一些问题及陆相储层的地质特征，以吐哈盆地温吉桑－米登油田（简称温米油田）中侏罗统三间房组辫状河三角洲储层为例，提出了一套陆相储层流动单元的研究思路和方法。流动单元研究分为二个层次，第一层次通过高分辨率层序地层学、储层结构分析、成岩非均质分析、断层封闭性分析确定连通砂体与渗流屏障的分布，第二层次通过储层质量评价确定连通体内部的渗流差异。据此思路，对工区辫状河三角洲储层进行了深入的流动单元研究。研究成果对提高温米油田注水开发效果具有很大的指导作用。

储层流动单元成因及其影响因素分析

目前对储层流动单元的研究方法有多种,但终究未有统一的结论,而对储层流动单元的形成及其影响因素的分析更少。针对这种情况,在简要分析储层流动单元特征和层次结构的基础上,较详细分析了储层流动单元成因及其影响因素。这些成因和影响因素包括沉积作用、成岩作用、构造作用和其它影响因素,并指出这些成因和影响因素与储层流动单元的关系。