Whole petroleum system and ordered distribution pattern of conventional and unconventional oil and gas reservoirs

The classical source-to-trap petroleum system concept only considers the migration and accumulation of conventional oil and gas in traps driven dominantly by buoyance in a basin,although revised and improved,even some new concepts as composite petroleum system,total petroleum system,total composite petroleum system,were proposed,but they do not account for the vast unconventional oil and gas reservoirs within the system,which is not formed and distributed in traps dominantly by buoyancedriven.Therefore,the petroleum system concept is no longer adequate in dealing with all the oil and gas accumulations in a basin where significant amount of the unconventional oil and gas resources are present in addition to the conventional oil and gas accumulations.This paper looked into and analyzed the distribution characteristics of conventional and unconventional oil/gas reservoirs and their differences and correlations in petroliferous basins in China and North America,and then proposed whole petroleum system(WPS)concept,the WPS is defined as a natural system that encompasses all the conventional and unconventional oil and gas,reservoirs and resources originated from organic matter in source rocks,the geological elements and processes involving the formation,evolution,and distribution of these oil and gas,reservoirs and resources.It is found in the WPS that there are three kinds of hydrocarbons dynamic fields,three kinds of original hydrocarbons,three kinds of reservoir rocks,and the coupling of these three essential elements lead to the basic ordered distribution model of shale oil/gas reservoirs contacting or interbeded with tight oil/gas reservoirs and separated conventional oil/gas reservoirs from source rocks upward,which is expressed as“S\T-C”.Abnormal conditions lead to other three special ordered distribution models:The first is that with shale oil/gas reservoirs separated from tight oil/gas reservoirs.The second is that with two direction ordered distributions from source upward and downward.The third is with lateral distribution from source outside.

Prediction of Sedimentary Microfacies Distribution by Coupling Stochastic Modeling Method in Oil and Gas Energy Resource Exploitation

In view of the problem that a single modeling method cannot predict the distribution of microfacies, a new idea of coupling modeling method to comprehensively predict the distribution of sedimentary microfacies was proposed, breaking the tradition that different sedimentary microfacies used the same modeling method in the past. Because different sedimentary microfacies have different distribution characteristics and geometric shapes, it is more accurate to select different simulation methods for prediction. In this paper, the coupling modeling method was to establish the distribution of sedimentary microfacies with simple geometry through the point indicating process simulation, and then predict the microfacies with complex spatial distribution through the sequential indicator simulation method. Taking the DC block of Bohai basin as an example, a high-precision reservoir sedimentary microfacies model was established by the above coupling modeling method, and the model verification results showed that the sedimentary microfacies model had a high consistency with the underground. The coupling microfacies modeling method had higher accuracy and reliability than the traditional modeling method, which provided a new idea for the prediction of sedimentary microfacies.

Integrated Reservoir Prediction and Oil-Gas Evaluation in the Maoshan Area

The Maoshan area is an area with well-developed igneous rocks and complex structures. The thickness of the reservoirs is generally small. The study of the reservoirs is based on seismic data, logging data and geological data. Using techniques and software such as Voxelgeo, BCI, RM, DFM and AP, the authors have made a comprehensive analysis of the lateral variation of reservoir parameters in the Upper Shazu bed of the third member of the Palaeogene Funing Formation, and compiled the thickness map of the Shazu bed. Also, with the data from ANN, BCI and the abstracting method for seismic characteristic parameters in combination with the structural factors, the authors have tried the multi-parameter and multi-method prediction of petroleum, delineated the potential oil and gas areas and proposed two well sites. The prediction of oil and gas for Well JB2 turns out to be quite successful.

Predicting the present-day in situ stress distribution within the Yanchang Formation Chang 7 shale oil reservoir of Ordos Basin, central China

The Yanchang Formation Chang 7 oil-bearing layer of the Ordos Basin is important in China for producing shale oil.The present-day in situ stress state is of practical implications for the exploration and development of shale oil;however,few studies are focused on stress distributions within the Chang 7 reservoir.In this study,the present-day in situ stress distribution within the Chang 7 reservoir was predicted using the combined spring model based on well logs and measured stress data.The results indicate that stress magnitudes increase with burial depth within the Chang 7 reservoir.Overall,the horizontal maximum principal stress(SHmax),horizontal minimum principal stress(Shmin) and vertical stress(Sv) follow the relationship of Sv≥SHmax>Shmin,indicating a dominant normal faulting stress regime within the Chang 7 reservoir of Ordos Basin.Laterally,high stress values are mainly distributed in the northwestern parts of the studied region,while low stress values are found in the southeastern parts.Factors influencing stress distributions are also analyzed.Stress magnitudes within the Chang 7 reservoir show a positive linear relationship with burial depth.A larger value of Young's modulus results in higher stress magnitudes,and the differential horizontal stress becomes higher when the rock Young's modulus grows larger.

Evaluation of reservoir environment by chemical properties of reservoir water‒A case study of Chang 6 reservoir in Ansai oilfield,Ordos Basin,China

The Ordos Basin is the largest continental multi-energy mineral basin in China,which is rich in coal,oil and gas,and uranium resources.The exploitation of mineral resources is closely related to reservoir water.The chemical properties of reservoir water are very important for reservoir evaluation and are significant indicators of the sealing of reservoir oil and gas resources.Therefore,the caprock of the Chang 6 reservoir in the Yanchang Formation was evaluated.The authors tested and analyzed the chemical characteristics of water samples selected from 30 wells in the Chang 6 reservoir of Ansai Oilfield in the Ordos Basin.The results show that the Chang 6 reservoir water in Ansai Oilfield is dominated by calcium-chloride water type with a sodium chloride coefficient of generally less than 0.5.The chloride magnesium coefficients are between 33.7 and 925.5,most of which are greater than 200.The desulfurization coefficients range from 0.21 to 13.4,with an average of 2.227.The carbonate balance coefficients are mainly concentrated below 0.01,with an average of 0.008.The calcium and magnesium coefficients are between 0.08 and 0.003,with an average of 0.01.Combined with the characteristics of the four-corner layout of the reservoir water,the above results show that the graphics are basically consistent.The study indicates that the Chang 6 reservoir in Ansai Oilfield in the Ordos Basin is a favorable block for oil and gas storage with good sealing properties,great preservation conditions of oil and gas,and high pore connectivity.

Evolution of lithofacies and paleogeography and hydrocarbon distribution worldwide(Ⅱ)

Based on the compilation and analysis of the lithofacies and paleogeography distribution maps at present and paleoplate locations during six key geological periods of the Mesozoic and Cenozoic,the lithofacies and paleogeography features and their development laws were expounded.Based on our previous research results on lithofacies and paleogeography from Precambrian to Paleozoic,we systematically studied the features and evolution laws of global lithofacies and paleogeography from the Precambrian and their effects on the formation of source rocks,reservoirs,cap rocks and the distribution of oil and gas worldwide.The results show that since Precambrian,the distribution areas of uplift erosion and terrestrial clastic deposition tended to increase gradually,and increased significantly during the period of continental growth.The scale of coastal and shallow marine facies area had three distinct cycles,namely,from Precambrian to Devonian,from Carboniferous to Triassic,and from Jurassic to Neogene.Correspondingly,the development of shallow carbonate platform also showed three cycles;the lacustrine facies onshore was relatively developed in Mesozoic and Cenozoic;the sabkha was mainly developed in the Devonian,Permian and Triassic.The Cretaceous is the most important source rock layers in the world,followed by the Jurassic and Paleogene source rocks;the clastic reservoirs have more oil and gas than the carbonate reservoirs;the basins with shale caprocks have the widest distribution,the most abundant reserves of oil and gas,and the evaporite caprocks have the strongest sealing capacity,which can seal some huge oil and gas fields.

A novel type curve for estimating oil recovery factor of gas flooding

A novel type curve is presented for oil recovery factor prediction suitable for gas flooding by innovatively introducing the equivalent water-gas cut to replace the water cut,comprehensively considering the impact of three-phase flow(oil,gas,water),and deriving the theoretical equations of gas flooding type curve based on Tong’s type curve.The equivalent water-gas cut is the ratio of the cumulative underground volume of gas and water production to the total underground volume of produced fluids.Field production data and the numerical simulation results are used to demonstrate the feasibility of the new type curve and verify the accuracy of the prediction results with field cases.The new type curve is suitable for oil recovery factor prediction of both water flooding and gas flooding.When a reservoir has no gas injected or produced,the gas phase can be ignored and only the oil and water phases need to be considered,in this case,this gas flooding type curve returns to the Tong’s type curve,which can evaluate the oil recovery factor of water flooding.For reservoirs with equivalent water-gas cuts of 60%-80%,the regression method of the new type curve works well in predicting the oil recovery factor.For reservoirs with equivalent water-gas cuts higher than 80%,both the regression and assignment methods of the new type curve can accurately predict the oil recovery factor of gas flooding.

An improved oil recovery prediction method for volatile oil reservoirs

To describe the complex phase transformation in the process of depletion exploitation of volatile oil reservoir,four fluid phases are defined,and production and remaining volume of these phases are calculated based on the principle of surface volume balance,then the recovery prediction method of volatile oil reservoir considering the influence of condensate content in released solution gas and the correction method of multiple degassing experiments data are established.Taking three typical kinds of crude oil(black oil,medium-weak volatile oil,strong volatile oil)as examples,the new improved method is used to simulate constant volume depletion experiments based on the corrected data of multiple degassing experiment to verify the reliability of the modified method.By using"experimental data and traditional method","corrected data and traditional method"and"corrected data and modified method",recovery factors of these three typical kinds of oil are calculated respectively.The source of parameters and the calculation methods have little effect on the recovery of typical black oil.However,with the increase of crude oil volatility,the oil recovery will be seriously underestimated by using experimental data or traditional method.The combination of"corrected data and modified method"considers the influence of condensate in gas phase in both experimental parameters and calculation method,and has good applicability to typical black oil and volatile oil.The strong shrinkage of volatile oil makes more"liquid oil"convert to"gaseous oil",so volatile oil reservoir can reach very high oil recovery by depletion drive.

Data driven prediction of oil reservoir fluid properties

Accuracy of the fluid property data plays an absolutely pivotal role in the reservoir computational processes.Reliable data can be obtained through various experimental methods,but these methods are very expensive and time consuming.Alternative methods are numerical models.These methods used measured experimental data to develop a representative model for predicting desired parameters.In this study,to predict saturation pressure,oil formation volume factor,and solution gas oil ratio,several Artificial Intelligent(AI)models were developed.582 reported data sets were used as data bank that covers a wide range of fluid properties.Accuracy and reliability of the model was examined by some statistical parameters such as correlation coefficient(R2),average absolute relative deviation(AARD),and root mean square error(RMSE).The results illustrated good accordance between predicted data and target values.The model was also compared with previous works and developed empirical correlations which indicated that it is more reliable than all compared models and correlations.At the end,relevancy factor was calculated for each input parameters to illustrate the impact of different parameters on the predicted values.Relevancy factor showed that in these models,solution gas oil ratio has greatest impact on both saturation pressure and oil formation volume factor.In the other hand,saturation pressure has greatest effect on solution gas oil ratio.

鄂尔多斯盆地马岭—乔川地区长6油层组油藏分布特征及控制因素

基于岩心观察、测井解释及开采数据分析,结合流体包裹体等测试,对马岭—乔川地区长6油层组的油藏分布特征及控制因素开展研究。研究结果表明,研究区油藏纵向上主要分布在长63油层段,长62、长61油层段含油性显著变差;平面上,长63油层段以L125,B452和L411井区为中心,油藏团块状分布,呈两条带沿北西南东向延伸,油层厚度主要在5~20 m之间,长62、长61油层呈孤立土豆疙瘩状分布,分布规模小。长6油层组油藏以岩性油藏为主,包裹体均一温度集中在70~90℃,荧光以黄褐色为主,结合区域埋藏史分析显示该区油藏充注为晚侏罗世和中-晚白垩世,表现为早期充注。长6油层组烃源岩厚度、距离,砂体砂质碎屑流砂体性质、物性和叠置类型是其形成油气藏的重要影响因素;长63油层段相比长62和长61油层段具有更靠近烃源岩,砂质碎屑流成因砂体分布广、孔渗条件好、叠置厚层砂体类型发育等优势。研究区最为有利油藏的勘探目标为长63油层段Y470,L374,B452等井区附近,有利勘探区面积达到517.28 km 2。

分支河流体系研究进展及应用前景展望

通过文献调研和地质分析,系统总结了分支河流体系(DFS)理论的研究进展、应用前景和发展趋势。研究结果表明:(1)当前DFS理论研究的五大重点分别是通过实例分析挖掘其科学内涵,探讨应用价值,解决概念争论;明确DFS是一个多种河道共生的沉积体系,不能理解为一种新的河道类型;河道网络和河型转换是DFS研究中的重要问题;建立和完善DFS的沉积模式;建立DFS储层预测模型。(2)开展DFS研究对促进陆相盆地沉积储层学科的理论创新和挖掘陆相盆地油气资源潜力具有重要理论意义和广阔的应用前景。(3)当前DFS研究主攻方向是建立沉积储层数据库,构建沉积模式和识别标志,形成河网体系和河型演变定量预测模型,实现不同建模方法的融合归一;未来DFS研究应当将沉积学与地貌学、地理学、现代地球信息科学技术相结合,应用大数据和智能化技术,实现对沉积体系的定量表征和储层定量预测。

致密油水平井温度剖面影响规律研究

由于目前缺乏可靠的致密油水平井温度剖面预测模型、对致密油水平井温度剖面影响规律认识不清,导致基于分布式光纤的致密油水平井产出剖面定量评价仍是一项技术难题。鉴于此,创建了考虑多种微热效应的致密油水平井温度剖面预测模型,探究了井筒温度剖面受不同单因素变化的影响,通过正交试验,确定不同因素的敏感性由强到弱依次为:产量、裂缝半长、储层渗透率、井筒直径、水平倾角、裂缝导流能力、储层总导热系数(Q>x_(f)>K>D>θ>F_(CD)>K_(t)),明确了影响致密油水平井温度剖面的主控因素为裂缝半长和储层渗透率。研究成果为定量分析致密油水平井井筒流动剖面、人工裂缝等参数提供了可用温度模型和理论支撑。

陆相断陷盆地相控油气特征及其基本模式

地质相是沉积地层内沉积物(岩)形成条件的物质表现,由宏观到微观分为4个层次,即构造相、沉积相、岩石相和岩石物理相。不同层次地质相的控油气作用具有不同形式的表现。研究表明,陆相断陷盆地内不同的构造单元、不同的沉积相控制着不同类型油气藏的形成与分布;不同的构造单元和不同的沉积相的储油气层的临界孔隙度和渗透率随埋藏深度增大而降低;在不考虑构造和沉积相背景条件下,不能依据地层的绝对孔渗条件判别和评价有效储集层。沉积颗粒不粗不细的优相砂岩类地层控制着油气的富集成藏;相同背景条件下相对高孔渗的储集层控制着油气的富集成藏。优相与相对高孔渗控藏是相控油气作用的基本模式。利用相控油气作用的基本模式可以预测有利成藏领域。

剩余油分布规律的精细数值模拟

以胜二区沙二段８ 单元为研究对象，建立了该开发单元储层物性和原油物性随不同开发阶段变化的数值模型，并在此基础上进行了精细油藏数值模拟研究。研究结果表明，渗透率、原油粘度和密度随不同开发阶段的变化对剩余油分布和油田开发效果影响均较大。对注水开发历史较长的油田，在进行精细油藏数值模拟时，应该考虑渗透率和原油物性随时间的变化，从而为进入注水开发的老油田的挖潜上产提供可靠的决策依据。通过对８单元的精细油藏模拟，掌握了目前该单元的剩余油分布规律和水淹状况。

构造建模约束地震反演技术——以大庆萨尔图油田南八区为例

为了充分发挥储层预测多学科的综合能力,对构造建模约束地震反演的作用和构造建模在储层反演与地质建模的区别进行了分析。在此基础上,详细阐述了实现构造建模约束地震反演的4个关键环节,即井-震联合小尺度构造解释、合理设计地质框架、不同尺度网格设计和曲线均一化处理。以大庆萨尔图油田南八区萨Ⅱ7-12沉积单元为例,通过与未进行构造约束的地震反演对比,总结出构造建模约束下地震反演的优势,主要体现在:①能够提高砂体识别的准确程度,尤其是定位河道砂边界位置效果显著,采用"井点定相、切片组形"的方法,完成了井震结合沉积微相的修正;②明确主力厚油层及主力砂体接触关系,增加断层附近预测的细节,尤其是断裂两侧砂体明朗化,有利于指导剩余油的挖潜。因此,构造建模约束地震反演技术能够降低反演的不确定性,对油田后续开发调整具有重要意义。

胡5块严重非均质极复杂断块油藏数值模拟研究

针对油藏存在的问题,在精细地质研究的基础上,根据渗流等效的原则,进行了网格粗化,应用数值模拟软件对严重非均质的极复杂断块——胡5断块进行了油藏数值模拟研究。通过模拟研究,得出了该断块的剩余油饱和度分布,对比分析了不同方式下的4个开发方案,推荐出了指导该油藏下一步生产的综合调整方案。

利用地震属性技术分析储层含油气信息——以塔里木盆地HD4油田为例

利用地震属性技术结合地层尖灭正演模型模拟,对薄储层厚度的变化以及储层含油气信息进行了详细的理论和实际分析:分析了地震对储层厚度的分辨率问题,提出了利用地震属性可以分辨小于1/4波长的储层;根据地震波传播过程中的振幅调谐理论,分析了地层厚度变化与振幅调谐之间的关系;利用大面元采集、相对保持振幅高分辨率处理的地震资料,进行了精细的构造解释;通过提取地震属性,结合地质条件分析和大量的井资料分析,对HD4油田油气分布特征进行了分析和预测,其结果极大地促进了油田的勘探和开发进程。

油气储层参数建模的“复合相控模型”法

利用沉积微相和油气水分布对砂岩油气储层的控制作用,提出了针对砂岩油气储层进行井间参数预测,研究砂岩厚度、有效厚度、孔隙度、渗透率、饱和度的平面分布,建立油气储层参数模型的方法——"复合相控模型"法。此方法的实质是实现了受地质和油气复合约束的井间参数预估,特别适用于井控不足的油气储层参数描述,是油气藏描述的一项实用技术方法。

小洼地区洼38井区精细构造解释与储层预测

为寻找洼 38井区新的出油点和储量增长点 ,借助Landmark一体化软件 ,应用相干体分析、可视化、地震属性分析等新技术对其进行研究。通过研究 ,进一步搞清了该区的沉积、构造、储层特征及油气分布规律 ,发现和落实有利圈闭 4个 ;同时指出了下步勘探的方向 :在清东陡坡带应注重断鼻的勘探 ,在潜山披覆构造带上应注重充填沉积体的勘探 。

严重非均质油藏高含水期剩余油分布研究进展

目前，我国东部大多数油田在经过长期注水开发后己进入高－特高含水采油阶段，但油藏内仍然有约５０％的可采储量，它们的分布日趋分散、复杂，开采难度越来越大，其中一个最主要的原因是油藏（或储层）的严重非均质性，文章对国内外剩余油分布状况进行了详细分析。针对我国东部老油田的开发现状，从开发地质的角度出发，详细论述了严重非均质油藏剩余油分布及其动态预测的研究内容和方法，并指出了相应的研究思路和技术关键。重建适合开发后期的具有预测功能的储层地质模型，对稳定东部，改善油田开发效果，提高油田最终采收率具有重大的意义。