The origin and accumulation model of crude oils from oil reservoirs Chang 9 and Chang 10 in the Yanchang Formation of the Ordos Basin

In the lower parts of oil reservoirs Chang 9 and Chang 10 of the Yanchang Formation are oil-bearing layers newly found in oil exploration in the Ordos Basin.Based on GC,GC-MS analyses of saturated hydrocarbons from crude oils and source rocks,reservoir fluid inclusions and BasinMod,the origin of crude oils,accumulation period and accumulation models are discussed in combination with other petroleum geology data in this paper.The result shows that(1) there are two different types of crude oils in oil reservoir Chang 9 in the Longdong and Jiyuan regions:crude oils of typeⅠ(Well D86,Well A44,Well A75,Well B227,Well X62 and Well Z150) are mainly de-rived from the Chang 7 source rocks(including mudstones and shales) and distributed in the Jiyuan and Longdong regions;those of typeⅡ(Well Z14 and Well Y427),are distributed in the Longdong region,which are derived from the Chang 9 source rocks.Crude oils from oil reservoir Chang 10 in the Shanbei region are mainly derived from the Chang-9 source rocks;(2) there are two phases of hydrocarbon filling in oil reservoir Chang 9 in the Jiyuan and Longdong regions and oil reservoir Chang 10 in the Shanbei region:The first phase started at the early stage of J2z.The process of hydrocarbon filling was discontinuous in the Late Jurassic,because of the tectonic-thermal event in the Ordos Basin.The second phase was the main accumulation period,and hydrocarbons began to accumulate from the late stage of J2a to the middle-late of K1,mainly at the middle-late stage of K1;(3) there exist two types of accu-mulation models in oil reservoirs Chang 9 and Chang 10 of the Yanchang Formation:source rocks of the reservoirs in oil reservoir Chang 9 in the Jiyuan region and oil reservoir Chang 10 in the Shanbei region,the mixed type of reservoirs on the lateral side of source rocks and source rocks of the reservoirs in oil reservoir Chang 9 in the Long-dong region.

Study on Productivity Model of Herringbone-Like Laterals Wells and Optimization of Morphological Parameters Considering Threshold Pressure Gradient in Heavy Oil Reservoirs

Compared with conventional well, herringbone-like laterals wells can increase the area of oil release, and can reduce the number of wellhead slots of platforms,?and?also can greatly improve the development efficiency. Based on threshold pressure gradient in heavy oil reservoir,?and?the applied principle of mirror reflection and superposition, the pressure distribution equation of herringbone-like laterals wells is obtained in heavy oil reservoir. Productivity model of herringbone-like laterals wells is proposed by reservoir-wellbore steady seepage. The example shows that the productivity model is great accuracy?to?predict the productivity of herringbone-like laterals wells. The model is used to analyze the branching length, branching angle, branching symmetry, branching position and spacing and their effects on productivity of herringbone-like laterals wells. The principle of optimizing the well shape of herringbone-like laterals wells is proposed.

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.

Identifying Oil，Oil－water and Water Reservoirs by the Method of Grey Poly－category

Grey Poly-category is a branch of Grey System(J belonging to System Theory.According to the System Theory,a fully determinable figure is called White Figure,a fully undeterminable figure is called Black Figure,and the figure between them is called Grey Figure.On the same principle,a fully determinable system,a fully undeterminable,and a partial determinable and partial undeterminable sys-tem are called White,Black and Grey System re-spectively.For the oil,oil-water and water reser-voirs,each type of reservoirs has its different log response values.These values are grey figures,not a fixed figure,and then,the system made of the fig-ures is a Grey System.

Geological Model of Pre-Jurassic Heterogeneous Basement and Hydrocarbon Productivity Prediction of “Oil-and-Gas Bearing Contact Zone Horizon” Between Paleozoic and Mesozoic Deposits of Ostaninskoye and Severoostaninskoye Oil-and-Gas Fields(Western Siberi

This work is devoted to the analysis of the formation conditions and geologic model of Paleozoic basement rocks of a number of oil-and-gas fields, located in Tomsk region(South of West-Siberian Oil-and-Gas Province,Russia).The research is based on integrated data interpretation of seismic exploration, well logging and deep drilling.The study is at the interfaces between exploration geophysics

Geomechanical response of overburden caused by CO_2 injection into a depleted oil reservoir

This study investigates the hydro-mechanical aspects of carbon dioxide(CO2) injection into a depleted oil reservoir through the use of coupled multiphase fluid flow and geomechanical modeling.Both singlephase and multiphase fluid flow analyses coupled with geomechanics were carried out at the West Pearl Queen depleted oil reservoir site,and modeling results were compared with available measured data.The site geology and the material properties determined on the basis of available geophysical data were used in the analyses.Modeling results from the coupled multiphase fluid flow and geomechanical analyses show that computed fluid pressures match well with available measured data.The hydromechanical properties of the reservoir have a significant influence on computed fluid pressures and surface deformations.Hence,an accurate geologic characterization of the sequestration site and determination of engineering properties are important issues for the reliability of model predictions.The computed fluid pressure response is also significantly influenced by the relative permeability curves used in multiphase fluid flow models.While the multiphase fluid flow models provide more accurate fluid pressure response,single-phase fluid flow models can be used to obtain approximate solutions.The ground surface deformations obtained from single-phase fluid flow models coupled with geomechanics are slightly lower than those predicted by multiphase fluid flow models coupled with geomechanics.However,the advantage of a single-phase model is the simplicity.Limited field monitoring of subsurface fluid pressure and ground surface deformations during fluid injection can be used in calibrating coupled fluid flow and geomechanical models.The calibrated models can be used for investigating the performance of large-scale CO2storage in depleted oil reservoirs.

中国石化油藏地球物理二十年发展与思考

油藏地球物理技术是综合应用多种地球物理资料与油藏动静态信息进行复杂油藏精细表征和动态监测的跨学科技术,对于提高油藏的储量动用程度和提高采收率具有重要的意义,是当前地球物理技术的重要发展方向。系统回顾了中国石化油藏地球物理提出的背景和过去二十年的发展历程,梳理了油藏地球物理技术系列,总结了在油藏地球物理基础研究、井中地球物理技术、多尺度资料联合反演、地球物理约束确定性建模、时移地震剩余油气预测、地震地质工程一体化、微地震油藏监测等方面的技术创新和应用效果。面对中国油气田勘探开发的深层、深水、非常规及老油田(“两深一非一老”)形势和一体化、智能化、绿色化挑战,油藏地球物理在油气产业技术致胜阶段仍然大有可为,要持续创新油藏地球物理技术,井、震、动、模一体化联合和人工智能应用,构建高水平的油藏地球物理勘探开发一体化、地质工程一体化解决方案,支撑油藏全生命周期建设。

适用于哈拉哈塘高温高盐岩油藏表面活性剂的研制及应用

为了研制出适用于哈拉哈塘油藏条件的表面活性剂驱油剂,对该储层地层流体及岩石润湿性进行了测试,基于此,采用二甲胺、全氟丁酸、氯丙烯、丙烯酰胺、对苯乙烯磺酸钠等为主要原料,合成了一种耐高温高盐含氟两性离子型高分子表面活性剂(GPHQ-2),并对其表面活性、润湿性以及洗油效率等进行了室内评价。实验结果表明,150℃、25×10^(4)mg·L^(-1)矿化度老化后的GPHQ-2仍能有效降低油水界面张力,可使岩心表面实现润湿反转,洗油效率可达43.4%,远高于常规石油磺酸盐的洗油效率(5.6%);GPHQ-2具有很好的驱油效果,可在水驱阶段原油采收率基础上提高22.84%;现场应用结果表明,目标井采取注GPHQ-2表面活性剂吞吐驱油措施后,日产油量从4.9t提升到8.9t,增产效果明显,且持续有效。说明GPHQ-2表面活性剂满足哈拉哈塘油藏提高采收率需求,并可对该类油藏表面活性剂增产提供理论和实践指导。

致密油储层压裂裂缝扩展规律分析及影响研究

以鄂尔多斯延长组长7裂缝性致密油储层为例,开展致密油储层裂缝扩展实验研究,分析裂缝扩展的影响因素,并对裂缝扩展规律进行模拟分析,实验结果表明:长7致密油储层岩石杨氏模量、泊松比和抗压强度波动范围广,造成数值差异较大;矿物组成分布差异为3%~46%,平均值为16.85%左右;该区块储层岩石发育部分的天然裂缝,储层最大水平主应力和最小水平主应力差异较大,储层水平和垂直方向上的孔、渗、饱等物性差异较大。天然裂缝的形成和发展受自然裂缝存在与地应力场差异这两个关键因素的显著影响,长7储层原始状态下裂缝的形态呈现低角度。

利用机器学习与改进岩石物理模型预测页岩油层系横波速度

传统的横波速度预测方法包括经验公式法和岩石物理模型法。前者适用于岩石矿物组分相对单一的储层,且受区域限制等因素的影响,不具有普适性,预测精度较低。后者需要根据不同的实际情况选择合适的岩石物理模型,才能达到预期的目的。大多数机器学习横波速度预测方法基于纯数据驱动,数据集的质量和数量将直接决定横波预测模型精度,并缺乏充分的物理内涵。为此,基于深度神经网络(DNN)的方法,假设研究区储层波传播方程的数学形式已知,通过测井数据训练DNN得到未知的弹性参数,以确立目的层的波传播方程。利用平面波分析法得到相应的纵波、横波速度,实现神经网络与理论模型的结合。此外,针对传统Xu-White模型的不足,考虑随深度变化的孔隙纵横比,提出了改进横波速度预测岩石物理模型。利用研究区较丰富的测井数据,分别采用构建的DNN模型和改进横波速度预测岩石物理模型预测横波速度,并与传统的Xu-White模型预测结果进行对比、分析。结果表明,由DNN模型和改进岩石物理模型均可获得较高精度的横波速度预测结果,且前者的预测效果更好。

非常规储层微纳米孔隙介质中流体相态研究进展

非常规油气储层具有岩石骨架颗粒小、比表面积大、微纳米孔隙发育的特点,流体与孔隙介质间存在着诸多复杂的界面效应问题,影响微纳米孔隙介质中流体的相态变化规律。对于受限域流体,经典油气相态理论方法忽略分子间相互作用及界面效应的影响,预测微纳米孔隙介质中流体相变特征存在偏差。为了更全面地揭示油气在受限空间中的相态特征及其微观作用机理,总结当前微纳米孔隙介质中流体相态研究技术现状,详细阐述微观实验测试、相态理论模型和分子模拟3种主流技术方法,指出3种技术各自的优缺点,并对未来流体相态研究技术提出展望。分析认为:微观实验测试方法可通过研究流体热力学参数的变化来确定流体相变点,由于实验误差、人为误差等原因,需与理论计算相结合;相态理论模型方法可通过改进临界参数场、考虑流体与孔壁界面作用、考虑相间毛管压力修正相平衡判据方程等方法建立纳米孔隙空间相态理论模型,但是由于没有综合考虑界面效应带来的影响且缺乏有力的实验数据支撑,难以推广应用;分子模拟方法能在分子尺度上揭示流体分子的相行为,但现有研究主要围绕小分子展开,并且与流体发生相变时的临界参数结合得较少。后续研究应以多界面效应耦合影响的微纳米孔隙介质中油气流体相变特征为研究对象,以微观实验、理论模型和分子模拟为技术手段,为描述微纳米孔隙介质中流体相态提供合理的实验测试手段和可靠的理论计算模型。

致密油藏驱渗结合采油可行性研究

致密油藏孔喉较小而渗吸作用显著,为提高致密油藏水驱效率,提出驱渗结合采油方法,同时利用驱替与渗吸作用。为验证该方法的可行性与主控因素,在水驱模型的基础上,考虑了渗吸作用,并基于实验数据特征建立了渗吸项模型,建立了驱渗结合采油数值模拟模型。结果表明,渗吸作用有效增加了注入水的波及面积,有效置换出基质中的原油,提升了采油效率;主控地质因素包括基质/裂缝孔隙度、渗透率和渗吸经验参数,主控工程因素包括注水压力、裂缝间距和半长;现场应用表明相较水驱方式,驱渗结合采油的日产油速度提高了约1倍,受效时间约为200 d,提高累产约为340 t,说明驱渗结合采油工艺可有效提高中国致密油藏的采收率,所建模型可用于驱渗结合采油的优化设计。

Research on Well Testing Interpretation of Low Permeability Deformed Dual Medium Reservoir

Considering the influence of quadratic gradient term and medium deformation on the seepage equation, a well testing interpretation model for low permeability and deformation dual medium reservoirs was derived and established. The difference method was used to solve the problem, and pressure and pressure derivative double logarithmic curves were drawn to analyze the seepage law. The research results indicate that the influence of starting pressure gradient and medium deformation on the pressure characteristic curve is mainly manifested in the middle and late stages. The larger the value, the more obvious the upward warping of the pressure and pressure derivative curve;the parameter characterizing the dual medium is the crossflow coefficient. The channeling coefficient determines the time and location of the appearance of the “concave”. The smaller the value, the later the appearance of the “concave”, and the more to the right of the “concave”.

准噶尔盆地阜康凹陷二叠系深层岩性油藏成藏条件及模式

利用有机碳、岩石热解、质谱-色谱、岩石薄片、铸体薄片和扫描电镜等实验,以准噶尔盆地阜康凹陷二叠系上乌尔禾组油藏为研究对象,文中通过对油藏类型及各控藏条件开展研究,揭示了阜康凹陷上乌尔禾组成藏模式。结果表明:1)芦草沟组咸水还原环境下沉积的Ⅰ类烃源岩水生生物供给充足,有机质丰度较高,成熟度高,具备良好生油潜力,为后期油气成藏提供了丰富的物质来源。2)上乌尔禾组为扇三角洲-湖泊沉积体系,埋深大,压实作用强烈,溶蚀孔和裂缝是深层特低孔特低渗储层的主要类型及油气运移的主要通道。3)乌三段泥岩盖层给油气保存创造了良好条件,通源断裂及伴生缝网给油气运移聚集提供最便利的通道,在超压体系作用下,油气源源不断地聚集成藏。4)各个成藏条件相互配置,形成“源储一体、断裂输导、超压聚集”成藏模式,油气不断聚集,形成现今的二叠系上乌尔禾组深层大型岩性油藏。该研究成果可为阜康凹陷上乌尔禾组深层油藏及国内其他岩性油藏的勘探提供参考依据。

松辽盆地北部下白垩统扶余油层源下致密油富集模式及主控因素

基于地球化学、地震、测井和钻井等资料,对松辽盆地北部下白垩统泉头组扶余油层地质特征、致密油富集主控因素及富集模式等进行系统分析。研究表明:①泉头组上覆上白垩统青山口组优质烃源岩,环凹鼻状构造发育,沉积砂体大面积连续分布,储层整体致密;②优质烃源岩、储层、断裂、超压和构造等多要素配置联合控制扶余油层致密油富集。源储匹配关系控制致密油分布格局;源储压差为致密油富集提供充注动力;断砂输导体系决定油气运移和富集;正向构造是致密油富集的有利场所,断垒带是向斜区致密油勘探重点突破区带;③基于源储关系、输导方式、富集动力等要素建立扶余油层致密油3种富集模式,一是源储对接油气垂向或侧向直排式:“源储紧邻、超压驱动、油气垂向倒灌或源储侧向对接运聚”;二是源储分离断裂输导式:“源储分离、超压驱动、断裂输导,油气通过断层向下运移到砂体富集”;三是源储分离断砂匹配式:“源储分离、超压驱动、断裂输导、砂体调整、油气下排后通过砂体侧向运移富集”;④油源条件、充注动力、断裂分布、砂体以及储层物性等方面的差异性造成扶余油层致密油的差异富集,齐家—古龙凹陷扶余油层具有较好富集条件,勘探程度低,是未来致密油探索重要新区带。

中国石油精细油藏描述技术新进展与展望

精细油藏描述研究是油田开发基础工作之一,其研究精度的不断提高,极大地促进了油田开发水平的提升。“十二五”和“十三五”期间,中国石油精细油藏描述研究针对多层砂岩油藏、复杂断块油藏、低渗透砂岩油藏、砾岩油藏、稠油油藏、特殊岩性油藏分别开展了技术攻关,形成了不同类型油藏配套技术系列。为了支撑剩余经济可采储量(SEC)储采平衡、老油田“压舱石”、采收率再提高、页岩油革命等“四大工程”,系统梳理中国石油精细油藏描述研究在5个方面的最新进展,分别是井震结合构造精细解释技术实现低级序断层定量描述,基于储层构型研究的单砂体刻画技术实现米级砂体描述预测,室内实验、数字岩心、物理模拟和数值模拟等方法技术实现综合剩余油表征,精细油藏描述成果平台建设实现研究过程协同共享和成果规范化存储管理,建章立制制定系列标准规范实现精细油藏描述研究规范化。通过系统总结精细油藏描述存在的8个方面问题,提出精细油藏描述的发展方向。

深层油藏传热模型及油柱高度计算

深层油藏储层埋藏深、厚度大,油井难以钻穿整个油层。针对深层油藏油柱高度的计算问题,考虑在油井投产后从油水界面到井底的垂向传热过程,建立了一个深层油藏传热模型。利用变量代换、分离变量及傅里叶变换等方法对模型进行了求解,获得了油藏油柱高度计算式。只需利用油井投产前和投产一段时间后的井底温度数据,便可计算油柱高度。以塔里木盆地某深层油藏某油井为例,展示了油柱高度的计算与应用。同时,利用该井的基础数据,代入传热模型,模拟计算了油井投产后不同时间下不同油层位置的温度值和温度梯度值,进而绘制了不同生产时间下储层温度分布曲线和不同储层位置处的储层温度动态变化曲线,结果表明油井投产后的储层温度分布呈非线性的动态变化特征。建立的传热模型可为深层油藏油柱高度的计算提供技术支持。

火山岩风化壳储层发育模式及测井划分方法

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页岩油储层普遍发育多尺度天然裂缝,天然裂缝是页岩油储层主要的储集空间和渗流通道,多尺度天然裂缝分布规律制约着页岩油气储层高效开发。本文以鄂尔多斯盆地庆城油田长7页岩油储层为例,结合地表露头、岩心、薄片、测井和地震等资料,在划分多尺度裂缝的基础上,明确了多尺度裂缝的发育特征,形成了多尺度裂缝建模方法,建立了典型区块X井区长71储层多尺度裂缝三维离散网络模型。根据蚂蚁体叠后地震属性明确了大尺度裂缝分布特征,用确定性方法建立了大尺度裂缝地质模型;结合储层地质力学方法和常规测井裂缝解释结果,建立了中、小尺度裂缝发育强度约束体,然后以发育强度约束体为约束,协同中、小尺度裂缝参数,采用随机建模方法分别建立了中、小尺度裂缝地质模型。最终将大、中、小尺度裂缝网络模型融合形成多尺度裂缝网络模型,并建立裂缝等效属性模型。结果表明X井区长71大尺度裂缝发育于该区东北部,中尺度裂缝和小尺度裂缝多发育于该区西部、西南部和东北部大尺度裂缝发育位置。建立的多尺度裂缝模型与单井裂缝发育规律和实际生产动态数据吻合,可为庆城地区X井区页岩油气增储上产提供地质依据。