Controlling factors of remaining oil distribution after water flooding and enhanced oil recovery methods for fracturecavity carbonate reservoirs in Tahe Oilfield

Based on comprehensive analysis of core, well logging, seismic and production data, the multi-scale reservoir space, reservoir types, spatial shape and distribution of fractures and caves, and the configuration relationship with production wells in fracture-cavity carbonate reservoirs were studied systematically, the influence of them on the distribution of residual oil was analyzed, and the main controlling factors mode of residual oil distribution after water flooding was established. Enhanced oil recovery methods were studied considering the development practice of Tahe oilfield. Research shows that the main controlling factors of residual oil distribution after water flooding in fracture-cavity carbonate reservoirs can be classified into four categories: local high point, insufficient well control, flow channel shielding and weak hydrodynamic. It is a systematic project to improve oil recovery in fracture-cavity carbonate reservoirs. In the stage of natural depletion, production should be well regulated to prevent bottom water channeling. In the early stage of waterflooding, injection-production relationship should be constructed according to reservoir type, connectivity and spatial location to enhance control and producing degree of waterflooding and minimize remaining oil. In the middle and late stage, according to the main controlling factors and distribution characteristics of remaining oil after water flooding, remaining oil should be tapped precisely by making use of gravity differentiation and capillary force imbibition, enhancing well control, disturbing the flow field and so on. Meanwhile, backup technologies of reservoir stimulation, new injection media, intelligent optimization etc. should be developed, smooth shift from water injection to gas injection should be ensured to maximize oil recovery.

Micro-geological causes and macro-geological controlling factors of low-resistivity oil layers in the Puao Oilfield

Low-resistivity oil layers are often missed in logging interpretation because of their resistivity close to or below the resistivity of nearby water layers. Typical low-resistivity oil layers have been found in the past few years in the Putaohua reservoir of the Puao Oilfield in the south of the Daqing placanticline by detailed exploration. Based on a study of micro-geological causes of low-resistivity oil layers, the macro-geological controlling factors were analyzed through comprehensive research of regional depositional background, geological structure, and oil-water relations combined with core, water testing, well logging, and scanning electron microscopy data. The results showed that the formation and distribution of Putaohua low-resistivity oil layers in the Puao Oilfield were controlled by depositional environment, sedimentary facies, diagenesis, motive power of hydrocarbon accumulation, and acidity and alkalinity of reservoir liquid. The low-resistivity oil layers caused by high bound-water saturation were controlled by deposition and diagenesis, those caused by high free-water saturation were controlled by structural amplitude and motive power of hydrocarbon accumulation. Those caused by formation water with high salinity were controlled by the ancient saline water depositional environment and faulted structure and those caused by additional conductivity of shale were controlled by paleoclimate and acidity and alkalinity of reservoir liquid. Consideration of both micro-geological causes and macro-geological controlling factors is important in identifying low-resistivity oil layers.

Necessity and feasibility of improving the residual resistance factor of polymer flooding in heavy oil reservoirs

The efficiency of water flooding in heavy oil reservoirs would be improved by increasing the viscosity of the displacing phase, but the sweep efficiency is not of significance due to the low mobility of the vicious oil. On the basis of mobility control theory, increasing the residual resistance factor not only reduces the water-oil mobility ratio but also decreases the requirement for viscosity enhancement of the polymer solution. The residual resistance factor caused by hydrophobic associating polymer solution is higher than that caused by polyacrylamide solution in brine containing high concentrations of calcium and magnesium ions. The results of numerical simulations show that the polymer flooding efficiency improved by increasing the residual resistance factor is far better than that by only increasing solution viscosity. The recovery factor of heavy oil reservoirs （70 mPa·s） can be enhanced by hydrophobic associating polymer solution of high residual resistance factor （more than 3） and high effective viscosity （24 mPa·s）. Therefore, increasing the residual resistance factor of the polymer solution not only decreases the requirement for the viscosity of polymer solution injected into heavy oil reservoirs but also is favorable to enhanced oil recovery during polymer flooding.

鄂尔多斯盆地中部罗庞塬地区长7储层控油性及有利区评价

致密油分布的控制因素研究与有利区评价影响着非常规油气的勘探部署。以鄂尔多斯盆地罗庞塬地区长7油层组致密油为研究对象,利用测井、钻井、岩心、压汞、试油成果等资料,研究储层砂体厚度、岩性、储集空间和物性等特征,明确油藏类型,探讨储层条件对致密油的控制作用并评价了有利区。研究表明:罗庞塬地区长7砂体厚度平均为22.6 m,储层岩性主要为细粒度的长石砂岩,储集空间以粒间溶蚀孔和粒间孔为主,其孔隙度平均为8.04%,渗透率平均为0.36×10^(-3)μm^(2),发育小孔-细喉型、细孔-细喉型和微孔-微喉型储层,油藏类型为透镜状致密油藏,呈现出成群、成带的准连续型分布特征,其分布主要受砂体厚度、砂地比、孔隙度、渗透率和砂岩泥质含量的控制,砂体厚度大、泥质含量低、物性好的细砂岩有利于致密油的富集。采用综合指数法,评价出长7油层有4个Ⅰ类区和5个Ⅱ类有利勘探区。

致密油储层含油性主控因素及分布特征——以鄂尔多斯盆地红河油田36井区长8油层组为例

鄂尔多斯盆地红河油田地质条件复杂,含油非均质性极强,导致水平井产能差异及开发难度大。文中基于钻、测、录井及岩心测试、生产动态等资料,对红河油田36井区长8油层组含油性主控因素及含油饱和度分布特征开展了研究。结果表明:1)红河油田由于油气充注强度整体较低,呈现“大面积含油、局部富集”的特点。2)断裂与储层物性是控制含油性的2个主要因素,不同尺度断裂及其伴(派)生裂缝带的含油性差异大。其中:中尺度断裂及其伴(派)生裂缝带既是良好的源-储输导体系,也能改善储层物性,是主要的油气富集带(区);裂缝带以外的基质区主要受储层物性影响,在优质储层发育部位,可发育形成次油气富集区。3)研究区存在断-缝输导成藏和源-储接触成藏2种油气成藏模式,由此建立了长8油层组致密油藏含油性差异成因模式,明确了高含油饱和度区呈“裂缝带内条带状分布、裂缝带以外沿优质储层片状分布”的特征,“雁列式中尺度断裂+优质储层”部位为有利的开发目标区。

Mechanisms and influencing factors of the oil bank in fire flooding

Based on the systematic summary of current research on oil bank, the definition of oil bank in the process of fire flooding and its quantitative indices were proposed; and a new one-dimensional positive dry-fire flooding model considering temperature gradient was established based on the steady flow theory of gas and liquid phases. Single factor analysis and orthogonal experiments were adopted to verify the reliability and reveal the formation mechanisms and the controlling factors of the oil bank. Then the optimal conditions for the oil bank to form were discussed. The study results show the formation of the oil bank is controlled by 3 factors:(1) Oil bank would come into being within a certain temperature interval and above a critical value of temperature gradient(absolute value), with temperature too high or too low and temperature gradient absolute value lower than the critical value, the oil bank couldn't form.(2) For fire flooding process in heavy oil reservoirs, the viscosity of oil influences the width of oil bank and the speed at which oil bank forms; the lower the oil viscosity is, the wider the oil bank is and the faster the oil bank forms.(3) Oil saturation could affect the developing temperature and speed of oil bank. The favorable temperature at which oil bank develops gets lower and the accumulating speed of oil gets faster when the oil saturation is higher. By orthogonal experiments with the model, the optimal combinations of reservoir conditions for forming oil bank during fire flooding in heavy oil reservoirs can be worked out.

延长油田H区块剩余油分布规律及开发技术研究

为了更好的明确延长油田H区域剩余油的分布特征、开发潜力,以及有效的开发策略,运用油藏工程、动态监测、数值模拟相结合的方法,认识剩余油分布规律及主控因素,进一步揭示剩余油分布特征,为下一步注水开发提供理论基础。依据油藏工程及数值模拟精细描述成果,提出了能够提高采收率的合理注采比及地层压力保持水平,优选出中高含水阶段密井网下合理的开发技术,为研究区高效注水开发提供可靠的技术支撑。

B301试验区油井结蜡主控因素及对策

B301试验区位于H盆地,该试验区目前油井结蜡现象严重,防蜡效果较差,防蜡措施有效期较短,无法满足油井防蜡的需要,亟需找到影响油井结蜡的主控因素。针对上述问题,通过室内实验对产出液中的蜡质、胶质、沥青质和机械杂质含量进行测定。利用Olga数值模拟软件对温度、压力、流速进行模拟。研究表明:蜡质、沥青质、机械杂质含量以及温度、流速为影响B301试验区油井井筒结蜡的主控因素,影响程度强弱依次为蜡质、温度、沥青质、机械杂质、流速。研究成果可为B301试验区进一步高效开发提供理论与技术基础,为高含蜡油藏防蜡方法提供参考。

苏北盆地高邮凹陷古近系阜宁组二段页岩油富集主控因素

高邮凹陷古近系阜宁组二段是苏北盆地页岩油勘探的重点区带和层系,已部署实施的8口页岩油水平井的成功,证实其具有非常大的页岩油勘探潜力和良好的勘探前景。针对该层段页岩油井产能存在差异、富集主控因素认识不清楚等难点问题,综合利用岩心、测录井、分析测试数据和生产动态数据等资料,对阜二段地质特征和页岩油富集主控因素进行研究。高邮凹陷阜二段泥页岩以长英质—黏土质混积岩和长英质—灰质/白云质混积岩为主,有机质丰度中等,有机质类型以Ⅰ型和Ⅱ1型为主;自下向上有机质类型由腐殖型向腐泥型逐渐转变,有机质丰度总体由低逐渐增高,具有较好的页岩油形成条件。综合岩相、生油性、含油性、储集性、可压性等多因素评价可知,高邮凹陷阜二段共发育Ⅴ-4~Ⅴ-9、Ⅳ-2~Ⅳ-7小层和Ⅱ~Ⅲ亚段三套勘探有利层段。阜二段页岩油富集具体表现为:①有利岩相组合是页岩油富集的物质基础,其中混积岩夹白云石条带是有利的源—储配置组合,页岩油产能高;②复杂的孔缝系统是页岩油富集的核心,层理缝和裂缝是页岩油流动的主要通道,有效沟通基质孔隙,提高页岩油导流能力;③较高的成熟度和良好的保存条件是页岩油高产稳产的关键,镜质体反射率(R_(o))介于0.8%~0.9%时滞留油含量相对较高,远离长期活动性断层的井游离烃含量(S1)相对较高。

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。

页岩储层非构造裂缝研究进展与思考

随着我国对非常规油气勘探理论的完善和技术的提高,页岩油气勘探开发不断获得突破,其战略地位也在不断上升。页岩储层的品质通常是制约其资源潜力的主要因素,其中裂缝是页岩油气富集、高产、稳产的关键。因此裂缝作为富有机质页岩储层重要的储集空间和渗流通道,其相关研究一直都是该领域内的重点。我国页岩储层内天然裂缝大量发育,而非构造裂缝同样比较发育,对页岩油气的富集和保存评价亦具有重要意义。目前对页岩储层构造裂缝的研究比较深入,而对页岩非构造裂缝的研究则相对薄弱。为此本文在充分调研近年来国内外页岩非构造裂缝研究成果的基础上,重点梳理了非构造裂缝的分类、识别与表征、主控因素、期次及演化序列等方面的研究进展。页岩储层非构造裂缝以成因和形态复杂、分布不规则、尺度较小为特征,依据成因机制差异可将其分为成岩缝、异常高压缝、层理缝和表生缝4个大类,它们的识别与表征目前主要还停留在定性描述的阶段;尽管不同类型的非构造缝主控因素存在差异,但均在不同程度上受控于沉积作用、成岩作用、矿物组分及含量、岩石力学性质,呈现出一定的共性。综合分析并指出了页岩储层非构造裂缝研究的关键问题及发展趋势:一是基于页岩储层岩心、薄片、成像测井、常规测井的典型特征,结合先进图像技术,建立不同类型不同尺度非构造裂缝综合有效识别与定量化表征新方法。二是针对页岩储层非构造裂缝的形成发育具有“多成因类型、多控制因素、多期次演化”的特点,并且页岩非构造裂缝的形成与演化与“古温压、古流体、古成岩”过程联系紧密。据此提出了利用页岩储层非构造裂缝中普遍存在的方解石等充填物的流体地球化学、同位素地球化学(C,O,Sr)及微区原位同位素年代学(U-Pb,Sm-Nd)等先进实验分析技术,综合确定页岩储层非构造裂缝形成时间和活动期次及演化序列是未来研究的关键手段。三是由页岩储层非构造裂缝发育程度与单因素主控因素之间的定性-半定量分析,向多个主控因素耦合控制下的非构造裂缝发育程度的定量研究方向发展,即采用数学方法确定不同主控因素对于裂缝发育程度影响的权重,并构建适合我国页岩非构造裂缝发育程度的综合指数与多个主控因素之间的定量关系模型。

鄂尔多斯盆地南缘宁县—正宁地区延长组地层结构重建及页岩油富集模式探讨

鄂尔多斯盆地延长组页岩油资源丰富,但不同地区勘探研究程度差异大,延长组地层结构及页岩油形成及富集控制因素认识有待深化。利用伊陕斜坡南部宁县—正宁地区新采集的三维地震资料,以及区内的钻井、录井、测井、各类分析测试成果,对延长组地层分布结构和长7段页岩油形成及富集控制因素进行了探讨。综合研究认为,研究区延长组长7—长2段地层具有逐层向湖盆中心进积的楔状地层结构特征;延长组物源主要来自秦岭造山带,各期楔形地层内顺物源方向以河流—三角洲—半深湖—深湖重力流序列充填,具有“同期异相”特征;长7段发育砂质碎屑流及浊流沉积,储层横向变化快,非均质性强,总体属于低孔—特低孔、超低渗致密储层;延长组围绕长7段主力烃源岩,具有上生下储、自生自储、下生上储三种成藏组合类型,长7段主要发育自生自储(夹层)型页岩油,具有优质烃源岩—优势相带—断裂—构造共同控藏特征,其中烃源岩控制页岩油有利发育区,优势相带和断裂控制页岩油富集部位。

姬塬地区长8油层组储层特征分析

为确定长8油层储层现今表征,储层物性受黏土矿物胶结物控制模式,储层沉积作用和沉积后期所经历的成岩变化,通过铸体薄片、扫描电镜等方法研究了储层基本特征和成岩作用及沉积作用,在整体低渗的背景下,部分位于相对渗透率较高区域的油井有较高的产量,理清研究区长8储层富集规律,对地区内岩石孔隙度下降因素进行剖析。结果表明,姬塬地区有利储层多发育水下分流河道和河口坝沉积,特别是砂体中心部位储层物性是最好,可见长8油层组的储集性能和渗流性能好,即粒间孔型、粒间孔+溶孔型和溶孔+粒间孔型。溶孔型、粒间孔+微孔型两种孔隙组合类型的渗流性能较差。微孔型和溶孔+微孔型两种孔隙组合类型的储集空间主要由半径极小的微孔构成,连通性较差,其孔隙内表面积和渗流阻力,储集性能和渗流性能较差。

苏北盆地高邮凹陷阜宁组二段页岩油赋存状态定量表征及控制因素

鉴于页岩油赋存状态对页岩油富集和可动性有重要影响,以苏北盆地高邮凹陷阜宁组二段(阜二段)页岩为研究对象,利用多温阶热解和激光共聚焦显微镜等技术,定量表征高邮凹陷阜二段页岩油赋存状态,明确赋存状态的控制因素。结果表明:高邮凹陷阜二段页岩油赋存状态分为游离油和吸附油两大类,以游离油为主,平均占总含油量的65.16%;不同岩相页岩油赋存状态差异明显,游离油占比由高到低依次为长英质页岩>长英—灰云质混积页岩>长英—黏土质混积页岩>灰云质页岩;有机质成熟度、总有机碳质量分数(w(TOC))、矿物组分和孔隙结构等因素共同控制高邮凹陷阜二段页岩油赋存状态。游离油和吸附油量主要受w(TOC)和孔隙结构控制,游离油量与w(TOC)呈弱正相关关系,吸附油量与w(TOC)呈强正相关关系。游离油、吸附油量与孔体积呈正相关关系,与比表面积相关性不明显。游离油和吸附油的比例主要受有机质成熟度、长英质矿物含量和孔隙结构影响,吸附油比例随有机质成熟度增高而减小,游离油比例与长英质矿物含量呈弱正相关关系。宏孔及微裂缝越发育,游离油比例越高。该结果对苏北盆地页岩油的规模勘探开发具有指导意义。

烹饪油烟中醛类形成的影响因素以及防控技术研究进展

气态油烟成分复杂且含有大量有害挥发性有机化合物,是居室空气的主要污染物之一,同时也是油烟臭味的主要来源,其中醛类占有主要比例。本文综述了烹饪油烟的形成、组成,油烟中挥发性醛类的危害、检测方法和形成的影响因素,并总结了目前油烟中醛的防控措施,以期为科学调控油烟中醛的污染提供理论依据。

窄条带状背斜油藏边部注水开发产能影响因素

JY油田Y油藏为典型窄条带状背斜油藏,其储集层注入水极易沿河道中心方向突进,导致油井快速水淹,产量递减快;由于对水体大小、构造幅度、储集层物性等产能影响因素认识不清,此类油藏开发难度较大。针对上述问题,建立了窄条带状背斜油藏精细数值模型,通过对比论证提出了“边部注水+逐步转注”开发,并在此基础上开展了水体大小、构造幅度、储集层物性等参数对产能的影响研究。结果表明:“边部注水+逐步转注”开发不仅可以增大边水能量,使得井网双向受效,还可以有效延缓构造高部位油井的见水时间,大幅度降低油井含水率。另一方面,在考虑油藏构造特征的前提下,量化了不同影响因素下的产能特征,明确了水体大小、构造幅度、垂向渗透率与水平渗透率之比等参数的合理界限,论证了不同储集层物性下油藏面积的适应性。可为同类型油藏改善注水开发效果提供借鉴。

鄂尔多斯盆地东南部长7段页岩油气富集主控因素

为明确鄂尔多斯盆地东南部长7段页岩油气富集主控因素,综合钻井、测井、岩心分析化验等资料,对研究区长7段页岩油气富集程度及其机理进行研究。页岩解析气量与烃源岩总有机碳含量呈正比,有机质含量控制页岩油气的总含量,有机质发育大量孔隙,页岩油气以吸附态和游离态赋存于有机孔隙中。储集层孔隙结构和孔隙度影响页岩油气的含量及赋存状态,吸附油气主要赋存于微孔中,游离油气主要赋存于中孔和大孔中,但中孔中游离气含量高于大孔,而孔隙度越大,页岩中油气绝对含量越高。砂岩夹层和富有机质页岩的配置关系控制着页岩油气的富集部位,根据粉砂岩、细砂岩与页岩的关系,延长组长7段页岩油气可划分为近源和源内2类,源内又可分为砂岩与页岩互层型、页岩夹砂岩型和页岩型;下伏于富有机质页岩中的砂体和透镜状砂体油气含量最高,其次是上覆于富有机质页岩的砂体和呈舌状或指状与富有机质页岩接触的砂体。

鄂尔多斯盆地富县西区长8储层特征及其控油作用

致密油主控因素研究一直是非常规油气地质理论的核心内容。以鄂尔多斯盆地富县西区长8油层组致密油为研究对象,利用测井、钻井、录井、岩心、薄片、压汞以及试油成果等资料,分析了储层砂体厚度、岩性、储集空间和物性等特征,弄清了长8油藏类型,揭示了储层条件对长8致密油的控制作用。结果表明:富县西区长8砂体厚度平均约4 m,储层岩性主要为中、细粒度的长石砂岩,储集空间以剩余粒间孔和粒间溶蚀孔为主,其孔隙度平均为8.04%,中值为7.5%,渗透率平均为0.36 mD,中值为0.23 mD,属于致密储层。长8油藏类型主要为透镜状岩性致密油藏,具有纵向多层叠置、平面连片分布的准连续型分布特征,不受区域构造控制。长8致密油的分布受砂体厚度、砂岩泥质含量、储层岩性和储层物性的控制。砂体厚度大、泥质含量低、物性好的中、细砂岩有利于形成致密油的富集高产。

中拐凸起南斜坡八道湾组油层低阻成因及识别

准噶尔盆地中拐凸起南斜坡下侏罗统八道湾组低阻油层与一般低阻油层对比,储集层具有形成时期早、埋藏深度大、岩石粒度较大、泥质含量低等特点,低阻成因具有较强特殊性。在对国内外典型低阻油层成因机理综合研究的基础上,利用该区钻井、录井、测井、试井、岩心化验分析等资料,从构造、沉积、成岩作用、储集层特征、成藏条件等多角度,开展八道湾组油藏低阻主控因素研究。该区油藏低阻的形成受宏观因素和微观因素共同控制,低构造幅度、弱水动力沉积等宏观背景下,低油水分异程度、高地层水矿化度及低凝灰岩岩屑含量,是油藏低阻的主控因素;束缚水饱和度偏低,是油藏低阻的次要控制因素。在此基础上,建立地层电阻率与油气指示系数关系图版,与该区试油和试采资料对比,符合率92.9%,为中拐凸起南斜坡八道湾组低阻油层的识别提供了依据。

松辽盆地双城断陷深层原油成藏模式

针对松辽盆地双城断陷深层原油认识程度低、成藏主控因素和深层原油成藏模式不明确的问题,本文利用岩石热解、氯仿沥青“A”和包裹体均一温度等测试资料,结合埋藏史-热史模拟、平衡剖面恢复等手段,通过对烃源岩厚度、排烃强度、圈闭形成、断-砂配置、超压与充注阻力耦合关系等成藏主控因素进行了系统分析。结果表明:1)双城断陷深层可分为登三段背斜、断背斜、断层-岩性油藏和营四段致密油等4种类型。2)登三段构造油藏受烃源岩、断裂和有效圈闭联合控制,高丰度的湖相泥岩是其物质基础;主成藏期前各类圈闭即已形成,断层是油气运移的重要目标;断-砂配置关系决定圈闭有效性。3)营四段致密油受岩性圈闭、排烃强度和超压影响,其中,排烃强度影响致密油宏观分布,生烃增压形成的超压是致密油充注主要动力。综合致密油成藏条件和成藏主控因素,建立西部构造带“源储分离、断层长距离输导、高点富集”、东部断阶“源储紧邻、断砂匹配短距离运移、有效圈闭聚集”和中央洼槽“源储共生、超压驱动裂缝运移、甜点富集”3种成藏模式。