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复杂小断块低渗透油藏主控因素与剩余油分布规律
The Main Controlling Factors and Remaining Oil Distribution in Lowly Permeable Reservoirs with Small Complex Fault Blocks
【作者】 吴志良;
【导师】 王震亮;
【作者基本信息】 西北大学 , 矿产普查与勘探, 2010, 博士
【副题名】以苏北盆地溱潼凹陷台兴油田为例
【摘要】 复杂小断块低渗透油藏的勘探、开发难度较大,目前该类油藏采收率普遍较低,开发效果差,剩余油分布规律复杂,具有较大的储量挖掘潜力。本文以苏北盆地溱潼凹陷台兴油田阜三段油藏为典型特例,重点研究复杂小断块低渗透油藏的主控因素与剩余油分布规律,认识此类油藏的地下面貌,研究有效的开发方式和开发对策,制定合理的科学挖潜方案,通过综合治理,以期获得较高的采收率,这对于提高复杂小断块低渗透油藏难动用储量的开发水平,实现资源接替有重要现实意义。从复杂小断块低渗透油藏主控因素入手,进行精细油藏描述研究,通过精细地层对比及三维地震人机联作构造解释,结合生产动态资料,以动静态综合识别技术落实内部低序级断层为突破口,建立精细构造模型,同时开展精细储层研究,对沉积微相及砂体展布规律进行深入分析,并加强油藏工程技术与动态分析相结合,根据影响剩余油分布的主要因素,对剩余油分布进行定性和定量描述,针对剩余油分布特点制定合理的挖潜对策。研究中采用了一系列特色方法和技术,如在构造研究过程中,充分利用钻井、测井和地震资料,做到井、震结合,通过地质标定、人机交互精细地震解释,为复杂小断块油藏低序级断层归位组合,准确刻画构造奠定了基础;在储层研究中,把储层单元细分至单砂体,进行储集岩的类型、岩相、岩性、分布范围、形态特征、孔隙结构和储油物性变化综合描述;在油藏精细描述的基础上,建立了油藏模型,结合动态监测成果,通过精细数值模拟,找出了剩余油的分布规律。通过本研究提出的综合治理措施,较为明显地改善了复杂小断块低渗透油藏的开发效果。主力断块加密调整,开发状况明显好转,油田产量上升,水驱采收率显著提高,低效区块通过零散调整恢复了正常生产。研究取得的主要认识有:(1)苏北盆地经过多期构造运动,断层相互切割,是复杂小断块油藏形成的主控因素;(2)储集岩的岩相、分布范围、孔隙结构和储集物性变化,直接控制着地下油气的分布和产能,是复杂小断块低渗透油藏形成的重要因素;(3)断裂系统发育的部位,断块破碎、复杂、面积小,往往一次井网储量控制程度低,是剩余油分布的主要富集区;(4)沉积微相过渡带,储层非均质性严重,水驱波及程度低,是剩余油分布的重要富集区;(5)断裂系统是复杂小断块低渗透油藏形成的主控因素,低序级断层是此类油藏剩余油分布的主要控制因素。
【Abstract】 It is very difficult to explore and develop low permeability reservoirs in small complex fault block, the recovery factor of which is usually low at present, the development effect of which is poor, and the remaining oil distribution of which is complicated with great tap potential of reserves. Take Fu3 Member reservoir of Taixing Oilfield in Qingtong Sag of Subei Basin as typically special example, the paper focuses on main controlling factors and remaining oil distribution of low permeability reservoirs of small complex fault block, recognizes underground features of this kind of reservoir, researches effective development methods and development countermeasures, and makes reasonable and scientific schemes for potential tapping to obtain higher recovery factor through comprehensive treatment, which have vital practical significance in improving the development level of hard-to-recover reserves of low permeability reservoir in small complex fault block to realize the resource substitution.The remaining oil distribution has been researched in main controlling factors, fine reservoir description, fine reservoir numerical simulation, and so on; and the potential tapping countermeasures have been discussed in the paper. Based on main controlling factors of reservoir, the fine reservoir description has been researched. Through fine stratigraphic correlation and interactive 3D seismic structure interpretation, combined with production performance data, determining internal low grade faults by dynamic and static comprehensive recognition technology, the fine structural model has been established, the fine reservoir research has been made, the distribution of sedimentary micro-facies and sand body has been deeply analyzed, and the combination has been strengthened between reservoir engineering technology and dynamic analysis. Through qualitative and quantitative description of remaining oil distribution based on main factors influencing remaining oil distribution, reasonable potential tapping countermeasures have been made in view of remaining oil distributing features.Some distinguishing methods and technologies have been used in the research:during research in structure, making full use of the drilling, well logging and seismic data, and combination of well logging and seismic lay a foundation for migration and combination of low grade faults of small complex fault block reservoirs and accurately specifying the structure, through geological calibration and interactive fine seismic interpretation; during research in reservoirs, subdividing the reservoir unit into single sand body, the comprehensive description has been made in category, lithofacies, lithologic character, distribution range, morphologic characteristics, pore structure and changes in physical properties of oil stored in reservoir rocks; based on fine reservoir description, the reservoir model has been established, and distribution laws of remaining oil have been found out, combining with dynamic monitoring and by using of fine numerical simulation. The fine research degree is a prerequisite of key technology to realize scientific and reasonable development of low permeability reservoirs of small complex fault blocks.By comprehensive treatment advice of the article, the exploited effect of small complex fault block and low permeability reservoirs can be evidently improved. Encrypting and modulating the brunt fault block, the result of exploited was evidently straighten up, the output increased, the harvest rat of water expel oil visibly advanced and the inefficient fault block resumed Normal production through scattered modulated.The cognitions obtained include:(1) multiphase tectonic activities of Subei Basin and mutual cutting of faults are main controlling factors for forming of small complex fault block reservoirs; (2) the distribution and productivity of oil and gas underground are directly controlled by lithofacies, distribution range and pore structure of reservoir rocks and changes in reservoir physical properties, which are important factors to form low permeability reservoirs of small complex fault blocks; (3) in the developed parts of fault system, the fault block is broken, complicated, and of small size with low control degree of primary well pattern reserves usually, which is main enrichment area of remaining oil distribution; (4) the transition zone of sedimentary micro-facies is important enrichment area of remaining oil distribution, with serious reservoir heterogeneity and low sweep degree of water flooding; (5) the fault system is the main controlling factor to form low permeability reservoirs of small complex fault blocks, and the low grade fault is the main controlling factor of remaining oil distribution of this kind of reservoir.
【Key words】 small complex fault block; low permeability; oil controlling factor; remaining oil; Taixing Oilfield; Subei Basin;