【作者】 黄德利；

【导师】 贾振岐；

【作者基本信息】 大庆石油学院 ， 油气田开发工程， 2010， 博士

【摘要】 为了进一步搞清大庆外围特低渗透裂缝性油藏渗流特征,以头台油田,榆树林油田扶余油层为例,本文针对大庆外围低渗透油田开发中存在的注水开发产能下降快、水驱采收率低以及储量动用程度低等难题,通过对国内外有关低渗透油藏非达西渗流方面的研究成果和文献的综合分析,确定了研究思路和研究内容,并在非达西渗流理论和实验两方面开展了大量工作。通过粘土矿物分析、电镜扫描、铸体薄片分析、恒速压汞、核磁共振测试等方法的综合研究,认为大庆外围低渗透油田扶杨油层储集空间主要有五种孔隙类型:粒间孔、溶蚀孔、微孔隙、晶间孔和裂隙,喉道以管状和片状的细喉道为主,而且储层的主要渗流通道为孔道型,这种细微孔道不可避免地增加油水流动阻力;同时发现,这类储层的基质孔隙、喉道、裂缝及相互连通关系都不同程度地控制流体渗流特性。室内实验表明单相油、单相水在大庆油田低渗透扶杨油层中流动时,表现了非达西渗流特征:渗透率越低,非达西渗流特征越明显;渗透率越低,其最小启动压力梯度和拟启动压力梯度越大;单相水流动产生非达西渗流的渗透率上限约为1mD;单相油流动产生非达西渗流的渗透率上限约为5mD。低渗透油层中油水两相渗流时,渗流曲线的非线性特征更加显著,油水两相渗流的拟启动压力梯度不只是含水饱和度的函数,它与驱替过程相关,并且大于水单相渗流的拟启动压力梯度,也大于油单相渗流的拟启动压力梯度。特低渗透岩心低速下水驱油相对渗透率曲线的特点是束缚水饱和度高,油水共渗范围小,油相相对渗透率下降快,残余油下水相相对渗透率抬不起来,残余油饱和度高。深入研究了特低渗透裂缝性油藏渗流特性及开发特征。提出了有效驱动体系的概念,并结合实际油田的开发论述了探索了构建有效驱动体系的压裂投产增加可动流体饱和度、采用矩形井网扩大可流动区域、基质与裂缝较佳组合提高驱油能力等做法。更多还原

【Abstract】 This study was performed to make clear the flow characteristics of the ultra-low permeability reservoir with fractures in the periphery of Daqing Oilfield, like the Fuyu oil layer in Toutai oilfield and Yushulin oilfield. Aiming at such problems existing in the low permeability reservoir development by water flooding at Daqing Oilfield as the fast decrease of oil production, the low recovery ratio and poor use of reserves, after comprehensive analyses of the research methods, results and literatures concerning non-Darcy flow at low-permeability reservoir home and abroad, the research ideas and contents were determined. Much efforts were put to both the theoretical and the experimental studies on the non-Darcy flow.Through the comprehensive studies by Clay-mineral Explanation, Scan Electron Microscopy, Cast Thin Section, Constant-rate Mercury Injection, Nuclear Magnetic Resonance and so on, it was found out that there are five primary types of reservoir spaces as intergranular pores, corrosion holes, micro-pores, intercrystal porse and the fracture at the low-permeability oil layers of Fuyang in the periphery of Daqing. The fracture takes the tubular and sheet-based thin throat as the major types, and the pores are the main flow channels of reservoirs. Inevitably, the fine pores increase the oil&water flow resistance. Also, such reservoir matrix pores, throat, fractures and their mutual links control the fluid flow characteristics at different extents.Laboratory Experiments proved that the flow of single-phase oil or single-phase water in the low permeability oil layers of Fuyang at Daqing oilfield shows non-Darcy characteristics; the lower the permeability, the more obvious characteristics of the non-Darcy flow, then the larger the minimum pressure gradient and the quasi-starting pressure gradient required. The limit of the permeability for the non-Darcy flow of a single water phase is 1×10-3μm2, the number for oil phase is approximately 5×10-3μm2.When two phases of oil & water flow in the low permeability reservoirs, the flow curve is more significant in the non-linear characteristics. Now the quasi-starting pressure gradient is not only a function of the water saturation, but also associated with the displacement process. It is greater than number of the single-phase flow of water in the state with residual oil and than the value of oil in the state of the irreducible water. The oil-water relative permeability curves of the ultra-low permeability cores at low speed are characterized by a high irreducible water saturation, a high residual oil saturation, a small range of two phase flow of oil and water, fast decline speed of the oil phase relative permeability and the low water-phase relative permeability at the state of residual oil.A great many researches were carried out about the flow characteristics and development features of ultra-low permeability reservoirs with fractures. A concept of the effective drive system was put forward. In combination with the actual oilfield development, several measures were explored to build the effective driving system, such as fracturing for production to increase the movable fluid saturation, using rectangular well pattern to enlarge the flow area, combining the matrix and fracture to improve the oil displacement capacity and so on.更多还原