单双模态结构砾岩地层岩电特性的数值模拟研究

发布时间：2018-05-25 03:18

本文选题：砾岩模态 + 岩电特性　；参考：《西安石油大学》2017年硕士论文

【摘要】：地层电阻率是储层解释评价的重要参数。随着勘探技术的发展,油田精细勘探逐渐成为勘探的主流,含有孔洞和裂缝的砂砾岩等电各向异性地层成为油田精细勘探的主要方向。本文将基于有限元软件COMSOL数值模拟研究恒定电流场中单双模态结构砾岩地层的岩电特性,为砾岩油藏的评价和解释提供理论支撑,为更复杂电各向异性地层岩电特性的数值模拟研究奠定基础。主要研究内容和成果包括以下几个部分。第一部分介绍了有限元基本思想以及COMSOL软件的数值计算流程。构建基于COMSOL软件数值计算砾岩地层模型,研究恒定电流场中砾岩地层电阻率的求解方法,分析了地层模型中电流的流动轨迹。此外,研究阿尔奇公式的物理原型其及物理意义,加深了对阿尔奇公式的理解,为砾岩地层岩电特性研究奠定基础。第二部分研究了单模态砾岩地层岩电特性。首先构建了单一椭球形砾岩地层模型,研究了砾岩球度、空间位置和倾角对整个地层电阻率的影响,得出球度、空间位置和倾角变化时,对单一方向电阻率有影响且呈现一定的规律,但不同方向电阻率变化规律不同。然后构建了基于单模态砾岩地层孔隙的孔喉模型,研究了喉道半径、孔喉基质电阻率、砾岩基质电阻率和孔隙延展方向对砾岩地层电阻率的影响,结果表明孔喉内流体电阻率是影响地层电阻率的主要因素,不同流体电阻率对应的地层电阻率变化规律不同。第三部分研究了双模态砾岩地层岩电特性。分析了双模态砾岩地层的沉积方式,构建不同结构的双模态砾岩地层,从双模态砾岩地层的微观结构出发研究其岩电特性,验证了双模态砾岩地层宏观岩电特性与微观岩电特性的一致性。构建双模态砾岩地层等效孔隙的毛细管孔隙模型,研究双模态砾岩地层中复杂孔隙对地层岩电特性的影响机理,得出孔隙最小半径和电流流向对地层电阻率影响较大。第四部分研究了双模态孔隙饱含水砾岩地层电阻率与Archie公式参数关系。分析了双模态砾岩地层孔隙饱含水时砾岩地层电阻率、地层孔隙度和地层因数三者之间的关系。构建双模态砾岩地层各向同性地层模型,数值模拟计算求出了对应的岩性系数和胶结指数。构建双模态砾岩地层各向异性地层模型,数值模拟计算求出砾岩地层张量地层电阻率与地层孔隙度的定量关系。结果显示地层因数在一定范围内为常数,与水电阻率有关。第五部分研究了双模态孔隙含油水砾岩地层电阻率与Archie公式参数关系。构建双模态亲油和亲水砾岩地层模型,研究双模态砾岩地层中孔隙含油水两相时地层电阻率、含油饱和度和电阻增大系数之间的关系,数值计算求出了对应的岩性系数和饱和度指数。然后研究了孔喉模型中孔喉含油水时的岩电特性,可以看出基质亲油时的地层电阻率远大于亲水时的地层电阻率。
[Abstract]:Formation resistivity is an important parameter for reservoir interpretation and evaluation. With the development of exploration technology, oil field fine exploration has gradually become the mainstream of exploration, and electrically anisotropic formations such as sand gravel containing pores and fractures have become the main direction of fine exploration. In this paper, based on the finite element software COMSOL numerical simulation, the rock electrical characteristics of single and double mode structure conglomerate strata in constant current field are studied, which provides theoretical support for the evaluation and interpretation of conglomerate reservoir. It lays a foundation for the numerical simulation of rock electrical characteristics in more complex anisotropic strata. The main research contents and achievements include the following parts. The first part introduces the basic idea of finite element and the numerical calculation flow of COMSOL software. A numerical calculation model of conglomerate formation is constructed based on COMSOL software. The method of calculating the resistivity of conglomerate formation in constant current field is studied and the flow path of current in the model is analyzed. In addition, the study of the physical prototype of the Archie formula and its physical significance deepen the understanding of the Archie formula and lay a foundation for the study of the lithoelectric characteristics of conglomerate strata. In the second part, the electrical characteristics of single mode conglomerate strata are studied. In this paper, a single ellipsoidal conglomerate stratigraphic model is constructed, and the effects of conglomerate sphericity, spatial position and dip angle on the whole formation resistivity are studied, and the variation of sphericity, spatial position and dip angle is obtained. It has some influence on the resistivity of single direction, but the variation law of resistivity in different direction is different. Then the pore throat model based on single mode conglomerate formation porosity is constructed, and the influence of throat radius, pore throat matrix resistivity, conglomerate matrix resistivity and pore extension direction on conglomerate formation resistivity is studied. The results show that the fluid resistivity in the pore throat is the main factor affecting the formation resistivity, and the variation law of the formation resistivity corresponding to the different fluid resistivity is different. In the third part, the electrical characteristics of bimodal conglomerate strata are studied. In this paper, the sedimentary mode of bimodal conglomerate formation is analyzed, and the bimodal conglomerate strata with different structures are constructed. The rock electrical properties of bimodal conglomerate strata are studied from the microscopic structure of bimodal conglomerate strata. The consistency of macroscopic and microscopic rock electrical characteristics of bimodal conglomerate formation is verified. The capillary pore model of equivalent porosity in bimodal conglomerate formation is constructed. The influence mechanism of complex pores on formation electrical properties in bimodal conglomerate formation is studied. It is concluded that the minimum pore radius and current flow direction have great influence on formation resistivity. In the fourth part, the relationship between the resistivity of bimodal pore saturated conglomerate and the parameters of Archie formula is studied. The relationship among resistivity, porosity and formation factor of bimodal conglomerate strata with water content is analyzed. The isotropic formation model of bimodal conglomerate is constructed and the corresponding lithologic coefficient and cementation index are calculated by numerical simulation. The anisotropic formation model of bimodal conglomerate formation is constructed and the quantitative relationship between formation porosity and Zhang Liang formation resistivity of conglomerate formation is obtained by numerical simulation. The results show that the formation factor is constant in a certain range and is related to the water resistivity. In the fifth part, the relationship between the resistivity of bimodal pore oil-bearing conglomerate and the parameters of Archie formula is studied. The relationship among resistivity, oil saturation and resistance increase coefficient of pore oil-water two-phase formation in bimodal conglomerate formation was studied by constructing two-mode oil-lipophilic and hydrophilic conglomerate formation models. The corresponding lithologic coefficient and saturation exponent are obtained by numerical calculation. Then the rock electrical properties of the pore throat with oil and water in the pore throat model are studied. It can be seen that the formation resistivity of the matrix hydrophilic is much higher than that of the hydrophilic.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P631;P618.13

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