【作者】 汪必峰；

【导师】 戴俊生；

【作者基本信息】 中国石油大学 ， 地质资源与地质工程， 2007， 博士

【摘要】 由粉砂岩、粉细砂岩和细砂岩组成的低渗透储层,表现出强烈的脆性特征。和其他类型裂缝相比,构造微裂缝在这类储集层中往往占主导地位。构造裂缝与构造应力场有关,是在大地静力场叠加构造应力场形成的古地应力场作用下的产物,现今地应力场不利于裂缝的形成,只对早期形成的裂缝起到改造的作用。如果储集层构造形态相对比较简单,经受的构造运动相对较弱,就可以通过应力场数值模拟的方法预测储集层裂缝开度、密度以及孔隙度、渗透率等参数。目前裂缝研究主要涉及三个方面的内容:地下裂缝识别、裂缝的空间分布预测和裂缝参数的定量表征。构造裂缝的发育规律、形态和空间分布特征以及渗流规律主要受控于构造应力场和储层岩石物理性质,因此国内外学者多采用构造应力场的方法预测构造裂缝,然后依据该方法得到的裂缝参数进行裂缝储集层渗流规律的研究。由于致密性储集层以构造裂缝为主,采用地质力学原理和方法,通过构造应力场数值模拟来定量表征裂缝已经成为裂缝预测的必然趋势。本论文研究是在前人研究成果的基础上,提出了同时考虑古、今地应力场综合作用的裂缝描述与定量研究方法。首先通过对相关文献调研,结合岩石力学手段,建立起适用于低渗砂岩储层的岩石破裂判别的方法。然后通过实验和理论建模的方法建立应力场和脆性岩层裂缝开度、密度的关系,并且以裂缝开度和密度为纽带,建立应力场和裂缝孔隙度、渗透率之间的定量化关系。最后根据古应力场下形成裂缝,现今应力场下改造裂缝的思路,在对迪那气田地质历史时期、现今和未来地应力场的数值模拟基础上,结合前面的破裂判别方法以及应力场与裂缝孔隙度和渗透率之间的定量关系,最终预测了迪那气田不同时期的裂缝参数的分布情况,实现了迪那气田下第三系储集层构造裂缝的定量预测。本论文研究成果一方面为其他地区低渗透储层裂缝的研究提供思路和方法技术,另一方面也为西气东输气源地第二大气田迪那气田实现高效、平稳、安全开发奠定基础,这也是本文研究的生产需求所在。更多还原

【Abstract】 Low permeability reservoir composed of siltstone, silt-fine sandstone and fine sandstone represents intensive brittleness. Tectoclase is the dominant in this kind of reservoir in comparison with other kinds of fractures. Relevant with tectonic stress field, tectoclase is the outcome of the paleo-ground stress field which resulted from the overlay of geo-static field and tectonic stress field. The present ground stress field is unfavorable for the forming of fractures and it just reconstructs the fractures that came into being in early era. If the reservoir possesses of a relatively simple structural attitude and bears relatively weak tectonic movement, the reservoir tectoclase aperture, density, porosity and permeability can be predicted by numerical simulation of the tectonic stress field. Nowadays, fracture research chiefly involves in three aspects: the identification of underground fracture, the prediction of fracture spatial distribution and the quantitative characterization of fracture parameter. The developmental law, conformation, spatial distribution and flow law of tectoclase is under control of tectonic stress field and reservoir petrophysical property. Therefore, many scholars from home and abroad predict tectoclase by tectonic stress field and research on fracture reservoir flow law by the tectoclase parameter produced hereby. Since fine and close reservoir mainly contains tectoclase, it is a certain tendency to quantitatively characterize fracture by the numerical simulation of tectonic stress field with the geomechanics theory and methods. On the basis of predecessors’achievements, this paper proposes fracture description and quantitative research method by considering the paleo and present ground stress field simultaneously. First of all, a rock burst law fitting for low permeability sand reservoir was set up by the combination of rock mechanics after a survey and study on relevant papers. Then, a relation between stress field and the fracture aperture and density of brittle reservoir was built up by experiment and theoretical modeling. A quantitative relation between stress field and fracture porosity and permeability was set up with the conjunction of fracture aperture and density. Finally, according to the thought that fracture was formed under paleo-stress field and reworked under present stress field, the distribution of fracture parameters in different periods were predicted on the basis of the numerical simulation of paleo, present and future stress field in conjunction with the abovementioned rock burst law and quantitative relation between stress field and fracture porosity and permeability in Di’na Gas Field. On one hand, this paper offers clue and method for research on fracture in low permeability reservoir in other areas. On the other hand it settles the foundation for developing the second biggest gas pool efficiently, steadily and safely in the project of transporting the natural gas from the west to the east, which is also the call for this paper.更多还原