致密气藏水平井体积压裂数值模拟

发布时间：2019-02-17 08:29

【摘要】：目前,各国致密气藏储层的采收率并不高,同一油田不同区块的动用程度也不尽相同,开采过程中遇到的问题也不相同。非常规油气藏和常规油气藏的不同之处不仅仅在于储层的渗透率小,还与储层埋深、地层微观孔喉结构以及不同成岩作用这些因素有关。本文通过铸体薄片、电镜扫描以及压汞实验等方法,对苏里格气田盒8段砂岩岩样的孔候结构进行了宏观和微观相结合的分析。得到了储层的砂岩类型、孔隙类型和孔隙组合类型。从国内外的现有的体积压裂的研究现状可以看出,体积压裂是现在最主要的非常规油气藏提高采收率的手段。但我国的现在仅在苏里格气田和长庆油田进行了大规模的应用。这说明,针对我国各个油田储层特征的有效措施,还要一个长时间的探索过程,各种难题才可以得到解决。为了更加符合我国的情况,就要从最根本上入手,例如体积压裂后的成缝机理和形成的裂缝形态,这样可以为产能模型的建立提供基础。还应研究体积压裂时,水平井筒长度、段数、簇数、簇间距、裂缝导流能力等一系列参数对压裂效果的影响,这样为现场提供理论支持。现阶段,主要的裂缝模拟方法为局部网格加密,这种方法作为一种简便的模拟方法,在模拟多条裂缝上表现了优势。本文采用体积压裂数值模拟主要方法为局部网格加密。在数模软件中建立理想模型,对体积压裂时,簇间距、簇数、段数以及裂缝半长进行优选。在前人研究的基础上,假设了地层中的流体先通过裂缝壁面流入裂缝,再通过裂缝直接流入水平井筒。因此,建立了将水平井筒看成直线源,裂缝看成条带源的,致密气藏体积压裂后非稳态产能模型。根据优选的方案,将数模得到的产量与建立的公式计算得到的产能进行对比,检验模型的准确性。
[Abstract]:At present, the recovery factor of tight gas reservoir is not high, the production degree of different blocks in the same oil field is different, and the problems encountered in the process of exploitation are also different. The difference between unconventional reservoirs and conventional reservoirs lies not only in the low permeability of reservoirs, but also in the factors of reservoir depth, micro pore throat structure and different diagenesis. In this paper, the pore and phenological structure of 8 member sandstone samples in Sulige gas field are analyzed by means of casting thin slice, scanning electron microscope and mercury injection test. The sandstone type, pore type and pore combination type of reservoir are obtained. From the current research situation of volume fracturing at home and abroad, it can be seen that volume fracturing is the most important means to improve oil recovery in unconventional reservoirs. But now only in Sulige gas field and Changqing oil field in our country has carried on the large-scale application. This shows that it takes a long time to explore the effective measures for reservoir characteristics of various oilfields in China before various difficult problems can be solved. In order to be more in line with the situation in China, it is necessary to proceed from the most fundamental aspects, such as the fracture formation mechanism and fracture morphology after volume fracturing, which can provide the basis for the establishment of productivity model. The influence of a series of parameters, such as horizontal wellbore length, section number, cluster spacing and fracture conductivity, on the fracturing effect should also be studied, which provides theoretical support for the field. At present, the main method of crack simulation is local mesh encryption. As a simple simulation method, this method has the advantage of simulating multiple cracks. In this paper, the main method of volume fracturing numerical simulation is local mesh encryption. An ideal model is established in the numerical simulation software to optimize the cluster spacing, number of clusters, number of segments and half length of fracture during volume fracturing. On the basis of previous studies, it is assumed that the fluid in the formation first flows into the fracture through the fracture wall, and then flows directly into the horizontal wellbore through the fracture. Therefore, the unsteady productivity model of tight gas reservoir after volume fracturing is established, in which the horizontal wellbore is regarded as a straight line source and the fracture is regarded as a strip source. According to the optimal selection scheme, the output obtained by the mathematical model is compared with the productivity calculated by the established formula, and the veracity of the model is tested.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE377

【参考文献】