压裂用支撑剂相关改性技术研究

发布时间：2018-01-29 04:19

本文关键词： 水力压裂支撑剂陶粒石英砂树脂改性技术　出处：《北京科技大学》2017年博士论文　论文类型：学位论文

【摘要】：随着全球非常规油气开发日渐风靡,水力压裂技术由于成本低廉、易实施且增产显著,逐渐发展成为难以取代的主流压裂手段。为应对新压裂环境的挑战,达到绿色环保、高效、低成本的目标,压裂液中含量约占9.5%的支撑剂组分的改性研发,获得越来越多的关注。常用支撑剂主要有原砂、陶粒和树脂覆砂。近年来,为提高油气开采率,并针对不同油气储层的条件,新型支撑剂如超高强、超轻、新型包覆改性类、自悬浮、棒状等进入人们的视野。我国非常规油气资源丰富,但低渗透、低压、低丰度的储层特点对压裂技术提出新挑战。本文首先调研了传统支撑剂到新型支撑剂的发展史,系统总结、分析了各类支撑剂的优缺点,预测未来支撑剂将向小尺寸、多功能、高性能、智能化,四个大方向发展。基于此,本文围绕化学改性、结构改性、物理改性三大方面分别对支撑剂进行疏水功能改性及pH响应智能改性、多形状设计、物理混纤等研究。支撑剂表面化学改性是本论文研究重点之一。通过化学改性,改变支撑剂表面亲疏水性能,可以调控油水的流通性质,从而有效提高油气开采量。第一部分选用不同尺寸的砂子、陶粒常规支撑剂,以及纳米硅、碳纳米管等小尺寸颗粒,分别通过小分子自组装法、疏水树脂润湿法及树脂包覆法进行疏水功能改性。通过接触角测试、毛细管法、傅里叶红外光谱测试、扫描电镜及能谱分析、原子力显微镜测试、热失重测试、渗流测试等对产品进行表征,进一步从微观化学、微观结构、微观力学等方面对不同改性方法进行理论研究并分析影响因素,得到颗粒尺寸越大,表面规整度越好,树脂润湿改性效果越好;支撑剂表面活性越高,改性效果越好。第二部分围绕化学智能改性展开,通过原子转移自由基聚合法(ATRP)制得疏水型、pH响应型智能支撑剂。改性过程中经聚合、水解等步骤,可控制支撑剂由亲水到疏水再到亲水的性能转变。围绕结构改性研究,提出四腿形、八腿形和空心型等新型支撑剂的设计,以增加堆积孔隙率,增大运移距离。分别使用Monte Carlo法和EDEM法对设计的新型支撑剂与传统球形支撑剂做孔隙度测试模拟,得到支腿数目越多,支腿越长,孔隙率越大的结论。使用3D打印机制作新型支撑剂,通过水流通实验,对模拟结果进行验证。选择综合性能最好的四腿(长)形支撑剂,通过动态运移模拟与传统球形进行对比,运移距离明显增大。在运移过程中,新型支撑剂可以翻滚前进,提高输送效率,支腿间交叉堆积可以有效控制回流。在物理改性研究方面,使用可降解聚乳酸纤维,对支撑剂进行混纤实验研究。支撑剂混纤可以有效降低垂直沉降速度,增加运移距离。通过热稳定性、沉降性测试等系列实验对纤维的尺寸、添加量等因素进行选择,再通过携砂与返排实验等研究,确认聚乳酸纤维可以有效增加压裂液携砂能力,降低支撑剂返排量,提高压裂液返排速度。
[Abstract]:With the popularity of unconventional oil and gas development in the world, hydraulic fracturing technology has become a mainstream fracturing method which is difficult to replace because of its low cost, easy to implement and significant increase in production, in order to meet the challenge of new fracturing environment. To achieve the goal of green environmental protection, high efficiency, low cost, fracturing fluid content of about 9.5% percent of the proppant component modification research and development, more and more attention. Commonly used proppant mainly raw sand. In recent years, in order to improve the oil and gas recovery rate, and according to the conditions of different oil and gas reservoirs, new proppant such as super high strength, super light, new coating modified class, self-suspension. Our country is rich in unconventional oil and gas resources, but has low permeability and low pressure. The characteristics of low abundance reservoirs pose a new challenge to fracturing technology. Firstly, the history of traditional proppant to new proppant is investigated, and the advantages and disadvantages of each proppant are analyzed systematically. It is predicted that the future proppant will be developed in the direction of small size, multi-function, high performance, intelligence and four major directions. Based on this, this paper focuses on chemical modification and structural modification. Three major aspects of physical modification were hydrophobic modification of proppant and intelligent modification of pH response, multi-shape design. Chemical modification of proppant surface is one of the key points in this paper. Through chemical modification, the hydrophobic property of proppant surface can be changed to regulate the flow of oil and water. In the first part, sand of different sizes, conventional proppant of ceramsite, and small size particles such as nano-silicon and carbon nanotubes were selected respectively through small molecular self-assembly method. Hydrophobic resin wetting method and resin coating method were used to modify hydrophobic function. Contact angle test, capillary method, Fourier transform infrared spectroscopy, scanning electron microscope and energy spectrum analysis, atomic force microscope, thermogravimetric test were used. The percolation test was used to characterize the product. Further, different modification methods were studied theoretically from the aspects of microchemistry, microstructure and micromechanics, and the influencing factors were analyzed. The larger the particle size was, the bigger the particle size was. The better the surface regularity, the better the effect of resin wetting modification; The higher the surface activity of the proppant, the better the modification effect. The second part is about the chemical intelligent modification, the hydrophobic type is prepared by atom transfer radical polymerization (ATRP). Ph responsive intelligent proppant. Through polymerization, hydrolysis and other steps in the process of modification, the properties of proppant from hydrophilic to hydrophobic and then to hydrophilic can be controlled. The design of new proppant, such as octahedron and hollow type, to increase the accumulation porosity. Monte Carlo method and EDEM method were used to simulate the porosity of the new proppant and the traditional spherical proppant. The more the number of legs was, the longer the leg was. The new proppant was made by 3D printer, and the simulation results were verified by the water flow experiment. The four-legged (long) proppant with the best comprehensive performance was selected. Compared with the traditional sphere, the dynamic migration simulation results in the obvious increase of the migration distance. In the process of migration, the new proppant can roll forward and improve the transport efficiency. The cross stacking between the legs can effectively control the reflux. In the physical modification research, the use of degradable polylactic acid fiber for the experimental study of the proppant. The proppant blend can effectively reduce the vertical sedimentation rate. Through a series of experiments, such as thermal stability, sedimentation test and so on, to select the fiber size, adding amount and other factors, and then through the sand carrying and back discharge experiments. It is confirmed that polylactic acid fiber can effectively increase the sand carrying capacity of fracturing fluid, reduce the amount of proppant backflow, and increase the rate of back discharge of fracturing fluid.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TE357.12

【引证文献】