压裂返排优化理论与应用技术研究

发布时间：2018-06-19 00:21

本文选题：压裂支撑剂回流 + 闭合模型　；参考：《西安石油大学》2015年硕士论文

【摘要】：对于低渗致密储层,压裂液强制返排技术是压裂施工结束后的常用技术。其中,裂缝闭合时间和位移的长短、支撑剂是否发生回流、是该技术成功与否的关键因素,影响着油井的正常生产和压裂的效果,直接决定着压裂液的返排率。裂缝闭合时间和位移的长短,将直接影响到压裂后裂缝的导流能力。为计算裂缝闭合时间和位移,从以下3方面开展研究:1)为更好模拟压裂液在裂缝闭合过程中的滤失情况,在考虑压裂液二维滤失的基础上,利用物质平衡方程建立裂缝强制闭合过程中的压裂液滤失模型;2)利用物质平衡原理和流体力学等相关知识,建立气井压后裂缝强制闭合模型,得到了水力压裂后在不同放喷油嘴尺寸下,井口压力随时间的变化趋势,计算出裂缝闭合时间和位移;3)分析裂缝闭合时间和位移的影响因素。针对支撑剂回流机理研究,详细分析了支撑剂运移回流的物理过程。支撑剂是否发生回流主要取决于返排的压裂液是否有足够的速度将最后一段单颗粒支撑剂起动以及放喷油嘴的大小对支撑剂回流的影响两个方面。通过对注入的最后一段支撑剂中的单颗粒支撑剂的受力分析,建立支撑剂回流的运动模型和起动模型。根据压裂液返排的特殊物理过程,建立裂缝强制闭合后油水平面二维两相流模型,进行数值差分求解得到裂缝闭合后的返排量,并结合裂缝强制闭合,即裂缝闭合之前,计算的返排量,求解出压裂液返排率并分析其影响因素。在理论模型的研究基础之上,开发压裂液返排率优化软件并进行实例计算。
[Abstract]:For low permeability and tight reservoirs, the forced return of fracturing fluid is a common technique after the end of the fracturing construction. In which the length of the fracture closure and the length of the displacement and the reflux of the proppant are the key factors for the success of the technology, it affects the normal production and fracturing effect of the oil well, and directly determines the return rate of the fracturing fluid. The fracture is closed. The length of time and displacement will directly affect the conductivity of the fracture after fracturing. In order to calculate the closing time and displacement of the fracture, the study is carried out from the following 3 aspects: 1) to better simulate the loss of the fracturing fluid during the fracture closure process. On the basis of considering the two-dimensional filtration of the fracturing fluid, the material balance equation is used to establish the forced closure of the fracture. The fracturing fluid filtration model in the process of fracturing; 2) by using the knowledge of the principle of material balance and the related knowledge of fluid mechanics, the forced closure model of the fracture of the gas well is established, and the change trend of the wellhead pressure with the time is obtained after the hydraulic fracturing, and the closing time and displacement of the crack are calculated, and 3) the fracture closure time and position are analyzed. In view of the backflow mechanism of the proppant, the physical process of the reflux of the proppant is analyzed in detail. Whether the backflow of the proppant is reflux depends mainly on the two aspects of the effect of the flow rate of the fracturing fluid on the back row, the starting of the last single particle proppant and the effect of the large small nozzle on the reflux of the proppant. After the force analysis of the single proppant in the last part of the proppant injected, the motion model and the starting model of the reflux of the proppant are established. According to the special physical process of the fracturing fluid reflux, the two-dimensional two-phase flow model of the oil horizontal surface after the forced closure of the fracture is established, and the numerical difference solution is used to obtain the back displacement after the fracture closure. Crack forced closure, that is, before the crack closure, the calculation of the return displacement, solved the return rate of fracturing fluid and analyzed its influencing factors. On the basis of the theoretical model, we developed the optimization software for the return rate of fracturing fluid and carried out an example calculation.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.12

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