微支撑剂运移及其沉降规律研究

Research on Micro-Proppant Transportation and Its Settling Law

摘要: 针对页岩以及致密油气储层进行水力压裂后，形成的微细裂缝难以得到有效支撑，造成压裂后增产效果不明显且产量下降速度过快的问题，提出使用微支撑剂对微细裂缝进行支撑。通常在致密油气与页岩油气的开发中不需要较高的裂缝导流能力，小粒径的微支撑剂即可满足导流要求。同时，小粒径微支撑剂成本较低且容易获取，能够达成经济开发的目的，并且由于微支撑剂粒径小，在滑溜水中分散开时可以表现出一定的悬浮性，在支撑裂缝时受到支撑剂沉降的影响较小，不易出现由于支撑剂提前沉降导致的支撑剂铺置效果不理想或铺置距离较短的问题，为此开展了微支撑剂在压裂液中的沉降性能评价。结论指出：微支撑剂与常规支撑剂相似，随着压裂液粘度的增大，微支撑剂的沉降速率会明显变慢；在相同粘度下，随着砂浓度的增大，主缝与分支缝的铺置高度与铺置面积都有所增大。

Abstract: Aiming at the problem that the microfractures formed after hydraulic fracturing of shale and tight oil and gas reservoirs are difficult to effectively support, resulting in the ineffective increase of production after fracturing and the rapid decline of production, it is proposed to use micro-proppant to support the microfractures. Usually, in the development of tight oil and gas and shale oil and gas, high fracture inflow capacity is not required, and small particle size micro-proppant can meet the inflow requirements. At the same time, small particle size micro-proppant cost is low and easy to obtain. It can achieve the purpose of economic development. Due to the small particle size of micro-proppant, when dispersed in the slick water can show a certain degree of suspension. When supporting the fracture, the settling of micro-proppant has less influence. It is not easy to encounter problems such as poor proppant placement effect or short placement distance caused by premature settling of the proppants. For this reason, the evaluation of the settlement performance of micro-proppant in fracturing fluid was carried out. It was concluded that, similar to conventional proppant, the settling rate of micro-proppant would be obviously slowed down with the increase of the viscosity of fracturing fluid; under the same viscosity, with the increase of sand concentration, the laying height and laying area of the main and branch seams were increased.