Study On Reflux Mechanism Of Fiber Control Proppant

Staged fracturing in horizontal well, with its outstanding advantage, has become the most effective way to develop reservoir that with both low permeability and porosity. However, beacause of its great scale and long clean-up hours, with the addition of high flow rate, proppant inclines to flowback during the period of fluid clean-up and gas production. Plenty of literatures prove that flowback of proppant is one of the most important issue that influence the fracturing effect, which is common in gas field like West of Chuanxi, Sulige, Xinjiang and Daqing. To solve this problem, techniques including resin proppant and fiber come into being. Meantime, with its flexible application, fiber has been the main control means which is most widely uesd now. But on account of the lack of in-depth study on fiber, selection of it on field is empirical. Such problems trigger the motivation of this research.Based on the problems above, combining mathematical modeling with experiment evaluation, this paper has carried out following study:(1) Amendment of mathematical model which is used for predicting proppant’s backflow lays foundation for study on techniques of controling principle;(2) Establishment of mathematical model of fiber’s influence, both from shear and extension strength, supplies basement of study on mechanics of fiber;(3) Experiment evaluation of fiber’s dispersing, suspending proppant performance and its influence on conductivity, providing basis for further optimization of fiber;(4) Given the results of experiment and mathematical model, forming suggestion for parameters optimization;(5) Offering guidance for field application and finally evaluating for its field effect.According to above research, breakthroughs obtained as follows:(1) The calculation results of the mathematical model established in this paper show that proppant pack could be stable when the fracture is wide for the strength of pack can withstand partial fluid’s pressure drop, which differs with the opinion of former scholars;(2) The mechanics model of fiber established in this paper can achieve optimization of related parameters, so as to solve empirical selection of fiber in field;(3) Utilizing experiment to verify the accuracy of models established in this paper, while the phenomenon aquired from visualised fracture device demonstrate that short fiber can attribute to conductivity and long fiber has remarkable suspending and stablizing ability.