Research On The Migration Law Of Diverting Agent In Hydraulic Fracturing

For different formation conditions,the hydraulic fracture shape may be horizontal or vertical.For vertical fracture,engineers usually pay close attention to the control of the fracture height extension.At present stage,the controlling fracture-height technology of diverting agent has developed to be a very important technical means in hydraulic fracturing.A comprehensive analysis of the existing research results shows that the research on the controlling fracture-height effect of the diverting agent mainly focuses on the stress shielding of the artificial barrier,but lacks the study of the transport process of the diverting agent in the fracture.The migration of the diverting agent in the fracture directly affects the formation of artificial barrier,and the stress shielding effect of the artificial barrier determines the effect of height control.Therefore,it is of important practical significance to study the migration law of the diverting agent.In this paper,the development and application of the controlling fracture-height technology at home and abroad were reviewed,and the working principle and basic functions of diverting agent were introduced,and the construction process of filling diverting agent into fracture in hydraulic fracturing was briefly described,and the mechanism of fracture-height control was expounded in detail from two aspects of linear elastic fracture mechanics and seepage mechanics.In order to analyze the migration law of the diverting agent,a three-dimensional model of the fracture was established,and a numerical simulation test of the diverting agent was carried out,in which the flow of diverting agent and fracturing fluid in fractures was simulated by using Fluent software.Then the migration characteristics of diverting agent particles were displayed,and the distribution of diverting agent in the upper and lower ends of crack was obtained.It was found that the construction parameters had a great influence on the migration of diverting agent,and the reasonable range of fracturing fluid viscosity,concentration,displacement,pumping time was obtained.In order to analyze the fracture-height controlling effect of the diverting agent,artificial cores and artificial fractures were made,and a indoor simulation experiment was carried out on the basis of the optimized parameters of numerical simulation.By comparing the increment of rupture pressure,the controlling fracture-height effect of diverting agent was quantitatively evaluated.The rationality of construction parameters was verified,and the concentration of diverting agent was further optimized.The test results show that the controlling fracture-height effect of diverting agent can be obtained by adopting reasonable construction parameters.In this paper,the controlling fracture-height technology of diverting agent were studied from two aspects of numerical simulation and laboratory experiment,which has certain guiding significance for actual fracture construction.