Study On Influencing Mechanism Of Hydraulic Fracturing Fluids Imbibition On Production In Tight Reservoir

Tight reserve is an important part of unconventional resource,due to the special properties of formation,it only can be effectively and economically developed with horizontal well and massive hydraulic fracturing technology.At the same time,high capillary will exist and then exert a significant effect on tight formation development because of the small pore throat radius.Therefore,analyzing the influencing factors of hydraulic fracturing fluids imbibition is of great importance to forecast formation productivity and make effective development plan.Firstly,this paper selects Xinjiang tight sandstone cores as research objectives to conduct static state hydraulic fracturing fluids imbibition experiments,and mass method and volume method are chosen to study the imbibition characteristics of dry cores and oil-saturated cores respectively,and effect of influence factors on imbibition rate and recovery are analyzed.Then grey relational analysis method is introduced to study the influencing extent of factors,and hydraulic fracturing fluids counts most for imbibition recovery.Secondly,basing on experiment results,numerical simulation method is applied to conduct experiments inversion to verify the accuracy of parameters setting and feasibility of simulation method,and then according to the matching model,factors and rules,which affect the imbibition process are studied.At last,field-scale tight gas reservoir model are established to analyze the effect of capillary pressure,hydraulic fracturing fluids viscosity and shut-in time on the saturation distribution,gas production and flowback rate,and it is concluded that relatively high gas daily production can be acquired by prolonging shut-in time,but with a low flowback rate.Besides,gas production can be forecasted by studying properties of formation and hydraulic fracturing fluids.This paper comprehensively analyzes the influencing factors and rules of hydraulic fracturing fluids imbibition with experimental method and numerical simulation method,which has a significant meaning for productivity forecasting and development plan making of tight gas reservoir.