Construction Of Proppant Functionalized With Microelements And Its Application In Fracture Monitoring

Fracturing technology is one of the core technologies for reservoir stimulation at present.Fracturing monitoring is the key content to evaluate the effect of fracturing construction and coordinate the adjustment of construction plan.Because fractures without proppant support will close quickly after the completion of the operation,only the fracture with proppant support is the main fluid channel during the oil and gas migration process.Therefore,the accurate position of proppant is the core of fracture monitoring.Tracer functionalized proppants provide an effective technical means for the indication of proppant position in fractures.However,at present,the research in this field is still in the beginning and trial stage,and there are some shortcomings such as small quantity,large dosage,low sensitivity and high environmental toxicity of tracer,which is not conducive to the practical application and promotion of well site.Because trace substance tracers have the advantages of high detection sensitivity,non-toxicity and variety,this paper will build a kind of trace substance tracer functionalized proppant in order to solve the above problems.The main research contents are as follows:Three kinds of representative trace substance tracers were successfully prepared by wet chemical method and embedded in the traditional proppant-quartz sand,A new type of trace substance tracer functionalized proppant was constructed.The main control parameters in the synthesis of functional proppant were optimized in detail,including the mixing ratio of quartz sand and polymer solution,polymer concentration,solvent type,heat treatment temperature and heat treatment time,etc.,so as to obtain the optimal conditions for the synthesis of functional proppant with trace material tracers.The key physical properties of the functionalization proppant and traditional proppant quartz sand,such as burning acid solubility,turbidity,apparent density,volume density,sphericity and conductivity,were further compared.Compatibility between the functionalized proppant and the Guar gum fracturing fluid commonly used on the well site was investigated.In order to realize the controllable release of tracer in practical application,the tracer was investigated in detail under different control conditions(Na Cl concentration0.1% ～ 10%;10 ～ 75 ℃).The results showed that the release of tracer slowed down with the increase of salt content in the solution,and accelerated with the increase of ambient temperature.Three common release kinetics models were used to fit the release kinetics curves of tracers,and the release kinetics of tracers under salinity and temperature control were summarized.Based on this,a set of experimental simulation system was designed to monitor the tracer flowback curve.The tracer release from the proppant was controlled by salinity.The influence of proppant position and flow rate on the tracer flowback curve was explored,and a method to estimate the proppant position based on the tracer flowback curve was established.