Preparation And Performance Evaluation Of Self-suspending Proppants

Self-suspended proppant is a new type of fracturing proppant that can reach the suspended state in the water.The self-suspending proppant can be distributed evenly in the crack to improve the effective contact area of the crack without the need of super-adjuvant,with out configurating fracturing fluid in the field,reducing the cost of equivalent per barrel oil and gas,it is with a certain application prospect and promotional value.In this paper,based on the theory of organic chemistry and polymer reaction,the mathematic model of sedimentation mechanics in the fluid,based on the law of single agent,the mechanism of self-suspension proppant was studied by the method of suspension proppant coating and the coating process and make the performance evaluation of the SSP.The evaluation criteria and physical and chemical properties of self-suspended proppant were established.The self-suspension support was obtained by using physical simulation machine.In this paper,a method of connecting organic polymer and inorganic proppant through a covalent bond is proposed.Methacryloyloxytitrisilane(KH570),γ-vinyltrimethoxysilane(A171),vinyltris(b-methoxyethoxy)silane(A172),vinyltris Ethoxysilane(A151)four silane coupling agents to modify the surface of the proppant.By means of infrared spectroscopy,wetting angle determination,element content determination and thermogravimetric analysis,four kinds of characterization methods show that the coupling agent and the proppant surface have been chemically bonded.The preparation method of self-suspension proppant was studied.The viscoelastic self-suspending proppant was successfully prepared by aqueous solution polymerization method based on polymer resin synthesis and swelling.The microstructure,sedimentation performance,potential analysis,viscoelasticity The suspension mechanism of viscoelastic self-suspending proppant in clean water was analyzed preliminarily.The sedimentation experiment shows that there is a weak positive correlation between the particle size sorting and settling time of the viscoelastic self-suspended proppant,and the settling performance is better than that of the conventional proppant in the gelatinous fracturing fluid,which is positively correlated with the polymer coating thickness,The viscoelasticity test showed that the solution of the polymer layer was in accordance with the power-law fluid model,which had viscoelasticity,and the drag force of elasticity was increased to promote the dominant factor of suspension.The expansion of the self-suspended proppant was successfully prepared by the four-component aqueous solution polymerization in P(AA-AM-AMPS-BIS).The monomer content ratio was optimized.The optimum reaction conditions were as follows: m(proppant): m(AM): m(AA): m(BIS).The optimum reaction conditions were as follows: m(proppant): m(AM): m(AA)): M(AMPS)= 620: 48: 41: 3: 8,the coupling agent concentration was 1%,and the initiator concentration was 1 ‰.The factors influencing the expansion performance were analyzed by DPS statistical software.The main influencing factors were acrylic acid content,the secondary influencing factors were the amount of coupling agent,and the salt content increased with the increase of salinity.The expansion of the self-suspended proppant was evaluated by the basic properties,microstructure,thermal stability,application performance and migration performance.It was found that the expanded self-suspended proppant could be expanded by 1.5-5 times with a bulk density of about 1.24 g / cm3,complete expansion time of 90 s,proppant coating rate of about 4%.The effect of cation was more serious,and the order of influence was Mg2+> Ca2+> K+> Na+.,the suspension support broken glue is not complete at 90℃,resulting in the laying of the permeability of less than conventional ceramic.After breaking the oil phase,the conductivity of the oil phase is slightly higher than that of the water phase.Based on the law of settling and migration of proppant,the mechanism of the expansion of the self-suspended proppant in the cracks was proposed.The effective density of the proppant after water was reduced,the settling velocity was reduced,and the fracturing fluid The ability to significantly improve the efficiency of the crack in the depth of the proppant;at the same time from the use of suspended proppant will form wedge cracks,affecting the fracture conductivity and oil production capacity.