Syntehesis Ofdi-hydro Sulfate Betaine And Study On Its Application In Aphron Drilling Fluids

At present,reports about the synthesis of gemini surfactants are not rare both at home and abroad.However,there is no report about the synthesis and properties investigation about zwitterionic gemini surfactants comprising double hydroxy,double sulfo groups and double quaternary ammonium salt.Recently,due to the characteristics of low density,recirculated,high viscosity-shearing,no need for special equipments and low cost,recirculated aphrons-based drilling fluids are used to protect the "three low" reservoir and low pressure,leakage formation.Combined the new achievements of gemini surfactant development with the new technologies of drilling fluids investigation,a new type of zwitterionic gemini surfactants,DBAs-n,comprising double hydroxy,double sulfo groups and double quaternary ammonium salt were designed and prepared in this paper,and their surface activities and other related properties were evaluated.The forming conditions and rheology character of DBA_2-12 and NaSal?sodium salicylate?wormlike micelle system were also discussed.A recirculated aphrons-based drilling fluids were designed using DBA_2-12 as the foaming agent and their rheology and application properties were evaluated in the lab.This paper gained the following achievements:?1?A novel di-hydroxyl-sulfate-betaine-type zwitterionic gemini surfactants,DBAs-n,were synthesized with three hydrocarbylation of amine using self-made 3-chloro-2-hydroxy-propanesulfonate,primary amine,dibromoethane,dibromobutane,dibromohexane,bromoethane,etc.,as the raw materials.The synthesis conditions of 3-chloro-2-hydroxy-propanesulfonate,primary intermediate products BAn and final productsDBAs-n were optimized.The molecular structure of intermediate products and final products were confirmed by infrared spectroscope and 1H NMR.?2?The surface activity and other properties of the final products were systematic studied,?The evaluation results showed that except for the products with n=8,thecmc values of DBAs-n were all among 10-4?10-5 mol/L and the ?cmc values were as low as 22.2 mN/m,indicating that this type of gemini surfactants have excellent surface activity.The effects of hydrophobic carbon atom number and spacer carbon atom number on the surface activity were discussed.? The ability of DBA_2-12 to change the wetting property of common glass was larger than that of DTAB and SDS.Under the same concentration,DBA_2-12 had the stronger ability to increase the contact angle of hydrophilic surface than SDS,but weaker than DTAB.The ability of DBA_2-12 to change the hydrophilic surface to hydrophobic surface was larger than that of DTAB and SDS.?The foam ability and the foam stabilization of DBA2-n was both larger than those of SDBS and DTAB.When the n was between 12?16,the V0 and,t1/2 of DBA2-ndecreased with increasing n.?The aggregation of series DBA2-n surfactants in aqueous was studied by combing dynamic light scattering and transmission electron microscope.When n increased from 12 to 14?16 and 18,the aggregation in aqueous changed from vesicles to fiber-like network structures.?Through intermolecular electrostatic interactions and hydrogen bond,NaSal leads to the growth and formation of the wormlike micelles.When[NaSal]/[DBA_2-12]=0.8,the zero-shear viscosity of the system was 10000 times of that without NaSal.The rheology behavior of this system fitted the Maxwell model among a quite wide frequency.?3?A aphrons-based drilling fluids were designed using DBA_2-12 as the foaming agent and their structure,rheology and application properties were investigated.? The micro-bubble drilling fluids based on DBA_2-12 had low filtration,and the half-life at room temperature was 4 d,even after rolling for 16 h.The system had good salt and calcium resistance.It also had good compatibility with shale hydration inhibitor K+,formation fluid and crude oil.The core damage rate was 37.83%,which was only half of that of common water-based drilling fluids.The damage only exited on the surface of the sidewall with little damage to the deep part.Silicone oil antifoaming agent GX-1 can effectively defoam the micro-bubble drilling fluids.?The particle size of micro-bubble system was analysized combing micro-image technology and Nano Measurer 1.2 software,and the effect of system composition and preparation condition on the size,size distribution and stability of the micro-bubble system was also discussed.? The rheology of micro-bubble system based on DBA_2-12 was investigated,and the effect of foam quality,temperature and pressure on the rheological parameters was also studies.The equations of consistency index K and flow pattern n with the temperature were established.