Preparation Of Sulphonic Acid Nano Scale Inhibitor And Its Migration In The Reservoir

Scaling is a common phenomenon in natural environment.Deposited scale particles will lead to serious threats to the safety and integrity of various industries particularly oilfield productions.The most commonly adopted engineering approach to control scale threat is chemical inhibition by applying scale inhibitor chemicals.However,conventional scale inhibitors cannot effectively enter the formation and remain in place.In order to solve this problem,quite a few studies have reported the laboratory synthesis and testing of scale inhibitor colloidal materials composed mainly of met al-aminophosphonate solids.But few researches has been conducted on the preparation of polymeric inhibitor based colloidal materials.In this study,Ba-PSS nanoparticles scale inhibitor was prepared by ultrasonic dispersion method and surfactant surface modification method using polyphenylene sulfonic acid（PSS）and barium chloride（Ba Cl₂）without phosphorus.The optimum synthesis conditions,scale inhibition performance,scale inhibition mechanism,dispersion performance,migration performance and reflux performance of Ba-PSS were studied.The main results were as follows:（1）The optimal synthesis ratio of Ba-PSS nano scale inhibitor was Ba Cl₂:PSS=2:1,the concentration of sodium dodecylbenzene sulfonate（SDBS）was0.2%,the concentration of potassium chloride was 0.2%.The optimal ultrasonic dispersion time was 10 min.The prepared Ba-PSS material possessed a particle size of 230 nm and the Zeta potential of-63 m V.（2）The ratio of Ba element to PSS monomer in Ba PSS scale inhibitor was 1:2.During the synthesis,Ba²⁺interacted with the sulfonic acid group of PSS to form Ba-O bond.The skeleton structure of PSS was not damaged during the preparation process of Ba-PSS,and it had high thermal stability below 400℃.The solubility of Ba-PSS increased with the higher temperature,and the static solubility can reach 64 mg at 70℃,which could fully dissolve and play the role of scale inhibition.（3）Ba-PSS had the same scale inhibition performance to calcium carbonate,calcium phosphate and barium sulfate scale as PSS under the same concentration of scale inhibitor.The scale inhibition efficiency was 53%for calcium carbonate scale,92%for calcium phosphate scale and 88%for barium sulfate scale.The scale inhibition performance decreased with the increase of Ca²⁺concentration.（4）The migration test results showed that the migration performance of Ba PSS was better than that of PSS and traditional phosphorus scale inhibitor after SDBS pre washing.The migration capacity of the Ba-PSS can be enhanced with SDBS surfactant preflush.Under the conditions of SDBS pre-washing,temperature of 20℃,linear flow rate of 5.5 m/d and packing particle size of 100～150μm,Ba-PSS had the best mobility and breakthrough efficiency of 74.6%.The mobility of scale inhibitor decreased with increasing temperature and flow rate.（5）Scale inhibitor reflux experiment indicated that Ba-PSS can return PSS inhibitor in a much more gradual manner with a significantly reduced inhibitor return mass in the early stage of reflux experiment,compared with PSS inhibitor.As a result,the squeeze lifetime of Ba-PSS was over 40 times longer than that of PSS,which can be characterized by the calculated NSL and SPD values.