Research On The Compatibility Of Wax Inhibitor And Low Dosage Hydrate Inhibitor

In the oil and gas industry, hydrate and wax solid deposition in oil and gas pipeline is keys of flow assurance. In order to prevent hydrate formation, low dosage hydrate inhibitor (LDHI) has been more and more widely used. At the same time the wax inhibitors (WIs) are frequently injected to control wax precipitation in oil and gas pipeline. There are different kinds of oil-field chemicals in one system. Whether the chemical additives have the mutual influence is important. This article mainly aims at the compatibility between wax inhibitors and low dosage hydrate inhibitors.In this study, performance tests of three LDHIs were carried out for 67% CH4/33% CO2gas hydrate formation. Using the isothermal cooling method at pressures of 9MPa and temperatures of 4℃. Next, we evaluated the effect of wax inhibitor on the LDHI performance. At last, this paper deduced the interaction mechanism at the molecular level via the surface tension measurement.We found that the best dosage of HY-1、Inhibex501 and KL-1 are lwt%、3wt% and lwt%, the induction time for 33%CO2/67%CH4 is 11.94hr,7.32hr and 8.27hr, respectively.The concept of %Performance was defined to quantify the effect of WI on LDHI performance. The results showed that the WIs could reduce the performance of LDHI. WI had a significant influence on the performance of HY-1, causing the %Performance to lose over 45%. The %Performance of Inhibex501 increased with increasing concentration for WI, the WI brought the %Performance of Inhibex501 down over 15%. While BHFL-02 had a more negative impact on the %Performance of KL-1 than WJH-01.Comparing deviations of the surface tension of the WI alone and WI/LDHI, the result is that the interaction enhanced with the deviation decreased. WJH-01 and HY-1 formed surface-active polymer/surfactant complexes, had a more stronger interaction than WJH-01/Inhibex501. We can see that BHFL-02 and Inhibex501 had a strong interaction.