Effect of ZnCl2 on the performance of antiscaling nanoparticles for long-lasting extrusion injection

In order to improve the scaling phenomenon caused by the produced water during oil and gas extraction, nanoparticles with anti-scaling effect have been developed. But the retention time of such nanoparticles in the formation has become a difficult problem to be solved. In this paper, two types of anti-scaling nanoparticles, EDTMPS-Na/CaCl2 and EDTMPS-Na/CaCl2/ZnCl2 were prepared by precipitation method. These anti-scaling nanoparticles ccould achieve long-lasting anti-scaling by releasing the effective anti-scaling components through the mechanism of “precipitation and re-dissolution”. Charectic experiments included infrared spectroscopy, EDX spectroscopy, thermogravimetric analysis and XRD were conducted to investigate their basic properties. Meanwhile, in order to test their retention and adsorption performance in the reservoir as well as their anti-scaling
ability, static adsorption and desorption experiments and dynamic squeeze injection experiments in sand-filled tubes simulating the actual conditions of the reservoir were carried out. The experimental results showed that the nanoparticles containing ZnCl2 have a tendency to crystallize, with lower solubility, enhanced adsorption and reduced weight loss. In the static adsorption test, the nanoparticles with ZnCl2 released active ingredients more slowly. In the dynamic experiment, the retention rate in the sand-filled tube increased, the retention time was extended, and the concentration of the active ingredient in the reflux solution could inhibit large-scale scaling. Compared with the nanoparticles without ZnCl2, the nanoparticles containing ZnCl2 had better long-term reflux performance and effectively reduced the number of dosing.
 

Yizhuo Ge, is a Ph.D. student at Petroleum Engineering College, China University of Petroleum- East China, with main research interests in oil and gas fieldapplied chemistry and drilling engineering. She works with professor Weian Huang who majors in modern drilling fluid technology.