Research into phase transformations in reservoir systems models in the presence of thermodynamic hydrate formation inhibitors of high concentration

Abstract

Gas hydrates have been and still remain a difficult problem in the oil and gas industry, solution of which requires considerable efforts and resources. In this work, the mechanism of phase transformations at negative temperatures in the formation of the solid phase is preliminarily studied using the reservoir system models consisting of a gas mixture and a solution of gas hydrate formation inhibitor of thermodynamic action with high concentration in distilled water. A system of three-dimensional lighting and image magnification is used to visually detect phase boundaries by creating optical effects. Thus, in the system “inhibitor solution – gas hydrate – gas” in the process of gas hydrate recrystallization in the conditions close to equilibrium, microzones of supercooled water may occur, which in the absence of gas molecules access is crystallized into ice. The result of such solid phase structure formation is its increased stability in nonequilibrium conditions for a relatively long period of time.

Development of methods of operative determination of parameters of repeated hydrate formation in layer systems of gas hydrate deposits

“…Therefore, in the case of the presence of these inhibitors in reservoir systems, the difference of the proposed method lies in the shift of the maximum mixture heating temperature in the process of dissociation to a lower one. However, the possibility of the simultaneous existence of ice crystals together with hydrate in this system under appropriate thermobaric conditions is not ruled out [22]. Therefore, at any inhibitor concentration in the solution, the maximum mixture heating temperature at the stage of gas hydrate dissociation should be above 0 °C.…”