Experimental Determination of Permissible Drawdown for Gas Field Wells on a True Triaxial Loading Unit

Abstract

One of the typical complications arising during the operation of wells in formations formed by weakly cemented rocks is sand production, when the sand from the reservoir enters the well together with the fluid. To study this issue, it is necessary to conduct experimental modeling of conditions in specific wells. This work is devoted to this method of studying the sand problem in gas fields. A unique research installation triaxial independent loading test system developed in IPMech RAS—TILTS—was used for experimental modeling of gas field bottom-hole zone. Nine specimens were made from core material of real gas field. Samples were used for physical modeling of the bottomhole formation zone. As a result of the studies, a significant anisotropy of strength properties of the studied rocks has been revealed. Due to anisotropy of strength properties, rock destruction along the contour of the well will be uneven—it will begin at the points corresponding to the upper and lower points of the contour of the horizontal well in the formation, and then will continue in this direction, forming a characteristic borehole collapse. Also, from the above data, we can conclude that the maximum pressure draw-down that can be safely given in the wells in the considered field should not be more than 0.5 MPa. Also, during all tests there was observed a decrease in permeability of samples, nevertheless final permeability remained big enough for effective operation of wells.