the relationship is derived where the inflation pressure under the element equals the formation pressure below the element times the ratio of the areas of for example surface 90 divided by surface 84 in the event of an increase in pressure from the formation the annulus pressure above the inflated element and outside of the compensating device c remains the same however the increase in the formation pressure is communicated through port 138 onto the balancing piston 96 since the pressure above the balancing piston 96 is increasing while the outer annulus pressure remains constant there is a net downward force on balancing piston 96 this is communicated through spacer 88 to the compensating piston 70 at the same time the rising formation pressure tends to increase the inflate pressure which presents an offsetting force in annular space 82 acting on surface 84 thus because the formation pressure increases and such pressure is communicated to above the balancing piston 96 any tendency to increase the inflate pressure due to a rise in formation pressure creates an offsetting uphole force on compensating piston 70 the increased inflate pressure acts on surface 84 thus offsetting the downhole increased force applied by a pressure increase from the formation acting in annular space 148 on the balancing piston 96 since.