The innovative Gas Migration Control Engineering Suite provides reliable, cost-effective well-cementing solutions. The software advisor, products, and services that comprise the suite enable evaluating gas migration severity risks and recommending tailored, optimized solutions based on gas migration severity and bottomhole circulating temperatures.
Gas migration is defined as gas entry into a cemented annulus creating channels with the potential to provide a flow path of formation fluids, including hydrocarbons, into the wellbore. This can cause gas/fluid flow in the annulus and can usually be detected by cement bond logs and/or by noticing unwanted pressures. Hydrostatic pressure loss before the cement slurry has achieved sufficient static gel strength to resist gas flow which can contribute to gas migration. When the hydrostatic pressure exerted by a cement slurry column maintains an overbalance of pressure on the gas-bearing zones in the formation, gas is prevented from percolating or channeling through the fluid column. However, the slurry has to be specifically designed to retain and transmit an overbalance of pressure when static gel strength is developing. This can be achieved in different ways such as with fluid loss additives that reduce slurry volume losses and with gel strength modifiers that can shorten transition time (the time it takes for a cement slurry to change from a fluid to a solid state). It is during the transition time, static gel strength is developed and the column must be able to transmit sufficient hydrostatic pressure on the formation. Halliburton has developed several slurry additives and cements that help reduce or control gas flow. TPE has developed an optimum way for hero perators to control gas migration in their wells.