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.
Predicting Gas Migration Potential
Halliburton has developed a gas Flow Potential Factor (FPF) analysis that can help operators accurately predict the potential of gas migration into their wells. After calculating the FPF and determining the severity of the gas FPF, operators can decide which treatment to use to control gas migration in their wells
Three Levels of Gas Migration Severity
FPF ranges can be broken down into three levels of gas migration severity:
1.Minor gas migration potential •Halad® family of fluid loss additives
•Densified Cement slurries
2.Moderate gas migration potential •Latex 2000™ cement additive
•Latex 3000™ cement additive
•GasStop™ cement additive
•Thixotropic cements
3.Severe gas migration potential •Super CBL® cement additive
•Foam cement
GasChek® Cement Additive
GAS-CHEK cement additive was introduced to provide an effective means of helping prevent gas flow into the annulus after cement has been placed. Historically, the industry has been plagued with the problem of annular gas flow following completion of cementing jobs. Numerous corrective practices have been attempted in order to help prevent annular gas flow, but previously no completely reliable process had been found.
GAS-CHEK cement provides a new cementing technique for annular gas flow problems. GAS-CHEK cement does not have to be used in the entire cementing operation but should be used across all possible gas invasion zones.
GasStop™ Cement
Designed to perform effectively in wells with over pressured zones
With Tuned Cementing Solutions™ systems, Halliburton has created a set of innovative fit-for-purpose solutions with the flexibility required to allow each system to be tuned specifically for a given set of wellbore conditions. GasStop cements form one of these families of fit-for-purpose solutions.
With GasStop cements you receive a system that can be effectively foamed or used as a conventional cementing solution. GasStop cements are designed to perform effectively in wells with overpressured zones with the potential for fluid influx into the annulus through unset cement using specially tuned systems. These zones are typically gas bearing, but the GasStop technology works equally as well for water or plastic salt flow. GasStop cements typically work by gaining gel strength development rapidly, in-situ volume generation, and/or increased compressibility.
For more specifications:
http://www.halliburton.com/en-US/ps/cementing/cementing-solutions/gas-migration/default.page?node-id=hehp8oyk
Predicting Gas Migration Potential
Halliburton has developed a gas Flow Potential Factor (FPF) analysis that can help operators accurately predict the potential of gas migration into their wells. After calculating the FPF and determining the severity of the gas FPF, operators can decide which treatment to use to control gas migration in their wells
Three Levels of Gas Migration Severity
FPF ranges can be broken down into three levels of gas migration severity:
1.Minor gas migration potential •Halad® family of fluid loss additives
•Densified Cement slurries
2.Moderate gas migration potential •Latex 2000™ cement additive
•Latex 3000™ cement additive
•GasStop™ cement additive
•Thixotropic cements
3.Severe gas migration potential •Super CBL® cement additive
•Foam cement
GasChek® Cement Additive
GAS-CHEK cement additive was introduced to provide an effective means of helping prevent gas flow into the annulus after cement has been placed. Historically, the industry has been plagued with the problem of annular gas flow following completion of cementing jobs. Numerous corrective practices have been attempted in order to help prevent annular gas flow, but previously no completely reliable process had been found.
GAS-CHEK cement provides a new cementing technique for annular gas flow problems. GAS-CHEK cement does not have to be used in the entire cementing operation but should be used across all possible gas invasion zones.
GasStop™ Cement
Designed to perform effectively in wells with over pressured zones
With Tuned Cementing Solutions™ systems, Halliburton has created a set of innovative fit-for-purpose solutions with the flexibility required to allow each system to be tuned specifically for a given set of wellbore conditions. GasStop cements form one of these families of fit-for-purpose solutions.
With GasStop cements you receive a system that can be effectively foamed or used as a conventional cementing solution. GasStop cements are designed to perform effectively in wells with overpressured zones with the potential for fluid influx into the annulus through unset cement using specially tuned systems. These zones are typically gas bearing, but the GasStop technology works equally as well for water or plastic salt flow. GasStop cements typically work by gaining gel strength development rapidly, in-situ volume generation, and/or increased compressibility.
For more specifications:
http://www.halliburton.com/en-US/ps/cementing/cementing-solutions/gas-migration/default.page?node-id=hehp8oyk
