Process and system for effective and accurate foam cement generation and placement

An apparatus for foaming cement used in cementing a casing in a wellbore, the casing and the wellbore defining an outer annulus therebetween, the apparatus comprising:

• a tubing lowered into the casing, wherein the tubing and the casing define an inner annulus therebetween;
• and
• a ported sub connected in the tubing;
• wherein a gas injected into the casing through the ported sub foams cement being displaced downwardly through the inner annulus, and the foam cement fills at least a portion of the outer annulus to cement the casing in the wellbore.

A method of cementing casing in a wellbore, the method comprising the steps of:

• lowering a tubing in the casing;
• displacing cement downwardly in an inner annulus between the casing and the tubing and out into an outer annulus between the casing and the wellbore;
• and
• foaming the cement in the annulus between the tubing and the casing.

A method of foaming a cement used in cementing a casing in a wellbore, the method comprising the steps of:

• lowering a plurality of nozzles into the casing on a tubing;
• displacing the cement downwardly through the casing past the plurality of nozzles;
• pumping a gas through the nozzles into the cement in an annulus between the tubing and the casing as the cement passes the nozzles to foam the cement;
• and
• placing the foam cement in an annulus between the casing and the wellbore.

A method of cementing a casing in a wellbore, the method comprising the steps of:

• displacing cement downwardly into the casing so that it exits the casing and enters an annulus between the casing and the wellbore;
• connecting a ported sub to a tubing;
• lowering the tubing into the casing;
• injecting a gas into the cement at a predetermined location in the casing through theh tubing and the ported sub wherein the injecting step starts approximately when a leading edge of the cement passes the ported sub in the casing;
• and
• increasing a rate at which the gas is injected from the leading edge of the cement to a trailing edge of the cement.

A method of cementing a casing in a wellbore, the method comprising the steps of:

• connecting a ported sub to an upper end of a lower tubing section;
• connecting an upper tubing section to the ported sub;
• lowering the ported sub into the wellbore with the upper tubing section;
• displacing cement downwardly in an annulus between the casing and the upper tubing section wherein the cement exits the casing and enters an annulus between the casing and the wellbore;
• and
• injecting a gas into the cement at a predetermined location in the casing as it passes the ported sub.

A method of cementing casing in a wellbore, the method comprising the steps of:

• connecting a jetting sub in a tubing;
• lowering the tubing in the casing;
• displacing cement downwardly in an annulus between the casing and the tubing, and out into an outer annulus between the casing and the wellbore;
• and
• injecting a gas into the cement through the jetting sub to foam the cement in the annulus between the tubing and the casing.