Settable, form-filling loss circulation control compositions comprising in situ foamed non-hydraulic sorel cement systems and method of use
This document relates to settable, non-hydraulic foamed cement compositions comprising nitrogen gas-generating compositions used for loss circulation control.
1. A foamed cementitious composition, comprising:
magnesium oxide (MgO);
a salt selected from the group consisting of magnesium chloride (MgCl 2 ), magnesium sulfate (MgSO 4 ), ammonium hydrogen phosphate (NH 4 H 2 PO 4 ), hydrates thereof, and any combinations thereof;
a nitrogen gas-generating compound;
a foam surfactant; and
an amine activator comprising an ethyleneamine.
2. The composition of claim 1 , wherein the foam surfactant comprises an alkyl sulfate salt with a C 12 -C 14 carbon chain, a betaine, or a hydroxysultaine, or any combinations thereof.
3. The composition of claim 2 , wherein the foam surfactant comprises cocoamidopropyl hydroxysultaine.
4. The composition of claim 1 , wherein the nitrogen gas-generating compound comprises an azo compound.
5. The composition of claim 4 , wherein the azo compound comprises azodicarbonamide.
6. The composition of claim 4 , wherein the azo compound is about 1% to about 10% by weight of the MgO.
7. The composition of claim 4 , wherein the ethyleneamine is selected from the group consisting of ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA).
8. The composition of claim 7 , wherein the weight ratio of the azo compound to the amine activator is about 5:1 to about 1:5.
9. The composition of claim 7 , wherein the amine activator is TEPA.
10. The composition of claim 1 , comprising a set retarder comprising at least one of hexametaphosphate, sodium borate, sodium citrate, citric acid, or an aminophosphonate.
11. The composition of claim 1 , comprising a viscosifier.
12. The composition of claim 1 , wherein the pH of the foamed cementitious composition is greater than about 4.