Method for suspending wells

A method for shutting in a well which minimizes damage in a formation comprising:

• (a) placing into said formation a solution containing water, a surfactant, and a chemical blowing agent;
• (b) causing said chemical blowing agent to decompose thereby forming a foam with said surfactant which foam establishes fluid flow, minimizes fluid retention, and forces formation fluids away from a wellbore in said formation;
• (c) pumping a solidifiable gel mixture into the formation's productive interval via said wellbore while formation fluds are being forced away and precluded from said wellbore;
• (d) causing said gel mixture to become a solid thereby forming a gel plug within said wellbore and a formation gel within said formation sufficient to withstand environmental formation conditions and pressures which cause hydrocarbonaceous fluids to flow into said wellbore from the formation areas near said wellbore;
• (e) placing in said wellbore on top of said plug an amount of a light weight or foamed cement sufficient to isolate said productive interval while being supported by said plug;
• and
• (f) allowing said cement to set which set cement in combination with said gel plug is competent to exclude productive fluids from said wellbore.

A method for shutting in a well which minimizes damage to a formation comprising:

• (a) placing into said formation a solution containing water and a chemical blowing agent and which agent is a member selected from the group consisting of sodium hydrogen carbonate and p-toluene sulfonyl hydrazide, an alkali metal salt of azodicarboxylic acid, azodicarbonamide, dinitrosopentamethylenetetramine, and p,p'-oxobis(benzenesulfonyl hydrazide);
• (b) causing said chemical blowing agent to decompose thereby liberating a gas which forces formation fluids away from a wellbore in said formation;
• (c) pumping a solidifiable gel mixture into the formation's productive interval via said wellbore while formation fluids are being forced away and precluded from said wellbore;
• (d) causing said gel mixture to become a solid, thereby forming a gel plug within said wellbore and a formation gel within said formation sufficient to withstand environmental formation conditions and pressures which cause hydrocarbonaceous fluids to flow into said wellbore from the formation areas near said wellbore;
• (e) placing in said wellbore on top of said plug an amount of cement sufficient to isolate said productive interval when said cement hardens while being supported by said plug;
• (f) allowing said cement to set which set cement in combination with said gel plug is competent to exclude productive fluids from said wellbore;
• (g) causing said solid formation gel, said gel plug, and said hardened cement to be removed after the well has been shut in for a desired time interval;
• and
• (h) producing thereafter hydrocarbonaceous fluids from said formation via said wellbore.