Method for counteracting land subsidence in the vicinity of an underground reservoir

Abstract

The invention relates to a method for counteracting land subsidence due to activities, such as production of resources, involving transport of materials to or from an underground reservoir (R) through a well (P) having a well bore (B) running in the direction of the reservoir. The method comprises the step of bringing reinforcing material into a casing present in the wellbore (B) and making the reinforcing material flow out through perforations in the casing for forming a number of reinforcing objects (D) of reinforcing material around the wellbore (D).

1 . Method for counteracting land subsidence due to activities, such as production of resources, said activities involving transport of materials to and/or from an underground reservoir (R; R 1 ; R 2 ) through a well (P) having a well bore (B; B 1 ; B 2 ) running in the direction of the reservoir, whereby the method comprises the steps of bringing reinforcing material into a casing ( 10 ) present in the wellbore and making the reinforcing material flow out through perforations ( 14 ) in the casing for forming a number of reinforcing objects (D; D 1 ; D 2 ) of reinforcing material around the wellbore, whereby the method comprises the step of forming cracks in the reservoir (R 2 ) surrounding the wellbore (B 2 ) and filling the cracks with the reinforcing material for forming the reinforcing objects (D 2 ). 
     
     
         2 . Method according to  claim 1 , whereby the reinforcing objects (D; D 1 ; D 2 ) have a dome or arch shaped cross-section. 
     
     
         3 . Method according to  claim 1 , whereby the reinforcing material comprises grout. 
     
     
         4 . Method according to  claim 2 , whereby the reinforcing objects (D; D 1 ; D 2 ) are formed around a substantially horizontal part of the wellbore (B; B 1 ; B 2 ). 
     
     
         5 . Method according to  claim 2 , whereby the perforations ( 14 ) are present in circumferential patterns in the casing ( 10 ). 
     
     
         6 . Method according to  claim 5 , whereby use is made of production perforations present in the casing ( 10 ) for production of resources, such as hydrocarbons. 
     
     
         7 . Method according to  claim 6 , whereby additional perforations are made in addition to the production perforations present in the casing ( 10 ) for production of resources, such as hydrocarbons. 
     
     
         8 . Method according to  claim 6 , whereby a pump is used to bring the reinforcing material into the casing ( 10 ). 
     
     
         9 . Method according to  claim 6 , whereby tubing ( 11 ) provided with a nozzle head is used to make the reinforcing material flow out through the perforations ( 14 ) in the casing ( 10 ). 
     
     
         10 . Method according to  claim 9 , whereby the casing ( 10 ) is dividable in sections by seals ( 21 ). 
     
     
         11 . Method according to  claim 9 , whereby the cracks are formed using the reinforcing material. 
     
     
         12 . Method according to  claim 9 , whereby the cracks are formed using fracking liquid. 
     
     
         13 . Method according to  claim 9 , whereby the reservoir is hardened, preferably by Nitrogen injection, prior to forming the cracks. 
     
     
         14 . Method according to  claim 9 , whereby the wellbore (B; B 1 ; B 2 ) remains intact for production of the resources. 
     
     
         15 . Method according to  claim 9 , whereby a pattern of reinforcing objects (D; D 1 ; D 2 ) is defined around adjacent wellbores (B; B 1 ; B 2 ) creating a foundation platter.