Cementitious compositions and cementitious slurries for permanently plugging abandoned wells and processes and methods therefor

Abstract

A dry cementitious composition which when slurried with water produces an economical hydraulic cementitious slurry for closing abandoned wells. The dry cementitious composition is a cement/CKD blend as the major component with a weight ratio of parts cement to parts of CKD between about 2/3 and about 3/1. Hydraulic cementitious slurries when cured can produce hard cementitious bodies which will meet or exceed the API specification for a competent hard plug. A process for blending the cement and CKD during transit from the cement source to the off-load site without requiring further blending after off-loading. Methods are provided for determining the formulation having the cheapest cost per unit volume of hydraulic cementitious slurry thereby enabling competitive quotes based on cf of hydraulic cementitious slurry required.

What is claimed is:  
     
         1 . A process for producing a dry blended cementitious composition comprising cement and CKD that is useful for forming an effective hydraulic cementitious slurry when slurried with water, the process comprising: 
 (a) loading into a suitable transporting container a predetermined weight of CKD;    (b) thereafter, loading into the container at a cement source site, a predetermined weight of cement on top of the CKD, the predetermined weights producing a weight ratio of cement to CKD between about 2/3 and about 3/1; and    (c) transporting the transporting container site to an off-loading site and allowing vibration of the transporting container during transit to automatically dry blend the cement and CKD sufficiently for forming an effective hydraulic cementitious slurry when slurried with water, without requiring any further dry blending of the cement and CKD after off-loading from the transporting container.    
     
     
         2 . The process of  claim 1 , wherein the dry blended cementitious composition is at least about 90% by weight cement and CKD.  
     
     
         3 . The process of  claim 1 , further comprising loading the predetermined weight of CKD into the container at the cement source site that the cement is to be loaded into the container.  
     
     
         4 . The process of  claim 1 , wherein the dry blended cementitious composition comprises about 40% cement and about 60% CKD.  
     
     
         5 . The process of  claim 1 , wherein the dry blended cementitious composition comprises about 50% cement and about 50% CKD.  
     
     
         6 . The process of  claim 1 , wherein the dry blended cementitious composition comprises about 60% cement and about 40% CKD.  
     
     
         7 . The process of  claim 1 , wherein the dry blended cementitious composition comprises about 30% cement and about 70% CKD.  
     
     
         8 . A process for producing a dry blended cementitious composition consisting of cement and CKD useful for forming an effective hydraulic cementitious slurry when slurried with water comprising: 
 (a) loading into a suitable transporting container a predetermined weight of CKD;    (b) thereafter, loading into the container at a cement source site, a predetermined weight of cement on top of the CKD, the predetermined weights producing a weight ratio of cement to CKD between about 2/3 and about 3/1; and    (c) transporting the transporting container site to an off-loading site and allowing vibration of the transporting container during transit to automatically dry blend the cement and CKD sufficiently for forming an effective hydraulic cementitious slurry when slurried with water, without requiring any further dry blending of the cement and CKD after off-loading from the transporting container.    
     
     
         9 . A process for forming a hydraulic cementitious slurry effective for closing an abandoned well comprising: 
 (a) dry blending a predetermined amount of cement and a predetermined amount of CKD to produce a dry blended cementitious composition, the predetermined amounts of cement and CKD having a weight ratio of cement to CKD between about 2/3 and 3/1; and    (b) slurrying the dry blended cementitious composition with a predetermined amount of water sufficient to form a hydraulic cementitious slurry effective for closing an abandoned well.    
     
     
         10 . The process of  claim 9 , wherein the dry blended cementitious composition is at least about 90% by weight cement and CKD.  
     
     
         11 . The process of  claim 9 , further comprising loading the predetermined weight of CKD into the container at the cement source site that the cement is to be loaded into the container.  
     
     
         12 . The process of  claim 9 , wherein the dry blended cementitious composition comprises about 40% cement and about 60% CKD.  
     
     
         13 . The process of  claim 9 , wherein the dry blended cementitious composition comprises about 50% cement and about 50% CKD  
     
     
         14 . The process of  claim 9 , wherein the dry blended cementitious composition comprises about 60% cement and about 40% CKD.  
     
     
         15 . The process of  claim 9 , wherein the dry blended cementitious composition comprises about 30% cement and about 70% CKD.  
     
     
         16 . A process for closing an abandoned well, comprising: 
 (a) dry blending a predetermined amount of cement and a predetermined amount of CKD to produce a dry blended cementitious composition comprising cement and CKD, wherein the predetermined amounts of cement and CKD have a weight ratio of cement to CKD between about 2/3 and 3/1;    (b) slurrying the dry blended cementitious composition with a predetermined amount of water sufficient to form a hydraulic cementitious slurry effective for closing an abandoned well;    (c) installing the hydraulic cementitious slurry in the abandoned well; and    (d) allowing the hydraulic cementitious slurry to cure in the abandoned well and form a competent hard plug.    
     
     
         17 . The process of  claim 16 , wherein the dry blended cementitious composition is at least about 90% by weight cement and CKD.  
     
     
         18 . The process of  claim 16 , wherein the hydraulic cementitious slurry is effective when cured in the abandoned well for forming a competent hard plug having a compressive strength of at least about 1000 psi with a maximum permeability of 0.1 millidarcey in the abandoned well.  
     
     
         19 . A method of determining cost for supplying dry blended cement and CKD to an off-load site comprising: 
 (a) determining a cost of procuring a predetermined amount of cement and CKD from a cement source;    (b) determining a transportation cost for delivering the predetermined amount of cement and CKD in a dry blended condition from the cement source to the off-load site;    (c) determining a cost of off-loading the predetermined amount of cement and CKD in the dry blended condition at the off-load site; and    (d) determining a cost for supplying cement and CKD in a dry blended condition to the off-load site by summing each of the above-mentioned costs.    
     
     
         20 . A method of determining a plurality of summed cost for supplying cement and CKD in a dry blended condition to an off-load site comprising: 
 (a) determining cost of procuring a predetermined amount of cement and CKD from a plurality of cement sources;    (b) determining transportation cost for delivering the predetermined amount of cement and CKD from each the plurality of cement sources to the off-load site;    (c) determining the cost of off-loading the predetermined amount of cement and CKD from each source at the off-load site; and    (d) determining cost for supplying blended dry cement and CKD to the off-load site by summing each of the above-mentioned costs for each of the cement sources thereby determining a plurality of summed costs.    
     
     
         21 . The method of  claim 20 , further comprising determining a yield resulting from forming a hydraulic cementitious slurry for each of the plurality of cement sources thereby determining a plurality of yields; and 
 providing a price quote for supplying a predetermined amount of dry blended cement and CKD to the off-load site based on the plurality of yields and the plurality of summed costs.    
     
     
         22 . A method of determining a lowest cost per unit volume of a hydraulic cementitious slurry comprising the steps of: 
 (a) determining cost of procuring a cement and a CKD in a predetermined weight ratio of cement to CKD at and from a cement source;    (b) determining yields of hydraulic cementitious slurries formed by slurrying a dry cement-CKD blend having the predetermined weight ratio of cement to CKD with various amounts of water;    (c) determining which of the hydraulic cementitious slurries when cured over a predetermined period of time will meet or exceed a predetermined specification; and    (d) determining a hydraulic cementitious slurry having a lowest cost per unit volume using the dry cement-CKD blend and which meets or exceeds the predetermined specification.    
     
     
         23 . The method of  claim 22 , further comprising determining a cost for supplying the dry cement-CKD blend from the cement source to an off-load site using the hydraulic cementitious slurry determined to have the lowest cost per unit volume and which meets or exceeds the predetermined specification.  
     
     
         24 . The method of  claim 22 , further comprising: 
 repeating steps (a), (b), (c) and (d) except with at least one more dry cement-CKD blend having a predetermined weight ratio of cement to CKD which is different than the first mentioned predetermined weight ratio of cement to CKD, and determining the hydraulic cementitious slurry having the lowest cost per unit volume with the at least one more dry cement-CKD blend; and    determining a cost for supplying one of the dry blends of the cement and the CKD from the cement source to an off-load site based on the hydraulic cementitious slurry determined to have the lowest cost per unit volume and which meets or exceeds the predetermined specification.    
     
     
         25 . The method of  claim 24 , wherein the first mentioned predetermined weight ratio of cement to CKD is about 2/3, and wherein the at least one more predetermined weight ratio of cement to CKD is about 3/2.  
     
     
         26 . The method of  claim 25 , wherein the at least one more predetermined weight ratio of cement to CKD also includes a weight ratio of about 1/1.  
     
     
         27 . The method of  claim 26 , wherein the predetermined specification is a cured plug having at least a predetermined compressive strength while not exceeding a predetermined maximum permeability.