Patent Application
20120234546
Fracturing earth formations in downhole industries such as those concerned with hydrocarbon recovery and carbon dioxide sequestration, for example, can increase permeation of the formation. Increased permeation often facilitates more complete drainage of hydrocarbons during the life of a well or greater total capacity of carbon dioxide storage.
In horizontal or highly deviated boreholes, however, fractures of a formation have a tendency to orient parallel to an axis of the borehole and accordingly limit depth of penetration in directions away from the borehole. These issues limit the effectiveness of the fracturing operation. Systems and methods to improve the effectiveness of fracturing are well received in the art.
Disclosed herein is a system for fracturing a formation. The system includes a tubular positionable within a formation borehole having at least one port therethrough configured to provide fluidic communication from inside the tubular to the formation borehole. The system also includes a seal sealably attachable to both the tubular and walls of the formation borehole, a seat in operable communication with the tubular and a member in operable communication with the seat such that movement of the seat relative to the tubular causes the member to engage the walls and provide stress thereto.
Also disclosed is a method of fracturing a formation, including sealingly attaching a tubular to walls of a borehole in the formation, pressuring up the tubular, deforming a member in operable communication with the tubular into engagement with the walls, urging the member longitudinally away from the sealing attachment, stressing the walls with the urging, and pressuring up the formation.
Further disclosed is a method of increasing depth of fracturing a formation which includes applying longitudinal loads to walls of the formation and pressuring up against the formation.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
Referring to
Referring to
A seal 58, shown herein as an o-ring, slidably sealingly engages the seat 42 to the tubular 14. The seal 58 is initially positioned such that the ports 26 are downstream of the plug 50 seated against the seat 42 thereby preventing fluidic communication between the inside 30 on an upstream side of the plug 50 and the annular space 32. After movement of the seat 42 in a downstream direction, and at least some deformation of the member 46 has occurred, the seal 58 is sufficiently moved to allow fluidic communication between the inside 30 and the annular space 32 through the ports 26. This fluidic communication allows for fracturing to take place via pressure supplied from a remote location through the tubular 14 and the ports 26. By positioning the ports 26 near the portion 54, flow through the ports 26 is focused more directly toward the fracture 40. This can further increase depths of the fractures 40 and positioning of proppant into the fracture 40.
Forces sufficient to cause deformation of the member 46 are generated by pressure against the plug 50 sealed against a frustoconical surface 62 of the seat 42. Protrusions 66 of the seat 42 extend radially through slots 70 in the tubular 14 and radially overlap the cone 52. As the seat 42 is moved (rightward in the Figures) the protrusions 66 move within the slots 70 loading frustoconical surfaces 63 of the cone 52 against the portions 54 of the member 46. The portions 54 are located on fingers 74 that are configured to deform under compressive loads of the member 46 between the cone 54 and a shoulder 78 of the tubular 14. The foregoing structure allows the portions 54 to move radially outwardly into engagement with the walls 38 of the borehole 18. Teeth 82 on the portions 54 bite into the walls 38 to discourage relative motion therebetween after engagement has been established. After such engagement continued forces on the seat 42 urging it further in the direction it has already traveled result in buckling of the fingers 74 thereby building stress in the formation 22 as the portions 54 are urged longitudinally away from the seal 34.
Embodiments disclosed herein optionally include sealingly engaging the tubular 14 to the walls 38 with a deformable element 86 positioned proximate the member 46. The element 86 can be configured to be structurally supported by and sealingly engaged to the shoulder 78 while being radially deformable in response to the buckling of the fingers 74. Sealing of the element 86 to the walls 38 would allow pressure in the annular space 32, supplied through the ports 26, to build between the seal of the element 86 and seal of the seal 34, thereby concentrating pressure to portions of the formation 22 located therebetween.
While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.
