Solid Chemical Well Treatment

Description

FIELD OF THE INVENTION

The present invention relates to hydraulic fracturing and delivery methods for well treatment chemicals.

SUMMARY OF THE INVENTION

The invention is directed to a method for fracturing a formation accessible through a wellbore. The method comprises the steps of providing an anhydrous silicate matrix formed to carry a well treatment chemical within the matrix to form a solid chemical and pumping the solid chemical, a proppant, and a fracturing fluid into the wellbore. The solid chemical is positioned within a fracture created by the fracturing fluid and provides a metered release of the well treatment chemical therefrom.

In another embodiment the invention is directed to a well treatment device. The device comprises an anhydrous silica matrix and a well treatment chemical held within the silica matrix to form a solid chemical. The chemical is releasable from the silica matrix within a wellbore.

In another embodiment, the invention is directed to a device for delivering a well treatment chemical into a wellbore. The chemical is prepared by a process. The process comprises providing a silicate matrix, heating the silicate matrix to drive off moisture contained therein to form an anhydrous silicate, and mixing the anhydrous silicate with a well treatment chemical to absorb the well treatment chemical with the silicate matrix to form a solid chemical.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic representation of an injection well and material delivery system for delivery of the well treatment chemical created in the process of FIG. 2.

FIG. 2 is a flow chart demonstrating a process of creating the solid well treatment chemical of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

A hydraulic fracture is formed by pumping the fracturing fluid into the wellbore at a rate sufficient to increase pressure downhole to exceed that of the fracture gradient of the rock. The rock cracks and the fracture fluid enters the rock, extending the crack. To keep this fracture open after the injection stops, a solid proppant, commonly sand, is added to the fluid.

The propped fracture is permeable enough to allow the flow of formation fluids to the well. Formation fluids include gas, oil, salt water, fresh water and fluids introduced to the formation during completion of the well during fracturing.

Turning to the figures in general and FIG. 1 specifically, shown therein is an injection well 10 for use with the claimed invention. The injection well comprises a well shaft 12 within a subterranean formation 14. The well shaft 12 comprises a vertical shaft 16 and may comprise a horizontal section 18. Further, the well shaft 12 comprises a well casing 20 that is adapted to seal a portion of the well shaft 12 such that fluids may not travel into our out of the subterranean formation 14 proximate the well casing. The well shaft 12 further comprises a production portion 22 that does not have a well casing 20 such that well treatment chemicals such as fracturing chemicals may be delivered to the subterranean formation 14 and desired products such as oil, natural gas, and natural gas liquids are removed from the subterranean formation.

A material delivery system 24 is provided at ground level proximate the injection well 10. The material delivery system 24 delivers products into the well shaft 12 for enhancement of the drilling process. The material delivery system is preferably used in conjunction with a fracturing system 26 for delivery of ground level fracturing fluid into the well shaft 12. The fracturing fluid, when delivered to the subterranean formation 14, causes hydraulic fracture and allows delivery of proppant and well treatment chemicals. The material delivery system 24 comprises a well treatment product 30 which is created through the process of FIG. 2.

With reference now to FIG. 2, a method for creating an enhanced well treatment product 30 for delivery to the subterranean formation 22 by the material delivery system 24 is shown. As one skilled in the art will appreciate, liquid products have associated weaknesses, such as immediate delivery to a treatment location and an inability to control the delivery of chemical product over time. The method shown in FIG. 2 provides an advantageous process for creating a well treatment product 30 in a solid matrix form. The method starts at 100. A silicate matrix is provided at 102. The silicate matrix is heated at 104 to drive off moisture contained therein. When the moisture is removed, an anhydrous silicate is left at 106. The anhydrous silicate is mixed with a well treatment chemical at 108 and the well treatment chemical is absorbed within the anhydrous silicate matrix at 110 to form a solid chemical. The solid chemical may then be coated with a resinous material at 112. The solid chemical, a proppant, and a fracturing fluid are pumped into the wellbore at 114. This causes the solid chemical to be positioned within the subterranean formation 14 and more particularly a fracture therein created by the fracturing fluid, providing a metered release of well treatment chemical at 116. The method ends at 118.

The solid chemical may comprise a silica spheroid, a silica pellet, or other shape. Preferably, the solid chemical silica matrix is a porous anhydrous silica spheroid. As used herein, “well treatment product” 30 comprises an advantageous chemical such as a scale inhibitor, corrosion inhibitor, paraffin product, H₂S scavenger, or foamer. Additionally, the product 30 could be an emulsifier, non-emulsifier, wetting agent, sludge preventive, retarder, suspension agent, anti-swelling agent, or stimulation additive.

One skilled in the art can envision other potential combinations of the principles disclosed in the above embodiments.