Hydraulic fracturing of shallow wells

A process for remediating an underground formation containing a contaminated groundwater, said process comprising:

• excavating a wellbore extending along an axis from a surface location to an underground location horizontally displaced from said surface location, a portion of said wellbore being located in an underground formation substantially within a zone of contaminated groundwater;
• forming a notch in the formation substantially along the axis of said wellbore portion in a substantially deviated portion of said wellbore located in said contaminated groundwater zone;
• introducing an amount of a fluid to said wellbore portion after notching at a fluid pressure which causes a fracture to initiate into said formation at said notch;
• and
• decreasing said fluid pressure.

A process for fracturing an underground formation containing contaminated water comprising:

• excavating a conduit extending along an axis from a surface location to a zone within an underground formation;
• creating a longitudinal notch in the formation at a depth and first peripheral position in said conduit at a location whereby said notch produces a higher maximum formation stress than a second peripheral position at said axial location when substantially equal fluid pressures are applied to said peripheral positions;
• and
• introducing a fluid-like substance to said peripheral positions for substantially selectively initiating a fracture at said first peripheral location.

A process for fracturing an underground formation comprising:

• excavating a conduit wall extending along an axis from a surface location to a zone within an underground formation;
• creating a stress riser at a first peripheral position in said conduit wall at an axial location which produces a higher maximum formation stress than a second peripheral position at said axial location when substantially equal fluid pressures are applied to said peripheral positions;
• and
• introducing a fluid-like substance to said peripheral positions for substantially selectively initiating a hydraulic fracture at said first peripheral location, wherein said underground formation is a vadose zone and said borehole is substantially deviated from a vertical direction.

An apparatus for remediating an underground formation containing water and fracturing the underground formation along a portion of a deviated wellbore in the formation having an axis and a non-circular pressure stress riser in the formation that extends substantially parallel to said axis, said apparatus comprising:

• a fluid conduit extending from a surface location to an underground location proximate to said stress riser when placed in said deviated wellbore;
• a packer attached to said fluid conduit which is capable of substantially restricting axial fluid flow in the annulus between said fluid conduit and said wellbore;
• and
• means for introducing an amount of fluid to said wellbore portion at a pressure sufficient to selectively initiate a fracture proximate to said stress riser in the formation while minimizing the initiation of substantial fracturing at other locations within the wellbore portion.

An apparatus for fracturing an underground formation along a portion of a deviated wellbore having an axis and a pressure stress riser that extends substantially parallel to said axis, said apparatus comprising:

• a fluid conduit extending from a surface location to an underground location proximate to said stress riser when placed in said deviated wellbore;
• a packer attached to said fluid conduit which is capable of substantially restricting axial fluid flow in the annulus between said fluid conduit and said wellbore;
• means for introducing an amount of fluid to said wellbore portion at a pressure sufficient to selectively initiate a fracture proximate to said stress riser while minimizing the initiation of substantial fracturing at other locations within the wellbore portion;
• a second packer attached to said fluid conduit wherein said stress riser is located between said packers when said apparatus is placed in said wellbore portion;
• means for rotationally orienting said fluid conduit;
• and
• a source of pressurized fluid connected to said fluid conduit.

An apparatus for hydraulically fracturing an underground formation from a borehole penetrating said formation along an axis, said apparatus comprising:

• a fluid conduit extending from a surface location to an underground location;
• means for creating a non-circular pressure stress riser extending substantially parallel to said axis in said formation, wherein said means for creating is attached to said fluid conduit and said pressure stress riser is non-circular in shape;
• and
• means for introducing fluid to said underground location at a pressure sufficient to initiate a hydraulic fracture proximate to said stress riser.