embodiments of the present invention provide a separate seal adapter that may be installed in a modified conductor housing . the seal adapter and modified conductor housing facilitate the drilling of well bores using standard sized drill bits , and allow for high pressure operation of the resulting wells . the example embodiment of the present invention will be discussed in an application using a standard 36 inch ( 0 . 9144 meter ) conductor having two bore holes . however , it is understood that appropriately configured embodiments of the present invention may be used with conductors of any size and having two or more bore holes . fig4 illustrates a perspective view of one embodiment of a high pressure seal adapter 100 according to the present invention . fig5 illustrates a top view of the high pressure seal adapter 100 of fig4 . fig6 illustrates a side view of the high pressure seal adapter 100 of fig4 and 5 . the seal adapter 100 includes a first bore 110 and a second bore 120 that allow equipment access through the seal adapter 100 and conductor housing 150 ( fig7 ) to the underlying conductor 12 . the first bore 110 and second bore 120 are separated by a central section 112 . as best shown in fig5 , a circular perimeter 113 of the first bore 110 extends slightly beyond a centerline 107 of the seal adapter 100 . the seal adapter 100 may include one or more seals 102 a , 102 b located in corresponding grooves 104 a , 104 b respectively around an outside perimeter 106 of the seal adapter 100 . in the embodiment illustrated in fig4 - 6 , the first bore 110 may include a circular flange 108 extending partially into the bore 110 around an inside surface 109 . the flange 108 may have a downward taper that helps to prevent the accumulation of debris which may occur with a flat shoulder , and which also assists in guiding tools going into the bore 110 before the riser is installed . the bore 120 includes a substantially vertical inside surface 121 . this will be discussed in more detail below . the seal adapter 100 may have a planar upper surface 117 a , and a planar lower surface 117 b . in this embodiment , the seal adapter 100 has a flattened oval “ racetrack ” profile as seen from the top ( fig5 ) with substantially straight long edges 103 a , 103 b and substantially circular end portions 105 a 105 b . however , it is understood that other profiles may also be used without departing from the scope of the appended claims . for example , in some embodiments , a triangular shaped seal adapter 100 may be used in drilling operations that provide for three well bores in a single conductor . the seal adapter 100 may also include a plurality of mounting holes 111 drilled adjacent the long edges 103 a , 103 b that facilitate the connection of the seal adapter 100 to the risers 40 a , 40 b and / or the wellheads 30 a , 30 b . alternately , the mounting holes 111 may facilitate the connection of the seal adapter 100 to the underlying conductor housing 150 . this will be discussed in more detail below . fig7 illustrates a perspective view of one embodiment of a modified conductor housing 150 that may be used with the seal adapter 100 of fig4 - 6 . fig7 a illustrates a cross - sectional side view of the high pressure seal adapter 100 of fig4 - 6 installed in the modified conductor housing 150 of fig7 . fig8 illustrates a cross - sectional side view of the riser 40 a installed on the high pressure seal adapter 100 as mounted on the conductor housing 150 , as shown in fig7 a . fig9 is a top perspective view of the riser 40 a and seal adapter 100 of fig8 . fig1 illustrates a cross - sectional side view of the seal adapter 100 in a reversed position on the conductor housing 150 . this facilitates the installation of another riser 40 b that may be used to facilitate well completion for the well bore 6 . it is understood that riser 40 a may also be repositioned above well bore 6 for this purpose . fig1 a illustrates a close - up cross - sectional view of the circled portion “ a ” of fig1 . the installation and operation of the seal adapter 100 will now be described with reference to fig7 - 10 . as discussed above , once the conductor 12 has been driven into the ground at the desired drilling location , the conductor housing 150 is installed onto the top 14 of the conductor 12 . this process is known to those of skill in the art , and will not be described in detail here . it is understood that the conductor 12 may also be used in subsea operations . embodiments of the present invention are thus not limited to surface wells , but may be used in any well drilling operation in which a conductor housing 150 is installed onto a conductor 12 . with reference to fig7 , once the conductor housing 150 has been installed onto the top 14 of the conductor 12 , the seal adapter 100 may be installed into the top of the conductor housing 150 . in this embodiment , a portion of central section 156 of the conductor housing 150 has been removed to provide a flange 157 to facilitate the connection between the seal adapter 100 and the conductor housing 150 . in this illustration , bore 110 of the seal adapter 100 is positioned above well bore 8 to facilitate well drilling operations ( fig7 a ). when installed in the conductor housing 150 , a portion of the lower surface 117 b of the seal adapter 100 rests on the corresponding flange 157 in the conductor housing 150 , while the upper surface 117 a of the seal adapter 100 is substantially flush with a top surface 155 of the conductor housing 150 . the seals 102 a , 102 b provide a pressure tight seal between the seal adapter 100 and an inside surface 152 of the conductor housing 150 . a bolt 132 may extend through corresponding holes in the risers 40 a , 40 b or wellheads 30 a , 30 b into each of the drill holes 111 of the seal adapter 100 . in alternate embodiments , the bolts 132 may extend through each of the drill holes 111 into corresponding holes in the conductor housing 150 to secure the seal adapter 100 to the conductor housing 150 . as shown in fig8 and 9 , the riser 40 a may then be installed in bore 110 of the seal adapter 100 above wellbore 8 . as is known in the art , the riser 40 a may be thinner on one side to allow dismantling of the trash cap 16 a ( fig8 ) while the riser 40 a is in place . a lower surface 41 of the riser 40 a may contact the flange 108 in the bore 110 of the seal adapter 100 . the riser 40 a may then be attached to the conductor housing 150 using a plurality of bolts 46 ( fig9 ). a trash cap 16 a may also be installed into bore 120 of the seal adapter 100 . the trash cap 16 a may include one or more seals 17 a , 17 b between the inside surface 121 of the bore 120 and an outside surface 18 a of the trash cap 16 a . the trash cap 16 a may also include one or more seals 17 b , 17 b between the inside surface 152 of the conductor housing 150 and the outside surface 18 a of the trash cap 16 a . after the riser 40 a is installed , various tools are run inside the riser 40 a to test the connection , drill for the next casing depth , wash the bore and to perform other well operations . once drilling operations are completed , the riser 40 a and trash cap 16 a are removed from the conductor housing 150 . with reference to fig1 , the seal adapter 100 may then be removed , rotated 180 degrees such that the bore 110 is positioned above well bore 6 , and reinstalled into the conductor housing 150 as previously described . a casing hanger 50 a may then be installed through bore 120 of seal adapter 100 , and connected to the conductor housing 150 . a trash cap 16 b may then be installed in the bore 120 of the seal adapter 100 , and onto the casing hanger 16 b to protect the casing hanger 16 b from debris . the riser 40 b may then be installed in bore 110 of the seal adapter 100 above wellbore 6 . drilling and other well operations are then commenced as previously described . fig1 a illustrates a close - up cross - sectional view of the circled portion “ a ” of fig1 . as best shown in fig1 a , one or more seals 42 are located at the bottom of the riser 40 a between an outside surface 44 of the riser 40 b and the inside surface 109 of the seal adapter 100 . similarly , the trash cap 16 b may also include one or more seals 17 a between the inside surface 121 of the bore 120 and the outside surface 18 b of the trash cap 16 b , as well as one or more seals 17 b between the inside surface 152 of the conductor housing 150 and the outside surface 18 b of the trash cap 16 b . by employing the seal adapter 100 in the modified conductor housing 150 , the thickness t r of the riser 40 b can be increased , while the total available thickness t total is approximately the same . this allows for increased pressures in the riser 40 b using the same conductors of the prior art . fig1 illustrates a cross - sectional side view of two wellheads 30 a , 30 b installed on the conductor housing 150 containing the high pressure seal adapter 100 of fig7 . in this completed well , both of the casing hangers 50 and wellheads 30 a , 30 b have been installed onto the conductor housing 150 . the seal adapter 100 is left in the conductor housing 150 . as shown in the illustration , the seal adapter 100 does not interfere with the installation of the wellhead ( s ) 30 a , 30 b . the final position and orientation of the seal adapter 100 does not affect well operations . subsequent operations from the installation of the wellhead 30 a , 30 b onwards are per normal well drilling and installation procedures , as know to those of skill in the art . as best shown in fig8 , 10 and 10 a , the seal adapter 100 addresses the problems discussed above by shifting the seal position of the risers 40 a , 40 b from the conductor housing 20 of the prior art to the seal adapter 100 . since the first bore 110 of the seal adapter 100 is slightly larger than what was available in the prior art , a riser 40 a having thicker walls may be used without reducing the size of the drill bit , or increasing the size of the conductor . the seal adapter 100 can be removed from the conductor housing 150 , rotated 180 degrees , and reinstalled in the conductor housing to facilitate riser installation through bore 110 of the seal adapter 100 to either of the 2 well bores 6 , 8 . this allows the risers 40 a , 40 b to be thicker than the conventional design , and still maintain the same inner diameter for equipment to pass through it . the thicker riser design allows for a higher overall pressure rating for each of the wells . by way of example and not limitation , a well that has been prepared as described above , and configured as shown in fig7 - 11 , may safely operate at pressures of up to 5000 psi ( 34 . 5 mpa ). it is understood that even higher pressures may be obtained by using non - standard materials for the seal adapter . it will be appreciated by a person skilled in the art that numerous variations and / or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described . the present embodiments are , therefore , to be considered in all respects to be illustrative and not restrictive .