Method and apparatus for isolating the bottom of a borehole from an upper formation

Claim 2

forming a first flow path from the drill string annulus, through the sub, and to the bit so as to enable drilling fluid to flow across the face of the bit as the bit penetrates a formation;

Claim 3

In drilling a borehole using concentrically arranged drill pipe and tubing string to form counter-current flow to and from the bit, with a cross-over sub connecting the drill bit to the drill pipe, a method of isolating the upper borehole annulus from the formation being penetrated by the bit comprising the steps of:

Claim 4

In drilling a borehole using concentrically arranged drill pipe and tubing string to form counter-current flow to and from the bit, with a cross-over sub connecting the drill bit to the drill pipe, a method of isolating the upper borehole annulus from the formation being penetrated by the bit comprising the steps of:

Claim 5

In drilling a borehole using concentrically arranged drill pipe and tubing string to form counter-current flow to and from the bit, with a cross-over sub connecting the drill bit to the drill pipe, a method of isolating the upper borehole annulus from the formation being penetrated by the bit comprising the steps of: 1. forming a first flow path from the drill string annulus, through the sub, and to the bit so as to enable drilling fluid to flow across the face of the bit as the bit penetrates a formation; 2. forming a second flow path from the borehole annulus, through the sub, and into the tubing string so as to enable drilling fluid and cuttings from the bit to return uphole; 3. flowing a blocking agent along either the first or the second flow path and into the borehole annulus in proximity of the sub so as to displace fluid from the borehole annulus and also to isolate the borehole annulus from the formation being penetrated by the bit; 4. resuming the borehole forming operation by flowing drilling fluid along the flow path set forth in steps (1) and (2) after the upper borehole annulus has been isolated from the formation in accordance with step (3).

Claim 6

In drilling a borehole using concentrically arranged drill pipe and tubing string to form counter-current flow to and from the bit, with a cross-over sub connecting the drill bit to the drill pipe, a method of isolating the upper borehole annulus from the formation being penetrated by the bit comprising the steps of: 1. forming a first flow path from the drill string annulus, through the sub, and to the bit so as to enable drilling fluid to flow across the face of the bit as the bit penetrates a formation; 2. forming a second flow path from the borehole annulus, through the sub, and into the tubing string so as to enable drilling fluid and cuttings from the bit to return uphole; 3. flowing a blocking agent along either the first or the second flow path and into the borehole annulus in proximity of the sub so as to displace fluid from the borehole annulus and also to isolate the borehole annulus from the formation being penetrated by the bit; 4. resuming the borehole forming operation by flowing drilling fluid along the flow path set forth in steps (1) and (2) after the upper borehole annulus has been isolated from the formation in accordance with step (3).

Claim 7

The method set forth in claim 1, wherein the drill bit is connected to the sub by an air hammer, and further including the step of flowing the blocking agent through the second flow path; and, using air to power the air hammer; and, using the spent power fluid from the air hammer to provide the drilling fluid.

Claim 8

forming a second flow path from the borehole annulus, through the sub, and into the tubing string so as to enable drilling fluid and cuttings from the bit to return uphole;

Claim 9

forming a second flow path from the borehole annulus, through the sub, and into the tubing string so as to enable drilling fluid and cuttings from the bit to return uphole;

Claim 10

flowing a blocking agent along either the first or the second flow path and into the borehole annulus in proximity of the sub so as to displace fluid from the borehole annulus and also to isolate the borehole annulus from the formation being penetrated by the bit;

Claim 11

flowing a blocking agent along either the first or the second flow path and into the borehole annulus in proximity of the sub so as to displace fluid from the borehole annulus and also to isolate the borehole annulus from the formation being penetrated by the bit;

Claim 12

The method set forth in claim 1, wherein the bit is a rotary rock bit, and further including the step of using a liquid drilling mud as the drilling fluid.

Claim 13

The method set forth in claim 1, wherein step (3) is carried out at spaced apart locations along the borehole as the borehole is formed, so as to present a continuous column of blocking agent which isolates the borehole annulus from the formation being penetrated by the bit.

Claim 14

resuming the borehole forming operation by flowing drilling fluid along the flow path set forth in steps (1) and (2) after the upper borehole annulus has been isolated from the formation in accordance with step (3).

Claim 15

resuming the borehole forming operation by flowing drilling fluid along the flow path set forth in steps (1) and (2) after the upper borehole annulus has been isolated from the formation in accordance with step (3).

Claim 16

The method set forth in claim 1 wherein step (3) is carried out by using an agent which is liquid in step (3), and which turns into a self-supporting mass prior to carrying out step (4) so as to form a continuous open hole packer in the borehole an-nulus.

Claim 17

forming the borehole for a limited length by carrying out step 4;

Claim 18

forming the borehole for a limited length by carrying out step 4;

Claim 19

flowing cementitious material along the second flow path and forcing the cementitious material radially away from the borehole;

Claim 20

flowing cementitious material along the second flow path and forcing the cementitious material radially away from the borehole;

Claim 21

The method set forth in claim 1 wherein step (3) is carried out In order to isolate the drill bit from a lost circulation zone, and further including using a sol as the blocking agent in step (3) which turns into a jel prior to carrying out step (4).

Claim 22

The method of claim 1, and further including the step of employing a sol as the blocking agent in step (3) and, allowing the sol to jel before commencing step (4).

Claim 23

repeating step (5) followed by repeating step (6) to thereby provide a vertical cementitious column so as to provide a bearing surface for above the ground structure.

Claim 24

repeating step (5) followed by repeating step (6) to thereby provide a vertical cementitious column so as to provide a bearing surface for above the ground structure.

Claim 25

The method of claim 1, and further including the following steps:

Claim 26

The method of claim 8, wherein a plurality of columns defined in step (7) are formed adjacent to one another to thereby form a platform having legs downwardly depending therefrom, wherein the legs are the individual columns of step (7).

Claim 27

A bit sub for connecting a drill bit assembly to a concentric dual pipe string for carrying out a drilling operation in a well borehole wherein the pipe string includes a drill pipe having a tubing string axially disposed therein to thereby form a counter-current flow path to and from the bit; the improvement comprising: said bit sub having a lower threaded passageway for being connected to the drill bit assembly, an upper threaded passageway for being connected to the drill pipe, and an inner tubing connector for being flow connected to the tubing string; said inner tubing connector being coaxially arranged respective to said upper threaded passageway thereby forming a sub annulus; said sub annulus being a continuation of the drill string annulus; means forming at least one radial passageway in said sub, said radial passageway being flow connected to the interior of said inner tubing connector; means forming at least one flow path from said drill bit sub annulus to said lower threaded passageway for forming a flow path from the drill string annulus to the bit; means forming a circumferentially extending enlargement about a marginal length of said sub; a lower edge portion of said enlargement forming a circumferentially extending shoulder; said shoulder having a marginal circumferentially portion thereof upwardly undercut to provide a ramada in the form of an inverted U-shaped passageway for communicating the exterior of the bit with the radial passageway; said ramada having a downwardly opening portion for enabling drilling fluid and cuttings from the bit to flow therethrough and into the radial passageway, through the inner tubing connector, and through the inner tubing string to the surface of the ground.

Claim 28

A bit sub for connecting a drill bit assembly to a concentric dual pipe string for carrying out a drilling operation in a well borehole wherein the pipe string includes a drill pipe having a tubing string axially disposed therein to thereby form a counter-current flow path to and from the bit; the improvement comprising: said bit sub having a lower threaded passageway for being connected to the drill bit assembly, an upper threaded passageway for being connected to the drill pipe, and an inner tubing connector for being flow connected to the tubing string; said inner tubing connector being coaxially arranged respective to said upper threaded passageway thereby forming a sub annulus; said sub annulus being a continuation of the drill string annulus; means forming at least one radial passageway in said sub, said radial passageway being flow connected to the interior of said inner tubing connector; means forming at least one flow path from said drill bit sub annulus to said lower threaded passageway for forming a flow path from the drill string annulus to the bit; means forming a circumferentially extending enlargement about a marginal length of said sub; a lower edge portion of said enlargement forming a circumferentially extending shoulder; said shoulder having a marginal circumferentially portion thereof upwardly undercut to provide a ramada in the form of an inverted U-shaped passageway for communicating the exterior of the bit with the radial passageway; said ramada having a downwardly opening portion for enabling drilling fluid and cuttings from the bit to flow therethrough and into the radial passageway, through the inner tubing connector, and through the inner tubing string to the surface of the ground.

Claim 29

The bit sub of claim 10, wherein said upper threaded passageway is in the form of a removable member, said removable member being cylindrical in form and having a lower threaded surface, threads formed externally of said inner tubing connector for threadedly engaging said lower threaded surface of said removable member.