US2813587A

US2813587A - Drill stem tester

Info

Publication number: US2813587A
Application number: US499949A
Authority: US
Inventors: Whitman D Mounce
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1955-04-07
Filing date: 1955-04-07
Publication date: 1957-11-19
Anticipated expiration: 1974-11-19

Description

Nov. 19, 1957 w. D. MoUNcE 2,813,587

DRILL STEM `'LESTER `Filed April '7, 1955 2 sheets-sheet 1 w. D. MoUNcE DRILL vSTEM TESTER Nov. 19, 1957 2 Sheets-Sheet Filed April 7, 1955 INVENTOR. Wh/'fm an D.. Mou/Ice,

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ATTORNEY DRILL STEM TESTER Whitman D. Mounce, Houston, Tex., assigner, by mesne assignments, to Esso Research and Engineering Com pany, Elizabeth, N. J., a corporation of Delaware Application April 7, 1955, Serial No. 499,949

8 Claims. (Cl. 166-103) This invention relates to the art of taking samples of the uid present within a subsurface formation. More particularly this invention relates to apparatus for taking a sample from a subsurface formation while drilling a borehole.

During the drilling of la borehole various factors such as an increase in the drilling rate, a flow of oil or loss of mud returns indicate that a drill stem test of the formation fluid is desirable. The sooner the test can be made the more useful the results obtained from the test will be. However, because of the delay associated with present testing methods and apparatus the test must be deferred until the drill pipe is removed from the borehole and a separate testing instrument is lowered into the borehole to the proximity of a formation to be tested.

My new apparatus and method provides a means for taking a drill stem test when it is felt that such a test is advisable, without requiring that the drill pipe be removed from the borehole.

Briefly described, my new apparatus for taking a drill stem test consists of a string of pipe which has attached to its lower end a drilling bit. During drilling operations, mud is flowed under pressure through the string of pipe and the drilling bit and up the annulus between the string of pipe and the side surface of the borehole. When it is desirable to take a drill stem test the flow of mud is temporarily discontinued and a weight such as a go-devil is dropped through the string of pipe. The go-devil actuates a plunger valve to permit the flow of fluid from a fiuid reservoir contained wherein the drill stem to an inflatable packer thus isolating the subsurface formation from which it is desired to obtain test fluids from the rest of the hole. Means are provided for effectuating the flow of the well fluids into the drill pipe. A swab may be lowered into the drill pipe to bring some of the sample fluids up to the surface. Means are also provided for removing the weight or go-devil with such removal permitting the resumption of drilling of the borehole without necessitating the removal of the drilling tool.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings in which:

Fig. 1 is a longitudinal view of the lower part of the string of pipe and the drilling bit;

Fig. 2 is a longitudinal sectional view showing, during drilling operations, the position of the valve means utilized for inflating and deflating the packer.

Fig. 3 is a longitudinal sectional view of the valve means showing its position after a go-devil has been dropped into the drill pipe to permit the inflation of the packer and the taking of a fluid sample from the subsurface formation;

Fig. 4 is a section taken through 4-4 of Fig. 3;

Fig. 5 is a section taken along 5-5 of Fig. 3; and

Fig. 6 is a longitudinal sectional view showing another form of go-devil which might be utilized in my well testing system.

States Patent 0 2,813,587 Patented Nov. 19, 1957 Referring to the drawings and more particularly to Fig. 1 numeral 10 represents a borehole which has been drilled into the subsurface formations such as the forma-l tions shown at 11 and 12. Formation 13 represents a porous subsurface stratum which has been penetrated by the drilling tool resulting in loss of returns or a fas/ter rate of drilling or a showing in the drilling mud of oil or other factors which might indicate a drill stem test is advisable. Figs. 1 through 5 show the elements of the apparatus which are utilized while the test is being made. As shown in Fig. l, packer 14 is in the inflated position thus sealing off subsurface formation 13. The. apparatus includes a string of pipe 15 which has connected thereto a drill collar 16. Connected at the lower end of the drill `collar is a drilling bit 17. Also included in the apparatus is a packer setting fluid reservoir 18 which may consist of a deformable bag. A valve means 19 is provided to control a flow of packer setting fluid between the packer setting fluid reservoir 18 and packer 14 for infiating and deflating packer 14. In Fig. l a go-devil 20 is shown in its position after drilling operations have been discontinued and the go-devil 20 has been dropped down the drill pipe 15 to engage a plunger 21 included in valve means 19. When plunger 21 has been depressed, formation fluids enter a fluid passageway leading from mud passages in the drill bit 17 up to a fluid passageway contained within go-devil 20 and then into the drill stem 15. The mud which is within the fluid passageway and the drill stem is first removed by continuously. lowering and raising a swab 22 and then the formation fluids will appear within the drill stem 15 and be removed to the surface. After the test has been made the swab which has an overshot 23 therein is lowered down the drill stem 15 to engage retrieving head 24 of the go-devil. When the swab is removed to the surface the go-devil 20 is also removed thus releasing valve means 19 resulting in the deflation of the packer 14 and permitting the resuming of drilling operations.

Fig. 2 shows in more detail the packer setting fluid reservoir 18 and the valve means 19. The position of valve means 19 shown in Fig. 2 is the position valve means 19 assumes during drilling operations. During drilling operations mud is pumped down the drill stem 15 and through fluid passageway 25 to the drill bit 17 (see Fig. 1) and thence up the annulus between. the string of pipe and the side surface of the borehole 1li. Some of the mud pressure is also conducted through passageway 26 to the underside of a plunger 21, which plunger is an important element of the valve means 19. Mud pressure is also conducted through passageway 2'7 against a fluid reservoir 18 which may consist of a deformable bag. De* formable bag 18 is filled with a fluid which is utilized to inflate the packer 14 of Fig. l. Plunger 21 has out therein a keyway 2S which rides along a key 29. Plunger 21 is biased upwardly (as shown in Fig. 2) by a biasing means 30 such as a compression spring. 1n addition to the force of compression spring 3i) the pressure transmitted through passageway 26 to the underside 31 of plunger 21 helps to maintain plunger 21 in its upper position despite the pressure of the drilling mud. Plunger 21 has a packer setting fluid inlet 32 and a packer setting fluid outlet 33 with a hollowed out portion 34 serving to conduct fluid from packer setting fluid inlet 32 to packer setting fluid outlet 33. A check valve 35 is included in the fluid passageway 34 to allow the fiuid flowing through hollowed out portion 34 to ow in one direction only. A passageway 36 leads from deformable bag 18 and then branches out into two

passageways

37 and 38. Another fluid passageway 39 is provided within the drill collar 16 for conducting packer setting fiuid passed through valve means 19 to the inflatable packer 14. Rubber O-rings 40 are provided in grooves 41 of plunger 21 to prevent the escape of fluids around plunger 21.

During drilling operations mud pressure is also exerted through passageway 27 against the deformable bag member 1S. However, plunger 21 is in a position so that no packer setting fluid flows into packer setting fluid inlet 32 whereas any fluids which may be present in packer 14 and fluid passageway 39 are permitted to flow through check valve 3S, fluid outlet 33 and fluid conducting means 38 into deformable bag 1d.

Fig. 3 shows the position of the deformable bag lil and valve means 19 after a go-devil 2t) has been dropped down drill pipe As shown in Fig. 3 go-devil 20 has yengaged the head dd of plunger 21 and moved plunger 21 downwardly against the bias of coil spring Btl. The head portion 45 of the go-devil 2li is formed so as to rest upon a seat member 46 formed within drill collar 16. The packer setting fluid inlet 32 is now disposed opposite to passageway 37 and the packer setting fluid outlet 33 is disposed opposite the passageway f7 which connects with passageway 39 leading to the inflatable packer 14. Hence after go-devil has been dropped on the seat 46 fluid pressure may then be applied by the mud pump at the surface around go-devil 2li through grooves 48 out in drill stem 1d and thence through passageway 27 against the deformable bag 1S. rlhis application of mud pressure effectuates the flow of packer setting fluid through passageway 36, inlet 32, check valve 35, outlet 33, passageway 47' and passageway 39 into packer 14. Check valve 35 prevents any flow of fluid from packer 14 back into reservoir 18. Mud fluid pressure is prevented from being applied through fluid passageway by means of gaskets 49 which provide for a fluid-tight engagement of go-devil 20 with the seat 46. Mud fluid pressure is also prevented from entering fluid passageway 25 through ports Sil formed in go-devil 2l) by a valve S1 which may consist of a spherical ball.

After the packer fflhas been inflated, swab 22 (see Fig. l) is lowered down into drill stem 15)'. By continuously lowering and raising swab 22 the mud within the drill stein is removed. The pressure within the subsurface formations forces the formation fluid up passageway 25 and into passageway 52 which is formed within the head 45 of go-devil 2li. rl`he formation fluid will unseat valve 5]. and flow out of ports Si) and through grooves 48 into the drill stem l5. The flow of the subsurface formation fluid is aided by suction created by the raising and lowering of swab 22. The swab 22 may then be raised to the surface and the formation fluid, gathered by said swab 22, l

examined. Swab 22 is then again lowered down the drill stem 15 and the overshot 23 grasps retrieving head 24 to allow for the pulling out of go-devil 2d.

After go-devil 20 has been unseated from seat tl-6 by overshot 23 plunger 21 will again be biased upwardly by compression spring allowing the packer setting fluid to flow from packer 1d through fluid passageway 39, packer setting fluid inlet 32, check valve 35, packer setting fluid outlet 33 and fluid conductors 3S and 36 to reservoir 1li. The mud pressure may then be again applied through fluid passageway 2S to the drill bit f7 and drilling operations resumed.

A construction of go-devil which might be utilized in place of a godevil such as that shown in Fig. 3 is shown in Fig. 6 wherein like numerals are used to refer to like parts. As shown in Fig. 6, a passageway 53 is bored through the entire length of go-devil 54 so the well fluids flowing into passageway 52 will flow entirely through the go-devil 5d and on np into the drill stem 15.

During drilling, when it is thought advisable to take a drill stem test, a gro-devil is dropped down the string of pipe and iinpinges valve means 19 and forms a fluid tight engagement with seat d6. The position of valve means 19 then permits the packer 1d to be inflated by the application of mud pressure against deformable bag 1S. The application of mud pressure is ceased after packer 14 becomes fully inflated. Swab Z2 is then lowered down the drill string 15 and continuously raised and lowered thereby swabbing out the mud remaining in the apparatus. The formation fluid then begins to flow through bit 17, passageway 25, passageway 52 and into the drill string. After the formation fluid has been removed from swab 22, the swab is lowered to engage retrieving head 24 of go-devil 20 and remove go-devil 20 from the drill stern 15. Upon the removal of go-devil 2f) the plunger 21 will be moved upwardly by coil spring 3d thus permitting the deflation of packer 14. Any earth formation fluid which remains in the drill pipe can then be brought out by reversing the circulation of the mud so that the mud is pumped down the annulus between the drill pipe and the side surface yof the borehole and up through fluid passageway 25. The apparatus is then ready for the continuance of drilling operations.

Although l have described my invention with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

l claim:

l. ln apparatus for making a drill stem test: a drill pipe; a drilling bit having at least one orifice therein attached to said drill pipe, said drill pipe having a fluid passage to said orifice in the drilling bit; an inflatable tubular packer on said drill pipe adapted to seal off the subsurface area to be tested; a flexible bag containing fluid within said drill pipe with means for subjecting said flexible bag to mud-pump pressure; a fluid passageway within said drill pipe to conduct fluid between the bag and the packer, valve means in said fluid passage to control the flow of fluid between said flexible bag and said packer; said valve means in one position preventing the flow of fluid from said flexible bag to said packer but permitting flow in another position from said packer to said flexible bag; a weight adapted to engage and move said valve means to permit the flow of fluid from the flexible bag to the packer thereby inflating said packer, said weight having a lluid passage adapted to coincide with the fluid passage to said drilling bit when the weight engages the valve means; and a valve in said weight fluid passage adapted to permit the flow of well fluids into said drill p2. In apparatus for making a drill stem test: a drilling bit having a fluid passageway therethrough; a hollow drill stern; said drilling bit being connected to the lower end of said drill stern; a deformable bag within said drill stem containing liquid; means in said drill stem for subjecting said deformable bag to mud flow pressure; a packer; liquid conducting means in said drill stem interconnecting said deformable bag and said packer; valve means in said liquid conducting means for controlling the flow of liquid between said deformable bag and said packer, said valve means being in a first position to obstruct the flow of liquid from the deformable bag to the packer; a go-devil adapted to be dropped upon and move said valve means to a second position so as to permit the flow of liquid to said packer thereby inflating said packer, said go-devil having a test fluid passageway and valve means for transmitting test fluid flowing into said drilling bit passageway under subsurface pressure from said drilling bit passageway to said hollow drill stem.

3. ln apparatus for making a drill stem test: a string of pipe adapted to be lowered into a borehole; a drill bit connected to the lower end of said string of pipe; said string of pipe having a seat formed therein; a fluid passageway in said string of pipe; means for flowing mud under pressure through said string of pipe and through said fluid passageway and out of said drill bit during drilling; a packer located on said string of pipe below said seat, said packer being deflated during drilling; a deformable bag filled with packer setting fluid within said string of pipe; a plunger also located Within said string of pipe; said plunger having a packer setting fluid inlet and a packer fluid outlet with a fluid passageway therein interconnecting said inlet and said outlet; first means in said string of pipe adapted to conduct packer setting fluid from the deformable bag to said fluid inlet; biasing means arranged in said string of pipe to bias said plunger to a position so as to maintain the fluid inlet out of coincidence with said conducting means during drilling; a go-devil adapted to be dropped upon said plunger to thereby move said plunger against said biasing means to cause said packer setting fluid inlet to coincide with said rst fluid conducting means and cause said packer setting fluid outlet to coincide with a second fluid conducting means in said string of pipe leading to said packer, said go-devil seating on said seat; means in said string of pipe for subjecting said deformable bag to mud pressure to thereby inflate said packer; means connected to said go-devil so as to provide a Huidtight connection between said fluid passageway in the string of pipe and a fluid passageway formed in the go-devil thereby permitting the fluids within the formation being tested to be flowed through the drill bit and up through the fluid passageway in the string of pipe.

4. In apparatus for making a drill stem test: a string of pipe adapted to be lowered into a borehole; a drill bit connected to the lower end of said string of pipe; said string of pipe having a seat formed therein; a fluid passageway in said string of pipe; means for flowing mud under pressure through said string of pipe and through said fluid passageway and out of said drill bit during drilling; a packer located on said string of pipe below said seat and above said drill bit, said packer being deflated during drilling; a packer setting fluid reservoir in said string of pipe; a plunger also located within said string of pipe, said plunger having a packer setting fluid inlet and a packer fluid outlet with a fluid passageway therein interconnecting said inlet and said outlet; first means in said string of pipe adapted to conduct packer setting fluid from the reservoir to said fluid inlet; biasing means arranged in said string of pipe to bias said plunger to a position so as to maintain the fluid inlet out of coincidence with said first fluid conducting means during drilling; a godevil adapted to be dropped upon said plunger to thereby move said plunger against said biasing means to cause said packer setting fluid inlet to coincide with said first fluid conducting means and cause said packer setting fluid outlet to coincide with a second fluid conducting means in said string of pipe leading to said packer, said godevil seating on said seat; means in said string of pipe for forcing fluid from said packer setting fluid reservoir to said packer thereby inflating said packer; means connected to said go-devil to provide a fluid-tight connection between said fluid passageway in the string of pipe and a fluid passageway formed in the ,go-devil when said godevil seats on said seat thereby permitting the fluids within the formation being tested to be flowed through the drill bit and up through the fluid passageway in the string of p1pe.

5. In apparatus for making a drill stem test provided with a drill pipe having a fluid passage therethrough and having a drill bit attached thereto: an inflatable packer connected into said drill pipe; a flexible bag containing fluid within said drill pipe with means for subjecting said flexible bag to mud-pump pressure; a fluid passageway between said bag and said packer; valve means within said passageway, said Valve means being adapted to control the flow of fluid between said flexible bag and said packer; a Weight movable through said drill pipe and engageable with said valve means to move said valve means from a first to a second position to permit the flow of fluid from the flexible bag to the packer thereby intlating said packer, said weight having a fluid passage adapted to coincide with the fluid passage in the drill pipe when the weight engages the valve means; a valve in said weight fluid passage adapted to permit the flow of well fluids into said apparatus.

6. Apparatus for use in a drill stem test comprising, a pipe string having a fluid passageway therethrough, a seating surface in said pipe string, an inflatable packer arranged on said pipe string below said seating surface, a sealed fluid reservoir in said pipe string, said reservoir being interconnected iluidly with said packer by a fluid conducting means, said fluid reservoir being deformable, means for conducting fluid pressure against said reservoir to inflate said packer, a Valve arranged in said fluid conducting means and normally in closed position for controlling flow of fluid from the reservoir to the packer, and a go-devil movable through said pipe string and seatable upon said seating surface to engage said valve to move said valve from a closed position preventing fluid flow from the reservoir to the packer to open position permitting fluid flow from the reservoir to the packer to inflate the packer.

7. Apparatus for use in a drill stem test comprising, a string of pipe having a fluid passageway therethrough, said pipe string having a seat formed therein, an inflatable packer in said pipe string, a sealed reservoir for inflation fluid in said pipe string, said reservoir being interconnected fluidly with said packer by a fluid conducting means, said fluid reservoir being deformable, means for conducting fluid pressure against said reservoir to inflate said packer, a valve in said fluid conducting means normally in closed position for controlling the flow of inflation fluid from the fluid reservoir to the packer, a go-devil movable through said pipe string to engage said valve and to move said valve from closed position preventing fluid flow from the reservoir to the packer to open position permitting the flow of inflation fluid to said packer, said go-devil being constructed to seat itself upon said seat in fluid-tight engagement, said go-devil having a fluid passageway therein communicating with said pipe string fluid passageway, and a valve in said go-devil fluid passageway for controlling the flow of fluid through said go-devil fluid passageway.

8. Apparatus for use in a drill stem test comprising, a pipe string having a fluid passageway therethrough, a seating surface in said pipe string, an inflatable packer arranged on said pipe string below said seating surface, a sealed fluid reservoir in said pipe string, said reservoir being interconnected fluidly with said packer by a fluid conducting means, said fluid reservoir being deformable, means for conducting fluid pressure against said reservoir to inflate the packer, a valve arranged in said fluid conducting means normally in closed position for controlling flow of fluid from the reservoir to the packer, and a godevil movable through said pipe string and seatable upon said seating surface, said Valve moving from closed position preventing fluid flow from the reservoir to the packer to open position permitting fluid flow from the reservoir to the packer, upon the seating of said go-devil on said seating surface, to interconnect fluidly said reservoir and said packer to inflate the packer.

References Cited in the file of this patent UNITED STATES PATENTS 2,497,185 Reistle Feb. 14, i950 2,582,530 Daetwiler Jan. 15, 1952 2,663,545 Grable Dec. 22, 1953