US1930987A - Method and apparatus for testing the productivity of formations encountered in wells - Google Patents

Description

J. T. SIMMONS Oct. 17, 1933.

METHOD AND APPARATUS FOR TESTING THE PRODUCTIVITY 0F FORMATIONS ENCOUNTERED IN WELLS 'Fild Feb. 10, 1926 Patented Oct. 17, 1933 METHOD AND APPARATUS FOR TESTING, THE PRODUCTIVITY OF FORMATIONS EN- COUNTERED IN WELLS John T. Simmons, El Dorado, Ark., assignor, by direct and mesne assignments, to Erle P. Halliburton, Los Angeles, Calif.

Application February 10, 1926.

19 Claims.

The present invention relates to methods and apparatus for testing the productivity of formations encountered in drilling oil and other deep wells, and refers particularly to methods and apparatus employed when such wells aredrille by the rotary method.

In the rotary method of drilling wells, the well is kept filledwith a mud-laden fluid. This mud-laden fluid is employed for the purpose of carrying away the detritus formed by the cutting bit and for maintaining a hydraulic pressure upon the sides of the hole, which prevents the hole from caving. In most wells drilled by the rotary process, it is impossible, Without danger to the hole, to remove the mud-laden fluid without providing some other support to conserve-the hole bore. Therhydraulic pressure of the mud-laden fluid in the well is very great, being often in excess of two thousand pounds per square inch. In most instances, this pressure is in excess of the head upon the cognate fluids, either oil, water or gas, encountered in the formations penetrated by the drill. Under these circumstances, while drilling theremay be no indication whatever at the surface of the well of the productivity or even existence of such cognate fluids. It is therefore necessary to perform a special testing operation whenever it is desired to determine whether such a formation contains a fluid which upon removal of the pressure of the mud-laden fluid will enter the well bore.

Under the present practice, when making such a test, it is necessary to remove the mud-laden fluid from the well bore until the hydraulic head of liquid within the well is sufliciently below the head of the cognate fluids in the formation in order to allow this latter fluid to enter the well bore. In order that this mud-laden fluidmay be removed from the well bore without danger of the well caving in, it is the general practice to set a string or strings of casing in the well so that this string or strings of easing may support the wall of the well when the mud-laden fluid is withdrawn. The lower portion of at least the inside string of casing is perforated in order that the fluids from the formation may enter the casing after the removal of the mudladen fluid. If a water sand has been encountered above the formation to be tested, it is necessary to run in a string of casing and cement or otherwise seal its bottom to the sides of the well bore at a point below the known water level, in order to protect the formation being tested from this upper water strata. This string of Serial No. 87,323

casing is then known as a water string. In testing a well, the hole below the bottom of this water string is then protected by another string set inside the water string.

In case the test develops that the formation tested is barren or not commercially productive or contains water and it is therefore desired to deepen the hole, it is necessary to refill the hole with mud-laden fluid, to remove if possible the inner perforated string, and to resume drilling; The cemented water stringhfiowever, must be left in the hole, which not 0 y entails the cost of this string but decreases the size of the hole which can be thereafter drilled. If the testing operation is repeated with the setting of successive water strings, the size of the hole may ultimately become too small for successful drilling operations and attempts to drill deeper must therefore be abandoned.

An object of the present invention is to provide a method and apparatus for testing formations which is cheaper, quicker and more effective than the methods now in use. More particularly an object of the present invention is to provide a method and apparatus for testing the formations penetrated by a drill, which method and apparatus may be employed without the necessity of removing the mud-laden fluid from method and apparatus for testing formations being pentrated by a drill, which method and apparatus does not entail decreasing the size of the well bore.

Another object of my invention is to provide a method and apparatus for obtaining a sample of the cognate fluid in the formation to be tested without substantial contamination of such sample.

In accordance with my invention, whenever it is desired to test the productivity of a formation in a well, I establish an empty chamber or conduit in the well bore adjacent the formation to be tested without removing the mud-laden fluid from the well, and then permit the cognate fluids of the formation to discharge into said empty chamber or conduit. In the preferred form of the invention, such empty chamber is established extending from the formation tested to the top of the well, whereby, in certain cases when the cognate fluids of the formation are under sufficient pressure, the well may commence producing through this conduit. In other cases where cognate fluids of the formation are not under such high pressure, the conduit may be again shut oil from communication with the formation after certain amount of the cognate fluids of the formation have entered the empty conduit or chamber. This closing of the conduit is effected by an operator at the top of the well who can open and close the conduit at will. Following the entrance of the cognate fluid into the empty conduit of chamber, the apparatus may be elevated to the top of the well with the entrapped fluid content. The conduit being closed, the mud-= laden fluid in the well is prevented from entering the conduit and contaminating the sample or otherwise interfering with the testing process.

The present invention also preferably embodies a means by which the formation to be tested may be sealed off from the hydraulic pressure of the mud-laden fluid standing within the well during the testing operation, and also includes a method and means by which the hydraulic pressure of the mud-laden fluid in the well may be reimposed upon the formation, after the completion of the testing operation without either of these steps requiring any removal of mud-laden. fluid from the well bore.

The present invention also provides a method and apparatus by which a formation may be tested through the penetration of the lower end of the testing apparatus into a so-called rat hole, or an extension of the well bore of reduced diameter, the bottom of the hole thus'leaving the hole provided with a seat above the formation to be tested which may be employed for setting of water or other string of easing if the test on the well establishes the productivity of a formation.

Various further objects and advantages of the present invention will appear from a description of a preferred form or example of the present invention. For this purpose, reference is made to the accompanying which an apparatus embodying the -in". ention and which further illustrates one example oi an apparatus which siutable for use in carrying out the proc- I ess embodying the present invention.

In the drawhig, wherein like symbols refer to like or corresponding parts throughout the 'several views,

Figure l is a side elevation of the device taken partly in section andwith parts broken away,

Figure 2 iso partial perspective view of the device with the parts drawn out for cleamess, and Figure 3 is a top plan view of the complete de vice shown in Figure 1.

The example of the apparatus illustrated is shown as consisting mainly of the following primcipal elements: A casing 23 or other means adapted to provide an empty chamber or conduit which may be lowered into a well bore and, when so lowered, provide an empty chamber adjacent the formation to be tested. In the preferred form of the invention where this member comprises a casing 23, there will thus be provided an empty chamber or conduit'extending from the formation to be tested up to the top of the well hole. The invention also comprises 3 the second major element a valve including the valve body 4 and head or bushing 19, which is adapted to normally close such chamber or conduit 23 from communication with the mud-laden fluid within the well fluids from the formation to be tested may be I permitted to discharge into the conduit or chamber formed by the casing or pipe 23 when the valve is operated as later described. I

Referring more particularly to the drawing,

the body 4 preferably formed of a body of steel or other appropriate material traversed longitudinally by one or more passages 5 and 6 here shown to be two in number and disposed diametrically of the body 4, which in the instance illustrated is round in cross-section.

The body 4 is provided with pins 7 and 8'extending respectively upwardly and downwardly therefrom, these pins being turned from a block of material of which the body portion is a part, or being otherwise produced, and the upper pin 7 being smaller in diameter as compared with the diameter of the lower pin 8. The lower pin 8 is of greater diameter as it is also traversed by passages which are continuations of the passages 5 and 6 in the body part 4. These passages converge downwardly and they both communicate at their base with the interior of the hollow adjusting sleeve 9 which is internally threaded at both ends to engage with external threads 10 upon the lower end of the pin 8 and with similar external threads ll upon the upper end of the inlet member 12. This inlet member 12 is indicated as preferably in the former a hollow perforated pipe or strainer which, when the invention is employed .to test a well through the employment of a socalled rat-hole, is adapted to fit into the rat hole and support the sides of said rat hole when the pressure of the mud-laden fluid within the well is sealed off fromsaid hole as hereafter described. This strainer is closed at its lower end by the plug 13 which may be removable and for this purpose it provided with screw threads indicated at let, for taking into complemental threads upon the lower end of the strainer. The

pin 8 is also of greater diameter in order to better receive the packer member 15. Thepackingmember 15 is indicated as being of frusto-conical shape so that it is adapted to wedge within the upper end of the rat hole Within'the well bore and thus seal the formation below from the pressure 01 the mud laden fluid within the well. For this purpose, the packer member 15 may, for example, be composed of rubber, lead or other appropriate material. The wider part of this packer member is disposed upwardly and the lower smaller end is disposed against the upper end of the adjusting sleeve 9 which forms an abutment for the packer member; The upper wide end of the packer member 15 fits against a shoulder 16 at the lower end of the body member 4. This shoulder is beveled or under-cut with its outer edge-depending below its inner circular edge.

1,930,987 packer member to be squeezed into the rat-hole and form a tight fit.

The upper divergent ends of the passages 5 and 6 open at opposite sides of the narrow upper pin 7 and these passages are adapted to register with similar passages 17 and 18 extending lengthwise through the head or bushing 19 of the valve which head is rotatably mounted upon the pin 7 and is secured thereto as by the lock nuts 20 and 21 screwed upon the upper externally threaded end of the pin 7 which is made of a length to project above the upper end of the bushing 19. This bushing 19 is also preferably cylindrical or substantially in the form of a barrel and is provided with external threads 22 upon its upper end for receiving the pipe or casing 23 indicated in dotted lines in Figure 1. The passages 17 and 18 open out upon the upper end of the bushing 19 and communicate with the interior of the casing 23.

The lower end of the bushing 19 is provided with a slot 24 to receive the pin 25 provided with the threaded shank which is secured in a threaded opening in the upper end of the body member 4.

It will be seen from the foregoing description that I have provided a valve at the end of the casing 23 which can be manipulated as desired from the surface of the well to close or open the empty chamber or conduit provided by the pipe or casing 23. The slot 24 and pin 25 between the head 19 and body 4 of the valve provides a means by which the relative rotation between the'head and body of the valve may be limited in order to facilitate registering the passages in the head with those in the body of the valve.. I

In the use of the preferred apparatus of the invention and in practicing the preferred method would interfere with the purity of the sample sought.

In this manner there is thus established an empty chamber or condu'it adjacent the formation to be tested, without the necessity of removing the mud-laden fluid from the well hole. It should be pointed out that the entrance of the mud-laden fluid into the empty chamber or conduit of the pipe or casing 23 should be prevented during the lowering of the apparatus in the well in order to prevent the pressure of the mud-laden fluid from filling up this empty chamber or conduit, whereby it would impose its hydraulic head upon the formation to be tested when the valve is opened and thus defeat the object of the testing method.

The packer 15 is lowered into the small hole at the bottom of the well which is called the rathole, and it is forced into this small hole, compressing the packer and thereby excluding all water from the well above. This squeezing or forcing of the packer 15 into the rat-hole also anchors the body against rotary or turning movement. Therefore, the pipe or casingv 23 may be rotated to cause similar rotation of the bushing 19 to effect registry of the passages 17 and 18 with to the operator when the passages have been brought into alignment and when this condition occurs, the fluid in the rat-hole will enter the strainer pipe 12 and ascend through the passages in the pin 8, body member 4 and bushing 19 into the casing 23. It will be obvious that if the pre sure of the cognate fluids within the formation is sufficiently high that production may then take place through the casing 23. When the pressure is not sufficient for this purpose and when a sample of suflicient mass has been received the bushing 19 is again rotated in the opposite direction in order to move the passages out of registry'and trap the sample in pipe 23:

The entire device. 5

may be then lifted to the surface and the possible production may be measured from the sand tested.

The strainer pipe 12 may or may not be. used and the valve and packer as constructed may be connected in the same manner as a bit to the drill stem and run into the hole in the same manner, making it possible within a very few minutes to gain the sample and to pull it to the surface.

It will be apparent that the packer 25 operates to remove the pressure of the mud-laden fluid in the well from the cognate fluids of the formation,

which are then free to discharge into the empty conduit formed by the casing 23 whenever the valve is opened to permit communication between the formation and this empty conduit. It will be further seen that as soon as the valve is closed and the testing apparatus started to be removed from the formation, thus releasing the packer, the pressure of this mud-laden fluid is again immediately reimposed upon the formation, thus preventing further discharge of the fluids of such formation. In this manner the well is always under control and no danger of blow-outs encountered. Moreover, the conduit being positively closed, during the withdrawal of the apparatus,-

the mud-laden fluid within the well cannot contaminate the sample or otherwise interfere with the testing operation. I

It is obvious thatv various changes and modifications may be made in the details of construction and design of the above specifically described embodiment of the apparatus of this invention without departing from the spirit thereof, and the particular embodiment of the method of the present invention is not limited nor dependent upon the use of the particular apparatus described nor is it limited to the particular details of the preferred method, but both method and apparatus of the present invention include all such changes, modifications, substitutions and equivalents as come within the scope of the following appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is:

part to receive the sample to be tested, said packer adapted to be positively pressed against the walls of the formation to seal off the same;

2. A' well testing device comprising a body part having a passage therein open at its bottom to receive the material to be tested; a packer adjoining said body part, a bushing having a passage adapted to register with the passage in the body part and connected for manipulation to the casing, and means to restrict the rotary movement of said bushing, said passages being constructed to receive the material to be tested, said packer adapted to be positively pressed against the walls of the formation to seal off the same.

3. A well testing device comprising a body part having a passage extending therethrough and opening at the ends thereof, a packer associated with said body part, a pin extending upwardly from said body part, a bushing rotating on said pin andv having a passage therein extending from end to end and adapted to register with the passage in said body part, said bushing having means to receive a casing in communication with the passage in the bushing, and means to confine said bushing on the pin, said passages being constructed to receive the material to be tested.

4. A well testing device comprising a body part having pins extending from the upper and lower ends thereof, the lower pin being of greater diameter than the upper, said body part and lower pin having a continuous passage therein open at its upper and lower ends, a packer extending about the lower pin, and a bushing mounted for rotation on the upper pin being connected to a string of casing and having a passage therein adapted to be moved into and out of registry with the passage in said body part and lower pin.

- 5. A well testing device comprising a body part having an upper pin, a bushing fitted to rotate about said upper pin and having a slot at its lowerend with threads at its upper end to receive a casing, said pin projecting upwardly above the bush-- ing and having means to hold the bushing on the pin, a stop member carried by said body part and projecting in the slot at the lower end of the bushing, said body part having a passage therein, said body part and bushing having passages adapted to register, and a casing carried by said body part. I

6. A well testing device comprising a body part having a lower pin projecting therefrom and forming a shoulder with the body part, said shoulder being under-cut, a downwardly tapering packer surrounding said'pin for engaging against said under-cut shoulder, and means at the lower end of said pin for constituting an abutment for said packer, said body part and pin having a passage therethrough, and means adjoining the upper end of said body part for opening and closing the communication of this passage with the casing above.

'7. A well testing device comprising a body part having a pin extending from the lower part thereof, said body part and pin having a passage therethrough, a packer extending about said pin, an adjusting sleeve on the lower end of said pin, a perforated pipe secured to the lower end of said sleeve, a plug in the bottom of said perforated pipe, and means above the body part for regulating the communication of the passage with the interior of the casing above.

8. A method of .testing the productivity of a formation encountered in a well containing drilling fluid, which includes lowering an empty string of pipe into the well through the drilling fluid to adjacent the formation, the pipe carrying a packer and having a valved inlet at its lower end which is closed while the pipe is being lowered, setting the packer above the formation to seal off the drilling fluid from the formation, opening the valved inlet after the packer is set to permit cognate fluid from the formation to enter the pipe, closingthe valved inlet against the entrance of fluid from the well by movement of thepipe,

inlet, and a valve for the inlet positively controlled by movement of the pipe to open and close the inlet while the packer is seated.

10. Apparatus for testing a well comprising a string of pipe to be lowered into the well, a packer carried by the pipe said packer adapted to be positively pressed against the walls of the formation to seal off the same and means at the lower end of the pipe to receive a sample from the well including an inlet and a valve for controlling the inlet, the valve being positively controlled by movement of the pipe to open and close the inlet while the packer is seated.

11. Apparatus for testing a well containing drilling fluid, which includes an empty string of pipe to be lowered in the well to adjacent the formation to be tested, means at the lower end of the pipe to receive a sample from the formation including an inlet opening into the pipe and a valve for controlling the inlet, and means carried by the pipe for sealing the well above the inlet said means consisting of a packer adapted to be positively pressed against the walls of the'formation to seal off the same, the valve being positively controlled by movement of the pipe.

12. Apparatus for testing a formation encountered in a well containing drilling fluid, which includes a single string of pipe to be lowered into the well to adjacent the-formation to be tested, a valved inlet at the, lower end of the pipe positively controlled from the top of the well by movement of the pipe and a packer carried by the pipe above the inlet, said packer. being adapted to be positively pressed against the walls of the formation to seal off the same.

13. Apparatus for testing the productivity of a formation encountered in a well containing drilling fluid, which includes an emptyv string of pipe to be lowered into the well to adjacent the formation to be tested, a packer carried by the pipe adapted to be positively pressed against the walls of the formation to seal off the same, means at the lower end of the pipe to receive a sample from the formation including an inlet opening into the pipe and a valve structure for controlling the inlet, the valve structure including a plurality of relatively movable parts one of which is secured to the pipe and another of which is connected to the packer.

14. Apparatus for testing the productivity of a formation encountered in a well containing drilling fluid, which includes a single empty 135. string of pipe to be lowered into the well to adjacent the formation to be tested, means lowered into the well by said string of pipe for seal ring off the drilling fluid from the formation to be tested, said sealing means being adapted to be positively pressed against the walls of the formation to seal off the same, means at the lower end of said string of pipe to receive a samplefrom the formationincluding an inlet opening into said pipe and a valve structure for controlling the inlet, said valve structure including a part connected to said sealing means and a part connected to said pipe. 15. Apparatus for testing the productivity of a formation encountered in a well containing 15 J 1,930,987 1 drilling fluid,comprising a single empty string 18. A method of testing the productivity oif a of pipe to be lowered into the well through the drilling fluid to adjacent the formation tobe tested, a packer lowered into the well by said string of pipe for sealing off the drilling fluid from the formation to be tested, said packer adapted to be positively pressed against the walls of the formation to seal off the same, means at the lower end of said string of pipe to receive fluid from said formation including an inlet opening into said pipe below said packer and a valve structure for controlling the inlet, said valve structure having a relatively station ary part connected to the packer and a relatively movable part connected to the pipe.

16. Apparatus for testing the productivity of a formation encountered in a well containing drilling fluid, comprising a single empty string of pipe to be lowered into the well through the drilling fluid to adjacent the formation to be tested, a packer carried by the pipe for sealing off the well above the formation an inlet below a the packer opening into the pipe, said packer adapted to be positively pressed against the walls of the formation to seal off the same, and a valve for the inlet, the setting of the packer and the operation of the valve being positively controlled by movement of the pipe.

17. Apparatus for testing a well containing drilling fluid, comprising a single string of pipe to be lowered into the well through the drilling fluid, said pipe being closed against the entrance of the drilling fluid, means at the lower end of o formation encountered in a well containing drilling fluid involving the insertion of only a single string of pipe into the well to make a test, which includes lowering a test string into the well through the drilling fluid with a packer carried by the string and a valve inlet at the lower end of the string closed against the entrance of fluid from the well, setting the packer above the formation and opening the valve to permit cognant fluid from the formation to enter the inlet, closing the valve to prevent the subsequent entrance of fluid from the well through the inlet and releasing the packer, and raising the test string with the inlet closed against entrance of fluid from the well to remove an entrapped sample.

19. An apparatus for testing the productivity of a formation in a well containing drilling fluid, comprising a string of pipe to be lowered into the well through the drilling fluid to adjacent the formation to receive a fluid sample therefrom and to be raised out of the well to remove with the well below the ;point at which thepacker seals oil. the well, and means for controlling the inlet to permit fluid from the formation to enter the pipe while the packer is set and to prevent fluid from entering the pipe afterthe packer is released and the pipe is being raised out of the well.

JOHN T. SIMMONS.

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