US 3241371 A
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March 22, 1966 J. M. HORETH AUTOMATIC DRILL CUTTINGS SAMPLER Filed Jan. 25, 1962 2 G F S %T l N HU W R W 2 W I OT L m 0A F S R O T A R B 7 V 7| 23 ll i l lI'i |I 8 I w 2 l 2 v W 2 O 3 2 2 w 2 2 JOHN M. HORETH INVENTOR.
M2762 AGENT United States Patent 0 3,241,371 AUTOMATIC DRILL CUTTllNGS SAMPLER John M. Horeth, Tulsa, Okla, assignor, by mesne assignments, to Esso Production Research Company, Houston, Tex., a corporation of Delaware Filed Jan. 25, 1962, Ser. No. 168,699 8 Claims. (Cl. 73-422) This invention is directed to apparatus for obtaining samples of entrained particulate solids contained in a flowing stream of fluid, and more specifically, for obtaining samples of cuttings from drilling operations. A device is provided for automatically collecting representative samples of fine cuttings directly from. a circulating stream of drilling fluid.
In the process of drilling boreholes into the earth, such as oil and gas wells and the like, a drilling fluid is continuously circulated from the surface of the earth to the bottom of the hole and back in order to cool and lubricate the drill bit, carry away the cuttings, and form an impervious coating on the wall of the borehole. The drilling fluid or mud being returned from the drill hole is discharged on to a shale shaker which typically comprises a screen and means for agitating the screen. The shale shaker is usually mounted above a mud tank where the larger cuttings are retained while the mud flows through into the mud tank for recirculation. It is com mon practice to sample the cuttings from the shale shaker to maintain a record of the formation being penetrated by the drill bit. Such samples have been collected more or less sporadically by manually catching a sample of the cuttings as they are discharged from the screen of the shale shaker. Such cuttings were then manually washed to remove adhering mud and then sacked for eventual investigation.
It is diflicult by such methods to satisfactorily correlate a given sample with an exact depth within the borehole. Not only is the manual approach inherently unreliable; there is also inadequate control of the particle size of the cuttings recovered from the shale shaker. By sampling from the circulating mud stream directly, fine cuttings which are usually lost over the shale shaker screen can be collected. Frequently, the fine cuttings are important in the evaluation of the formation interval being penetrated by the drill bit. Thus, it is obviously desirable to obtain representative samples of a controlled particle size. The apparatus provided by the invention achieves this result.
Proper evaluation of formations being penetrated by a drill bit depends almost entirely upon the availability of representative drill cutting samples. In fact, careful examination of properly collected cuttings can yield data surpassing much of that obtainable from the most expensive well logging instruments in use today. In many instances, however, the collected samples are inadequate because of careless collecting techniques. Particularly, much of the fine sand cuttings from friable sandstones pass through the shale shaker screen. Detection of these fine cuttings is frequently of prime importance since they may represent key stratigraphic markers or hydrocarbon reservoirs.
In a rotary drilling rig, the drilling fluid return line which runs from the well head to the shale shaker is sub stantially horizontal, with a slight slope downward from the well head to the shale shaker. The apparatus of the invention is adapted for attachment to this section of the drilling fluid return line. The device comprises tubular 3,241,371 Patented Mar. 22, 1966 means extending through a lower portion of the return line and terminating a substantial distance Within the return line, the terminus of said tubular means having an opening therein adapted to receive a portion of the contents flowing within the return line. Hinged valve means are provided in operative association with said opening, along with means for automatically opening and closing said valve means periodically. Second valve means are provided at the other end of said tubular means, including means for automatically opening and closing said second valve means while the first valve means is closed.
The apparatus also includes a funnel and washing means for collecting and washing the mud sample as it is dumped from the above mentioned tubular means. The funnel empties onto a sieve screen which is vigorously agitated by conventional vibrating means. The function of the screen is to hold the cuttings as they accumulate, to grade the sample as to the desired particle size, and to provide rapid drainage for the washings. After each preselected interval of drilling depth, for example every ten feet, the accumulated cuttings are removed from the screen as a finished sample, placed in a container and labeled with the drilling depth.
A detailed description of the invention is provided by reference to the accompanying drawings.
FIGURE 1 is an elevational view, partly in section, showing a complete embodiment of the apparatus.
FIGURE 2 is a fragmentary elevational view of the preferred embodiment.
The apparatus of FIGURE 1 includes sampler tube 11 adjustably inserted into flow line 12 and equipped with automatic hinged flapper valves 13 and 14. The valves are actuated through linkage means 15 and 16, respectively, driven by solenoids 17. The solenoids operating the two flapper valves are connected to switches which in turn are operated by an automatic timing device. The switches and timing unit are indicated diagrammatically by numeral 18. The timer operates the solenoids at a suitable interval, for example, once every half minute. The operation of the two valves is staggered. First the valve in the mud stream opens, allowing: the tube to fill with mud. After about 10 seconds it closes again, then the bottom valve is opened, discharging the contents of the tube.
The sample is directed through funnel 19 onto screen 20 which is agitated by vibrator 21. Funnel 19 is equipped with washing means such as water inlet 22 and spray nozzles 23. Nozzles 23 may extend around the full perimeter of funnel 19. The need for vibrating screen 20 arises from the inherent tendency of the drilling fluid to form a gel. Vibration breaks up the gel and thereby facilitates washing of the cuttings, and the passage of discardable fines through the screen, while the desired sample is retained.
The mesh size of screen 20 is selected in accordance with the size of cuttings which it is desired to collect. The preferred size is SO-mesh for typical. use, since cuttings and other particles which pass this screen are of little or no value for purposes of geological interpretation. They are simply recirculated in the mud system.
The rate at which cuttings collect on screen 20 depends on the frequency of sampling and upon the drilling rate. But the sampling rate is arbitrarily selected and held constant. Therefore, the rate of cuttings accumulation on screen 20 is made to depend directly upon the drilling rate.
Thus it becomes convenient to control the discharge of cuttings samples from the screen by obtaining a signal from the depth counter of a drilling-time recorder, such as the Geolograph Recorder, manufactured by The Geolograph Company.
It is common practice to obtain a signal from the Geolograph by installing a microswitch to be activated by one of the gears in the depth counter of that instrument. The microswitch is in turn electrically connected to a mechanism for discharging the contents of screen 20 after each desired interval of drilling depth, for example every ten feet.
Cuttings generally settle to a depth of about 3 to 5 inches along the bottom of drilling fluid return line 12. The depth varies depending on the flow rate and the average particle size of cuttings contained in the drilling fluid. Because of the bed of cuttings which tends to form in line 12, the sample tube 11 must extend within line 12 to a level just above the bed depth in order to permit valve 13 to swing open and shut without interference from the bed, and in order that tube 11 may receive representative samples. Accordingly, means for adjusting the distance by which tube 11 and flapper valve linkage 15 extend into line 12. are provided in the form of sleeve 24, having flange 25, secured to adapter 26, which in turn is welded to an opening provided in line 12. Flange is also provided with a bushing 27 to accommodate the movement of linkage assembly 15. Set screws 28 hold the device in place at the desired level. O-ring seals 29 and 30 are provided to prevent leakage around tube 11 and linkage 15, respectively. Other means for adjusting the height of tube 11 may be provided, such as a rack and pinion gear arrangement.
The opening in tube 11 covered by flapper valve 13 is shown having a 45 inclination facing the drilling fluid flow. Such inclination is deemed preferable in order to facilitate the entry of a sample into the tube; however, it is not critical since the drilling fluid and cuttings would nevertheless enter tube 11 even if the opening were not in clined with respect to the direction of mud flow. Moreover, tube 11 need not be of circular cross-section as shown. It may instead have a rectangular elliptical, polygonal or other cross-section if desired.
Although other valve means may be substituted for the hinged flapper valves 13 and 14, the flapper valves are considered essential if the device is to enjoy prolonged, trouble-free operation since other valves, with sliding movements and the like, are readily fouled and eroded by fine cuttings and other solids normally associated with a drilling fluid. A sealing ring of soft rubber or similar material is desirable to prevent leakage of the flapper valve. Springs 31 and 32 are provided to hold the valves in a closed position when not activated by the solenoids.
Solenoids 17 are not shown in detail since they may be of any conventional design, as readily appreciated by one skilled in the art. Moreover, the solenoid drive provided for the flapper valves may be replaced by hydraulic or air driven pistons or the like.
Similarly, the solenoid switches and timer unit are not shown in detail since they too may be of any conventional design. A suitable unit is the Industrial Multi- Cam Timer, Model MC-4, obtained from the Industrial Timer Corp., of Newark, NJ.
Referring now to the preferred embodiment of FIG- URE 2, sleeve 33 is attached to bushing 27 and encloses linkage assembly 15. The sleeve is made of any tough, flexible material, such as rubber or plastic, and is sealed at each end in order to protect linkage 15 from the erosive action of entrained solids flowing within line 12. Moreover, sleeve 33 replaces O-ring 30 and provides in its place a more positive exclusion of solids from the bore of bushing 27, whereby the operation of valve 13 is kept smooth. The sleeve may be shortened, to enclose only the first joint of linkage 15, without departing from the scope of the invention. The remainder of the apparatus,
4 not shown in FIGURE 2, is the same as that shown in FIGURE 1.
While various embodiments of the invention have been fully described, it is obvious that further modifications will occur to those skilled in the art. Accordingly, it is intended to include all such modifications within the scope of the following claims.
What is claimed is:
1. In a rotary drilling rig, including a conduit system for circulating a drilling fluid downhole and then back to the surface of the earth, a sampling device for obtaining cuttings from drilling fluid in the return line of said system which comprises: tubular means extending through a lower portion of said return line and terminating a substantial distance within said return line, the terminus of said tubular means having an opening therein adapted to receive a portion of the contents flowing through said return line, hinged valve means connected to said tubular means for closing said opening, means for opening and closing said valve means, second valve means at the other end of said tubular means, means for opening and closing said second valve means, and timing means connected to the first and second valve actuating means for coordinating the operation of said valves.
2. Apparatus as defined by claim 1, further comprising sieve means in combination with said tubular means and adapted to receive the contents discharged from said tubular means.
3. Apparatus as defined by claim 2 further comprising funnel means in combination with said tubular means and adapted to guide the contents of said tubular element, periodically released by said second valve means, onto said sieve means.
4. Apparatus as defined by claim 2, further comprising means in combination with said sieve means for vibrating said sieve means.
5. Apparatus as defined by claim 3, further comprising means in combination with said funnel means for flushing the contents of said funnel means onto said sieve means.
6. A sampling device for obtaining representative samples of entrained particulate solids contained in a flowing stream of fluid, comprising a tubular element; means connected to said tubular element for adapting one end of said tubular element to be inserted into and attached to a flow line the contents of which are to be sampled; first hinged valve means affixed to said one end of said tubular element; means for operating said valve means comprising a rigid elongated element aflixed to said valve means and extending through an opening provided therefor in said adapting means; a flexible sleeve member enclosing said elongated element and sealing said opening as a protection against the erosive action of said entrained solids; second valve means aflixed to the other end of said tubular element; first valve actuating means for periodically opening and closing said first valve means; second valve actuating means for opening and. closing said second valve means; and timing means connected to the first and second valve actuating means for' coordinating the operation of said first and second valve; actuating means.
7. A device as defined by claim 6, further comprising mounting means permitting adjustment of the distance by which said tubular element extends into said flow line.
8. A device for obtaining representative samples of' entrained particulate solids contained in a flowing stream of fluid, comprising a tubular element; means connected to said tubular element for adapting one end of said tubular element to be inserted into and attached to a flow line the contents of which are to be sampled; first hinged valve means aflixed to said one end of said tubular element; means for operating said valve means comprising a rigid elongated element aifixed thereto and extending through an opening provided therefor in said adapting means, Sefllmg mean$ slidably ngaging said elongated element and mounted in said opening; second valve means aflixed to the other end of said tubular element; first valve actuating means for opening and closing said first valve means; second valve actuating means for opening and closing said second valve means; and automatic timing means connected to said first and second valve actuating means for coordinating the operation of said first and second valve actuating means,
References Cited by the Examiner UNITED STATES PATENTS 2,516,097 7/1950 Woodham et a1. 73-422 X 2,528,955 11/1950 Hayward 73-153 X 2,665,409 1/ 1954 Rogers 73-422 X 6 2,750,043 6/1956 Thompson 73-42l X 2,883,856 4/1959 Youngman 73-153 X OTHER REFERENCES Periodical: The Oil and Gas Journal, article by Paul Reed entitled Methods for Catching Rotary Drill Samples in Oklahoma, June 10, 1937 issue, pp. 42-44 and 48 in Engineering and Operating Section.
RICHARD C. QUEISSER, Primary Examiner.
JERRY W. MYRACLE, JOHN P. BEAUCHAMP,