US1964912A - Process and apparatus for producing oil wells - Google Patents

Description

My 3, 93% E. P. HALLIBURTQN PROCESS AND APPARATUS FOR PRODUCING OIL WELLS I Filed July 18", 1952 2 Sheets-Sheet l Inventor Attorney 2 Sheets-Sheet 2 Inventor Altameyg Juiy 3, 1934. E. P. HALLIBURTON PROCESS AND APPARATUS FOR PRODUCING OIL WELLS Filed July 18, 1932 4 mm, H 9 7 /1 F 51+ 1 A I H Patented July 3, 1934 when p EIftfllfiESS AND APPARATUS FOR PRQDUGING WELLS Application July 18, 1932, Serial No. 623,165

11 (Claims.

This invention relates to a process and apparatus for producing or flowing oil from oil wells.

in the production of oil from oil wells it is frequently found that the oil will not flow to the surface of the well under the natural rock pressure in the oil formation. It is also thegenrule that even t'lose wells which when first drilled flow freely, after a period of operation W will no longer continue to flow oil to the surface. There are other cases in which there is so much gas encountered in the well, in addition to the oil, that gas will prevent the production of oil from the well unless the gas is permitted to 35 escape in large and uneconomical quantities.

it is the general object of the present invention to provide a process and apparatus for flowing oil from oil wells, which process and apparatus is capable of more correctly propor- 29 tioning the amount of gas and oil in the flowing stream from the well so that the gas is withdrawn with the oil only in the correct proportion.

It has been found possible by a correct proportioning of the oil and gas in an oil well to cause many wells to flow which otherwise would not produce oil, except by pumping or baling, and it has been further found possible to greatly prolong the period of time that an oil well will 30 continue to how through the proper proportioning of the oil and gas in the well. 7

The invention is of particular value in producing oil from wells in. which the oil is under low natural rock pressure, such as will not permil; any substantial natural flow of oil from the well. Thepresent invention in such cases is designed particularly for the purpose of regulating and controlling the passage of gas from the well so that gas will escape from the well only 30 when there is an amount of oil available in the well to be raised by a definite proportion and quantity of gas.

The invention includes a process and apparatus designed for the purpose of most eiiiciently and automatically introducing the-gas into the oil to be raised in order to secure or take advantage of the expanding effect of the gas as it is elevated in the well hole.

Another important feature of the present invention refers to the inclusion in the process and apparatus or" steps and means. designed for the purpose of controlling the iiow of oil from a well where the well is being operated under a proration rule, or where for other causes frequent periods of interruptions of the production of the well are to be expected.

Normally, when a well is shut down it is shut down by the operation of a valve located at the surface of the well. When it is desired to start the well up again and the valve is open, it quite frequently is found that the well will no longer flow oil. It appears that when the oil well is shut down-and oil is permitted to rise in the string of tubing of the well and remain there quiescent for a period of time that the expansive gas of the oil in the tubing of the well becomes separated from the oil, so that such oil no longer possesses any expansive properties and will not flow. The hydrostatic head of such oil upon the formation from which the oil originated at the same time prohibits the entrance of further oil and gas into the well. Prolonged pumping and baling of the well after each shut-down is, therefore, necessary before the well will again how. I have discovered that by shutting down the well at a point close to the formation from which the oil originates and letting the oil remaining in the well fiow out of the well under its natural expanding properties, so that at the end. of each 3Q shut-down the well is substantially free of oil, that it is possible by opening the valve in the well near the formation to secure a substantially immediate production of flowing oil from the well without the necessity of any baling or pumping. In such a case it will be seen that there is presented to the formation from which oil is to be produced at each re-opening of the well a passage for the oil, which is to a substantial extent at least empty and, therefore, there is at the moment of opening the valve a large reduction of pressure right at the oil formation. This causes the gas in the oil to rush in an en:- livened condition into the well tubing, establishing a prompt and steady how of oil. By this presentation of an empty or substantially empty conduit for the oil it has been found possible to cause the flowing of many oil wells which heretofore it has been found necessary to pump or bale for the production oi oil.

The process and apparatus of the present invention, therefore, is designed to and does ac complish the following major objects and ad vantages:

(1) It permits many wells to flow 011 to the surface without the necessity of pumping or baling the wells, where these wells heretofore have been produced only by pumping and baling;

(2) It permits the well to be prorationed or operated and then shut down repeatedly and at frequent intervals without the necessity of baling or pumping the well after each shut-down period, but leaves the well in condition for immediate production at any moment.

Various other objects and advantages of the present invention will be apparent from the description of a preferred form or example of a process and apparatus embodying the invention. For this purpose, I have hereinafter described, with reference to the accompanying drawings, a preferred form or example of a process and apparatus which embodies this invention.

In the drawings,

Figure 1 is an elevation of an oil well containing an apparatus embodying the present invention, the view being mainly in vertical section;

Figure 2 is an enlarged elevation of a portion of theapparatus;

Figure 3 is a further enlargement, mainly in vertical section;

Figure 4 is an enlarged elevation taken through the lower part of the well hole and apparatus, showing the packing means and barrier for the lower end of the hole;

Figure 5 is a section on the line 55 of Fig ure 4;

Figure 6 is a section on the line 66 of Figure 3; and

Figure 7 is a section on the line 77 of Figure 3.

Referring to the drawings, there is illustrated a well hole leading to an oil producing formation 3. As is the usual practice, the well hole is encased throughout a considerable portion of its depth by a well casing 2. In order to produce oil from such a formation, there is lowered into the well a string of tubing 4, which at its lower end is provided with a collar 5 which normally closes the tubing from communication with the well bore so that entrance of either gas or oil into the tubing is under control of certain special appliances. To the collar 5 is attached a perforated pipe 6, which at its lower end carries a valve 14 and a packer 7. From the lower end of the packer 7 there is extended a perforated pipe 8.

Any usual or preferred type of packer 7 may be employed, but I have shown the packer as comprising, for example, a number of expansion rings 9 having packing tubes 10 under operation of a gland 11. A slip joint 11 permits relative vertical motion between the gland 11 and packer body 7 for the purpose of expending and contracting the packer as required in the various operations.

The purpose of the packer 7 is to prevent all passage of gas and oil up the well casing 2, except as its passage is through the perforated tube 8 and connecting passageways with the controlling devices therein, which are hereinafter described.

Above the packer 7 the perforated tube 8 communicates with the valve 14, which is thus located in the apparatus at a point in the well hole in close proximity to the formation from which oil is to be produced and which provides a means by which the production of oil and gas from the well hole may be shut off or started up by a controlling operation instigated right at or in relatively closer proximity to the formation than is the general practice. The particular valve shown is of a stop cock type intended to be operated by relative rotation of the tubing 4 and the body of the packer 7, there being gears 15 for so controlling the opening and closing of the cock 14.

The top of the packer body '7 is tapered upwardly to provide a mounting for slips 17, which are movable downwardly and outwardly into engagement with the casing walls 2 in order to provide a means for anchoring apparatus in the bottom of the well hole. In order to operate said slips, links or rods 19 are connected to the slips and hence to the collar or head 18 at the lower end of the valve 14, and a slip joint 20 is provided at the upper end of the valve body to permit a relative motion between the packer body and valve for operation of said slips 17.

In the operation and use of the apparatus and process of this invention the space above the packer 7 is when the well is shut down free to a large extent of oil, so that there is very little downward pressure against the packer to hold the same in position. Since the oil and gas in the oilformation may be under considerable pressure, it is frequently desirable to have a positive means for locking the packer in the bottom of the well hole.

The portion of apparatus having to do mainly with the flow of the oil under regulated conditions to the surface of the well. comprises mainly an oil valve 21, a gas valve 22 and cooperating controlling float 23. The oil valve 21 is formed mainly by perforations or openings 24 in the collar 5, which are vertically spaced apart so as to establish greater or less flow of oil into tubing 4, depending upon the vertical position of the sleeve valve 25. The sleeve valve 25 is provided with a connecting rod 26 attached to the float 23 so as to be moved upwardly and downwardly by the vertical motion of the float 23. The float 23 is preferably an annular float surrounding the tubing 4, and the rod 26 is normally guided by a flange 27 formed on the collar 5. The weight of 115 the float 23 may in some cases be somewhat greater than would be floated by oil in the casing 2, in which there are provided springs 28 for the purpose of supporting the portion of the weight of such float. The gas valve 22 is positioned above 120 the float 23 and is formed by a collar 29 which forms a sort of Venturi throat in which there is a mixing nozzle 30 for the purpose of adequately jutting and mixing the entering gas and oil. The collar 29 is further provided with a plurality of 125 lateral holes or apertures, some of which are vertically spaced apart under the control of the valve sleeve 31. The valve sleeve 31 is provided with a valve connecting rod 32 which is fastened at its lower end to the float 23. The connecting 130 rod 32 is preferably guided in its vertical motion by a flange 33 on the collar 29.

At the upper end of the well casing there is shown a casing head 34 of any usual or prefened construction having a packing gland 35 through which the tubing 4 may pass and through which it may be rotated and with a suitable bearing 36 at its upper end for a collar 37 of the tubing.

There is also preferably provided a valve controlled'line 38, by means of which gas may be withdrawn as desired from the space between the casing 2 and tubing 4.

With the apparatus thus described, the process of producing oil and gas from an oil well is as follows:

The apparatus is lowered into the well hole and packer 7 set in position. During this installing operation, the tubing 4 is closed from communication with the contents of the well, and preferably substantially empty of oil. When the valve 14 is opened and in operation, oil and gas pass into the perforated pipe 8 and rise upwardly and outwardly through the perforated pipe 5 into the space between the tubing 4 and well casing 2, where in part the oil and gas separate. Neither the oil nor the gas may enter the tubing 4 until oil has entered the apparatus to such an extent that it rises up around the float 23 sufficiently to carry the float upwardly in the well hole. As the float rises upwardly in the well hole it opens the oil valve 21, permitting the oil to enter the tubing 4, and simultaneously opens the upper gas valve 22, permitting gas to enter the tubing 4. The amount that both of these valves are open depends upon the height of oil in the well, and thus the passage of gas through the tubing a is proportioned to the amount of oil entering the well, and also passing through the tubing 4. It will thus be seen that the gas and oil are introduced into the string of tubing in the oil well in substantially predetermined proportions and separately and at spaced apart points. In this manner, it has been found possible to proportion the gas passing from the well through tubing 4 to the oil passing through the tubing in the correct proportions to secure a maximum flow of oil. In this manner, a great saving of gas in the oil well is accomplished, and it is possible to secure-a flow of oil with a third or quarter the volume of gas which in many cases has been found necessary before the installation of this apparatus.

The operation of each individual oil well differs somewhat from the operation of other oil wells. In some cases, an apparatus will be operated with the valve lying at the top of the casing 2 closed, so that gas is neither taken from thewell nor added to the well. except that which flows out of the well through the tubing 4 with the oil produced. in other cases, it may be that there is not sufficient gas in the oil for proper production. in which case gas may be passed through the line 38 into the well hole for assisting in raising the oil. and th s passage of gas may be either continuous or intermittent. V

In other cases. it will be found that the oil will contain so much gas that the gas must be removed in part separate from the oil before any oil can enter the oil well, for otherwise it will exert such a large pressure on the oil producing formations as to inhibit entrance of oil into the well. In such cases, there may be a steady or intermittent release of gas pressure from the casin 2 surrounding the tubing 4 simultaneously with the production of oil and gas through the tubing 4.

A particularly advantageous feature of the present process and apparatus of producing oil and gas from a well is that when the well is prorationed or for any other reason it is desired to shut the well down at frequent intervals, this may be accomplished simply by closing the valve 14. In such a case, the oil well will continue to keep on producing oil and gas as long as there is sufiicient oil above the valve 14 and in the casing 2 to'keep the float 23 in an elevated position and until the tubing 4 has become substantially cleaned out of oil. Thus, at eachshutdown period the tubing 4 becomes free of oil and there is no the flow of oil, which is frequently nee :ssary with the generally used processes and apparatus for producing oil from wells.

The gas ports shown in the apparatus may in certain forms of the invention be constructed in size relative to the oil ports in various arrangements, depending upon the different wells and flow positions desired. For example, the gas ports may be optionally installed in the apparatus so that during the vertical movement of the sleeve valve the uncovered area of the gas ports may vary in one 01 the following three manners:

l. The gas ports may progressively increase as to total area, but proportionately decrease in relation to the total area of the exposed oil pbrts;

2. The gas ports may progressively increase as to total area, but proportionately increase in relation to the total area of the exposed oil ports; and

3. The gas ports may progressively increase as to total area, but remain proportionately constant in relationto the total area of the exposed oil ports.' 4

While the particular form of the process and apparatus herein described is well adapted to carry out the objects of the present invention, it is to be understood that various modifications and changes may be made, all without d ing from the principles of the invention, and this invention includes all such modifications and changes as come within the scope of the appended claims.

I claim:

l. A process of producing oil from a well, which comprises passing oil and gas into the Well hole surrounding a string of tubing, and causing the oil and gas to enter said tubing only when the level of the oil in the well is greater than a predetermined height, the entrance of gas into the tubing being dependent upon a suppy of oil being present for simultaneously entering the tubing and being proportional to the oil entering the tubing.

2. A process of producing oil from an oil well through a string of tubing normally closed from communication with the well, which process includes sealing oi the space surrounding the tubing from normal communication with the oil bearing formation, thereby forming a controlling chamber around the tubing, passing oil and gas from the formation into said controlling chamber, permitting the oil to rise in said controlling chamber to a predetermined height and then ,causing oil and gas to enter separately into said tubing, the gas entering the tubing at a place spaced vertically upwardly from the oil entrance and at a rate in proportion to the rate of entrance of oil into said tubing.

3. A process of producing oil from an oil well through a string of tubing normally closed from communication with the well, which process includes sealing oil the space surrounding the tubing from normal communication with the oil bearing formation, thereby forming a controlling chamber around the tubing, passing oil and 1-1;:

gas from the formation into said controlling chamber, permitting the oil to rise in said controlling chamber to a predetermined height and then causing oil and gas to enter separately into said tubing, the gas entering the tubing at a mation to such control chamber, and permitting the oil and gas in such control chamber to continue to flow through said tubing for a portion of time thereafter and until the greater part of the tubing becomes free of oil.

4. A process of producing oil in a well, which comprises packing the well off from the oil producing formation and controlling the passage of oil and gas from the formation into the oil well at a point relatively close to the oil producing formation, permitting the oil to rise to a predetermined height at least in the oil well before it is admitted to the producing tubing and thereafter admitting the oil and gas to such producing tubing and gas at separate inlets vertically' spaced apart and in proportion.

5. A process of producing oil in a Well, which comprises packing the well oiT from the oil pro-,

ducing formation and controlling the passage of oil and gas from the formation into the oil well at a point relatively close to the oil producing formation, permitting the oil to rise to a predetermined height in the oil well before it is admitted to the producing tube and thereafter admitting the oil and gas, in definite proportions, to said producing tubing through separate inlets vertically spaced apart, and separately passing gas to or from the well to the surface of the well.

6. A process of producing oil in a well, which comprises packing the well off from the oil producing formation and controlling the passage of oil and gas from the formation into the oil well at a point relatively close to the oil producing formation, permitting the oil to rise to a predetermined height at least in the oil well before the oil or gas is admitted to the producing tubing and thereafter admitting the oil and gas to such producing tubing at separate inlets vertically spaced apart and in proportion and shutting oif the flow of oil from the formation to the well hole at such point located relatively close to the oil producing formation as required by proration program while permitting after each shut-down the oil in the tubing to continue to flow to substantially reduce the oil therein.

'7. A process of producing oil from an oil well, which comprises permitting oil and gas to enter the space in the well hole surrounding the string of tubing and controlling the entrance of oil and gas into said tubing separately and proportional to the height of oil in said space around said tubing whereby the entrance of both gas and oil in said tubing is dependent upon the oil level being greater than a certain height in said well, and varying the area of the streams of entering gas and oil into the well tubing in accordance with said height of oil.

8.'An apparatus for producing cil in an oil well comprising a string of tubi..g normally closed from communication with the well, means for sealing off the space surrounding the tubing from normal communication with the oil bearing formation, valve control means operable by movement of the pipe for controlling the passage of oil from the formation by said sealing means into the space surrounding the tubing, and means for separately admitting oil and gas to said tubing in accordance with the height of soil in the space surrounding said tubing.

9. An apparatus for producing oil from an oil well, which comprises a string of tubing normally closed from communication with the well, means for sealing off the space surrounding the tubing from normal communication with the oil bearing formation, valve control inlet means operable by movement of the tubing relative to said sealing means for permitting the flow of oil and gas from the formation by said sealing means into the space above the sealing means and surrounding said tubing, separate means for introducing gas and oil into said tubing located above said sealing means, and a float for operating said latter means, said float being disposed surrounding the tubing above said sealing means.

10. An apparatus for controlling the flow of gas and oil from an oil well, which comprises a string of tubing adapted to be lowered into a well hole and closed at its lower end, a pair of v vertically spaced apart valve sleeves for said tubing adapted to uncover progressively increasing entrance area as the same' are elevated, and float means for actuating said valve sleeves by the height of oil surrounding said tubing.

11. An apparatus for controlling the production of gas and oil from an oil well comprising a string of tubing adapted to be lowered into a well hole and carrying a pair of vertically spaced apart valve members, a float connected with said valve members for jointly actuating the same so that the entrance of oil and gas into said tubing is proportional to the vertical position of said float, and a spring means for engaging said float for supporting a portion of the weight thereof.

ERLE P. HALLIBURTON.

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