US2268010A - Method of and means for cementing well formations - Google Patents

Description

Dec. 30, 1941. v, M 2,268,010-

METHOD OF AND MEANS FOR CEMENTING WELL FORMATIONS Fil ed April 15, 1939 2 SheetsShet 1 graze/WWO Dec. 30, 1941 v. E. BAUM 2,268,010

METHOD OF AND MEANS FOR CEMENTING WELL FORMATIONS Filed April 15, 1939 2 Sheets-Sheet 2 awe/WM Vic for 5. 6620177 ous methods have been v suificient volume to Patented Dec. 30, 194i METHOD OF AND MEANS FOR CEMENTING WELL FORMATION S Victor E. Baum, Tulsa,

Texas Okla, assignor to Merla. Tool Corporation, Dallas, Tex., a. corporation of Application April 15, 1939, Serial No. 267,991 3 Claims. (01. 166-1) This invention relates to new and useful im-.

provements in methods of and means for cementing well formations.

In the drilling of wells for oil and gas, it

the usual practice to drill the well down to the producing sand or formation and'set a casing above such formation, after which drilling is continued into the oil or gas sand or formation. It rather frequently occurs that the drill bit penetrates a water sand or formation which may be immediately below and adjacent to the producing formation, with the result that the water from the water producing formation admixes with the oil and interferes with the flow of the oil from the well. In many instances, the water may cone or channel upwardly, and practically kill the well so that the flow from the oil and gas producing formation is substantially cut off. 7

Where the well bore is drilled through the oil and gas producing formation into the water sand or formation therebelow, it has been common practice to introduce cement into the bottom of.

the bore to provide a cement plug therein; Vari-=.

employed for introducing this cement but cement plugs have been found unsatisfactory because the water eventually seeps around them and after a time flows in kill the well. In order to completely close the water formation with'cement it is necessary that the cement be forced deeply into the formation so as to obviate the possibility of flow around the cement. However, difliculty has been experienced in forcing cement into the water formation without also forcing said cement upwardly into the oil sands or formation. i It is, therefore, one object of this invention to provide an improved method of efliciently sealing off the water producing sands or formation without affecting the oil and gas. producing formation, whereby danger of destruction of the well by water is eliminated. An important object of the invention is to provide an improved method of cementing the water 4 producing formation below an oil and gas producing formation, wherein the cement is forced laterally into the water stratum to fill up the pores and interstices thereof so as to prevent a flow of water from said stratum into the well bore or into the oil and gas producing formation.

A particular object of the invention is topro vide an improved method for cementing the water stratum which includes,'maintaining a fluid preser than that maintained in the bore, whereby in elevation, of an formation and introducing cement into the bottom of the bore under a pressure slightly greatsaid cement is directed outwardly and radially of the bore and is forced into the water stratum to seal off the same.

A particular object of theinvention is to provide an improved method wherein a column of cement is introduced into the well bore and its direction and rate of movement is controlled by controlled pressure applied to opposite ends of said column.

Another object of the invention is to provide I an improved apparatus for cementing wells which includes a tubular conductor for conduct ing the cement to the bottom of the well, together with a valve in the lower end of the conductor capable of normally sustaining the weight of the column of cemen said valve being operated by a differential in pressure thereacross.

whereby a surface control of the operation'of the valve may be maintained and the cement may be effectively forced into the formation.

A further object'of the invention is to provide an improved method of the character described for cementing oil the water sand from the oil formation which includes the step of packing on? between said sand and said formation, whereby such sealing aids in directing the cement in a lateral or radial direction from the well bore, whereby the water sand may be sealed oil without affecting the oil formation A construction designed to%arry out the invention will be hereinafter'described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, in

which an example of the invention is shown, and

wherein:

Figure 1 is a view, partly in section and partly the improved method,

Figure 2 is a vertical, sectional view of thelower end of the bore showing the cement in place,

sure in the well bore to prevent flow from the oil Figure 3 is a transver e, vertical, sectional view of the control valve, v

Figure 4 is an enlarged, horizontal, cross-sectional view, taken on the line l-l-of'Figur'e 3,

Figure 5 ,is an enlarged,hori zontal, cross-sec tional view, taken on the line 5 5 of Figure 3,

Figure 6 is a transverse, vertical, sectional view of thepacker, and V apparatus for carrying out ed or closed position.

Figure 7 is a view, similar to Figure 1, showing the apparatus without the well'packerassembly.

In the drawings, the numeral l9 designates a well bore which has been illustrated as extending through an oil and gas producing formation or stratum A and into a water sand or formation B which is located immediately below the oil'and gas formation. A well casing II is disposed within the bore and has its lower end cemented, or otherwise secured in place withinsaid bore, said lower end terminating adjacent the upper portion of theoil stratum A. The upper end of the casing projects from the well bore and has the usual casing head 12 secured thereto. The head is provided with an outlet pipe l2a through which communication with the interior of the casing may be established. A well tubing l3 extends axially through the casing head and casing and is suitably supported in said head. The upper end of the tubing is connected by an elbow Ma with a pipe H which may serve either as an inlet or outlet to conduct fluids to and from said tubing. The lower end of the tubing terminates at the lower end of the well bore and may rest on the bottom thereof, as is illustrated in Figure 1.

As hereinbefore stated, the location of a water sand immediately below the oil and gas producing formation in a well bore permits the'water to flow into the bore and interfere with the natural flow from the oil and gas formation. The water enters the bore and flows upwardly, channelling through the well fluids. If the condition is present for any length of time, the water may wash away the wall of the bore, and eventually, said water impedes and interfereswith the flow from the formation A to such an extent that the well is killed and no oil and gas is produced. It is therefore, notonly desirable but essential that the water formation B be closed so as to prevent the flow of water.

In carrying out the invention, a valve 15 is connected in the tubing string l3 near the lower end thereof. This valve includes a tubular body l6 (Figure 3) which has its upper end connected to the tubing by a coupling collar H. The lower portion of the collaris threaded into the upper end of the body and the bore 18 of the collar is tapered or reduced toward its lower end. An annular valve seat l9 surrounds the lower end of the bore and is arranged to be engaged by a valve member 20. The valve member includes a cylindrical head 2| having an annular bevelled seating surface 22 at its upper portion; and above the seating surface the head is reduced to provide a conical tip 23. The head is movable within the bore 24v of the tubular body and has radial guide wings or ribs 2 la on its exterior surface for holding said head in axial alinement as it moves within the bore. Manifestly, when the head is in itsuppermost position within the bore, the bevelled surface 22 thereof is engaging the seat to close the bore of the collar l1. g

The valve head is provided with an axial dc pending guide stem 25 which has its lower end slidable in an elongate sleeve 26. The sleeve is mounted within a transverse spider 21 which is formed within a collar 28 threaded into the lower end of the bore of the body IS. A coiled spring 29 surrounds the stem and its upper end engages the underside of the valve head while its lower end rests on a follower ring 30 which is supported on the sleeve 26., The spring constantly exerts its pressure to urge the valve head to a seat- It will be evident that with the valve head in its seated position. any fluid pressure below the valve member is added to the spring to hold said valve'closed and in order to unseat the valve head, a pressure must be built up in the tubing l3 above the head suiilcientto overcome the pressure acting from below plus the spring pressure. Thus, the valve member is operable by the pressure differential thereacross and by varying the tension or pressure of the spring 29, the differential necessary to operate the valve may be varied.

The collar 29 which is mounted in the lower end of the tubular body is connected by a swaged nipple 9| and coupling 92, with the upper end of the tubular mandrel 33 of a well packer 34. The packer may be of any desired construction and, as illustrated, includes the mandrel having an upper confining thimble 35 secured thereon. An annular elastic packing sleeve 33 surrounds the mandrel with its upper end engaged within the thimble 35. A lower thimble 31 is slidable on the mandrel and has the lower end of the packing member engagedtherein. The lower thimble is coupled to an anchor tube 39 which is arranged to rest on the bottom of the well bore. The tube is formed with a plurality of inlet openings 39 to establish communication between the interior of the well tube and the well bore.

In cementing oi the water sand or formation B, the valve I5 is connected in the tubing string l3 and the well packer 34 is mounted below the valve as has been described. A suitable fluid or liquid under pressure is then introduced into the casing H and this'fluid is preferably an oil so as not to contaminate the producing formation A with a foreign substance. The fluid is under a suflicient pressure to kill the well and prevent a flow of well fluids from the formation A or a flow of water from the water sand B.

After flow into the bore has been halted, the tubing string l3 having the valve l5 and packer 34 therein is lowered until the anchor tube 38 strikes the bottom of the bore. At such time, a

continued lowering of the tubing imposes the weight of the tubing on the elastic packing sleeve 36 of the packer, whereby said sleeve is distorted radially outwardly into sealing contact with the wall of the well bore. It is preferable that the anchor tube be of such length that the packer is located at the. lower end of the oil producing formation A, whereby the sealing occurs at this point.

During the lowering of the tubing string the valve element 20 is in a closed position with the valve head 2| engaging the seat 19 whereby flow through the tubing is prevented. The valve head is held in its seated position by the coiled spring 29 and also by the pressuremf the fluid in the bore outside the tubing, which pressure is acting against the undersideof the valve element through the openings 39 and bore of the tube and mandrel. P

After the .packer has been set, as described, the cement is introduced into the upper end of the tubing l9 through the-pipe l4 and this cement falls downwardly through the well. tubing and its downward movement is checkedby the closed -TaTlve element 20. The cement ismaterially heavier than the fluid column outside of the tubing and, therefore, the coiled spring 29 is of such strength as to compensate for the diiference in weight betweenthe cement and the fluid in the bore, whereby this spring plus the fluid pressure is suflicient to-hold the valve bore.

, 2,268,010 3 is to be introduced. Therefore, the cement is (not shown). As explained, the weight 'of the column alone is' not 'suflicient to unseat the valve element. As a pressure is built up above the cement column, the differential across the valve element is increased until the fluid pressure and spring acting to hold the valve closed, is over come and at this point the valve element is unseated to allow the cement to flow downwardly through the packer and tube and into the well' This flow of the cement into the bore will be retarded by the fluid pressure and, therefore, such flow will be relatively slow. As the cement enters the bore, it flows outwardly into the formation B because said formation is relatively porous and offers less resistance than the fluid pressure in the well bore. Therefore, the cement drives the water deeper into the formation B and follows said water. In actual practice, the cement will force the fluid pressure below the packer back into,- the formation and will completely encircle the anchor tube, 39. The packer being in an'expanded position will prevent a direct upward flow of the cement around the tubingand any tendency of the cement to by-pass around the exterior of the packing sleeve 36 will be defeated by the fluid pressure in the bore acting on the the producing formation A will set up a resist-- ance to the flowing cement and since said cement will naturally follow the line of least resistance, it will flow deeply into the water sand B to completely plug the same. The. arrangement forces the cement to travel in a substantially lateral or horizontal plane whereby the water sand B is sealed off. After the cement is introduced into the formation B, the tubing is raised so as to permit the cement to flll the lower end of the bore. The fluid pressure is maintained' in the bore outside the tubing until the cement hardens. Manifestly, the cement does not enter the oil and gas formation A and does not interfere with natural flow therefrom where the fluid pressure in the casing and bore is removed. A

It is obvious that the valve i5- provides a means whereby the column of cement may be sustained in the tubing until it is desired to introduce the same into the formation. By properly controlling the fluid pressure in the bore outside the tubing and the pressure above the cement column, it is possible to eject the cement from the tubing substantially at any desired rate. This eliminates the cement rushing from the lower end of the tubing and upwardly into the casing and bore, which action is caused by the uncontrolled weight of the. cement column.-

Therefore, the method contemplates 'control of the cement as it is forced into the formation.

The control of the cement is accomplished by the valve and, since the spring 29 of the valve l5 may be readily changed to compensate for variations in the height of the cement column,

' formation A. It will be manifest that the maintenance ofthe fluid pressure in the bore and on a simple control valve capable of operating under various conditions and at various pressure differentials is had It is pointed out that although the use of a well packer has been found desirable, it is not essential to the invention. This packer may be entirely eliminated, as shown in Figure '7. When the packer is omitted, the pressure of the fluid column in the bore is suflicient to permit the cement from travelling upwardly in the bore since such pressure presents greater resistance 1 to the flowing cement than does the water sand or formation B.

'. The foregoing description'of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details ;of the illustrated construction, may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I .claim and desire to secure by Letters Patent is:

l. The method of cementing a water stratuir which is adjacent andbelow an'oil producing stratum which consists in, introducing a fluid under pressure into the well bore to halt natural flow from the strata, packing off between the water and oil strata, introducing a column of cement into the well bore, sustaining the column in the lower end of said bore, applying a pressure .to the upper end of the column to force the same into the bore against the fluid pressure therein, and utilizing the pressure of the fluid in the bore-to force the cement to travel radially of p the boreand laterally into the water stratum to plug the same. r I

2. An apparatus for cementingoff the water formation of a well bore including, a tubular conductor adapted to extend axially through the well'bore, means for creating a fluid pressure within the bore ,to prevent natufal flow, from the formation into the bore, means for-packing off between the conductor and thebore above the water formation, a valve in the lower end of the conductor having one side exposed to the pressure in the bore whereby such pressure urgesthe valve to a closed position, means for introducing cement into the conductor above the the formation into the bore, means for packing off between the conductor and the boreabove the up variations in pressures in the bore, etc., whereby water formation, a valve 'in the lowe'r end of the conductor having one side exposed to the pressure in the bore whereby such pressure-urges the valve to a closed position, a resilientmeans associated with the valve for also urging the valve to a closed position, means for introducing cement into the conductor above the closed

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