WO1989009869A1

WO1989009869A1 - An apparatus for, and method of, filling well casings

Info

Publication number: WO1989009869A1
Application number: PCT/EP1989/000328
Authority: WO
Inventors: George Edward Myles; Charles Alexander Forbes
Original assignee: Weatherford U.K. Limited
Priority date: 1988-04-08
Filing date: 1989-03-28
Publication date: 1989-10-19
Also published as: GB8808300D0

Abstract

A filling head assembly (60) is suspended in the top of a casing section (20). Mud or other filling material is introduced into the casing section (20) via a fill line (50). Flow control means (71, 72) associated with the fill line (50) are responsive to an operator controllable means (100) including a pneumatic circuit (101). Sensing means (80) are coupled to said pneumatic circuit (101) so that the flow of filling material into the casing section (20) ceases when the filling material reached a predetermined level.

Description

An Apparatus for, and Method of, filling well casings

This invention relates to an apparatus for, and method of filling well casings and, more particularly but not exclusively, for filling well casings being laid from a sea-going drilling rig.

In the process of drilling wells, the bored hole is lined with a metal casing made up of a string of interconnected casing sections which are lowered section by section from the drilling rig floor. Each casing section is connected by a casing joint or collar to the previously lowered casing section. This process also entails filling the last lowered casing section with a filling material which in the oil industry is mud in fluidized or flowable form. Hitherto on an oil drilling rig the process of filling a casing has been accomplished by using a manually operated casing fill line. This fill line is connected to a supply of filling material (mud). The flow of the filling material is manually controlled by an operator who directs the outlet of the line into the last lowered casing section which projects upwards frorr. the drilling rig floor.

This process has two major problems in terms of safety and time. In terms of safety, the process can give rise to accidents to personnel due to such factors as:

(a) The need for the operator to carry the fill line across a busy rig floor in order to fill the lowered casing section; (b) The need for the operator to stand by the casing whilst other associated drilling rig operations are in progress which at times places the operator in a vulnerable position; (c) The upper extremity of the casing section may be at a raised level relative tc the drilling rig floor due to equipment associated therewith which in turn may necessitate the operator having to support himself at a level above the drilling rig floor in a potentially hazardous position; and (d) This manual process can give rise to excess filling material (mud) being spilt on the rig floor thereby producing potentially dangerous conditions under foot.

In terms of time the sequence of operating steps in this process involves filling the well casing sections between successive steps of lowering casing sections. The filling step itself may require time for the carrying of the fill line to and from the casing section, as well as the actual filling time. In consequence, the filling time, which occupies a series of separate and distinct steps in the process, is time which adds to the overall time taken to place and fill the complete casing. The operating costs of drilling rigs are such that reductions in the total time for casing operations are constantly sought after.

The present invention, at least in its preferred embodiments, seeks to provide an apparatus for, and method of, filling well casings which avoid the aforesaid disadvantages and which enable the filling of well casings to be carried out in an efficient and advantageous manner.

According to one aspect of the present invention there is provided an apparatus for filling well casings, which apparatus comprises support means for supporting a casing section which is to be lowered into the well, a fill line for conveying filling material for filling said casing section, said fill line extending from connection means for connection to a supply of filling material to a filling head assembly for deliverinσ the fillinc material into said casino section, flow control means for controlling the flow of filling material through said filling head assembly, sensing means for sensing the presence of filling material in said casing section, operator controllable means for use by an operator at a location distanced from said support means, said operator controllable means being operatively connected to said flow control means, said operator controllable means being coupled to said sensing means to receive an indication of a predetermined condition and being automatically operable in response thereto to cause said flow control means to terminate the flow of filling material.

According to a second aspect of the present invention there is provided an apparatus for filling well casings, which apparatus comprises support means for supporting a casing section which is to be lowered into the well, a fill line for conveying filling material for filling said casing section, said fill line extending from connection means for connection to a supply of filling material to a filling head assembly for delivering the filling material into said casing section, flow control means for controlling the flow of filling material, sensing means for sensing the presence of filling material in said casing section, operator controllable means for use by an operator at a location distanced from said support means, said operator controllable means being operatively connected to the flow control means, said operator controllable means being coupled to the sensing means to receive an indication of a predetermined condition and being automatically operable in response thereto to cause said flow control means to terminate the flow of filling material, said flow control means comprising at least one valve means for closing the flow of filling the valve means being a normally closed valve means which is opened in response to actuation of the operator controllable means, wherein the operator controllable means includes a pneumatic circuit, the valve means being pneumatically operable to open in 5 response to air flow thereto via the pneumatic circuit, said air flow being above a predetermined pressure value to open the valve means, the valve means closing when said pressure value of the air flow to said valve means falls below said predetermined value. 0 Other preferred features of this apparatus are set out in the appended Claims.

According to a third aspect of the present invention there is provided a method of filling well casings, comprising the steps of:- 5 supporting a casing section by support means above a rig floor in readiness to be lowered into a well bore hole, arranging a filling head assembly in a position to deliver the filling material into the casing 0 section, providing a fill line for conveying filling material for filling said casing section, arranging said fill line to extend between connection means for connection to a supply of filling 25 material and the filling head assembly, providing flow control means for controlling the flow filling material, providing sensing means for sensing the presence of filling material in said casing section, 30 providing operator controllable means for use by an operator at a location distanced from said support means, said operator controllable means being operatively connected to the flow control means and being coupled to the sensing means to receive an

^•_ς indication of a predetermined condition and being automatically operable in response thereto to cause said flow control means to terminate the flow of filling material, and actuating the flow of filling material during lowering of the casing section.

It has been found that at least preferred embodiments of the above-defined apparatus and method have the following advantages.

(1) The filling of the casing section is accomplished automatically;

(2) the filling operation can be sequenced to take place as the casing section is being lowered;

(3) The filling operation can be carried out by a single operator who is also in control of the casing operation. This operator can operate at a location distanced from the well thus avoiding the aforementioned safety hazards;

(4) The flow control means enables the apparatus to be failsafe in the event of loss of power; and (5)The mode of filling avoids spillage of the filling material on the rig floor.

The sensing means claimed and described below in relation to the preferred embodiments takes the form of a pneumatically operable level sensing means. Whilst alternative sensing means may be employed such as a flow meter or a float mechanism or an ultrasonic level control, the pneumatically operable level sensing means is advantageous in that it responds to the level of the filling material reaching the sensing means. This simple, yet effective, criteria enables the flow of the filling material to be stopped when the level is predetermined relative to the top of the casing section. In contrast a flow meter system is designed to allow ε known volume of fluid to pass. Since casing section lengths and diameters may vary, the precise volume of filling material required for each successive casing section may differ. This would require the operator to input information to the flow meter on each occasion that the length/volume is changed, whereas this is avoided by the aforesaid means.

The operator controllable means of the preferred embodiment is pneumatically operable since for use on drilling rigs this has the advantages that (a) air supplies are readily available, (b) the pneumatic components are reliable, and (c) it avoids the use of electrical cables which on an oil rig would require additional safety checks and precautions.

For a better understanding of the present invention reference will now be made, by way of example, to the accompanying drawings, in which:-

Fig. 1 shows, schematically, one embodiment of an apparatus in accordance with the invention for filling well casings;

Figures 2A shows, on an enlarged scale, the filling head assembly and sensing means of the apparatus of Figure 1; Figure 2B show, on an enlarged scale, an alternative filling head and sensing means for use with the apparatus shown in Figure 1; and

Figure 3 shows, diagrammatically, an operator controllable means with a pneumatic circuit for the apparatus of Figure 1.

Referring to Figure 1, there is shown support means 10 for supporting a casing section 20 which is to be lowered into a well 30.

A fill line 50 for conveying filling material for filling the casing section 20 extends from connection means 55 for connection to a supply 66 of filling material to a filling head assembly 60 for delivering the filling material into the casing section 20. Flow control means comprising valves 71, 72 control the flow of filling material. Sensing means 80 (Fig. 3) sense the presence cf filling material in the casing section 20.

Operator controllable means 100, as shown in Figure 3, are for use by an operator at a location distanced from the support means 10. The operator controllable means 100 are operatively connected tc the valves 71, 72 and coupled to the sensing means 80.

In response to an indication of a predetermined condition, the operator controllable means 100 are automatically operable to cause the valves 71, 72 to terminate the flow of filling material.

In this embodiment the support means 10 is constructed as a travelling block 11 operable by the operator to lower the casing section 20 by means of the string elevators 14. String elevators 14 are clamped on the casing section 20 in known manner after the casing section has been brought into position by raising elevators (not shown) and connected to a casing joint mounted on the previously lowered casing section. Usually the casing section 20 will have another casing joint (not shown) mounted at the top thereof before it is raised into position so as to facilitate the joining on of the succeeding casing section. The filling head assembly 60 is supported on the travelling block 11 by means of a sling 16 attached to the hook 12 and centered between the bails 13 thereof by guide members 15.

It will be seen from Figure 1 that the fill line 50 is supported at its mid point where a coupling piece 52 is suspended from a derrick on the drilling rig (not shown). This arrangement facilitates the movement of the top section of the fill line 50 as the filling head assembly 60 is lowered from the position illustrated towards the drilling rig platform 40 during lowering of the casing section 20.

As illustrated in this embodiment the valve 71 is located at and associated with the connection means 55 and the valve 72 is located at and associated with the filling head assembly 60. Each valve 71. 72 is a normally closed valve and is opened pneumatically in response to actuation of the operator controllable means 100.

Turning now to Figure 3, the operator controllable means 100 includes a pneumatic circuit 101. The valves 71, 72 are pneumatically operable to oper. in response to air flow thereto along the line 129 from air supply 116. The valves 71, 72 close when the pressure of the air in line 129 falls below a predetermined value, for example 5.5 bar (80 pεi). In the pneumatic circuit 101, a pneumatically operable pilot valve 102 is diεplaceable between an operating position and a shut-off position. In its operating position, the pilot valve 102 directs the air flow via line 129 to the valves 71,72 to maintain them in an open condition and permit the flow of filling material. In its shut-off position, the pilot valve 102 inhibits the flow of air in line 129 causing the valves 71, 72 to return to a closed condition and terminate the flow of filling material. The valves 71, 72 are designed to operate such that the valve 71 at the connection means 55 closes before the valve 72 at the filling head assembly 60.

The pilot valve 102 is pneumatically displaceable to its operating position in response to actuation of a first manually operable pneumatic valve 106 designated a 'START' button which is so arranged that upon actuation thereof it opens a pneumatic line 121 between a first pneumatic source 112 and the pilot valve 102. Source 112 may be taken off an air supply at 0.7 bar (10 psi ) . The pilot valve 102 is pneumatically diεplaceable to its shut-off position in response to actuation of a shuttle valve 104 which, when actuated to adopt an open condition thereof, opens a pneumatic line 125 between a second pneumatic pressure source 118 and the pilot valve 102. Actuation of the shuttle valve 104 ensures thereby closure of the valves 71, 72.

The shuttle valve 104 is responsive via a pneumatic line 123 to a second manually operable valve 108 designated an 'Emergency STOP ' button for the purpose of closure of the valves 71, 72. The second manually operable valve 108 is connected to second pneumatic source 114 which may also be taken off an air supply at 0.7 bar (10 psi).

The shuttle valve 104 is also responsive to the sensing means 80 generating an indication of the predetermined condition for the purpose of closure of the valves 71, 72.

The sensing means 80 comprises a pneumatically operable level sensing means arranged to respond to the level of filling material in the casing section 20 rising to a level determining said predetermined condition. As can be seen from Figs. 2A and 2B the sensing means 80 includes a hose 81 arranged in juxtaposed relationship at the filling head assembly 60 with an outlet 61 for filling material.

As shown in Fig. 3 a pneumatic line 131 from sensing unit 110 carries low pressure air from the second pneumatic pressure source 118 to the sensing means 80 which, as shown in Figs. 2A, 2B, comprises hose 81 which has a ball-valve 82 therein. In this embodiment, the level determining the predetermined condition is the level at which the low pressure air is prevented by the filling material from leaving the hose 81 whereby a back pressure develops to initiate the aforesaid indication at the sensing unit 110 which switches the air supply 118 via line 127 to cause shuttle valve 104 to re-set.

It will be noted from Figs. 2A and 2B that the hose 81 of the sensing means 80 may be located alongside or within the delivery part of the filling head assembly 60. Each filling head assembly 60 has a connector piece 62 for connection "of the fill line 50. Each will be arranged relative to the travelling block 11 such that the outlet 61 thereof is below the level of the string elevator 14. It will be readily appreciated that the apparatus is failsafe since failure of the air supply

116 will automatically cause the valves 71, 72 to close and to stop the flow of filling material through fill line 50.

It will also be readily appreciated that once the casing section 20 is positioned as shown in Figure 1 with the filling head assembly 60 and the string elevators 14 in position, the operator can actuate the START button associated with the first manually operable valve 106 and the flow of filling material commences.

The casing section 20 can be filled as it is lowered by the string elevators 114 (and hoist). This enables a considerable saving in operating time. The sensing means 80 will automatically stop the flow of filling material when the filling material reaches the bottom of hose 81. This enables the string elevators 14 to be removed. Then the support means 10 can be raised along with the filling head assembly 60. Pick-up elevators can then place another casing section 20 in position. The support means 10 can be brought into position for the string elevators 14 to be clamped. This step automatically brings the assembly 60 into the position in which the outlet 61 is positioned for the next filling operation. Once the pick-up elevators (not shown) have been removed, the sequence can be repeated.

Claims

CLAIMS :

1. An apparatus for filling well casings, which apparatus comprises support means (10) for supporting a casing section (20) which is to be lowered into the well (30), a fill line (50) for conveying filling material for filling said casing section (20), said fill line (50) extending from connection means (55) for connection to a supply (66) of filling material to a filling head assembly (60) for delivering the filling material into said casing section (20), flow control means (71, 72) for controlling the flow of filling material through said filling head assembly (60), sensing means (80) for sensing the presence of filling material in said casing section (20), operator controllable means (100) for use by an operator at a location distanced from said support means (10), said operator controllable means (100) being operatively connected to said flow control means (71, 72), said operator controllable means being coupled to said sensing means (80) to receive an indication of a predetermined condition and being automatically operable in response thereto to cause said flow control means (71, 72) to terminate the flow of filling material.

2. An apparatus for filling well casings, which apparatus comprises support means (10) for supporting a casing section (20) which is to be lowered into the well (30), a fill line (50) for conveying filling material for filling said casing section (20), said fill line (50) extending from connection means (55) for connection to a supply (66) of filling material to a filling head assembly (60) for delivering the filling material into said casing section (20), flow control means (71, 72) for controlling the flow of filling material, sensing means (80) for sensing the presence of filling material in said casing section (20), operator controllable means (100) for use by an operator at a location distanced from said support means (10), said operator controllable means (100) being operatively connected to the flow control means (71, 72), said operator controllable means (100) being coupled to the sensing means (80) to receive an indication of a predetermined condition and being automatically operable in response thereto to cause said flow control means (71, 72) to terminate the flow of filling material, said flow control means (71, 72) comprising at least one valve means (71, 72) for closing the flow of filling material, the valve means (71, 72) being a normally closed valve means (71, 72) which is opened in response to actuation of the operator controllable means (100), wherein the operator controllable means (100) includes a pneumatic circuit (101), the valve means ^"171, 72) being pneumatically operable to open in response to air flow thereto via the pneumatic circuit (101), said air flow being above a predetermined pressure value to open the valve means (71, 72), the valve means (71, 72) closing when said pressure value of the air flow to said valve means (71, 72) falls below said predetermined value.

3. An apparatus as claimed in Claim 2, wherein the pneumatic circuit (101) comprises a pneumatically operable pilot valve (102) displaceable between an operating position and a shut-off position, the operating position of the pilot valve (102) directing an air flow to the valve means (71, 72) to maintain same in an open condition and permit the flow of filling material, the shut-off position of the pilot valve (102) inhibiting the flow of air to the valve means (71, 72) thereby to return same to a closed condition and terrr^nate the flow of filling material.

4. A apparatus as claimed in Claim 3, wherein the pilot valve (1CΣ. is pneumatically displaceable to its ooeratiπ: position in response to act sticr. cf ε first manually operable pneumatic valve (106) so arranged that upon actuation thereof it opens a pneumatic line (121) between a first pneumatic source (112) and the pilot valve (102).

5. An apparatus as claimed in Claim 3, wherein the pilot valve (102) is pneumatically displaceable to its shut-off position in response to actuation of a shuttle valve (104) which, when actuated to adopt an open condition thereof, opens a pneumatic line (127) between a section pneumatic pressure source (118) and said pilot valve (102), actuation of the shuttle valve (104) ensuring thereby closure of the valve means (71, 72).

6. An apparatus as claimed in Claim 5, wherein the shuttle valve (104) is responsive to a second manually operable valve (108) for the purpose of closure of the valve means (71, 72).

7. An apparatus as claimed in Claim 5, wherein the shuttle valve (104) is responsive to the sensing means (80) generating an indication of said predetermined condition for the purpose of closure of the valve means (71, 72).

8. An apparatus as claimed in Claim 2, wherein said sensing means (80) comprises a pneumatically operable level sensing means (81, 82) arranged to respond to the level of filling material in the casing section (20) rising to a level determining said predetermined condition.

9. An apparatus as claimed in Claim 8, wherein said level sensing means (81, 82) includes a hose means

(81) arranged in juxtaposed relationship at the filling head assembly (60) with an outlet (61) for filling material and conducting low pressure air flow thereto, the level determining said predetermined condition being the level at which the low pressure air is prevented by the filling material from leaving the hose means (81) whereby a back pressure develops to initiate the aforesaid indication.

10. An apparatus as claimed in Claim 2, wherein the valve means (71) is associated with the connection means (55).

11. An apparatus as claimed in Claim 2, wherein the valve means (72) is associated with the filling head assembly (60).

12. An apparatus as claimed in Claim 2, wherein the flow control means (71, 72) comprises two valve means (71, 72), one of said valve means (71) being located at and associated with the connection means (55) and the other of said valve means (72) being located at and associated with the filling head assembly (60).

13. An apparatus as claimed in Claim 2, wherein the support means (10) comprises elevator means (11) for the filling head assembly (60) coupled to elevator means (14) for the casing section (20).

14. A method of filling well casings, comprising the steps of:- εupporting a casing section by support means (10) above a rig floor (40) in readiness to be lowered into a well bore hole (30), arranging a filling head assembly (60) in a position to deliver the filling material into the casing section (20), providing a fill line (50) for conveying filling material for filling said casing section ( 2C ; , arranging said fill line (50) to extend between connection means (55) for connection to a supply of filling material and the filling heed assembly (63), providing flow control means (71, 72' for controlling the flow of filling material, providing sensing means for sensing the presence of filling material in said casing section (20), providing operator controllable means (100) for use by an operator at a location distanced from said support means (10), said operator controllable means (100) being operatively connected to the flow control means (71, 72) and being coupled to the sensing means (80) to receive an indication of a predetermined condition and being automatically operable in response thereto to cause said flow control means (71, 72) to terminate the flow of filling material, and actuating the flow of filling material during lowering of the casing section (20).