GB2178780A - Side drive drilling - Google Patents

Abstract

Disclosed is apparatus and a method for drilling/reaming of offshore or onshore oil or gas wells from a rig platform (10) by using a motor (26) driven rotatable, axially stationary, kelly (22) for rotating an axially moveable kelly driven bushing (36) and drive 30 assembly (46-62) to impart torque to drill pipe 20. The motor (26), kelly (22) and kelly driven bushing (36) are located 32 apart from the drill pipe rotational axis and hence referred to as a side drive. This apparatus and method allows well bore drilling and reaming with 20 multi-connected drill pipe (triples) without heavy duty top drive motors and attendant heavy duty electrical cables, without increasing conventional derrick height thereby facilitating retro-fitting of existing derricks and may be practiced either on floating or stationary platforms. <IMAGE>

Description

SPECIFICATION Side drive drilling Background of the invention This invention relates to the drilling of oil gaswells, offshore or onshore, and is particularly directed to a method and apparatus for drilling such wells in triples (three drill pipe lengths connected together as a unit).

The conventional and most widely used drilling system includes a platform with a rota ry table on a platform for imparting torque to a vertically moveable kelly and to drill pipe, a derrick, and a traveling blockassemblywithin the derrick for raising and lowering the drill pipe through an opening in the platform. Each section ofthe drill pipe is connected one at a time to the traveling block assembly and lowered through the rotarytablefordrilling the well bore. In this conventional system, reaming, that is, withdrawing the rotating drill pipe from the well bore, is simply a reverse procedure also disconnecting the pipe one section ata time at the platform level.Thisconventional system is used on continuously moveable platforms such as on ships, or semi-submersibles, and on stationary platforms including jackups ortension leg platformsforwell drilling and on stationary platforms foronshorewell drilling.

More recently, there has been developed a system fordrilling in triples. In such a system,three drill pipes are connected together as a unit and then lowered as a unit through the platform. This triple drilling system is considered faster than the conventional system because the three drill pipes are connected together outside the drilling area. It has been found also that the triple drilling system has particular advantages during reaming operations. Forfurtherdetails in such systems, reference is made to U.S. Patents to Boyadjieff, Nos. 4,421,179; 4,437,524; 4,449,596; and 4,458,728.

In the patented systems, also referred to as top drive systems, a large motor, mounted on rails, moves vertically within the derrick, to apply rotary motion tothetop drill pipe of the three drill pipe unit.

However, the patented top drive systems, while saving time, also had important drawbacks. The installation of the top drive unit requires significant rework of an existing rig since it requires the derrick to be increased in height. The large torque places heavy loadsonthe rails. The top drive unit requires 1000 amp 75ft long cable in the derrick area which is always a tremendous hazard, especially on a moveable platform where motion compensators are used.

Those using the top drive system are also concerned about the down time since the large motor is a com plicated device and often the operators retain the conventional rotary table and kelly drive as backup. In addition, because ofthe weight of the top drive,the top drive has to be set aside arida hook applied to the traveling blockforhandling heavy casings.

The present invention improves both the conventional single drill pipe drilling system and the systems for drilling in triples utilizing the top drive unit and thus hasthefollowing advantages: existing drilling tools can be used, it is an inexpensive system, it can be installed in any rig with the minimum rework, there is no need for high power electrical drives located on the derrick, it permits the use ofan internal blowout preventer system, it is simple, light in weight and requires no reeducation orspecialtraining ofthecrew, it is usable on floaterswith existing motion compensators, and it allows the running of heavy casing.

Itwill be apparent also to those skilled in the art from a study of the drawings, the Summary and the Detailed Description hereinafter,thatthere are many other advantages to this invention not detailed above.

Summary ofthe invention The apparatus and method ofthis invention comprises a vertically disposed stationary kelly extending substantially the height of the derrick and driven buy a conventional motor located near the platform level or below with a kel Ey driven bushing connected to the kelly to be driven thereby. The kelly driven bushing moves vertically on the kelly and is connected to a drill pipe drive shaft on a drilling assembly by a drive assembly. With the vertical movement of the kelly driven bushing and the sprocket assembly, suitable torque is imparted tothe drill pipe to accomplish drilling and reaming in triples.

An upper link adaptor is also provided with means for handling heavy casing.

Brief description ofthe drawings Figure 1 is an elevational view of a typical derrick on a platform without a rotarytable and incorporating the side drive ofthis invention, Figure2 is an enlargement ofthe drilling system shown in Figure 1 in the area encircled by the arrow 2, Figure3 is a side view, taken along line 3-3 of Figure 2, showing the drilling system, Figure4is a cross sectional viewtaken along line 4-4 of Figure 2, showing the chain sprocket drive assembly for imparting torque to the drill pipe, Figure 5is a view, like Figure 4, but showing the assemblyforimparting torque to the drill pipe as a belt pulley assembly.

Figure 6 is a cross sectional view, taken along line 6-6 of Figure 4, showing the driving sprocket and part ofthe kelly driven brushing vertically broken away to show its connection to the kelly driven bushing, Figure 7is a cross-sectional view, taken along line 7-7 of Figure 6, showing the kelly driven bushing, Figure 8is an elevational view in cross-section, taken along line 8-8 of Figure 4, showing the driven sprocket, and Figures 9 and 10 are side and front views, similarto Figures 2 and3, but showing motion compensators as partofthe drilling system.

Detailed description Figure 1 shows a platform 1 with a central opening 12, through which drilling and reaming operations may be conducted and a derrick 14 ofthe convention al size and type supported on the platform 10. Drilling system 16 for raising and lowering drill pipe connected thereto is located within the derrick 14 and only partly shown in the drawing. This drilling system 16wilI be described in detail hereinafter but atthis point it should be noted that three sections of drill pipe 20 are connected together as a unit above the platform for drilling and reaming. This is called drilling or reaming in triples and those shown above the platform are shown connected to similar units below the platform.The center ofthe opening 12, the line of travel of apparatus 16 and the rotational axis ofthe drill pipe 20 are on the center lineofthe derrick 14 in the conventional manner. This will be referred to as the main or drilling axis. The platform and derrick may be located on a floater (i.e., ship or semisubmersible) or a stationary offshore platform (i.e., tension leg type) for drilling on a sub-sea well or may be part of a land based rig for drilling an onshorewell.

In accordance with this invention, and asshowp in Figure 4, an elongated solid rod 22 with flat sides 24 (three shown) extends essentially the height of the derrick 14and is connected to a motor and a gear box 26, shown below the platform 10 and to one side of the opening 12. The motor can be the conventional horizontally mounted motor as now used for driving rotary tables. A second opening 28 is provided in the platform 10 to one side of opening 12 to allow connection ofthe rod 22 to the motor and gear box 26. This elongated rod 22, referred to as a kelly, is centrally located of vertically disposed guide means in the form of channel members 30, (I-beams) attached at several places along the heighth of the derrick, para- llel to the main axis.Any suitable means may be provided for attaching the guide meanstothe derrick with sufficient strength to withstand any torque imparted thereto; fourteen bars 32 being shown schematicallyin Figure 1. The motorand gear box 26 may be located at the platform level or above at the convenience ofthe operator and attached to the platform or lower part ofthe derrick in any suitable manner.

The main requirement is that the motor and gear box are positioned to one side of the opening 12and connected to rotate the vertically disposed kelly.

Further, suitable bearings (not shown) for the kelly may be provided atthetop and bottom thereof and attached in any suitable mannerto the derrick to stabilize the kelly and allow rotation ofthe kelly for minimum friction.

Rotatablydriven bythe kelly is a kelly driven bushing 34 (shown in phantom in Figure 4 but in more detail in Figure7) positioned on a carrier 36 within the channel member 30 with suitable bearings 40 tofacilitate vertical movement of the carrier and kelly driven bushing. Only four of eight bearings 40 are shown suitably attached to the carrier 36. The number and type of such bearings is within the purview of those skilled in the art.

The kelly driven bushing 36 is provided with a plu rality of rollers42 (three shownl, arranged triangular- ly, to engage similarly numbered flat sides 24 on the kellysothatthekellymayimparttorquetothe bushing. The arrangement of the rollers would depend on the number of flat sides on the kelly. As shown, the rotary table rollers 42 are themselves provided with suitable bearings 44to facilitate their rotation with respect to the kelly and to minimize friction during vertical movement of the kelly driven bushing 340n the kelly.

In the embodimentshown in Figures4 and 7,the kelly driven bushing 36 is suitably affixed to a sprocket 46 so as to rotate with the kelly driven bushing 36 and drive a drive chain 50 coupled thereto. This sprocket 46 is also the driving element of a chain sprocket assembly to be described. In the embodiment shown, the means for fixing the kelly driven bushing 36 to the sprocket 46 is a plurality of bolts 52.

Suitable bearings 54 located between a sprocket housing 56 and the sprocket 46 facilitate rotary movementwith a minimum of friction.

Drivingly connected to the sprocket 46 by the drive chain 50 is a larger sprocket 62 affixed for rotating a drive shaft 64. The drive shaft is centrally bored for drilling fluid as is conventional. As shown in Figure 1, 4 and 8, the housing 56 encloses the chain sprocket arrangement, contains oil to lubricate and cool the chain sprocket arrangement, and suitable seals 70 are located at all necessary places to prevent leakage.

The drive shaft 64 forms part of the drilling system 16 and imparts rotation to the drill pipe, and all driven elements, kelly driven bushing and chain sprocket arrangement are located on a block 68 which moves vertically as part of the drilling system 16. The sprocket 62, like the sprocket 46, is provided with suitable bearings 66 between the sprocket and housing 56 to minimize friction.

Figure 5 illustrates an alternative to the chain sprocket drive assembly. In this figure, the two sprockets 46 and 62 and chain 50 are replaced with two pulleys 46a and 62a and a drive belt 50a. These latter elements were given the same reference numerals but with the suffix "a " since they function as a drive assembly inthe same manner as the chain sprocket assembly.

It is understood that the chain sprocket or belt drive assemblies are shown by way of example. Other drive means such as a geartrain may be used to imparttorquefrom the kelly driven bushingtothe drilling assembly.

Thus far described, it can be seen that this invention differs from the prior art in several ways. The kelly driven bushing is no longer located at the platform level nor on the main or drilling axis and is no longer a driving element for imparting torque to a vertically moveable kelly. Rather, the kelly driven bushing is a driven element and the kelly is the driving element and the latter is stationary relative to the platform. In other words, the kelly driven bushing and kellyfunction in this invention exactly opposite to theirfunction in a conventional drilling system. It should be apparent also that, with the vertical kelly and its power source located at the one side ofthe main axis and with the capability ofthe kelly driven bushing to move vertically, a large motor and the attendant complica- tions of high electrical power cabie to drive such a large motor at the top ofthe derrick have been eliminated. Additionally, it should be apparent that, with the elimination ofthetop drive motor, the heightofthe derrick no longer needs to be raised. Thus, a conventional derrick can be constructed, or a conventional derrick can be retrofitted, fortriple drilling and reaming.

Now in more detail of the drilling system 1 6for raising and lowering drill pipes and othertubular members as well as raising and lowering the rotary table and chain sprocket arrangement, attention is now directed to Figures 2,3,9 and 10.

These figures illustrate the drilling system 16 for raising and lowering the drill pipe and which is also used for raising and lowering the kelly driven bushing and the chain sprocket drive arrangementand,the embodiment disclosed also shows means by which heavy casing can be raised and lowered.

Thus, the drilling system 16 includes traveling block 80 typically connected to a crown block (not shown) atthetop ofthe derrick. The crown-block supports a swivel 82, the kelly driven bushing 36 and chain sprocket drive arrangement 46-62 (or46a-62a) supported on the block 68, and connected to driven shaft 64, an internal blowout prevention device 86, a hydraulic swivel 90, a heavy duty link adapter 92 with an upper kelly cock valve 94 located therebelow, a sub 86 for tripping with a stabbing bell 100 connected thereto. Links 102 attach a drill pipe elevator 1 04to theheavydutylinkadapter92.

To handle heavy casing, an upper link adapter 106 may be attached to the traveling block 80 and connected by heavy duty links 102 to the heavy duty link adapter 92.

The drill pipe elevator 104 is connected to the top of the three drill pipes connectedfortripping pipe.

Figures 9 and 10 illustrate the drilling system 16 with motion compensator 110 attached thereto to illustrate the fact that this invention can be used with such equipment. Since all other parts of drilling 16 are the same as described in connection with Figures 1,2 and 3, they are given the same reference numbers.

Also, since motion compensators are old and wellknown, no further description of their operation is thought necessary.

Claims (15)

1. A system for drilling an oil or gas well, comprising: first means for raising, lowering and rotating drill pipe through an opening in a platform to lower, raise and drive a drill bit used in drilling said well; said opening and first means being operable on one vertical axis,and second means operable on a second vertical axis for imparting torque to said drill pipe.

2. A system as claimed in Claim 1 wherein said second means applies said torqueto the top of said drill pipe.

3. A system as claimed in Claim 2 wherein a plurality of drill pipes are connected as a unit and torque is applied to the top of the unit.

4. A system as claimed in Claim 2 wherein said drill pipe is connected in threes as a unit and torque is appliedtothetopoftheunit.

5. In a system for drilling oil and gas well, having a platform with an opening through which drilling operations may be conducted and further including a derrick on said platform and centered oversaid opening, the improvement compromising; drive means, an elongated rod means disposed within said derrick and connected to said drive means to be rotated thereby, said rod means being parallel to the center of said opening and vertical centerline of said derrick, driven means responsive to the torque applied to said rod means by said drive means and connected to drilling means whereby drilling operations to be carried outthrough said opening.

6. The system as claimed in Claim 5 wherein said drilling means comprises more than one drill pipe section connected together as said driven means is imparting torque thereto.

7. The system as claimed in Claim 6 wherein said rod means is a kelly and wherein said driven means includes a kelly driven bushing moveablevertically on said kelly.

8. The system as claimed in Claim 7 wherein said driven means also includes a chain and sprocket assembly comprising one sprocket attached to said rotary table and a second sprocket attached to a shaft with said chain encompassing both said sprockets and with said shaft connected in driving relationship to said drilling means.

9. The system as claimed in Claim 7 wherein said driven means also includes a belt and pulleyassembly comprising one pulley attached to said rotary table and a second pulley attached to a shaft with said belt encompassing both said pulleys and with said shaft connected in driving relationship to said drilling means.

10. The system as claimed in Claim 9 wherein said driven means includes vertical guide means attached to said derrick for quiding said keliy driven bushing in its vertical movement.

11. A method of drilling a well bore beneath a platform which has an opening through which drilling operations can take place, comprising the steps of: raising and lowering drill pipe in one vertical axis through the center of said opening, applying powertothe top of said drill pipe from a source of power which is spaced from said main axis.

12. A method of drilling a well bore beneath a platform which has an opening through which drilling operations can take place, comprising the steps of: providing a source of rotary power in area ofthe platform but spaced from said opening, providing meansforraising and lowering drill pipe through said opening and for raising and lowering means which is continuously driven by said power source to provide rotary powerto said drill pipe, which is applied substantially above the platform level as said drill pipe is raised and lowered th rough said opening.

13. The method as claimed in Claim 12wherein the rotary power is applied to thetop of said drill pipe.

14. Asystemfordrilling anoilorgaswell,sub stantially as herein before described with reference to the accompanying drawings.

15. Amethodofdrillingawell borebeneatha platform which has an opening through which drill ing operations can take place, substantially as hereinbefore described with reference to the accompanying drawings.