AU2020103298A4 - new design of drill pipes and casings - Google Patents

Abstract

The invention relates to drill pipes with ribs and rings to improve pipe strength against helical buckling and bending. It is found that the level of helical buckling of the drill pipes with ribs, is less than pipes without ribs. It can replace the heavy wall drill pipe (HWDP) that is mostly used for hard rock formation.

Description

New design of drill pipes and casings

Department of Geology, Moscow Institute of Geology, Russian Republic, Email: alien.an(ayahoo.com.au 2Department of petroleum engineering, Curtin University, Australia, Email: palexeigy7mail.com,

Abstract In this paper we present experimental results of drill pipes with ribs, rings and those on pipes without ribs. The purpose for doing these experiments is to test the influence of ribs on improvement of the drill pipe strength against buckling. WE carried out compression test on both types of drill pipes (ribbed and non-ribbed drill pipes), where it was noticed that the level of helical buckling of the drill pipes with ribs, is less than pipes without ribs. We conducted some mathematical modelling to characterise this effect. The results of these calculations were that the drill pipes with ribs were stronger than those without ribs. The drill pipe with ribs and rings called DPRR (Drill, Pipes, Ribs, Rings) .It can replace the Heavy Wall Drill Pipe (HWDP).DPRR is mostly used for hard rock formation. DPRRs similar to regular drill pipes, being of the same length of Range II DP (27 to 30 ft.), the same as HWDP and with longer tool joints. We would like to make helical buckling index for different types of drill pipes (E 75, X95, J105, S 135), casings and collars, and weight of drill mud and formation stresses. Increases of weight of mud with collapse pressure in annulus can cause in theory helical buckling of drill string. Formation stress (vertical, maximum and minimum horizontal, hoop stresses) during drilling operations and production can cause helical buckling of pipes. It is a good idea to create a unique helical buckling index (AN index, constant) name of the author of this article.

Keywords: drill pipes, casings, collar, computer modelling, helical buckling and bending. 1. Introduction With the increase in demand of natural hydrocarbon as the main source of energy, industries endeavor to use advanced rotary drilling techniques to drill wells in a situation where it was not possible more than two decades ago. Now the technologies are available to drill through a complex reservoir using directional drilling technology. Directional drilling, especially drilling a horizontal well becomes a norm to exploit the unconventional complex reservoir. Among many challenges regarding drilling such wells, helical buckling is one of the main challenges which frequently causes failure of drill pipes during drilling operations. There are numerous reports of oil and gas companies from around the world. The deviation of the section of drill pipes causing the deviation of the well bore from the vertical direction in turn causes torque and high drag force. As a result, it leads to a 'lock up'. It is similar to the behavior of the hand - drill increasing contact which forces the lock -up situation. There was some information that drill pipes were bending from the bottom of the well, seven meters from this part and other lengths at a five degree bending of the pipe. This stops the rotation occurring at a time depending on geological conditions, after the pressure on the bit. When the depth is big enough to bend the pipe, depending on the weight of the string of pipes, meeting at the depth around 500 to 3000 meters, the pipe can be retrieved from the well. If there is a long string of pipe, it is automatically bent at around one degree (hole spiraling). After this the small bending drilling can cease. The pipe can be removed and the drilling process can be repeated a few times. Buckling behavior of tubular drills inside wellbores is the major subject of many articles [1-9]. Different aspects of the phenomenon are discussed including sinusoidal and helical buckling [2]. The influence of torque current Helical Models are valid for vertical wells and directional wells, but the validity of these solutions for deviated wells is not known. It has been generally recognized that connectors (tool joints and couplings) should have some effect on the buckling of the pipe. The equilibrium equitation for helical buckling tubing with weight is solved by an approximate method that produces a generalized form of the Lubinski result.A new definition of the neutral point is derived, based on a contact of recreation. A numerical analysis puts the Lubinski solution [3] in a technical context that allows further development, such as type ready string well bores and friction. The connectors should have some effect on the buckling of the pipe and the connector outside. The diameter may be 50% greater than the pipe body diameter. The analysis of buckling has had extensive attention in the last 20 years. Torque adds a new dimension to the buckling problems without torque buckling it occurs only for a positive effect axial force (compressive axial force pulse and pressure effects). Formulae for torque on the drill pipe or collar are needed to determine the maximum torque a drill pipe collar will take before it buckles, that is the level of torque at which, a casing will buckle. There is also equilibrium analysis, such as, contact force between the casing and the well bore. The behavior for drill pipes is shown below with picture a, b, c, d (helical buckling) figure 18. The helical buckling of drill pipes can be as a result of either buckling of the collar, buckling of the pipe or both the collar and the pipe.Drill pipe buckling is one of the major issues encountered during drilling deviated wells. The world of well engineers has had to wrestle with this problem of pipe-buckling during drilling in the process of the extraction of hydrocarbon resources. There are many cases, where it is identified as potential drilling failure by drill pipe buckling during drilling deviated wells. There have been several attempts to solve this problem as reported in much published literatures [3-5]. This paper seeks to propose a new design of drill pipes that minimizes the chance of drill pipe failure due to buckling. A good understanding of the buckling behavior of pipes in a drilling operation is very important to the industry. Long slender columns such as drill pipes have a low resistance to any bending and tend to fail by buckling, when subject to a vertical compression load. A long slender drill pipe used to drill a wellbore is subjected to a compression load on the base that is less than the hook load. Helical buckling can occur in the lower part of the pipe. Buckling forces are resisted by the moment of inertia of a pipe. Lubenski provided the first theoretical approach [3, 5] to account for sinusoidal buckling of vertical wells. The moment of inertia of the drill pipe is usually big enough to prevent buckling If a helical tendency exists above the drill collar, helical buckling may occur in the drill pipe. If the drill pipe is rotated in a buckling condition, the tool joints will undergo quick failure by pipe fatigue. The solution of such a condition is to use enough heavy walled drill collars in the lower section of drill string so that the desired weight may be applied into the bit without creating a buckling tendency of the drill pipe. The point above where there is no tendency to buckle is referred to as the "neutral point". In practice, the current design is to maintain the neutral point below the drill pipe (at the drill collar) during the operation. Many published articles have been published in the literature and have indicated strong influence of buckling and its potential impact on the efficiency of the drilling operation. Since AN's, and Lubinski's first theoretical approach [3,5] to sinusoidal buckling for vertical wells buckling of tubing, drill pipes, casing and coil tubing, this behavior has been studied by a number of engineers. There are publications covering almost every particular case of the buckling problem like helical buckling, the influence of friction, torque effect and the influence of well bore curvature. However, it is possible to find a solution to this problems 2. Proposed Drill Pipe To avoid helical buckling of drill pipes, it was suggested to design new generation of drill pipes: In this article a new form of drill string is presented that can minimize the chances of helical buckling and increase the efficiency of drilling. A new design of pipes was developed to overcome this problem which is shown in Figures 1-4. Figure 1 shows ribs helping to resist helical buckling. Figure 2 shows the view of the pipe and the location of ribs on the drill pipe. Figure 3 shows the stress state in steel at natural points. Figure 4 shows the new design of drill pipes. To avoid the helical buckling, a new generation of drill pipes or casing is proposed as shown in Figure 5. The drill pipe weighs less, which is modelled to increase stiffness without increasing the weight. The new design of drill pipes and the casing are considered next. This case study is based on practical experiments and calculations (table 1 and appendix) and Figures 6-18. Figures 6 presents normal drill pipe, Figure 7 shows buckling of the drill pipe under 1,400kN of pressure. Next, figure 8 represents pipe with ribs under 1,700 kN of pressure. The buckling which occurs is less in figure 9 than that which occurs in figure 10. Figure 11 demonstrate comparison of pipes with and without ribs under 1,400kN. In experiment were used hydraulic ram in department of mechanical engineering, Curtin University. Figure 12 comparison of a normal pipe with one using ribs under 1,700 kN of pressure. Figure 12 shows the same pressure but different deformation % of drill pipes. Figure 13 shows different pressure and different deformation % of drill pipes. Figure 14 present the same pressure but different deformation % of drill pipes with ribs and without ribs. Figure 15 presents different pressure but the same deformation % of drill pipes. Figure 16 demonstrates deflection (mm) of drill pipes without ribs. Figure 17 shows deflection of drill pipes with ribs. Figure 18 presents the different types of helical buckling. In this paper, a new generation of drill pipe design is proposed. The potential application of this pipe with detail design is discussed. Ribs have been constructed on 3 by 3/3 on the outside of the drill pipes and casing. The ribs on casing will be 10 mm and 20 mm wide outside on the surface of the casing. The ribs on drill pipe will be 8 mm and 16 mm outside on the surface of the drill pipe. One third (1/3) of regular length of drill pipes or casing is three (3) times the length from top to bottom. Alternatively, the length is divided by three (3) or the rings placed in 10 mm radius from the bottom, up to the middle outside the casing or drill pipe. This makes the structure of the drill pipe stronger without increasing the weight of the drill pipe. The length of drill pipe is 31 ft (9.39m) and OD is 5",ribs 7.05 m and each rib is 2.35m. Gaps are 2.34 m.Each gap is 0.58m.Gaps are 25% of the length of drill pipes. The circumference of drill pipes is 37.8 cm.There are 6 gaps with total length of 9.45 cm,with each gap atnI.57 cm .All the rings are 28.35 in length, with each ring at 9.45 cm.The length of the casing is 40 ft (12 m).The outside diameter of casing is 40 ft (12m).The outside diameter of the casing is9.625".The total length of the gaps is 3 m, with each gap at 0.75m.The total length of all the ribs is 9m.,with the length of each rib at 3 m.The total circumference of the rings is 72.76 cm.The total length of the gaps is 18 cm,with each gap at b3 cm.The rings have a total length of 54.57cm,with each ring at18 cm.The length of the drill collar is 31.6(9.57)m),and the outside diameter is 8".The total length of the ribs is 7.18m,with each rib at 2.39m.The total length of the gaps are 2.39m and each gap is at 0.598m .The length of the gaps 25% of the circumference of the drill colar.The total length of of the gaps is 15.12 cm.The whole length of the rings for the drill collar is 60.4 cm,each is 2.52 cm and rings are 45.36 ,wich ring at15.12 cmThat was all about increasing stiffness of the drill pipes or casing. The situation will be the same as with the frame in the construction. It has more thickness in three natural points as shown by Figure 3. As well, it will be thicker in all ribs and rings areas. All ribs are located by 120 degrees between each other .New design of drill pipes is figure 4 (ribs and rings)

3. Direct Stress or Normal Stress

Stress normal to the plane is usually denoted "normal stress" and can be expressed as

a= Fn/ A

where

a= normal stress ((Pa) N/M2 , psi)

Fn = normal componentforce (N, lbf(alt. kips)) (2, A= area (M, in

4. Manufacturing

1) Press ribs at steel factory (2) Form the ribs (3) Make the drill pipe weigh less, which is modelled to increase stiffness without increasing weight. An and me have three inventions in 2005 [10] 1. Ribs on drill pipe, casing and collars. 2. Different collars on ends of pipes, to keep them in order, logistic.

5. Experimental Investigation A worthwhile experiment for the new design of drill pipes was to install 25 cm 5 "DP, installed in used but in good condition, pipes. Ribs were pressed, forming the ribs at the mechanical laboratory, in Perth.. The drill pipe weighed less, which increased the stiffness without increasing weight. Analysis of tubular welded ribs on the walls of pipes were tasted by using a compression test. Different pipes were put under compression test consecutively. Pipes with ribs and without ribs were examined in compression test up to 1370 kN on pipes without ribs and with ribs, 8.3 kN per second. Pipes with ribs had 3mm deflection and without ribs, 16mm deflection, which is three times less deflection. Pipes with ribs had less deflection and as a result less helical buckling. We measured deflection with a computer. The second experiment was with a pipe with ribs. Pressure 1700 kN, more pressure than for normal pipe (1400kN) but the same deformation as with normal pipe. It was expected that the new design of pipes with ribs was not bent as a pipe without ribs and that in order to escape bending the pipe seven meters from the bottom of the well, that any bending of moving layers, floating stone, rocks research drilling or exploration drilling would render the drill pipe useless. The results were seen on the diagram experiments. It was found that ribs on pipes helps against helical buckling in directional or horizontal drilling. Increased stiffness reduced bending. New generation drill strings minimized helical buckling Figures show the deformation of drill pipe (found out from experience see diagrams) before and after modification. It was obvious from the test that proposed modified drill strings reduced the chance of failure and the overall drilling efficiency. The best design required computer modeling. Any likely results from such modeling formed the basis to potential commercial interest, such as collaboration with the Semetoma Company (Tokyo, Japan), if intellectual property safeguards were assumed. Figures 1-5 are draft of a new design of drill pipes.

6. Experimental Results Helical buckling is a common problem in the installation of sections of drilling pipes (known as drilling strings) [1, 2] The addition of external ribs to piping was considered as a possible way in which this problem could be reduced. Methods(compressional test):in the experiment reported, here one section of conventional steel pipe (S -135) had external ribbing added (Figures 5-11) another identical section of pipe (wall thickness 6 mm) was left unchanged. An experimental pressure device was used (Figures5-11) and the unmodified and schematic modified section of pipe was placed in the device and pressure was applied from 0 to 1700 KN vertically downloaded using a hydraulic ram. The time for deformation and amount of deformation was recorded. Three experiment were completed for design of drill pipes. For each experiment, we used different pressure (from 1400 to 1700 kN)

Results

Table 1: Experimental data Pressure kN % deformation sec No ribs 1400 36 168,67 ribs 1700 22 204,81 Pressure 18% difference No ribs 1400 36 168,67 ribs 1400 0 168,67 Deflection mm No ribs 1400 14(10-24) 168,67 ribs 1400 3(4,6-7,6) 168,67

Figures 12-17 present these results in more detail. As seen in Figures 12-14, deformation increases in a linear way, more in pipes without ribs. As seen in Figures 15-17, pressure increase, deflection more in pipes without ribs, than pipes with ribs.

7. Discussion

The idea behind of this new design of drill pipes was based on these experiments. There is a spiraling hole which causes helical buckling and as a result friction is caused, which results in damage from abrasive wear of tool joints. The purpose of this exercise was the drill string (depth of well bore is 3000 m, drill pipes are in sections at the beginning of the well boring or 24 m from the bottom) One of the best solution for helical buckling is to make some sections of drill pipes at the depth of 300 m, 1500 m in a borehole from ceramic. At this point a fuser section of ceramic pipes is measured from the bottom, first 24 m is made with ceramic pipe divided into 3 sections, and then regular pipe is used. Then at the depth of 1500 m in a borehole another section of ceramic pipes. Ceramic drill pipes are recommended for the above scenario. After this, regular pipes till is 300 m of the depth in a borehole. Then another of the ceramic pipe. This is the same situation for drill pipes with ribs or heavy drill pipes. Both apply to certain sections of drill strings. From the report published by Apache [5] they have experienced problems with tool joints with abrasions, which is the result of helical bucking of drill pipes, bending, hole spiraling or collapse forces on the drill pipe. This paper discussed the new drill string design for typical DP 5",DC 9-5/8",drill collar 8" .The new design of drill string costs is less, more efficient and is more economical. The whole drill string is moving downwards with less stress on drill pipes, puling under the weight of the drill string and the drill bit. Thicker pipes in the drill sections near the base of pipes will ensure less chance of buckling. The best solution is to use drill pipes with ribs and rings for horizontal and directional drilling. They are stronger and more flexible, so we can use drill pipes with ribs and ribs and rings outside or inside the drill pipes, or in a combination of the two. We can use drill pipes with ribs and rings outside or inside drill pipes, or in other combinations.

8. Conclusion A new design for drill pipes ,casings or collar have been observed It is called DPRR (drill pipe with ribs and rings),that looks very similar to regular drill pipes, having the same length of Range II DP (27 to 30 ft). Compression experiments were performed on ribbed and unrubbed pipes. Figures (4-10) show the results of deformation before and after modification. From these resultsitwas concluded that anew generation drill string composed ofribbed pipes reduced thechance offailure andincreased the overall drilling efficiency, because ribs increased stiffness and reduced bending of drill pipes and casing. This made the structure of both the drill pipe and casing stronger. The idea was to make a drill collar and couple of sections of drill string from the bottom from ceramic (alumina AL203, fused quartz S102 or zirconium dioxide ZrO2) or to make ribs on the surface of drill pipes. It could be possible to make a ceramic collar and a few sections of drill string with ribs and rings, outside or inside of drill piping and/ or casing.

Bibliography:

[1] Newman, K. R." Safely Exceeding the "Critical Buckling "in Highly Deviated Holes "SPE 1929".

[2] Guo,Q. "Mathematical Study of the Stability of a Long Elastic String Subjected to the Combining Loads of Tension, Compression and Axial Torsional Loads" New Mexico Institute of Mining and Technology 1992.

[3] Lubinski. A.,"A Study on the Buckling Of Rotary Strings" "API Drilling Production Practice 1950".

[4] Timoshenko.S. "Strength of Materials, Part 1 and Part 2" Krieger Pub..Co.1983.

[5] An, Alien received the Patent Request Provisional Application IP AUSTRALIA on the 3 0 th September 2005 PERTH. The Strengthening of Drill Pipes and Casing" MGRI (Moscow Geological Institute)

[6] Mitchell, R.F."Effects of Well Deviation on SPE" 1997 Enertech Engineering and Research Co.

[7] Mitchell, R.F. "Exact Analytical Solutions for Pipe Buckling in Vertical and Horizontal wells" SPE April 2001 Enertech Engineering Research Co.

[8] Mitchell, R.F. "General Analytical Solution for Pipe Buckling in Vertical Wells" SPE March 2003Enertech Engineering and Research Co.

[9] Bourgoyne A. "Applied Drilling Engineering" Louisiana State University 1991 the behaviour of drill pipe. 60 50 O 40 30 20 0 -

10

PRESSURE(MPA) - WITHOUT RIBS (BLUE) - WITH RIBS (RED) APENDEX

Rib increases the overall cross-sectional area of pipe, which in turn increases the stiffness (ElI)

E - modulus of elasticity of pipe

I - area moment of inertia of pipe\

Ah 2=7/32*r 4

I=Ah2

h is distance from neutral axis

A2>A1,12>Il

F = y/A

Where F, is applied force to crush

a = strength of material = constant as area increases so too does the load it will take. Failure will occur when stress exceeds strength of the material buckling.

lMPa = 1 N/mm 2

Afibs = Kr2

Aube = 21Rt

Where, r is the radius of ribs, R is internal radius of drill pipe, t is thickness of drill pipe

The area that the ribs add to the cross-section even is the equivalent at less than 1 mm increase wall thickness of the pipe.

Area of tube is 0.054 m2 2 Area of ribs = 0.00276 m2

Theoretical Analysis

This paper offers a solution that may reduce damage of pipes through fatigue fracture. Reinforcement with ribs will compensate/strengthen pipes to better withstand overload thrust and safeguard against helical buckling in this manuscript we considered the load which buckling drill pipes without ribs and not buckling with ribs. The buckling of drill pipes was analysed by Timoshenko and Lubinski.By lubinski compressive force

Fi = Ap * Pi

Fi = compressiveforce

Ap = area correspondingto parcker bore ID

Pi = pressure inside the tubing at the parker level

Displacement vector can be expressed by [1]

U. (X, y, Z) = - z V (X) ; uy (x, y, z) = 0 ; U '(x, y) = W (x)

where (X y IZ)are the coordinates of a point in the beam, UT)' '1 are the components of the displacement vector in the three coordinate directions, Wis the angle of rotation of the normal to the mid-surface of the beam, and Wis the displacement of the mid-surface in theZ-direction.

We chose shot drill pipes to show the affiance of experiments with shot pipes helical buckling is less

References

[1] Timoshenko

Drill Pipes > Damage

= EI dxo) MM=Edw "i" Bending

(MY

Mb Yield stress

o-I Mcapacity r Figure 19 shows bending moment

4 4

Io=ring+ 32 +e A r 32 +

I =I rin+2 T+g2 2 7 r + Z4 4

x 12 Figure 20 shows cross-section of drill pipe with ribs'e'

;T = r4 -r4

4

Io =-r 4

h -a a ' 2 2) 2 2

3 ( "h a a (+ d) 2 2)+ h a e22 12 12 2 2 Figure 21 shows

flange

IX = bhh 3 12

0 ±Ae 2 Parallel axis theorem Figure 22 shows cross-section of drill pipe with different type of rings

rcEI Ae2

_2 Arr Ar 2 Figure 23 shows cross-section of

drill pipe with ribs with axis and distance between ring and centre of the drill pipe

P o-0= <_ o AP

Pcap =ua y Ap

bulk c < cap Figure 24 shows the compressional pressure on drill pipe

Figure 25 shows the example of new design rill pipe and casing. New placement of ribs and rings

F (- = A

F= a-A

FkN(,T- in Pa, A mm2

a- strength of material - constant As area increases so too does the load it will take

Failure will occur when stress exceeds strength of the material buckling

NOMENCLATURE

Ap cross-section of drill pipe

Ar cross-section of rib a radius of drill pipe b c length of drill pipe d length of bit

E young's modulus

e distance between radius of drill pipe and cross-section length 'd'

lo moment of inertia of drill pipe cross-section

Ir moment of inertia of cross-section rib

Mb mending moment

Pcap compressional pressure capacity

P local localised compressional pressure

Pbuck buckling pressure

Rout outer drill pipe radius

Figure 1: Drill pipe with ribs. The ribs help to resist helical buckling

Figure 2: Top down view of pipe, the location of the ribs on the drill pipe

Figure 3: The stress state in steel at natural points

Figure 4: Proposed drill pipe

Figure 5: Normal drill pipe with both ribs and rings

Figure 6: Normal drill pipe

Figure 7: Buckling of the drill pipe under 1,400 KN of pressure

++

Figure 8: Pipe with ribs under 1,700kN of pressure the buckling which occurs is less in figure 9

than that which occurs in figure8 (under less pressure)

Figure 9: Drill pipe with ribs which under 1,400kN of pressure experiences no buckling

Figure 10: Comparison of pipes with and without ribs under 1,400kN of pressure

Figure 11: Comparison of a normal pipe with one using ribs under 1,700kN of pressure

Figure 12: the same pressure but different deformation % of drill pipes with ribs and without ribs.The red color indicate pipe with ribs and blue color indicate pipe without ribs

Figure 13: different pressure and different deformation % of drill pipes with ribs and without ribs the red colour indicates pipe with ribs and blue colour indicates pipe without ribs

Figure 14: the same pressure but different deformation % of drill pipes with ribs and without ribs. The red colour indicates pipes with ribs and blue colour indicates pipes without ribs

Figure 15: different pressure but the same deformation % of drill pipes with ribs and without ribs the red colour indicates pipe with ribs and blue colour indicates pipe without ribs

Figure 16: drill pipe without ribs

Figure 17: drill pipe with ribs

Figure 18

a)Helical buckling of collar c) Helical 2020103298

buckling of drill pipe drill pipe Natural point Natural point

collar

drill pipe collar

b) helical buckling of drill pipe and collar drill pipe natural point d) no helical buckling drill pipe

collar collar