Journal of Multidisciplinary Engineering Science Studies (JMESS) ISSN: 2458-925X Vol. 4 Issue 11, November - 2018 Design And Fabrication Of A Prototype Offshore Blowout Preventer(Bop) Stack

1 Falade, A.A ,1 Oso,O.O and 1 Rotimi,I.A 1Department of Minerals and Petroleum Resources Engineering, Federal Polytechnic, Ado Ekiti, Ekiti State. Corresponding author: [email protected], [email protected]

The blowout preventer on an oil rig is controlled by series of pressure vessels, valves and lines. An Abstract—One of the first pieces of safety accumulator as seen below consist of control and equipment designed for oil and gas production, pressure vessels that kept charged to control thin the blow out preventer(BOP) is a large valve at rams and valves on the BOP stack. Some of these well that can be closed if the drilling crew loses accumulators can be quite large on modern drilling control of oil or natural gas while drilling or rigs, unlike the small one below which pulling unit. performing a work over. If theses fluids manage to BOPs are used on land well, offshore rigs, and enter the wellbore, they may threaten the safety of subsea well. Land and subsea blowout preventer are the rig and crew. The BOP is designed to either secured to the wellbore known as the wellhead. BOPs close an open wellbore, seal around tubular on offshore rigs are mounted below the rig deck. components in the well, or cut through drill pipe. Subsea preventers are connected to the offshore rig The Blowout preventer come in two basic types above by a drilling riser that provide a continuous on this design: They are Annular Preventers and pathway for the drill string and fluid emanating from Ram Preventers. The annular Preventer has its the wellbore in effect a riser extends the wellbore to outer length dimension of 500m and its inner the rig. (David, 2010). length of 440mm, breadth of 250mm seating on a connector of head flange 50mm thickness of Blowout preventer were developed to cope with length 350mm with same 350mm dimension extreme erratic pressure and uncontrolled flow making the bottom flange. At the top flange where (formation kick) emanating from a well reservoir it carries the annular Preventer and at the bottom during drilling. Kick can lead to potentially catastrophic edge where it becomes the head of the Shear event known as a BLOWOUT. An addition to Ram. The Pipe Ram, Blind Ram and Shear Ram controlling the downhole (occurring in the drilled hole) dimensions is as follows: Pipe ram and Blind Ram pressure and the flow of oil and gas. Blowout welded together making a total length of preventers intended to preventing tubing (e.gdrill pipe dimension 790mm(a semicircular opening and well casing), tools and drilling fluid from being created);this entity gives room to close annular blow out of the wellhore(also known as bore hole, the space. It has an integral Choke and Kill lines hole leading to the reservoir) when a blowout where fluid passes through to kill the well threatens. Blowout preventers are critical to the safety pressure in case of fluid entering well bore. The of crew, rig (the equipment system used to drill a choke and kill lines has a diameter of 200mm. The wellbore) and environment and to the monitoring and shear ram has a total length of 420mm with maintenance of well integrity: thus blowout preventers hexagonal arms of 275mm length attached to the are intended to provide fail-safety to the system that shear ram and Pipe ram. Attach on the hexagonal include them. (Collins, 2006) arm are short pipes of length 200mm cut on the Pressure control system otherwise known as a hexagonal arms along the ram sections. Blowout Preventer is a one of the primary function of Keywords—Annular Preventer, Blind Ram, drilling fluid is to prevent the flow of formation fluid into BOP, Fluid, Pipe Ram and Shear Ram. the wellbore. This formation fluid can either be water, oil, gas or the combination of these fluids. Weight of Introduction mud must be heavy enough to provide an Blowout preventer is a large, specialized valve or overbalance for safe withdrawal pipe, but this also mechanical device usually installed redundantly in much not be so heavy as to cause lost of circulation or stacks used to seal, control and monitor oil and gas impede the penetration rates. wells. Blowout preventer are design to control When a permeable formation is drilled that has underground pressure that may reach the surface and fluid pressure in excess of the hydrostatic pressure cause a blowout. The BOP stack consists of several exerted by the mud Colum, formation fluids (gas, oil or different devices that either close in the annulus or water) begins to flow into the wellbore. This flow of the open wellbore or close in around or shear the drill pipe formation fluid into the wellbore is known as KICK and string. this can be controlled by the well control system before the condition becomes more pronounced. However failure of the well control system to put the

www.jmess.org JMESSP13420402 2249 Journal of Multidisciplinary Engineering Science Studies (JMESS) ISSN: 2458-925X Vol. 4 Issue 11, November - 2018 dangerous signal under control result into uncontrolled Table 1: Dimensions For Construction/Fabrication flow of the formation fluid even to reach the surface is SPECIFIED the most spectacular expensive and hazardous part of S/N COMPONENT DIMENSION(mm) drilling (Ayodele, 2003). A blowout preventer system Annular Preventer should allow for movement of the drill string in or out 1 550 Length(Outer) of the well under pressure. This pipe movement is Annular Preventer called “stripping” and is done by allowing a small 2 440 Length(Inner) amount of the wellbore fluid under pressure to escape past the preventers as the pipe is moved. This 3 Annular Preventer Height 250 reduces frictional wear on the sealing element by 4 Pipe Ram Length 395 lubricating it. (Wikipedia, 2000). 5 Pipe Ram Height 790 6 Shear Ram Length 400 Objectives of the work: 7 Shear Ram Height 420 1)The Use of 3D AutoCAD of the design as 8 Connector Length 350 working guide. 9 Connector Height 250 Full Height of the BOP 10 1710 2)Material Selection; Used of Mild Metal (Steel Stack Material) to Construct and Fabricate the Model.

Scope of The Design and Fabrication DESIGN PARAMETERS: The following The project covers the use of AutoCAD; an Parameters are considered in the design: engineering working drawing which is a guide to achieve the fabrication and construction of the system 1)Well Realted Factor through material selection at the Olusegun Obasanjo Depending on the reservoir pressure of the well, Centre for Engineering Innovation of the Federal the higher the reservoir pressure, the higher the rate Polytechnic Ado Ekiti where Lathe, Folding, Drilling, of kick that could occur, then the average reservoir Milling ,Cutting and some other machine were utilized must be established through pressure survey to know in achieving the assembly. the rating of the BOP that can control such well. In this Materials And Methods proposed design, the BOP is designed to withstand a pressure rating of 3000psi. The following are materials and equipment use for the construction of the bop stack model; 2)Inside Facility Rating The bop stack was design designed using a)Piston Ram Rating And Packing Unit(Moving autographic design; some of the equipment used in in Parts).The ram position indicator allows the visual and fabricating the various parts of the bop stack is as positive indication that the rams are: open, closed, or follows: closed and locked. Compatible with Shear, Pipe or variable bore rams.  Folding machine  Drilling machine b)Hydraulic Fluid Properties: Extremely dilute,  Welding machine environmentally friendly water- based hydraulic fluids  Cutting tools such as cutting disc, grinding must be used due to the discharge into the ocean to stone prevent back- pressure on the vent circuit. The materials used are 25mm mild steel pipes, c)Accumulator Capacity: This canister component 3mm Plate, Packets of Electrode, red oxide paint, remotely actuates hydraulic pressure on the BOP, bolts and nuts, 15mm steel pipe for Connector make store fluid sent from the rig. During emergency up, 4mm plate for hexagonal arm length, Three Oxy pressurized fluid from this canister can provide force acetylene gas cylinders used. to power the blind shear ram. Welding Machine; the welding machine used in 3)Centering Of Drill String And Ram Extension fabrication is electric arc welding machine which has Configuration: Centre and hang off the drill string in its main source from electricity and makes use of the wellbore electrode. Welding is a fusion process in which 4)Wedged Faced(Conical Faced) Piston: welding rod is coat into the previously fixed space Annular preventer uses the principle of a wedge to between the metal to be joined (shapman, 1996). shut in the wellbore, It has a donut-like rubber seal, Drilling Machine; the machine was used to known as elastomeric packing unit, reinforced with produce hole in some parts, in order to facilitate steel ribs .Situated in the BOP housing between the bolting in some parts of the bop stack. head and hydraulic piston. When the piston is actuated, its upward thrust forces the packing unit to CUTTING MACHINE; the machine was used in constrict, like a sphincter, sealing the annulus. cutting the material into the required size.

www.jmess.org JMESSP13420402 2250 Journal of Multidisciplinary Engineering Science Studies (JMESS) ISSN: 2458-925X Vol. 4 Issue 11, November - 2018 5) Dual Pod Control System: An operable dual – semicircular opening that could shear off tubular and pod control system to ensure proper and independent casing section in the place operation of the BOP system. The activity of the annular preventer with the Fabrication Of The Bop Stack Model elastomeric packing unit installed (conical paced) gave an expected outcome when actuated, the The construction of the prototype BOP stack was packing element seal off around the annulus to carried out at the Obansanjo Engineering Innovation prevent pressure influx center, Federal Polytechnic Ado Ekiti workshop. Table 3: Result Showing Details of Dimension The BOP STACK was made from a Mild of Components Pipes(Steel) of 25mm thickness which makes up the annular Preventer unit, the three ram sections and the DATA UNITS VALVES connector made from 15mm pipe. Cutting was done Metal Pipe thickness for 25 using oxy acetylene gas cutting machine and folding Annular Preventer and mm the metal sheet of 3mm plate for the hexagonal arms Ram Sections attached to the 25mm pipes making up the ram Mild Steel Pipe thickness mm 15 sections. This five major components(Annular for Connector Preventer, Connector, Pipe Ram, Blind Ram and Mild Steel Plate thickness mm 12 Shear Ram) make up the BOP STACK using folding for hexagonal arm machine, and subsequently welded to the shape of Annular preventer height mm 250 the BOP STACK. Annular preventer length mm 440 Table 2: Describing The Selected Materials Packing element Nil Nil Shear ram circular radius mm 395 S/NO Selected Components Reason for selection Shear ram height mm 790 materials Pipe ram length mm 395 25mm Contains packing Annular Pipe ram height mm 790 1 metal pipe elements that seals preventer BOP stack total height mm 1710 in thickness around the drill pipe. Shuttle valve mm 50 25mm Has a semi-circular Piston mm 20 2 Pipe ram metal pipe opening that seal of in thickness around drill pipe. Activity And Output: Details of output from the Has a semi-circular project i.e result obtained from the study. 25mm opening with a cutting 3 Shear ram metal pipe Table 4: Table Showing Expected Outcome edge that can shear off in thickness the drill pipe. ACTIVITY OUTCOME It does not have a 25mm Shuttle valve for blind, semi-circular opening; 4 Blind ram metal pipe shear and pipe ram, piston The corresponding shear, the face of the element in thickness ram, packing unit, blind and pipe ram can be is flat. hydraulic fluid and operated. Thus effect the 15mm mild This Connects the accumulator being operation of shut-in. 5 Connector steel pipe Annular Preventer to designed and installed thickness the Ram Sections The ram section of the BOP as a section for Ram extension sealing annular and a configuration and DISCUSSION semicircular opening that centering drill string could shear off tubular and Discussion Of The Bop Stack casing section is in place The BOP stack fabricated with a metal mild pipe of Annular preventer thickness 25mm as shown in table 2 below which is installation with the When actuated the used to fabricate the Annular preventer, Pipe Ram, elastomeric packing unit packing element seal off Blind Ram and Shear Ram, 3mm mild steel plate to installed (conical faced) around the annulus to make the hexagonal arm attached to the three ram pressure safety valve preventer pressure influx sections, Red Oxide as a base paint to reduce installation with flange and corrosion, bolt and nut and 12mm plate used as gasket installation hexagonal arm.

Analysis showed performance with the installation of the annular preventer, shear ram and blind ram. It Conclusions and Recommendations was worked over to install ram extension configuration Conclusion as well as to accommodate drill string. From the studies of fabrication of BOP stack The expected outcome of the activity of ram through construction method, the following conclusion extension configuration is for sealing and a can be reached;

www.jmess.org JMESSP13420402 2251 Journal of Multidisciplinary Engineering Science Studies (JMESS) ISSN: 2458-925X Vol. 4 Issue 11, November - 2018 (1)Design and fabrication is the best approach Ayodele C.O,.(2003): The Concept of Oil Well through detailed drawing to produce a workable, Drilling Technology( Drilling Rig) pg 70 Godliness functional and a teachable model of a BOP stack Press and Publisher, Ado Ekiti, Nigeria. suitable for institution and some allied industries Collins Phil (2006): A-Z Drilling Requirement (2)The fabrication and construction carried out was Selection, 1st Edition Journal, Fact Publication ltd, that shuttle valves was installed at a respective Lagos, Nigeria. locations as for pipe ram and shear ram sections to Encyclopedia Britannica 2015 actuate the semicircular section for sealing the wellbore http:// en.wikipedia.org/wiki/main page (3)The fabrication was actualized, showing the Hammer David (2010): “ Discovery of Second annular preventer, shear ram and pipe ram with the Pipe in Deep water Horizon Rigor Sturs Debate piston ram attached to the sections amaong Experts”. Recommendation Henry Mattew (2010): “ Blow Out Preventer, Say Leak May Be Closer to a Solution” New York Times. Any BOP stack fabricated and designed must be able to make up with the investment returns for these Thomas H (2003): Water Well Design and reasons, the optimal oil productions and longer life of Construction., ANR Publication 8086. http:// the well must be given a high priority. groundwater.ucdavisedu The following recommendations are hereby Schlumberger Oilfield Glossary suggested from the study: http://www.glossary.oilfield.slb.com (1) A suitable working detail drawing (Auto CAD 3D) should be draw for the anticipated job UK Offshore Operators Association(UKOOA)- For Students (2) The design data should be carefully studied before using it to design the various explored view i.e. http://www.oilandgas.org.uk/education/students/intr annular preventer, shear ram and soon o.cfm Williams B.(2008): Uses of Blowout Preventers pg REFERENCES 80, British Info Publication, UK 4TH Edition Andrew C. (2010): “BOPs Oil Disaster Puts Spotlight in Small Texas Firm” Associated Press WIKIPEDIA(2000) http://en.wikipedia.org/wiki/Main Page.

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Figure 1. The Isometric View Of The Bop Stack.

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FIG 2 Showing The Fron View

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FIG 3: Shear Ram Details

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FIG 4: Pipe Ram Details

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FIG 5: Side View

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FIG 6: Connector Details.

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