SCSSV Full Report

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Tubing Retrievable Sub Surface Safety Valve Page 4

Project Report

On

“Tubing Retrievable Sub-Surface

Safety Valves”

Summer Internship

1

st

_June-25

th

_July2008

At

Submitted To:

Mr. Cecil Antao

(Ops/Mktg Account Manager)

Submitted By:

Ashwin Soni

Abhishek Bansal

Metallurgical Engineering & Material Science

Gas Engineering

2005-2010

2005-2009

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ACKNOWLEDGEMENT

We sincerely thank Mr. C.K. Pathak (Country Manager, India & Bangladesh, BOT) for providing us with this opportunity to learn and be part of this prestigious organization. We would give our special thanks to Mr. Cecil Antao (Ops/Mktg Account Manager, BOT) for guiding us throughout the eight week summer internship program and helping us in each and every aspect as our mentor regardless of the busy schedule he had which kept our morals high.

We give special thanks to Mr. Abhishek Kaushic (Sales Manager, BOT), Mr. Sushil Keshkar (Ops/Mktg Account Manager, BOT), Mr. D.K. Shayamal (Ops/Mktg Account Manager, BOT) and Mr. Rudappan Silvaguru (Field Service Manager, BOT) for providing us support and a platform to interact with the BOT team.

We extend our sincere thanks to the Field Engineers, Commercial Team, Logistics and Supply Chain Management Team, IT and Finance Department for providing us with the knowledge of the operations and sharing their vast experiences with us.

This summer internship has been a valuable learning experience and has helped us gain a perspective of the MNC culture and the corporate environment. We respect the core values of the company “Integrity, Teamwork, Performance and Learning “and will try our best to incorporate them into our actions. We thank Baker Oil Tools for providing us all the information required and allowing us to use it in this report.

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CERTIFICATE

This is to certify that the project entitled

“Tubing Retrievable Sub-Surface Safety Valves”

Submitted by

Mr. Abhishek Bansal

B.Tech., Gas Engineering (2005-09)

from

University of Petroleum & Energy Studies, Dehradun

&

Mr. Ashwin Soni

Dual Degree, Metallurgical Engineering & Material Science (2005-10)

from

IIT Bombay, Powai

is an approved record of work carried out by them at

Baker Oil Tools, Baker Hughes, India Project Office, Mumbai

under proper guidance for a period of eight weeks

(w.e.f. 1

st

_{June to 25}

th

_{July, 2008).}

____________

Cecil Antao

(Ops/Mktg Account Manager)

Baker Oil Tools, Baker Hughes Asia Pacific Ltd. Mumbai

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1. A Brief Review of the Summer Internship

The summer internship at Baker Oil Tools started w.e.f. 1st_{June to 25}th_{July i.e. for a period}

of eight weeks. On the first day, the HSE orientation took place wherein we were told about the Safety Policies of BOT. It was followed by a presentation on the core values of Baker Hughes “Learning, Performance, Teamwork and Integrity”. In the following two weeks presentations were delivered by the Finance Team, IT Team, Logistics and Supply Chain Management Team and the Commercial Team. They envisioned us about the task their team performs in order to carry out smooth and unrestricted operations in BOT.

For the next 6 weeks we were taken to workshops at ITS (International Tubular Services) at Ghansoli and British Gas, Wadala situated in Mumbai. In the workshops we gained valuable experience by working along with the Field Engineers. We learned about various products of Baker Oil Tools such as Liner Hangers, Multilateral Assembly, Full Bore Isolation Valve, External Casing Packer etc. We also assisted the Field Engineers working on live project for the BOT customers like GSPC, BG and ONGC and participated in breaking and redressing of various tools.

We also were taken to Baker INTEQ workshop for one day visit to have a glance of the equipments available there.

On the last day of the Internship we delivered a presentation on the project to the BOT team on the Project assigned to us i.e. “Tubing Retrievable Sub Surface Safety Valves”.

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2. CONTENTS

ACKNOWLEDGEMENT ... 5

1. A Brief Review of the Summer Internship ... 7

2. CONTENTS ... 8

3. LIST OF FIGURES AND TABLES ... 12

4. INTRODUCTION ... 13

5. BAKER HUGHES INCORPORATED ... 14

5.1 About Baker Hughes ... 14

1.1.1 Drilling & Evaluation ... 14

1.1.2 Completion & Production ... 16

1.1.3 Reservoir Technology and Consulting... 17

5.2 Financial Highlights ... 19

6. BAKER OIL TOOLS ... 20

6.1 THE Completion Company ... 20

6.2 THE Workover Company ... 20

6.3 THE Fishing Company ... 20

7. SUB-SURFACE SAFETY SYSTEMS ... 22

7.1 Introduction ... 22

7.2 Overveiw ... 23

Rating Envelope ... 23

RBT Threads ... 23

Unique Flapper Design ... 24

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Control Line Connection ... 27

7.3 Basic Principle ... 29

1. Sub-Surface Controlled SSSV’s: ... 29

2. Surface Controlled SSSV’s: ... 29

Contrast between SSCSV’s and SCSSV’s: ... 30

Versions of Safety Valves: ... 30

7.4 Industry Standards for Subsurface Safety Valves ... 31

8. Tubing Retrievable Surface Controlled Sub Surface Safety Valve (TRSCSSV) ... 34

8.1 Assembly Drawing and Component List ... 34

8.2 Working of a TRSCSSV ... 36

8.3 Models Available ... 37

CEMENTSAFE™ SERIES SUBSURFACE SAFETY VALVE ... 38

Onyx™ SERIES SUBSURFACE SAFETY VALVES ... 39

REALM™ SERIES SUBSURFACE SAFETY VALVE ... 41

TITAN™ SERIES SUBSURFACE SAFETY VALVE ... 42

SelecT™ SUBSURFACE SAFETY VALVE ... 44

NEPTUNE™ SERIES NITROGEN-CHARGED SUBSURFACE SAFETY VALVE ... 45

TRITON™ SERIES BALANCE LINESUBSURFACE SAFETY VALVE ... 47

T-SERIES™ SUBSURFACE SAFETY VALVE ... 49

8.4 Models available in T-Series ... 50

T (E) Series ... 50

TM (E) Series ... 50

TSM (E) Series and TUSM (E) Series ... 50

8.5 The Basic Hydrostatic Pressure Calculations ... 51

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Fail-Safe Setting Depth Calculations ... 52

Opening and Closing Pressure Calculations ... 53

8.7 Design Principles and Philosophy ... 56

Flow Tube Design Features ... 56

Debris Exclusion/Control Design Consideration:- ... 57

Scale Deposition prevention: ... 57

Flow Tube Closure Assist Tool ... 57

How side loading and torsional forces on a rod piston are perceived and designed ... 58

Dual opposite wound Power Spring... 59

8.8 Technical Evaluation of the ‘T’ Series SSV Equipment ... 59

Outer Housing thread seal design philosophy ... 59

Permanent Lock Open Features... 60

Evaluation of dynamic seal assembly and metal-to-metal stop seals ... 60

Components of dynamic seal assemblies and metal-to-metal stop seals: ... 61

Baker Oil Tools' Detent System for the 'T'-Series Safety Valves ... 63

Flapper and hinge pin design ... 64

Table 3- Features and Benefits of Wedge Shape Flapper ... 65

Table 4- Features and Benefits of Curved (Slim line) Flapper ... 66

Self-Equalizing Mechanism ... 68

Control Line Jam Nut Connection ... 72

Debris and Sand exclusion barriers ... 73

8.9 ‘T’ Series accessory tools ... 74

Flapper Lock Open Tool ... 74

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Separation Sleeve ... 76

Control Pressure Communication Tool... 77

9. CONCLUSION ... 78

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3. LIST OF FIGURES AND TABLES

Table 1- List of TE 5 (5.5") Components ... 35

Table 2- Fail Safe Setting Depth Calculations for the T (E) - 5 (5.5”) model (7) ... 55

Table 3- Features and Benefits of Wedge Shape Flapper ... 65

Table 4- Features and Benefits of Curved (Slim line) Flapper ... 66

Figure 1- RBT Thread Performance Envelope ... 24

Figure 2- Self Equalizing Mechanism ... 25

Figure 3-Curved Flappers ... 26

Figure 4-Chemical injection feature simplifies the completion and maximizes the benefits from injection process ... 27

Figure 5- Control line and its connections ... 28

Figure 6- A Sub Surface Safety Valve ... 29

Figure 7- Model "T (E)-5" Safety Valve (Assembly Drawing) (7) ... 34

Figure 8- Subsurface Safety Valve Type ... 37

Figure 9- RBT Thread connection... 59

Figure 10- Dynamic Seal Assembly ... 61

Figure 11- Location of Metal to Metal Stop Seal ... 62

Figure 12- Detent System/Shock Absorber ... 63

Figure 13- Wedge Shaped Flapper (Three point contact shown above) ... 64

Figure 14- Curved Flapper Design ... 66

Figure 15- Single Hinge Flapper Assembly ... 67

Figure 16- Baker Jam Nut ... 72

Figure 17- Debris and Sand Exclusion Barriers ... 73

Figure 18- Flapper Lock Open Tool ... 74

Figure 19- Wireline Insert Safety Valve ... 75

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4. INTRODUCTION

The safety systems are required for the protection of the personnel around the platform, the environment and to prevent any production losses. It is also required for shutting in a well, in case of emergency shut down due to catastrophe, production testing, inspection and other routine operations. The safety valves keep the well shut in when the control line pressure is released and open up when the pressure is again maintained (in surface controlled type safety valves). There are various versions of such subsurface safety valves available with Baker Oil Tools. They are either surface controlled or subsurface controlled. The surface controlled one is available in two types, one is tubing retrievable and other is wireline retrievable. The tubing retrievable subsurface safety valves are most widely used in the oil industry and are available in various models for various applications. They are available in various designs offering different features which have been discussed further.

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5. BAKER HUGHES INCORPORATED

5.1 About Baker Hughes

(1)Baker Hughes provides the worldwide oil and natural gas industry products and services for drilling, formation evaluation, completion and production. We create value for oil and gas producers by providing advanced, reliable technology to find, develop, produce and manage oil and gas reservoirs. We also provide reservoir engineering and other consulting services. Baker Hughes operates in over 90 countries serving independent, international and national oil companies.

Baker Hughes is the only major oilfield service company structured around strong product-line divisions that are focused on Best-in-Class products and services. Our divisions are organized in two segments -- Drilling & Evaluation and Completion & Production -- which share common opportunities in developing and delivering technology solutions during distinct phases of oil and gas development.

The newly-formed Reservoir Technology and Consulting Group includes two consulting firms – Gaffney, Cline & Associates and GeoMechanics International – that provide technical and commercial consulting, with unique capabilities in reservoir engineering and geomechanics.

1.1.1 Drilling & Evaluation

Our Drilling & Evaluation segment includes divisions that apply their products and services primarily during the drilling process to improve efficiency, reduce risk and acquire accurate information. The segment includes Baker Atlas, Baker Hughes Drilling Fluids, INTEQ and Hughes Christensen.

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Baker Atlas

Baker Atlas offers a complete range of down-hole well logging services for every environment including advanced formation evaluation, production and reservoir engineering, petro-physical and geophysical data acquisition services. In addition, perforating and completion technologies, pipe recovery, and processing and analysis of open and cased hole data complete the service range.

Baker Hughes Drilling Fluids

Baker Hughes Drilling Fluids provides fluids systems and services that help optimize the drilling and completion processes maximize hydrocarbon production and manage drilling waste. Leading technologies include environmentally compliant water-based and synthetic-based mud systems and remediation fluids that can restore productivity from damaged wells.

INTEQ

INTEQ provides real-time services to help oil companies drill more efficiently, evaluate geologic formations, and place wells in productive zones within the reservoir. Important technologies include automated rotary steerable directional drilling systems, high performance drilling motors, and integrated logging-while-drilling assemblies. INTEQ also provides data communications, data management and expert centers to improve drilling operations and enhance formation evaluation.

Hughes Christensen

Hughes Christensen is the leader in Tricone™ and PDC drill bit, ream-while-drilling and casing drilling technology. Hughes Christensen application and design engineers work with customers to provide the best drill bit for the application to continuously improve drilling performance.

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1.1.2 Completion & Production

Our Completion & Production segment includes divisions that apply their products and services primarily during the well completion, field production, transportation and refining processes. The segment includes Baker Oil Tools, Baker Petrolite, Centrilift, and the Production Optimization business unit.

Baker Oil Tools

Baker Oil Tools provides completion and intervention solutions that help manage cost and reduce risk while optimizing production. The division has a comprehensive line of completion systems, which maximize performance and safety from the reservoir to the surface. Wellbore intervention solutions address issues ranging from temporary well abandonment and fishing to casing exits, wellbore cleaning, and isolation, remediation and stimulation operations.

Baker Petrolite

Baker Petrolite provides chemical technology solutions for hydrocarbon production, transportation and processing, and also delivers pipeline integrity services. Baker Petrolite is a leader in oil/water separation technology and in solutions to control corrosion, deposition, bacteria and H2S in producing wells and production facilities. To serve refinery and petrochemical customers, Baker Petrolite provides chemicals and technical support to enhance plant processes, improve productivity, manage water treatment, and resolve environmental issues.

Centrilift

Centrilift provides artificial lift systems, including electric submersible pumps (ESP) and progressive cavity pump systems, as well as specific engineering, project management and well monitoring services. Centrilift has expanded the applications for ESP systems to harsh downhole environments that include high gas to oil ratio, heavy oil, high temperatures and abrasive laden fluids. New systems also address the needs of coalbed methane and subsea production.

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ProductionQuest

Baker Hughes formed its ProductionQuest business unit to provide technology and services that help maximize recovery from both new and mature fields. The unit provides production optimization services centered on the well bore, including permanent monitoring, chemical automation, intelligent production systems, and consulting services. The unit also includes the Baker Hughes Integrated Operations group, which manages projects and combines technologies and services from Baker Hughes divisions and subcontractors to meet customer objectives for both well construction and production optimization.

1.1.3 Reservoir Technology and Consulting

Baker Hughes recently formed the Reservoir Technology and Consulting Group to enhance the company’s capabilities in reservoir engineering, geomechanics and energy consulting services. The group currently includes Gaffney, Cline & Associates and Geomechanics International, Inc., which continue to operate as stand-alone consulting firms.

Gaffney Cline & Associates

Gaffney Cline & Associates is an international advisory firm focused on providing integrated technical and managerial services to all sectors of the oil and gas industry. For more than 45 years GCA has provided strategic and detailed advice aimed at achieving practical and commercially viable results. In addition to reservoir engineering, GCA advises a wide group of clients in exploration, reservoir evaluation, field development, drilling and production, pipeline, refining and LNG projects throughout the world.

GeoMechanics International

GeoMechanics International is a leader in consulting, training and software in the field of geomechanics and its application to oil and gas reservoirs. GMI was founded in 1996 by a team of experts from Stanford University's Department of Geophysics, and each of its

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Tubing Retrievable Sub Surface Safety Valve Page 18 consultants is a recognized leader in the field of geomechanics. GMI methods are focused on applying geomechanics modeling to the entire life of a reservoir and are based on 20 years of R&D and more than 12 years of practical application to oilfield problems. These methods have been proven to reduce exploration risk, save Non-Productive Time (NPT) and help increase production and recoverable reserves.

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5.2 Financial Highlights

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Price & Volume

Recent Price $ 81.36

52 Week High $ 100.29

52 Week Low $ 62.65

Average Vol (Mil) (RTMA) 89.629

Beta 1.36

Share Related Items

Market Cap. (Mil) $ 25,060.540

Shares Out (Mil) 308.020

Float (Mil) 305.600 Dividend Information Yield % 0.64 Annual Dividend 0.52 Payout Ratio (TTM) % 10.69 Financial Strength Quick Ratio (MRQ) 1.87 Current Ratio (MRQ) 2.79 LT Debt/Equity (MRQ) 16.87 Total Debt/Equity (MRQ) 25.09

Mil = Millions RTMA = Rolling Three Month Average TTM = Trailing Twelve Months MRQ = Most Recent Quarter

Asterisk (*) indicates numbers are derived from Earnings Announcements Pricing and volume data as of Jul 11, 2008.

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6. BAKER OIL TOOLS

(3)Baker Oil Tools leads the world in completion, workover and fishing solutions that help exploration and production companies maximize value from their hydrocarbon-bearing assets. Since its earliest days, the Baker name has been synonymous with excellence in down-hole and surface technology, performance and reliability. In the current era of riskier environments and higher stakes, those qualities are more valuable than ever.

6.1 THE Completion Company

Baker Oil Tools′ undisputed role as the industry leader in reliable, performance-based completion solutions is based on the world′s most reliable sealing and anchoring technologies, meticulous planning, and a no-nonsense approach to risk avoidance. From the Model D Packer to the FORMation Junction™ Multilateral Completion System, H2O-PAQSM and H2O-FRAQSM production enhancement processes, and InForce™ and InCharge™ Intelligent Well System and High-pressure/high-temperature environments – Baker has built a track record second to none by working closely with its customers to meet or exceed their needs in virtually every completion application.

6.2 THE Workover Company

When well maintenance or remediation operations become necessary, Baker Oil Tools applies more than five decades of industry-leading mechanical and inflatable packer technologies to provide integrated solutions that maximize productivity and minimize cost. At the forefront of Baker′s capabilities are its award-winning through-tubing workover technologies, which allow zonal isolations, water shutoffs and well cleanouts to be performed simply, without killing the well or pulling the production tubing.

6.3 THE Fishing Company

Fast, reliable solutions and around-the-world/around-the-clock service make Baker Oil Tools the preferred provider for both traditional and through-tubing fishing and re-entry projects. Baker engineers apply practical field experience to industry-leading cutting,

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Tubing Retrievable Sub Surface Safety Valve Page 21 fishing and milling capabilities to provide a range of solutions that are the most advanced and comprehensive available.

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7. SUB-SURFACE SAFETY SYSTEMS

7.1 Introduction

(4)In 1969, an operator lost control of a platform and spilled 4.2 million gallons of crude into the ocean, killing birds and contaminating beaches. Over 10,000 Loons and Western Grebes were killed. This spill was off the coast of Santa Barbara, encircled Anacapa and the eastern each of Santa Cruz Island, and earned the distinction of being the largest oil spill in California not to mention the most publicised. The Santa Barbara oil spill is considered one of the key events responsible for promoting the modern environmental movement.

A post-mortem on the accident showed that the well developed a leak in the tubing and casing between the ocean floor and ocean surface. This allowed the oil to flow, unchecked, into the ocean. Several attempts to regain control proved to be unfruitful. The well was finally brought under control by drilling a relief well and pumping in heavy fluids. This highly visible spill brought public attention to the need of safety equipment. A Subsurface Safety Valves would have allowed the operator to regain control of the oil flow immediately.

Shortly after the Santa Barbara oil spill, the petroleum industry began an accelerated program for the development of standards in relation to safety valves. The American Petroleum Institute’s Production Department in Dallas, took the lead in developing specifications and funding an independent test laboratory. Initial testing was done from 1973 - 1974 at Southwest Research Institute in San Antonio, Texas.

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7.2 Overveiw

Baker Oil Tools (BOT) is one of the leading suppliers of subsurface safety system equipment. Full line of subsurface safety valves are available for surface-controlled and subsurface-controlled tubing retrievable and wireline retrievable applications. Each valve includes Baker's proven technologies and innovations that have set many industry standards.

Rating Envelope

The combination of innovative computer programs and exhaustive laboratory testing has enabled Baker Oil Tools to develop an industry standard for predicting safety valve housing performance capabilities under all loading conditions. This conservative design approach ensures the thread's ability to withstand aggressive down-hole environments. The results of this evaluation are plotted in a graphical format which provides visual indication of the safe operating range for the safety valve. With this load envelope, operators can safely plan their completions with confidence that Baker Oil Tools' safety valves will protect their people and investments.

RBT Threads

Through extensive FEA analysis and technical research, Baker Oil Tools offers RBT premium thread connections. The efficiency of the RBT thread design allows Baker Oil Tools to offer the smallest OD's for a given tubing size across the safety valve portfolio. The RBT premium thread connections bring the superior protection and life extending advantages of metal-to-metal sealing technology to thousands of Baker safety valves. The connection's two-step design distributes thread load to impart greater strength than single-step designs. The metal-to-metal seal points at the box and pin noses provide enhanced pressure-containing capabilities. The combination of this two-step, ultra slim-profile thread and the use of high tensile strength materials allows for the slimmest outside diameters on the market.

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Figure 1- RBT Thread Performance Envelope

The RBT thread also includes an innovative center torque shoulder design. The torque shoulder provides superior resistance to back-off in down-hole service. In addition, damage is prevented to the metal-to-metal seals during high torque loads and precisely controls make-up loss.

Unique Flapper Design

Focusing on providing customer solutions along with using state of the art engineering practices, Baker Oil Tools has introduced several industry firsts relating to its unique flapper design. Baker Oil Tools was the first to offer a patented through the flapper equalizing feature which has proven to reduce operating costs for operators. The self-equalizing feature allows operators to open subsurface safety valves against differential pressure.

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Figure 2- Self Equalizing Mechanism

This unique design is resilient to debris and erosion which provides ultimate long-term reliability. The equalizing system has been used successfully in HP/HT and Big Bore applications where equalizing high pressures and large volumes can prove challenging. Baker Oil Tools also provided the industry's first wireline damage resistant flapper design. This design was created after careful review of mean-time-to-failure statistics relating to all subsurface safety valve designs. This analysis revealed that a good portion of failures could be eliminated with a wireline damage resistant flapper. The new flapper design protects the seal surface from wireline damage if an operator accidentally closes the valve during wireline operations. The protection offered by the wireline damage resistant flapper extends the safety valve life for operators.

Baker Oil Tools was the first company to design a 4-1/2 in. safety valve to be installed inside 7 in. casing and a 7 in. safety valve to be installed inside 9-5/8 in. casing. The key ingredient to this success was the unique curved flapper design. The curved flapper design was made possible by advanced machining processes, innovative engineering practices, and exceptional quality control. These ultra-slimline curved flappers allow operators to reduce their overall costs and maximize their return on investment by maintaining a large bore ID while reducing the casing sizes needed for the completion.

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Figure 3-Curved Flappers

For high flow rate natural gas applications, Baker Oil Tools recognized the need to design and manufacture one of the world's most rugged flapper designs. Every flapper design goes through an intricate engineering process to ensure the flapper can meet the demands of high gas velocities. Baker Oil Tools' flapper designs have been verified by gas slam tests to the highest rates available in the world.

Chemical Injection Capabilities

Scale, paraffin, or hydrate formation continues to pose significant risks to operators in obtaining desired returns on their investments. Formation of these solids can jeopardize safety valve function by impeding flow tube movement, thereby requiring intervention. With this in mind, it is the culture within Baker Oil Tools to look for ways to simplify completion designs that will increase system reliability and decrease operator cost while maximizing performance.

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Figure 4-Chemical injection feature simplifies the completion and maximizes the benefits from injection process

A result of this culture is the optional chemical injection feature available with the Titan™ Series Subsurface Safety Valve. This innovative design incorporates a field-proven double-poppet system that permits chemical injection directly into the safety valve. Combining this feature with a Titan Valve will virtually eliminate the need for any chemical injection mandrel in the tubing string above the safety valve. This will save the customer money and simplify the completion by reducing the number of components and tubing connections. Injecting chemicals directly into the spring cavity also ensures that the customer will receive the maximum benefit of the injection process by allowing injection directly where it is needed. For valve designs that do not offer the integral chemical injection feature, Baker Oil Tools offers a chemical injection sub that can be mounted directly on top of the Tubing Retrievable Safety Valve (TRSV).

Control Line Connection

Baker Oil Tools offers control line in a variety of lengths and materials. The standard control line provided is welded and drawn and complies to ASTMA269 specifications. Seamless and encapsulated control line is available upon request. Encapsulation improves the crush and abrasion resistance of the control line and can be offered in a variety of materials to suit the customers' down-hole environment. Baker Oil Tools offers a variety of control line connections to match the application. The Baker metal-to-metal jam nut, which

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Tubing Retrievable Sub Surface Safety Valve Page 28 is standard for valve working pressures of 10,000 psi (689 bar) and below, provides reliable control line connections at the safety valve. This jam nut features a front and rear ferrule design that reduces the potential leak path from control line to annulus. For working pressures greater than 10,000 psi (689 bar), Baker Oil Tools offers Autoclave connections. (5)

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7.3 Basic Principle

Depending on the environment and on the type and pressure of the produced effluent, it may be necessary to place a SubSurface Safety Valve, SSSV, inside the well itself. It supplements the one(s) on the wellhead if they should happen to be out of order (valve failure, wellhead torn off, etc).

(6)There are two types of SSSV’s:

1. Sub-Surface Controlled SSSV’s:

These valves that were often called storm chokes are now termed SSCSV (SubSurface Controlled Subsurface Safety Valves). They are set and retrieved by wireline. They close the well following a modification in flow conditions where they are located:

a) Either when the ambient flow rate increases (and so the pressure loss across the valve also increases)

b) When there is a pressure drop opposite the valve.

Baker Oil Tools Manufactures injection valves and velocity valves which fall under SSCSV’s

2. Surface Controlled SSSV’s:

The SCSSV’s (Surface Controlled Subsurface Safety Valve), of the fail safe type, are controlled from the surface by hydraulic pressure in the control line and are normally closed (i.e. closed when no pressure is applied in the control line). The control pressure acts n a jack which pushes a sleeve back thereby opening the valve. At the same time it compresses a powerful return spring. As long as the control pressure is kept at the set

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Tubing Retrievable Sub Surface Safety Valve Page 30 operating value, the valve remains open. However, if it falls below a certain threshold then the valve will close automatically solely under the effect of the return spring.

Contrast between SSCSV’s and SCSSV’s:

The SCSSV does not depend directly on ambient flow conditions in the well, but rather on one or more parameters measured at the well head. This also allows the subsurface valve to be controlled via a number of safety systems connected to process facilities. The well’s safety can therefore be achieved manually or automatically whether the trouble is directly related to the well or not: fire, explosion or impact, process problem, etc. Depending on the degree of safety required, the wellhead safety valve alone can be closed or, in conjunction with it, the subsurface safety valve can also be closed.

Due to the design of the hydraulically controlled valve, the depth at which it can be installed in the well is limited by the capacity of its running string. The spring must be sufficiently compressed to overcome the opposing force due to the weight of the hydrostatic column of the hydraulic fluid in the control line that governs the valve and acts directly on the jack.

Also due to its design, the valve could not be opened as long as the pressure difference between above and below the closing and sealing mechanism exceeds an average of 0.7 MPa (100 psi), so that the valve will not be damages when it opens. Some valves are equipped with an internal equalization device. Here, all that is required to reopen the valves is to increase the pressure in the control line with the well head closed. Otherwise it is also necessary to recompress the tubing above the valve (by means of a pump, a nearby well, etc.)

The SCSSV closing and sealing mechanism is either a flapper valve or a ball valve. For a long time preference was given to ball valves, mainly because of the sealing quality, even though the sleeve weldment (pivot cage) is complex and fragile. Currently check valves seem to be preferred choice as they are much simpler, more rugged and robust (i.e. safer). Also, a lot of progress has been made regarding the reliability and tightness of flappers.

Versions of Safety Valves:

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Tubing Retrievable Sub Surface Safety Valve Page 31 2. Tubing Retrievable: Screwed onto the tubing and pulled out with all or part of the

equipment in the well.

7.4 Industry Standards for Subsurface Safety Valves

The recognized industry standard for Subsurface Safety Valve systems is published in the American Petroleum Institute Specifications, API Spec 14A and API RP 14B. These two documents prescribe the minimum standards for quality assurance and performance to provide the maximum reliability of Subsurface Safety Valve equipment. They also provide guidelines for the design, installation and operations of safety valve systems. The following is a brief overview of these standards.

API 14A

The API 14A specification covers Subsurface Safety Valves, Safety Valve Locks, Safety Valve Landing Nipples, and all components that establish tolerance and/or clearances which may affect performance or interchangeability.

Classes of Service

Subsurface safety valves, safety valve locks and safety valve landing nipples must meet acceptable standards for materials manufacturing and testing for one of four classes of service.

Class 1 - Standard Service is for use in oil or gas wells which do not exhibit the detrimental effects caused by sand or stress corrosion cracking.

Class 2 - Sandy Service is for use in oil or gas wells where a substance such as sand could cause valve malfunction or failure (this valve must also meet the Class 1 service requirements).

Class 3 - Stress Corrosion Cracking Service is for use in oil or gas wells where corrosive agents could cause stress corrosion cracking. This valve must meet the requirements for a Class 1 and Class 2 valve and be manufactured from materials which are resistant to stress corrosion cracking.

Within this service class there are two sub-classes, 3S for sulfide stress cracking service and 3C for chloride stress cracking service. Metallic material, suitable for a 3S environment, shall be in accordance with NACE MR0175.

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Tubing Retrievable Sub Surface Safety Valve Page 32 Class 4 - Weight Loss Corrosion Service is for use in oil or gas wells where corrosive agents could be expected to cause weight loss corrosion. Class 1 or Class 2 and be manufactured from materials which are resistant to stress corrosion cracking.

A Subsurface safety valve which has qualified for Class 1 or Class 2 service will be considered qualified for Class 3 service without requalification testing, when it is manufactured from materials resistant to stress corrosion cracking.

Traceability

All components, weldments, subassemblies and assemblies of SSSV equipment shall be traceable except, Springs, Beans, Common hardware.

Hardness

Each pressure containing part shall be hardness tested in accordance with API.

Equipment Marking

SSSV equipment marking on the exterior surface with the manufacturer’s name or trademark, monogram, rated working pressure, class of service, model number, serial number, date of manufacture, and pressure classifications. This list is a general requirements, see specification of specific requirements.

Supplied Documentation

Each monogrammed SSSV, SV Locks and Nipples shall be delivered to the operator with a Manufacturer’s Shipping and Receiving Report and an Operating Manual.

Dimensional Inspection

All traceable components, except elastomeric seals, must be dimensionally inspected to assure proper function and compliance with design specifications and drawings.

Welding

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API RP 14B

The API RP 14B specification covers considerations for system design, instructions for safe installation, repair, and guidelines for operating and testing to assure sage and efficient performance of the SSSV system. Also included are procedures for reporting failures. This recommended practice is directed toward wireline, tubing retrievable and pumpdown SSSV systems.

Inspection and Testing

Safety valve inspection begins on location where documentation should be checked to verify serial numbers, size in accordance with the design, and that the safety valve lock for a retrievable safety valve is compatible with the landing nipple in the well.

Before running the SCSSV in the well, connections should be tightened or checked in accordance with operating manual. Ascertain that all visible sealing elements are not damaged or deformed, and that all other visible features do no exhibit marring distortion that may interfere with safety valve operation.

On new and replaced SSSVs, the opening and closing hydraulics pressures should be verified according to the operating manual. Ascertain that the SSSV will operate fail-safe at the setting depth before installation.

After installation of the SSSV in the well, the valve should be closed under minimum no-flow conditions by operations of the surface control. Verification of closure may be accomplished by wire-line, pressure build-up or flow test. If the well is capable of flow, the SSSV can be tested for leakage by opening the surface valves to check the flow. The SSSV is then reopened following the operation manual.

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8. Tubing Retrievable Surface Controlled Sub Surface Safety

Valve (TRSCSSV)

8.1 Assembly Drawing and Component List

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Table 1- List of TE 5 (5.5") Components

S.NO Component Name Quantity

1 Top Sub 1

2 Sliding Manderal Nut 1

3 Dynamic Seal Assmbly 1

4 Coupling Jamnut 2 5 Piston 1 6 Thread Protector 1 7 Cylinder Sub 1 8 Bearing 1 9 Set Screw 1 10 Coupling 1 11 Power Spring 1 12 Flow Tube 1 13 Spring Stop 1 14 C-Ring 1 15 Flapper Stop 1 16 Flapper Base 1 17 Spring Housing 1

18 Flapper Stop Seal Assembly 1

19 Flapper Pin 1

20 Torsion Spring 1

21 Equalizer Flapper Assembly 1

22 Flange Face Spacer 1

23 Resilience Seal 1

24 Rear Ferrule 2

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8.2 Working of a TRSCSSV

The working principle for all TRSCSSV is same. These valves are controlled from the surface via a small diameter hydraulic control line connecting the safety valve to the surface Emergency Shut-Down System. Since the valve is of the normally closed type, when the applied control line pressure is removed, the valve returns to the closed position thus shutting in the well.

The control line is connected to the top sub through the jam nut connection. The control line allows the control line fluid to fill inside the control chamber. The hydraulic oil used as the control line fluid is used to pressurize the piston in the control chamber. The piston in-turn pushes down the power spring. The piston is connected to the flow tube through coupling thus allowing it to move down as the spring is compressed.

As soon as the flow tube comes in contact of the closed flapper, it pushes the plunger of the equalizing port. The equalizing port allows the differential pressure across the flapper to equalize. As soon as the differential pressure is equalized, the flow tube pushes down the flapper to open position.

To again close the flapper, the pressure in the control line is bled off. This decompresses the spring and the flow tube moves up. The flapper then closes and the metal to metal seal doesn’t allow any fluid to pass through it. Thus the flow from the well is suspended and the well is shut in.

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8.3 Models Available

[Source: Baker Oil Tools Catalog]

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C

EMENT

S

AFE™ SERIES SUBSURFACE SAFETY VALVE

DESCRIPTION

The CEMENTSAFE™ Series tubing retrievable surface controlled subsurface safety valve is designed specifically for use in cement-through and frac-through applications. In addition, the CEMENTSAFE offers superior performance in applications that require the exclusion of flowing debris from the working components of the TRSV.

The CEMENTSAFE utilizes a piston with non elastomeric dynamic seals to isolate the control chamber and spring cavity from cement and produced fluids. This exclusion feature not only protects the sealing surfaces of the actuation system but also excludes cement or other debris from entering the flapper cavity of the safety valve.

The CEMENTSAFE incorporates the successful features from the T-Series™ product offering such as metal-to-metal housing seals, metal-to-metal containment below the flapper, thru-the-flapper self equalizing, and secondary puncture communication. This combination of features ensures the performance required to meet the demands of harsh environments in cement-through and frac-through applications.

FEATURES/BENEFITS

• Complete exclusion of well bore fluids from the spring and flapper cavity - Ensures smooth and reliable operation in cement-through and frac-through applications

• Non elastomeric piston actuator system - elimination of elastomers and their inherent problems

• Unique curved flapper - optimizes OD to ID relationships

• Metal-to-metal seal technology - 100% metal-to-metal sealing and containment of well bore fluids when the valve is in the closed position

• Patented thru-the flapper equalizing system - most successful and widely used system available to the market

• RBT Housing Seals - two step metal-to-metal sealing system provides strength and sealing under the harshest conditions

• Patented radial punch control fluid communication system – eliminates accidental communication primarily associated with linear shifting sleeves

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Onyx™ SERIES SUBSURFACE SAFETY VALVES

DESCRIPTION

The Onyx™ Series, is the industry's first 7 in. tubing Retrievable Safety Valve (TRSV) that can fit inside a 9-5/8 in. casing with cable bypass capabilities. In addition, Baker Oil Tools has designed the industry's first 4-1/2 in. TRSV to fit inside a 7 in. casing.

The Onyx Series of tubing retrievable surface controlled subsurface safety valves are specifically designed for big bore applications. Onyx Series safety valves are based on the successful T-Series™. The Onyx Series combines a patented, state-of-the-art closure mechanism and premium housing threads to produce the industry's first tubing retrievable safety valves that offer full-opening production in smaller casing sizes. As a result, operators get multiple benefits: the lower cost of smaller-OD casing, flexibility in designing their completions, and higher production rates typical of larger tubing sizes.

FEATURES/BENEFITS

• Slimline OD - enables larger tubing to be installed without sacrificing the full opening for maximized production

• Reduces completion cost (CAPEX) - the valve permits operators to use smaller casing programs

• Broader application coverage - ability to run capillary lines for downhole instrumentation or chemical injection and/or cables for electric submersible pump operation as well as dual completion installations

• Non elastomeric dynamic seal assembly - withstands extreme pressures and temperatures exceeding 28,000 psi and 450°F

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Tubing Retrievable Sub Surface Safety Valve Page 40 • Ultra strong curved flapper design - resistant to high impact loads in high flow rate applications

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REALM™ SERIES SUBSURFACE SAFETY VALVE

DESCRIPTION

The new REALM™ Series tubing retrievable surface controlled subsurface safety valves are specifically designed for high pressure / high temperature (HP/HT) applications. REALM Series safety valves build upon the success of the T-Series™ and use state-of-the-art technology to provide the industry's most reliable safety valve for these critical applications.

The REALM Series reduces operating expenses by providing absolute pressure ratings. The control chamber, dynamic seal system and rod piston are capable of withstanding full differential pressures. This capability eliminates the requirement to stage tubing pressures during installation, thus reducing installation cost and risk of over pressuring the valve. Baker Oil Tools utilizes a unique design approach combining cutting edge design techniques with the industry's most rigorous test program to provide safety valves specifically designed for HP/HT applications.

FEATURES/BENEFITS

• Absolute pressure ratings - no staging of tubing pressure

• Ultra strong curved flapper design - designed to withstand extreme differential pressures • RBT Housing Seals - two step metal-to-metal sealing system provides strength and sealing under the harshest conditions

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TITAN™ SERIES SUBSURFACE SAFETY VALVE

DESCRIPTION

Baker Oil Tools' commitment to innovation has resulted in the Titan™ Series surface controlled subsurface safety valve. Innovative field-proven technology that reduces the number of typical safety valve failure modes has been a hallmark of Baker Oil Tools' safety valves through the years. Titan standard features include: wireline damage resistant flapper, non elastomeric seal technology, and metal-to-metal containment of wellbore fluids in the closed position. These standard features deliver unprecedented reliability, efficiency, and adaptability.

One-quarter of all safety valve failures occur due to wireline damage during interventions into the wellbore. The Titan incorporates the damage resistant characteristics of the successful SelecT™ flapper design to virtually eliminate this failure mode. This design ensures all seal surfaces are protected from wireline contact even during accidental closure of the valve during wireline operations.

The Titan can be tailored to your specific needs, with available options such as integral chemical injection capability, wireline damage resistant seal bores, and various control system stop seal versions. An optional thru-the-flapper self equalizing system is also available to minimize operational expenses while maximizing productivity.

FEATURES/BENEFITS

• Field-proven technology - basic design features have been carried over from the highly successful T-Series™ and SelecT portfolios

• Patented thru-the-flapper self-equalizing - most successful and widely used system available to the market

• Wireline damage resistant flapper - design protects sealing integrity during wireline operations

• Patented lock open system - achieved via one wireline trip and allows flow through the locked open valve with no ID restriction

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Tubing Retrievable Sub Surface Safety Valve Page 43 • No shifting sleeves required to communicate - impossible to inadvertently communicate the hydraulic chamber

• Metal-to-metal seal technology - 100% metal-to-metal sealing and containment of wellbore fluids when the valve is in the closed position

• Optional chemical injection capability - injection mandrel within the TRSV eliminates the need for a mandrel above the valve and allows injection of fluids directly into spring cavity for maximum effectiveness

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SelecT™ SUBSURFACE SAFETY VALVE

DESCRIPTION

The SelecT™ is a tubing retrievable surface controlled subsurface safety valve that is designed to address the unique challenges that shallow set safety valves (typically <1,000 ft ) must endure. An ultra strong power spring delivers high closing forces needed to provide reliable and consistent closings in the presence of paraffin and other produced solids. One-quarter of all safety valve failures occur due to wireline damage during interventions into the wellbore. The SelecT design team developed an advanced flapper design to virtually eliminate this failure mode. This design ensures all seal surfaces are protected from wireline contact even during accidental closure of the valve during wireline operations.

Combining design enhancements with the successful features of the industry leading T-Series™, the SelecT addresses applications for smaller tubing sizes ranging from 2-3/8 in. - 3-1/2 in.

FEATURES/BENEFITS

• Ultra strong power spring - ensures smooth and reliable closures

• Wireline damage resistant flapper - design protects sealing integrity during wireline operations

• Patented thru-the-flapper self-equalizing - most successful and widely used system available to the market

• Metal-to-metal seal technology - 100% metal-to-metal sealing and containment of wellbore fluids when the valve is in the closed position

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NEPTUNE™ SERIES NITROGEN-CHARGED SUBSURFACE SAFETY VALVE

DESCRIPTION

The Neptune™ Series nitrogen charged tubing retrievable surface controlled subsurface safety valve is designed for completions requiring low operating pressures due to control system limitations. The Neptune operating system contains many patented features that provide simple, reliable, and fail-safe operation in the most critical applications.

The Neptune Series incorporates integral nitrogen charged systems within the valve, which oppose the hydrostatic pressure acting on top of the piston. The dynamic seal configuration used for the operating piston is a significant engineering achievement that utilizes the industry's first non elastomeric seal technology for nitrogen charged safety valves. Unlike other nitrogen charged designs, the Neptune Series' patented operating system is designed to be fail-safe closed in all applications even if the primary nitrogen chamber pressure is lost. The operating system is also far less susceptible to failing due to debris in the control line or hysteresis as all ball check seats, Belleville washers, and collets have been eliminated.

The Neptune Series comes standard with two totally independent operating systems and an integral control line filter. These features deliver the redundancy and assurance required in remote subsea wells. When it comes to your critical applications, the Neptune's innovative design and simple operation make it the only logical choice to protect your investment.

FEATURES/BENEFITS

• Two independent and operating systems - offers redundancy to maintain dependable valve operation

• Simple operation - uses the same moving parts of a conventional TRSV

• Patented fail-safe operating system - ensures fail-safe operation in all applications

• Innovative non elastomeric seal technology - an industry first for nitrogen-charged valves • Operating system is free of ball check seats - virtually eliminates failure due to control line debris

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Tubing Retrievable Sub Surface Safety Valve Page 46 • Optional integral control line filter - provides clean and trouble free operation

• RBT Housing Seals - two step metal-to-metal sealing system provides strength and sealing under the harshest conditions.

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TRITON™ SERIES BALANCE LINESUBSURFACE SAFETY VALVE

DESCRIPTION

The Triton™ Series balance line tubing retrievable surface controlled subsurface safety valve is designed for completions requiring low operating pressures due to control system limitations. The Triton combines the field-proven technology of the industry leading T-Series™ with a hydrostatically balanced rod piston to achieve simple, reliable and fail-safe operation.

Baker Oil Tools used a revolutionary design approach focusing on the elimination of previous balance line failure modes. As a result, the Triton Series offers fail-safe operation in every application. The non elastomeric rod piston design is also configured to make the operating pressure insensitive to tubing pressure.

These design features are essential in providing a low-operating-pressure safety valve for deepwater completions.

Failure to close due to the buildup of wellbore debris and in-service friction is one of the most common failure modes of TRSV's. The Triton Series rod piston configuration is designed to reduce the potential of this failure mode. Pressure can be applied to the balance line to assist in closure if the valve is unable to close due to the buildup of debris and additional friction.

Baker Oil Tools is committed to being the industry leader in offering versatile solutions for demanding applications. The Triton Series teams with the Neptune™ Series and Titan™ Heavy Sprung designs to deliver reliable solutions for almost every deepwater/subsea application.

FEATURES/BENEFITS

• Low operating pressure at any setting depth - reduces operating system investment • Simple operation - uses the same moving parts of a conventional TRSV

• Patented fail-safe operating piston - previous balance line failure modes eliminated and ensures fail-safe operation in all applications

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Tubing Retrievable Sub Surface Safety Valve Page 48 • Patented thru-the flapper equalizing system - most successful and widely used system available to the market

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T-SERIES™ SUBSURFACE SAFETY VALVE

DESCRIPTION

Baker Oil Tools' T-Series™ tubing retrievable safety valves offer unmatched protection from low end standard service through HP/HT applications. With T-Series Safety Valves, one can count on premium performance and long-term reliability for the life of the well which is attributed to complete removal of elastomeric compounds and elimination of linear shifting sleeves. Incorporating non elastomeric dynamic seals and metal-to-metal housing connections eliminates the possibility of explosive decompression which is commonly associated with elastomeric compounds. Extensive studies by operators and independent research institutes have shown that accidental actuation of shifting sleeves and subsequent control fluid communication is one of the primary causes for safety valve failures. By removing all shifting sleeves from the T-Series valve, Baker Oil Tools has eliminated one of the most common failure modes found in safety valves.

The T-Series versatile design is ideal for a variety of applications including deepwater completions. The T-Series Heavy Sprung Safety Valve features an extra strong power spring to overcome the additional hydrostatic pressure associated with deep setting depths. The reliability and simplicity of the T-Series have made it one of the most successful safety valves in the industry. The high spring closure force guarantees performance in the presence of paraffin or other produced solids.

FEATURES/BENEFITS

• Subsurface safety valve leader - successful field experience minimizes operating risk • Non elastomeric dynamic seal assembly - withstands extreme pressures and temperatures exceeding 28,000 psi and 450°F

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8.4 Models available in T-Series

There are various versions of T-Series safety valves available, depending upon the valve OD and the rated working differential pressure.

The rated working pressure varies from 5000 psi to 13500 psi. The OD’s are available ranging from 23/8_{in. to 7 in.}

In all, the different versions of T series can be broadly classified as follows:

T (E) Series

The Models “T(E)-5” and “T(E)-10” Tubing Retrievable Safety Valves are non-equalizing or self equalizing flapper-type subsurface tubing mounted safety valves. The self-equalizing version utilizes an Equalizing Flapper Assembly. The “TE-5” and “TE-10” are similar except for rated working pressure. The “T (E)-5” is rated for 5,000 psi working pressure, and the “T (E)-10” is rated for 10,000 psi.

TM (E) Series

The Model TM (E)-5 Tubing Retrievable Safety Valves are non-equalizing and self-equalizing flapper-type subsurface tubing mounted safety valves rated for 5,000 psi working pressure. The TM series valves utilize a redundant full open and full closed static metal to metal seal on the dynamic actuator.

TSM (E) Series and TUSM (E) Series

The TSM (E) and TUSM (E) series have all the features of the TM (E) series and apart from that they have a slim line outside diameter and ultra slim line outside diameter respectively. These valves have a curved slim line flapper installed instead of a wedge shaped flapper (present in T and TM series).

Curved shape of flapper allows for smaller O.D. of flapper housing or larger I.D. of flow tube compared to wedge shape flapper valve.

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Tubing Retrievable Sub Surface Safety Valve Page 51 Reduced O.D. or increased I.D. allows user more liberty in safety valve applications. A larger diameter TRSV can be run inside casing that would normally require a down-sized tubing string. A smaller pressure drop can be anticipated for a wireline valve application.

8.5 The Basic Hydrostatic Pressure Calculations

Hydrostatic pressure is created by the weight of a column of fluid. It is measured in psi or pounds per square. It always acts on down-hole tools when they are run in liquids. There can also be differences between the hydrostatic pressure in the annulus and tubing of a well, due to the use of different weight fluids in the tubing and casing. Such differences can elastically collapse or balloon, and therefore, lengthen or shorten; the tubing string. Another example is the effect of hydrostatic pressure in the opening and closing of sub-surface safety valves. The hydrostatic pressure or the tubing pressure opposes the opening pressure of the safety valve and this, to open the safety valve; the opening pressure mist offset the tubing pressure. Thus, the opening pressure of the valve is the tubing pressure + normal opening pressure of the safety valve. In the closing of the safety valve, the hydrostatic pressure or the tubing pressure actually helps to close the valve, due to the hydrostatic force acting on the valve actuator’s hydraulic piston area.

Hydrostatic pressure has to be calculated using the fluid gradient. This number has the units of psi/ft. Using data such as lbs/gal. Or API Gravity (if dealing with hydrocarbon liquids), one can calculate the hydrostatic pressure by:

1) Finding the fluid gradient in the Packer Calculations Handbook 2) Multiplying this by the depth of interest.

8.6 Fail-Safe Setting Depth

The fail-safe setting depth of a single line control SCSSV is defined as the maximum setting depth at which the valve will close while opposing the hydrostatic pressure in the control line. The fail-safe depth of a SCSSV is dependent on numerous factors, such as force of the power spring, actuator piston area, pressure gradient of the control line fluid and the annulus fluid, as well as friction force developed when actuating the SCSSV.

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Tubing Retrievable Sub Surface Safety Valve Page 52 For a particular SCSSV, the piston area and the spring force are constant, although the setting depth may increase by adding additional spring force, the pressure gradient of the control line fluid is the determining factor. If the annulus fluid is heavier than the control line fluid, and there is a possibility that the control line could break, the hydrostatic pressure applied at the working fail-safe setting depth, the theoretical depth should be modified by a safety factor of 1.2 to 1.5 to compensate for potential increase in mechanical and seal friction. Per API 14A, Fail-Safe Setting Depths are calculated with salt water in the control line plus and an additional 15% is factored in, thus the actual Fail-Safe Setting Depth of a valve is normally 28% greater with hydraulic oil in the control line.

Increased setting depths can be important for several applications:

In areas where it is desirable to place a safety valve below the level at which paraffin/scales occur

In the arctic, where the safety valve should be installed below permafrost zone

In platform, subsea, or arctic applications, where it is desires to ensure that no hydrates will form at the valve

In areas where the threat of earthquakes could cause tubing to leak below a shallow set safety valve.

Fail-Safe Setting Depth Calculations

The fail-safe setting depth calculation is based on the condition that the control line parts at the surface controlled subsurface safety valve and annulus fluid is introduced into the control chamber.

The fail-safe setting depth calculation is a force balance of the vertically downward acting forces and the vertically upward acting forces.

Downward Acting Forces

1. Hydrostatic Head = (Setting Depth x Hydraulic Gradient) x (Maximum Piston Area) = (Sd)(g)(A)

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Tubing Retrievable Sub Surface Safety Valve Page 53 3. Accumulated Friction = This factor includes all sources of friction such as spring friction, seal friction, flow tube friction, etc., and is to be determined from testing or good engineering judgment = Ff.

Upward Acting Forces

1. Minimum Power Spring Force with Valve in Closed Position - Fs.

2. Forces = (Sd)(g)(A) + W + Ff - Fs = 0 Vertical Direction = 0 Therefore … (Sd)(g)(A) + W + Ff = Fs and … Sd = (Fs - W - Ff)/(g)(A)(SF) where:

SF = Safety factor, generally 1.15

Minimum and maximum fail-safe depths are to be determined, considering the variation in spring valves as well as component tolerances.

Opening and Closing Pressure Calculations

The full opening pressure is to be calculated based upon the power spring(s) force in the full open position and the associated dynamic friction.

The full open pressure calculation is based on the assumption that only the pump pressure from the surface is available to open the valve. That is, this calculation ignores the hydrostatic head in the control line. The full open pressure calculation is a force balance of the vertically downward acting forces and the vertically upward acting forces.

Downward Acting Forces

1. Pump Pressure Force = (Full Open Press) x (Minimum Piston Area) = (Po)(A)