Ocean. Pipeline Solutions. Patent Rights Granted. Ocean Tel

Transcription

1 Ocean Pipeline Solutions Patent Rights Granted Ocean Tel P.O. Box Houston, TX

2 Scope of activities Licensing and support for the engineering, supply and installation of Bending Restrictor Pipe Joints (BRPJ) 2

3 Bending Restrictor Pipe Joint BRPJ Bending commences at the downstream end. 3

4 Bending Restrictor Pipe Joint BRPJ Bending continuous subsequently. 4

5 Bending Restrictor Pipe Joint BRPJ Bending continuous subsequently. 5

6 Bending Restrictor Pipe Joint BRPJ Bending continuous subsequently until supported on the seabed. 6

7 Bending Restrictors Have A Long History Cold bending of pipelines using bending restrictors were performed in the South Pass area of the Gulf of Mexico in the early 1970-ties. This technology is a further development with the additional advantages of controlling the ovality of the pipe section being bent. Courtesy Subsea7 7

8 Cold Bending Is Common Practice The design criteria for this method are the same as for cold bending of pipelines using the Reeling, S Curve and J tube installation methods. BRPJ facilitates omnidirectional bending in conformance with bending radius, strain level and ovality specifications. 8

9 Installation At Escarpment Excessive moments cause deformation of the pipeline during the installation. 9

10 Installation At Escarpment The same excessive moment achieves controlled bending by including BRPJs. Progression of the bending increases the support angle resulting a decreased moment, which may necessitate applying external loads and left in place for hysteresis reasons. 10

11 Installation Across Channels Optimized with one to three bending restrictor assemblies. Weight and or volume of water added in the sag bend to achieve the profile. Natural free span length Free span lengths reduced 11

12 Bending Restrictor Pipe Joint - BRPJ Width of gaps and spacing determine the selected strain level/bending radius. A B - Bending on the tension side result in closing of slots in the pinned connections at A preventing further bending and then continues sequentially - Bending on the compression side commences by closing of the gap between the collars and end section at B and then continues sequentially 12 at A

13 Bending Restrictor Assembly The BRPJ and the adjoining pipe sections of increased wall thickness are designed for the maximum moment when crossing an obstruction or required to bend the pipeline to the chosen strain level Additional BRPJ are joined in series depending on the profile of the obstruction Sections with increased wall thickness added based on the moment and the installation accuracy 13

14 Implementation The two basic functions of the BRPJ are to control the ovality and the bending strain the latter which is independent of the water depth but controlling the ovality is The initial phase of designing and testing the BRPJ confirms that the design criteria are complied with. These activities are identical to all components used in the offshore industry assuring acceptability for inclusion in a project The remaining activities of the implementation are part of the installation phase where the procedures used are common practice Courtesy Subsea7 14

15 Two Basic Functions The BRPJ controls the strain level and the ovality The section modulus of the bending restrictor is added to the section modulus of the pipeline being plastically deformed. The combined increased section modulus lowers the stress to a value below the yield point and further deformation ceases. Maximum strain Collars restrain the ovality with the maximum at the neutral axis. Maximum strain

16 Stress Strain Relationship API 5LX 16

17 Pipe Being Bent Analyzed Using Finite Element Procedure The pipeline part is evaluated considering the hydrostatic head, service, buckling, operational and environmental variables for the specific location. Moment required to achieve bending for the stress at the chosen strain level Radial loads emanating from content, hydrostatic head, internal pressure and expansion Increased Pipeline section subjected to bending Increased section section modulus modulus Bending restricting part guarantees that the bending strain and ovality are not exceeded which is modeled in the analysis. Forces determined by the analysis are considered in the design of the bending restricting components. 17

18 Bending Restricting Components D C - Collars D transfer tension forces by closing of slots when the pipeline elongates in tension - Collars C transfer compression forces by gaps closing - Annulus between the collars C and the pipeline facilitates continuous bending and controls the ovality - The internal diameters of collars D are dimensioned to alleviate transfer of hoop stresses - The section modulus of collars C and D are added to the pipeline when the slots and gaps close resulting in discontinued yielding - Components shown in red are of pipeline grade and green in high strength forged material - All components are corrosion coated with thermal spray aluminum (TSA) - Length of pipe section subjected to bending depends on the selected bend angle and strain level 18

19 Example Bend Capabilities DNV-OS-F101 allows 5% strain with additional requirement P 19

20 Bending Restrictor Pipe Joint BRPJ Creates a bend in conformance with the strain criterion regardless if soil indentation occurs, free spans and high spots are crossed to rest on the seabed. 20

21 Installation Using Common Work procedures - Prefabricated BRPJ is added to the pipeline on the installation vessel the same as common pipe joints - Locating the BRPJ in the pipeline make up governed by a long baseline acoustic array identically to terminating a pipeline - Accuracy of ±1 meter achievable plus consideration for meandering of the pipeline - Moment experienced during the installation phase induces the bending Courtesy Chevron - Final profile if required is achieved by placing weights at locations with the added alternative of including a volume of water in the sag bend. - Weights left in place for hysteresis reasons. 21

22 Installation At Escarpment Volume of water can be added in the sag bend to achieve the final profile. Contained with a mono directional pig. 22

23 Installation procedure Locating BRPJ in pipeline the make up - Transponder placed at location for bending - Pipeline marked at A when on installation vessel - ROV with transponder located at A when resting on the seabed - Distance between A and the bending location determined to an accuracy of ±1 m - BRPJ located at the same distance from A by measuring the added pipe length - Contingency for meandering of the pipeline during the installation and placement tolerance is considered A 23

24 Horizontal Deviation Expansion loop and change in direction through the heading of the installation vessel. Restrains horizonal movements and provides axial expansion. Host or Manifold 24

25 Horizontal Deflection At Mudslides Bending takes place if mudslide occurs. Bending restrictor installed during pipeline installation Direction of Mudslide Horizontal restraint installed subsequent to the pipeline installation 25

26 Solutions For Pipeline Displacements The risk of unacceptable compressive stresses dynamically imposed due to lateral pipe displacement at faulting seabed or sediment movement. Including BRPJ at high risk locations provide remedies for loadings. Courtesy Subsea7 26

27 Solutions For Pipeline Displacements When installing pipelines in deeper waters, the response of submarine slopes is a major geo-hazard issue partly due to the consequences for pipelines traversing the slopes. The dynamic and permanent displacements of the slope can exert axial loads and large bending moments on the pipeline. Including BRPJ at high risk locations provide remedies for loadings and as an insurance contingency for collapsing escarpments. 27

28 Pipeline Solutions Offer - Cold bending of submarine pipelines in any plane up to the maximum allowable strain criteria achieved during the installation phase - The bending takes place close to the seabed during the installation operations when additional length to follow an undulating seabed is created - Solutions are applied as a remedy when crossing seabed obstructions or environmental conditions, which otherwise require preparatory or remedial work - Benefits are realized when crossing escarpments, achieving a shorter direct route, contingency for mudslides, shore crossings and when short radius turns are required. - Contingency for collapsing seabed results in bending at predetermined criteria and alleviates interruption of production. 28

29 Ocean We thank you for your interest and are looking forward to participating in your projects 29