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Subsea Sand Management – Path C: Removal With Disposal (B-FSM-179)

After separation reintroduce to production line (bypass method)

New flow stream

  • Put sand in dedicated transport line, pig container, or float to surface

Clean and discharge (see module FSM-M8)

  • Requires sea floor disposal

Inject into disposal well

  • Slurry fracture injection

Repackage

  • Compress or use adhesive/cement to make “brick” for disposal or pickup
  • Containerize – put into container for disposal or pickup

Disintegrate (Comminution)

  • Use grinding, ultrasonic pulse, electrical discharge or chemicals to reduce particle size and put back into flow line

References:

  1. Rawlins, C.H. and Ditria, J.C., 2019. “The Subsea Sand Management Challenge – What to do with the Sand?”. Offshore Technology Conference, Houston, TX, 6-9 May, OTC-29278-MS. https://doi.org/10.4043/29278-MS
  2. Rawlins, C.H. 2019. “Enhanced Production Through Surface Facilities Sand Management.” SPE Distinguished Lecturer presentation. Link here
  3. eprocess-training.com

Next week I will continue discussion recommendations for subsea sand management.

Subsea Sand Management – Path B: Treatment (Particles or Flow Path) (B-FSM-178)

The Treatment Approach seeks to modify either the sand particles or the flow path to reduce or eliminate the deleterious effects of sand on subsea equipment.

Modify Particle Morphology

  • Change particle to smoother shape to reduce erosion rate – remove or smoothen sharp edges

Modify Particle Size

  • Reduce particle size below critical level where erosion is minimal

Particle Coating

  • Coat particle to smoothen out sharp edges or modify density – both to reduce or minimize erosion rate

Partial/Full Chemical Dissolution

  • Dissolve whole or parts of particle to remove sharp edges or reduce size below critical level – both to reduce or minimize erosion rate

Migrate particles to center of pipe flow

  • Keep particles from impacting pipe or components

An interesting example is shown in the figure below. Solid particles below a critical threshold size have a negligible effect on pipe component erosion. This threshold size is 100 microns for sand in water and 20 microns for sand in erosion. You don’t need to remove the particles below this threshold size.

References:

  1. Rawlins, C.H. and Ditria, J.C., 2019. “The Subsea Sand Management Challenge – What to do with the Sand?”. Offshore Technology Conference, Houston, TX, 6-9 May, OTC-29278-MS. https://doi.org/10.4043/29278-MS
  2. Rawlins, C.H. 2019. “Enhanced Production Through Surface Facilities Sand Management.” SPE Distinguished Lecturer presentation. Link here
  3. eprocess-training.com

Next week I will continue discussion on the three category paths.

Subsea Sand Management – Path A: Conventional Approach (B-FSM-177)

The Conventional Approach uses known or standard methods or technology.

Exclusionary Production

  • Install downhole completion equipment
  • Reduce well output below sand production level

Flow Design

  • Lower velocity in piping to minimize erosion
  • Increase velocity to prevent solids from settling

Material Design

  • Design components with manageable erosion or increase MOC for longer erosive life (material type or thickness)

Leave sand in-place and remove during periodic maintenance.

References:

  1. Rawlins, C.H. and Ditria, J.C., 2019. “The Subsea Sand Management Challenge – What to do with the Sand?”. Offshore Technology Conference, Houston, TX, 6-9 May, OTC-29278-MS. https://doi.org/10.4043/29278-MS
  2. Rawlins, C.H. 2019. “Enhanced Production Through Surface Facilities Sand Management.” SPE Distinguished Lecturer presentation. Link here
  3. eprocess-training.com

Next week I will continue discussion on the three category paths.

The Subsea Sand Management Challenge (B-FSM-176)

What to do with the sand? That is the subsea sand management challenge. It is the most important issue for subsea sand management. eProcess conducted a study that analyzed 33 options for handling sand in production at the sea floor.

These options can be separated into three “paths” or categories;

  1. Conventional: Manage solids production or system configuration using established design rules or technologies
  2. Treatment: Modify the solids, in-situ, to reduce or eliminate their deleterious effects
  3. Removal/Disposal: Separate solids from the well fluids and manage as separate flow stream

These three paths will be covered in further detail in subsequent posts. Below is a mind map of the 33 options for reference.

 

Many of these options have a large technology gap – i.e., difference between current state of the technology to where the technology needs to be for ready deployment.

References:

  1. Rawlins, C.H. and Ditria, J.C., 2019. “The Subsea Sand Management Challenge – What to do with the Sand?”. Offshore Technology Conference, Houston, TX, 6-9 May, OTC-29278-MS. https://doi.org/10.4043/29278-MS
  2. Rawlins, C.H. 2019. “Enhanced Production Through Surface Facilities Sand Management.” SPE Distinguished Lecturer presentation. Link here
  3. eprocess-training.com

Next week I will start discussion on the three category paths.

The Five Steps of Sand Management for Subsea (B-FSM-175)

Applying the Five Steps of Sand Management to Subsea is the same methodology used as for surface facilities.

Separation: required

  • Separation will take place either in the separating vessel with jetting or with subsea wellhead desander

Collection: required

  • Collection will take place in the separator vessel bottom section or dedicated subsea wellhead desander accumulator

Cleaning: not required

  • Cleaning will not be required. If subsea solids discharge is ever allowed, then yes cleaning could be used – but that disposal step is doubtful

Dewater: probably not required

  • Dewatering always depends on the final solids disposal route – for injection or pipe transport no, but for containerization with retrieval then yes it will be required

Transport: required

  • Sand will need to be disposed of from process once separated

References:

  1. Rawlins, C.H. and Ditria, J.C., 2019. “The Subsea Sand Management Challenge – What to do with the Sand?”. Offshore Technology Conference, Houston, TX, 6-9 May, OTC-29278-MS. https://doi.org/10.4043/29278-MS
  2. Rawlins, C.H. 2019. “Enhanced Production Through Surface Facilities Sand Management.” SPE Distinguished Lecturer presentation. Link here
  3. eprocess-training.com

Next week I will start discussion on the three categories for design approaches.
 
 
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