VSEP Industries

Slop Oil Treatment

Slop Oil Treatment Using VSEP® Microfiltration

Advanced Separation for Offshore Platforms and Onshore Slop Ponds

Solve the Industry’s Most Persistent Separation Challenge: Slop Oil

Slop oil and slop water are unavoidable byproducts of oil production. They accumulate in offshore platforms, onshore production facilities, tank farms, and long‑term storage ponds, often becoming some of the most difficult fluids to treat in the upstream value chain.

New Logic Research’s VSEP® (Vibratory Shear Enhanced Processing) Microfiltration (MF) system provides a proven, field‑deployed solution that breaks stable emulsions, separates free oil, and delivers clear water even when conventional separators fail.

New Logic has deployed multiple offshore VSEP MF systems for a major global oilfield service company, providing treatment of highly emulsified slops directly at the platform. We have also successfully pilot-tested VSEP for onshore slop oil ponds to accelerate pond closure and eliminate legacy waste liabilities.

Why Slop Oil Exists and Why It’s So Hard to Treat

Slop oil is generated throughout upstream operations, including:

Sources of Slop Oil / Slop Water

  • Separator upsets causing off-spec oil/water mixtures
  • Tank bottoms (BS&W) including solids, asphaltenes, and sludge
  • Pipeline pigging returns containing oil, solids, and water
  • Chemical-laden emulsions from corrosion inhibitors, demulsifiers, and surfactants
  • Drain systems, deck wash water, and operational flushing
  • Long-term slop pond accumulation in mature fields

Why Traditional Treatment Fails – Slop oil typically contains:

  • Highly stable oil-in-water and water-in-oil emulsions
  • Asphaltenes, resins, waxes, and fine solids
  • Surfactants from production chemicals
  • High suspended solids and colloidal particles

These components prevent effective separation in:

  • Free-water knockouts
  • Electrostatic treaters
  • Heaters / heater treaters
  • Induced or dissolved gas flotation (IGF/DAF)
  • Plate coalescers
  • API separators
  • Centrifuges

Stable emulsions frequently persist for years, especially in onshore slop ponds where sunlight, aging, and chemical migration reinforce emulsion stability.

The VSEP® Advantage: Microfiltration That Breaks Emulsions

VSEP MF is different from all other membrane or mechanical separation systems.
It applies high‑frequency vibrational shear directly to the membrane surface, suppressing fouling and enabling separation of fluids that cannot be processed by crossflow membrane systems.

How VSEP MF Works on Emulsified Slop Oil

  1. Slop oil/water feed enters the vibrating membrane stack.
  2. VSEP’s torsional shear amplitude (~½ inch displacement) disrupts boundary layers and breaks stable emulsions.
  3. Free oil and suspended solids are rejected at the membrane surface.
  4. Clear permeate (water) passes through the MF membrane.
  5. Concentrated oil/solids are discharged as a manageable waste or recyclable oil stream.

Slop Oil Treatment samples from VSEP system.

VSEP MF Filtrate and Slop Oil Feedwater

What VSEP MF Separates – Technical Breakdown for Engineers

Microfiltration (0.05–0.2 µm nominal) effectively separates:

Rejected (Concentrate Stream):

  • Free oil droplets (all sizes)
  • Emulsified oil droplets
  • Asphaltenes, resins, waxes
  • Suspended solids (sand, silt, scale, iron sulfide, corrosion products)
  • Biofilms and biomass
  • Colloidal solids and fines
  • Tank-bottom sludge particles
  • Pigging debris
  • Organic emulsifiers

Permeate (Filtrate):

  • Clear water with very low oil content
  • Dissolved salts (TDS) and dissolved organics that pass MF
  • Water suitable for:
    • Further polishing
    • Biological treatment
    • Disposal to overboard (offshore) after polishing
    • Reuse as utility water

VSEP MF results:

  • De-oiled water can be ocean discharge, disposal well injected, or treated with conventional methods
  • Separated oil can be processed for recovery
  • VSEP performs the difficult work of emulsion breaking so that normal treatment methods can be used

Why VSEP Outperforms Conventional Options

1. Treats Emulsions That Other Systems Cannot

Traditional flotation, settling, or coalescing cannot separate chemically stabilized emulsions.
VSEP’s vibratory shear destroys interfacial films and enables membrane separation of these stubborn fluids.

2. High Solids Handling – VSEP tolerates:

  • High TSS (>10,000 mg/L)
  • Sludge, BS&W
  • Aged pond material
  • Wax/asphaltene-rich crude residues

3. Small Offshore Footprint – Offshore units are:

  • Compact
  • Modular
  • Low-operator-attention systems
  • Delivered skid-mounted for rapid integration

4. Reduces Costly Slop Transfer – Offshore operators save millions annually by:

  • Reducing vessel transport of slops to shore
  • Minimizing storage volume
  • Lowering environmental exposure

5. Enables Slop Pond Closure Onshore – VSEP can:

  • Rapidly process years-old slop oil ponds
  • Dewater emulsions and sludge
  • Generate clear water and reduce pond volume
  • Accelerate environmental closure

Containerized VSEP MF System for offshore platforms.

Containerized VSEP MF System for Offshore Platforms

Applications Across the Oil & Gas Sector

Offshore Production

  • Slop oil / slop water dewatering
  • Closed/open drain systems
  • Deck drainage
  • Emulsified oily water treatment

Onshore Production

  • Slop oil ponds
  • Tank bottom waste
  • Heater-treater slops
  • Wastewater treatment plant (WWTP) upsets
  • Pipeline pigging liquids

Refineries / Terminals

  • API separator sludges
  • Tank cleanup waste
  • Mixed oily wastewater

Why Global Operators Choose VSEP®

  • Proven offshore installations with a major oilfield services provider
  • Demonstrated ability to break emulsions and deliver high-quality permeate
  • Robust membrane life due to vibratory shear
  • Compact, modular, and easily integrated
  • Drastically reduces transport and disposal costs
  • Accelerates closure of legacy slop ponds

Case Study – Offshore Slop Water

In 2014, New Logic supplied six containerized ATEX approved VSEP MF systems to a major oil services company. They deployed these at several offshore oil platforms around the world. These systems are still in operation. The systems are small and compact and are designed for about 4 gpm. The system filters the slop water/slop oil and removes free oil producing filtrate that meets ocean discharge requirements. The system recovers 80% of the volume as filtrate. The remaining concentrate is loaded on a barge transport for delivery to onshore treatment. The VSEP reduces the volume and cost of this transport by 80%. The system operates at between 5º and 25º C and achieves a flux rate of 14 GFD.

Slop oil samples

VSEP mass balance for slop oil.

Get the Most Advanced Slop Oil Treatment System Available

VSEP MF is the only membrane technology capable of reliably treating:

  • Highly emulsified slop oil
  • Complex slop pond mixtures
  • Offshore slops containing surfactants and solids
  • Aged, chemically stabilized emulsions

If your facility struggles with recurring slop oil volumes or legacy slop ponds, VSEP MF offers a proven, high-performance solution.

Get a Site‑Specific Cost & Performance Analysis

VSEP® performance depends on feedstock, solids loading, membrane selection, and recovery targets.

For a no cost custom performance projection, contact a VSEP engineer:  info@vsep.com

Learn More

New Logic Research has been deploying VSEP® membrane systems for oil and gas applications since 1987. Our engineers have conducted dozens of pilot trials and commissioned commercial systems across North America, South America, and Europe

Content reviewed by New Logic Research Process Engineering Team – specialists in high‑shear membrane systems for industrial wastewater.

Frequently Asked Questions (FAQ) – VSEP® Slop Oil Treatment

  1. What is slop oil and why is it difficult to treat?

Slop oil is an off‑spec mixture of crude oil, produced water, solids, and production chemicals generated from separator upsets, tank bottoms, pigging returns, and drain systems. It typically contains highly stable emulsions, asphaltenes, resins, and fine solids, making it resistant to conventional separation methods such as flotation, settling, and coalescing. These characteristics cause traditional oil-water separation equipment to foul, short‑circuit, or require excessive chemical treatment.

  1. How does VSEP Microfiltration break oil-water emulsions?

VSEP uses torsional vibratory shear directly on the membrane surface. This high‑frequency shear disrupts boundary layers and breaks interfacial films responsible for emulsion stability. As a result, VSEP MF can separate free oil, emulsified oil, and suspended solids—something no other membrane technology can do reliably in slop‑oil service. The permeate is clear water, while the concentrate contains recoverable oil and solids.

  1. How does VSEP compare to centrifuges, flotation units, or electrostatic treaters?

Unlike flotation, settling, or electrostatic treatment—which depend on gravity, droplet coalescence, or electrical fields—VSEP is not sensitive to droplet size, chemical surfactants, or emulsion stability.
VSEP advantages include:

  • Consistent separation regardless of emulsion chemistry
  • Ability to handle very high solids loading
  • No dependency on demulsifiers
  • Compact footprint for offshore installations
  • High uptime with minimal operator intervention
  • Lower lifecycle OPEX than centrifuges or thermal systems
  1. Can VSEP treat slop oil from offshore platforms?

Yes. New Logic has deployed multiple VSEP MF systems offshore with a major oilfield services provider. These units treat slop oil/water directly on the platform, reducing or eliminating the need to ship slops to shore. Offshore operators benefit from:

  • Major reductions in vessel transport costs
  • Lower storage tank requirements
  • Onboard treatment of emulsions, sludges, and drains
  • Compliance with tight water-discharge regulations after polishing
  1. What is the footprint and power requirement of a VSEP unit?

VSEP systems are compact and modular. Offshore systems typically fit within constrained deck space and can be containerized. Power requirements vary by model, but units are designed for low energy consumption relative to thermal or mechanical separation systems, thanks to vibratory shear that minimizes fouling and pressure loss.

  1. What membranes are used in VSEP Microfiltration for slop oil?

VSEP supports a wide range of polymeric and specialty membranes configured for high‑fouling, high‑solids applications. MF membranes (0.05–0.2 µm) are standard for slop service, selected based on:

  • Solvent resistance
  • Compatibility with production chemicals
  • Temperature limits
  • Fouling characteristics
  1. Does VSEP comply with ATEX requirements for offshore and hazardous zones?

Yes. VSEP systems can be provided in ATEX-compliant configurations for operation in classified hazardous environments, including Zone 1 and Zone 2 areas typical of offshore platforms and onshore production facilities. Electrical components, enclosures, motors, and instrumentation are selected to comply with applicable ATEX directives and customer specifications.

  1. What are typical permeate oil-in-water (OIW) levels after VSEP?

VSEP Microfiltration permeate typically achieves very low OIW, often suitable for:

  • Downstream polishing with walnut shell filters, IGF, or membranes
  • Reuse as utility water
  • Injection (after conditioning)
  • Regulatory-compliant disposal (after polishing, offshore or onshore)
  1. Can VSEP integrate into existing production or slop handling systems?

Yes. VSEP units are modular and can be integrated into:

  • Existing slop oil tanks
  • Closed and open drain systems
  • Skid‑mounted offshore treatment packages
  • Tank cleaning campaigns
  • Slop pond reclamation systems

Instrumentation and control can integrate with platform DCS/SCADA systems via standard protocols.