Composition, testing of Water-Oil emulsions for mobility, conformance control and production of heavy oil

Challenge Summary

Some of the oil producing assets have high water cuts around 85% and have conformance problems. For treatment of near well bore zones, and also deep reservoir zones through stimulation of injection and production wells, additional agents are being looked for. One of the promising methods is to use water-oil and oil-water emulsions, as well as their combinations with some chemicals such as: nanoparticles, polymers, and surfactants and others, used for their stabilisation.

Also, the water-oil emulsions have been used for the non-thermal extraction of heavy oil. In one of the reservoir there is a significant change of oil viscosity observed along vertical section of the reservoir from 15-400 cp. It is necessary to explore the opportunity of using the emulsions for this heavy oil extraction.

It is necessary to explore the mechanism of water shut offs (in producing wells) and mobility control (on injection wells) using fluid-fluid interactions, core-flood tests, and field tests, propose the equipment for the industrial production of the emulsions at field conditions, and perform field tests of the selected compositions of emulsions.

Challenge Scenario

Multiple intrinsic interactions might be possible between the oil-water emulsions, water and oil, and formation due to the fact, that oil, water, and emulsions properties might be different in the reservoir.

The most optimal chemical compositions of the water-oil emulsions are to be determined, depending on the type of the planned activity:

  • Mobility control: Water diversion from flushed channels in injection wells, water shut off in production wells
  • Extraction of heavy oil in Bhagyam field

There is a need to understand how much and what kind of properties of emulsions should be injected into the reservoir in order to mobilize the heavy oil and improve the mobility control.

There has to be reasonable explanation of the physics and chemical mechanisms involved during the application of the reservoir.

Profile of the End-User

Reservoir Engineers, Production Technologists, Well Services specialists

Functional Requirements of the End-User

  • Compositions of the fit for purpose emulsions, taking into account the reservoir properties such as mineralogy, permeability, porosity, oil and water properties, formation damage and interaction with existing chemistry such as surfactants and polymers.
  • Build-up of the theoretical model, justification of the results using the theoretical models, and quantitative simulation of the achieved results using proxy core and well-reservoir model.

Functional & Operational Capabilities

  • Selected chemical composition must be effective, decreasing the mobility, sweeping the oil and cheap in manufacturing. The equipment for production should be available on the market for easy deploy and mobilisation.
  • Developed technology should be validated with the series of coreflood test and with proxy core and well/reservoir simulations.
  • Developed technology has to be simple in use at well site, i.e. including only bull-head operations, without significant downhole interventions, there should be periodical quality control measures and express tests of the equipment and produced emulsions in place.
  • In order to diminish the risk of losing the well injectivity/productivity completely, in case of the overdosage of the emulsions, there should be possibility to unlock the reservoir by injection of some solvents. These solvents should also be selected properly with minimum risk for the well and reservoir, be available on the market, and cheap.

Operational constraints

  • The manufacturing of the emulsions should consider using different petroleum liquids available in the field such as its own produced oil, gasoline, and others. The nanoparticles and other modern techniques for stabilisation of the emulsions should be studied.
  • There should be a mobile production unit at field site, the process of emulsions production, and operated equipment should be periodically quality controlled.

Expected Tangible Benefits and Measurable Gains

  • Increase in injection/production conformance
  • Decreasing the water cut of the filed production
  • Sweeping more oil, increasing reserves

Performance Metrics or Outcomes

  • Prove of decrease in water mobility on core-plugs
  • Ability to restore the productivity by injection of unlocking agent/solvent, proved with core-plugs tests
  • Incremental Reserves due to improvement of water injection conformance and production well conformance, in field test
  • Decrease in Water cut, reduce liquid load of the system, increase in daily oil production for treated producers
  • Increasing the injection conformance
  • Improving sweep efficiency