ENHANCED OIL RECOVERY FROM THE

PERSPECTIVE OF NANO TECHNOLOGY;

Changes in interfacial tension and wettability

PRESENTED BY ; STEPHEN ADJEI

ROLL NO ; 14MT000605

MTECH PETROLEUM- PE

SCOPE

Introduction

Literature review

Report Details

Conclusion

OBJECTIVES

• To determine how Nanotechnology can be used in Enhanced Oil Recovery to cause wettability alterations and reduce interfacial tension.

• To study the factors that bring about oil entrapment

INTRODUCTION

• Production of the initial oil in place can be achieved by three main techniques. Primary recovery, Secondary recovery and Tertiary / Enhanced oil recovery

PRIMARY RECOVERY

• This is via the natural drive mechanism occurring in the reservoir; Water drive, depletion drive , gascap drive, gravity drive or a combination of drives. This can recover only 10 - 20% of the Initial Oil in Place.

• If the reservoir energy is not enough to lift fluids an artificial lift is installed to lift produced fluids to surface

SUCKER ROD PUMP – ARTIFICIAL LIFT

SECONDARY RECOVERY

• These involve the injection of water or gas to displace oil and drive it to wellbore without changing the properties of the fluid.

ENHANCED OIL RECOVERY

• Includes chemical flooding , thermal flooding and miscible flooding methods. These changes the properties of the fluids to improve sweep efficiency by reducing the mobility ratio between injected and in-place fluids, eliminate or reduce the capillary and interfacial forces and thus improve displacement efficiency.

IMPROVED RECOVERY METHOD EXAMPLES CHALLENGES

Secondary OIL Recovery

40% recovery of OIIP)

Water Injection

Gas Injection

For water injection, Incompatibility

between injected fluid and formation

fluid leads to formation damage and

scale formation

the injected fluids often quickly

channel through the formation

bypassing most of the oil in place due

the unfavourable mobility ratios

Enhanced Oil Recovery

(up to 75% recovery of OIIP)

Chemical Flooding- (Polymer/Surfactant)

Thermal flooding

(Steam flooding/ In situ combustion)

Gas injection- CO2 injection

high costs, potential corrosion of the

formation and fluid loss during the flow

through the reservoir

channelling of steam

Very low Viscosity of CO2 results in poor

mobility control

THE WAY FORWARDThe world is in a phase where there is an increased demand of energy sources (particularly oil and gas) and reduced production due to mature oilfields. There is a need for new technologies which can help improve production from the reservoir and develop new fields. Nanotechnology offers promising solution for the same

SORRY NO OIL

WHAT IS NANOTECHNOLOGY

• (Bueno, 2004 as cited in (Fletcher and Davis, 2010) defines nanotechnology as the direct control of materials and devices on the atomic and molecular scale; nanoscale, which is about 1 to 100 nanometers. (1nm is a billionth of a meter, or 10-9 of a meter).

WHY NANOTECHNOLOGY

• Properties of materials change as their size approaches the nanoscale.

• As a particle decreases in size, a greater proportion of atoms are found at the surface compared to those inside. This increase in surface area leads to an increase in the rate of reactions which occur on the surface of the material.

• Has added properties such as lightness, mechanical strength and corrosive resistant as compared to their larger- scale counterparts.

APPLICATION IN PETROLEUM ENGINEERING

Based on their properties of lightness, strength and corrosive resistance to build better materials for production

Nanosensors which give more detailed information in the reservoir

For Enhanced Oil Recovery

APPLICATION IN ENHANCED OIL RECOVERY

• Trapped oil can be recovered by reducing the capillary forces which prevent oil from flowing within the pores of the reservoir rock and to the wellbore. And this can be done by reduction in the oil- water interfacial tension and wettability alterations.

rP ow

c

cos2

Pc = Capillary pressure between oil and water

ow = Interfacial tension between oil and water,

dyne/cm

= Oil/water contact angle, degrees

r = Radius of capillary tube, cm

For an Oil/ water system

INTERFACIAL TENSION

• It is the boundary tension between two immiscible fluids.

• Reduction of the oil- water interfacial tension leads to easy flow of trapped oil since the stronger the interfacial tension, the more work is needed to bring molecules to the surface.

The interfacial tension itself is caused by the imbalance in the

molecular forces of attraction experienced by the molecules at

the surface as shown below

WETTABILITY

• This is the preference of a solid to be in contact with one fluid rather the other.

• This affect location, control and distribution of fluids in the reservoir.

• It is defined by the contact angle measured through the denser phase.

• For Homogenous wettability, the entire rock surface has a uniform molecular affinity for either water or oil.

• For Heterogeneous wettability, distinct surface regions exhibit different affinities for oil or water. From water- wet to neutral wet and from oil water to water wet.

θ < 90---------- water wet

θ > 90----------- Oil wet

θ = 90----------- no preference for oil nor water

CHANGING INTERFACIAL TENSION AND WETTABILITY USING THE PROPERTIES OF NANOTECHNOLOGY

• Using the properties of nanoparticles, nanotechnology can be used in

EOR is to improve the properties of the injected fluid; to reduce

interfacial tension and enhance viscosity and secondly to improve

fluid rock interaction properties; wettability.

Large surface to volume ratio: Provides an enhanced activity and contact area; and organizing water flood and surfactant flooding. These provides tremendous driving force for diffusion thereby causing a reduction in interfacial tension.

Tailored Molecules

This an excessive chemical loss during chemical injection hence the expected efficiency is not achieved. But the responsivity of nano particles can be tailored for specific tasks. Very efficient scientifically tailored chemical compounds in the nano size range can critically change the fluids interfacial tension

Small Size;

Films are held at surface by intermolecular forces which act over short range

(Fletcher and Davis, 2010). The diameters of pores in normal oil reservoirs are

generally in the order of micrometer, so nanoparticles not only enter oil

reservoirs but also show a penetration effect excited by thermal and dynamic

energy resulting in desired changes. These nano particles are also able to interact

with the mineral components of the rocks hence contributing to wettability

alterations

High Chemical reactivity; Its high chemical reactivity can be used to reduce

the binding forces between the rock and fluid and fluid - fluid

Enhanced thermal properties

Surfactants need to be stable at high temperatures and pressures and or high

pump rates and share rates. Nanoparticles have high tensile and thermal

strength that will strive under these conditions. Gives high effect thermal

degradation hence be able to be adsorbed on the rock surface to reduce

interfacial tension

Nano Sensors

Deployed into pore space by means of nano dust. Provides data on reservoir

characterization, fluid flow modelling and fluid type recognition. This can be

used to detect the bypass oil after EOR. Which is based on the identification and

excitation of chemotaxonomic markers present in them. Since microbes thrive

on oil water surface, wherever they will be detected it is a sign that oil is present

there. This data is used to enable for efficient strategies to cause the alterations

in wettability and interfacial tension

Improvement in the Property of Injected fluids

Nanoparticles when mixed with the injected fluid enhances its viscosity, density,

surface tension and thermal conductivity hence improving the ability of injected

fluids to alter rock and fluid properties

CONCLUSION

• The properties of nanoparticles enhance the conditions necessary for alterations of wettability and reduction of interfacial tension necessary for a more efficient recovery of oil.

REFERENCESA.J.P FLECTHER, J.P Davis. "How EOR can be transformed by Nanotechnology." Presented at SPE Improved Recovery Symposium. Tulsa ,Oklahoma, USA : SPE, 2010.

Cocuzza Matteo, Pirri Candido , Rocca Vera and Verga Francesca. "Current and Future Nanotech Application In The Oil Industry." American Journal of Applied Science 9(6).ISSN 1546-9239 (2012): 784-793.

Shallab Ayatollahi, Mohammed M. Zerafat. "Nano- Technology Assisted EOR Techniques; New Solutions to Old Challenges." presented at SPE International Oilfield Nanotechnology Conference. Noordwijk- Netherlands: SPE, 2012.

Sunjay. "Nano-science & Technology in Upstream." presented at 8th Biennial International Conference and Exposition on Petroleum Geophysics. HYDERABAD, 2010. 29.

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