GEOXPLORA Technology Co., Ltd.

Mechanism of U-TEM – Sound-Electric Integrated

In the oil and gas layer, U-TEM technology integrates generators that can stimulate both transient electromagnetic and ultrasonic fields to affect the formation.


The sound-electric integrated actions can destroy the structure of the plug, generate new microfracture flow channels, reduce the interfacial tension of the fluid and the viscosity of the crude oil.
Mechanism of U-TEM – Ultrasonic Waves
When the ultrasonic wave is excited in the wellbore, its energy acting on the formation is selective in frequency.

The performance can be optimized by adjusting the planned operating parameters based on the wellbore and formation conditions.

Transmission coefficient is maximized to more than 95% at wellbore ultrasound acoustic window.

Ultrasonic wave can transmit further when it reaches resonant frequency with the formation.
Based on case studies from Russia and China, operation in one well can also significantly affect the production of adjacent wells hundred meters away. Ultrasonic energy simulated in the wellbore transmits in horizontal direction, which can be used for layered operations.

a)Schematic diagram of the probe in the cased hole and the vibrating surface of the sound wave emitted by the probe

b)The ultrasonic energy excited by the transducer in the well is mainly along horizontal direction
Mechanical vibration causes formation medium to change significantly in its:

Ultrasonic sound source

Result in:

Reduced adhesive forces between plugging particles and formation pore throats.

Creation of new micro-cracks.

Reduced oil-water interfacial tension in the layer.

After ultrasonic vibration (0-4min), original cracks on the rock sample developed into micro-cracks.

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Mechanism of U-TEM – Transient Electromagnetic field
U-TEM technology, employing the principle of switching on-off electric current twice per second, generates a positive-negative time-dependent transient electromagnetic field in the wellbore. The electrical energy stored in the inductance and capacitance is released, forming a transient response that penetrate through the casing at the midpoint of the excitation coil, enters the formation, and then begins to diffuse in the formation.

Propagation process near the well of transient electromagnetic field excited in cased hole
The charged particles, forced by high-speed alternative electromagnetic field in positive-reverse direction, oscillate and change in shear stress. Causing the plugging to loosen, move and change in shape and distribution, breaking adsorption to pore throat, cleaning pore space and unclogging the throat.

The electrical double layer exists in liquid-solid interface of porous medium with the change in electric field distribution of the interface caused by the electromagnetic field reduce interfacial tension and improve fluid mobility.
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Mechanism of U-TEM – Full Type Plugging Removal
Remove microbial plugging and induced particle plugging

During normal well operations, such as drilling, completion, workover, stimulation or enhanced recovery.

Factors
- Damage caused by fine migrations - Fluid loss into formation matrix - Solid particles from drilling fluid physically plug or bridge across flow paths - Near-well soil contaminated by microbial populations’inhabitants

Solutions
- Destroying the structure of plugging particles and reducing the adhesive force between pollutants and rocks - New microfractures created by rock fatigue - Movement of charged particles forced by transient electromagnetic field - Location change of the plugging in pore throat increases the oil production rate

Descaling and wax removal
Affected by changing temperature and pressure conditions in the production conduit

Scale: mineral salt deposits occur on wellbore tubulars and components

Paraffin: hydrocarbon compounds precipitates on production components is normally found in the tubing close to surface, heavy paraffins occur as wax-like substances

In severe conditions


- Scale creates a significant restriction, or even a plug, in the production tubing.

- Paraffin can also form at the perforations, or inside the formation, reducing oil production.

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Solutions


- Scale and paraffins are dispersed into very fine particles.
- Paraffin and asphaltene are emulsified, and viscosity is reduced.


Before
After
Reduce fluid viscosity and oil-water interfacial tension

Both are crucial factors affecting fluid mobility. The lower the viscosity and interfacial tension are, the less the resistance of fluid flow is, therefore oil production can be improved.

Solutions


- Viscosity reducing

       Heating

      Crude oil emulsification


- Interfacial tension lowering


      Periodic expansion and construction of pore diameter


      Electric field force

After ultrasonic treatment for 30min, the viscosity of crude oil was greatly reduced by 30-50% at all temperatures

After 30 minutes of operation, the oil emulsified and the viscosity decreased.

Why you choose U-TEM

- Green and environment-friendly

U-TEM is a Pure physical method and new-fluid-free operation, it will not introduce any potential  pollution and damage to the reservoirs;


- Significant effect for improving productivity

U-TEM is suitable for all types’ plugging removal of reservoir pollution and can overall solve the plugging problem of oilfields;


- Flexible Designed Operation

Pro-job design for each U-TEM operation ensures to meet all specific goals;


- Easy Operation

only need to connect to the wireline and then lower U-TEM to the target layer, which is simple and easy to operate.
 
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