Solvents

• Uses

• Types and Selection

• Application

• Handling

• Disposal

8/25/2015 1 George E. King Engineering

GEKEngineering.com

Solvent Types

• Checks:

– Flash point (safety issues for pumping)

– Solubility of damage in solvent

– Stability of solvent

– Seal stability in solvent

– Disposal ease

8/25/2015 2 George E. King Engineering

GEKEngineering.com

Solvent Types and Uses

• Xylene – removes most wax, asphaltene, sludges

• Toluene, same uses as xylene, but has lower flash point and harder on seals.

• Lemonol – may be a passable xylene substitute, safer, but test on the deposit at well conditions.

• Kerosene – removes wax, some sludges

• Crude oil – removes some wax, but generally poor response or very slow

• #2 diesel – not recommended unless filtered to 5 microns with beta of 1000.

8/25/2015 3 George E. King Engineering

GEKEngineering.com

First Treatment

BP

Begin pumping xylene @ 3bpm

Pumping xylene @ 7 bpm

Slowdown pump & swap to diesel tank. Begin pumping diesel @ 8 bpm

Note: Pressure increasing on wellhead @ ~8,000 gals of ???

Completed pumping diesel @ 8 bpm

SD and begin flushing of equipment.

Start breaking over @ 8 bpm

8/25/2015 4 George E. King Engineering

GEKEngineering.com

Second Treatment

BP

A-5

3500

4000

4500

5000

5500

6000

6500

7000

1/15/06 14:30 1/15/06 15:00 1/15/06 15:30 1/15/06 16:00 1/15/06 16:30 1/15/06 17:00 1/15/06 17:30

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

BHP

BPM

start xylenestart diesel

xylene at perfs

8/25/2015 5 George E. King Engineering

GEKEngineering.com

Solvents, Instead of Acids

• use for removal of:

– Sludges – best solvent depends on composition

– Emulsions – solvent depends on composition

– Paraffins - xylene, kerosene, condensates, some oils

– Asphaltenes – xylene, toluene, lemonol – dispersants

• Poorest solvents? - #2 diesel (loaded with wax) and dead crude oils (asphaltic growth issues and wax loadings)

8/25/2015 6 George E. King Engineering

GEKEngineering.com

Solvent Volumes

• paraffin removal

– 10 to 15 gal/ft of affected zone.

• asphaltene removal

– 10 to 25 gal/ft - and this won’t dissolve much!

– 100 grams of xylene dissolves 9 grams of asphaltenes

8/25/2015 7 George E. King Engineering

GEKEngineering.com

0

1000

2000

3000

4000

5000

6000

7000

8000

0 1000 2000 3000 4000 5000

Bott

om

Ho

le P

ress

ure

(p

sig

)

Total Liquid Rate (stbf/d)

1 - Hydraulics Base

2 - PRSS 770.000

3 - PRSS 1050.000

1 - IPR Base

2 - SKN 2.000

3 - SKN 16.000

Boqueron 02

Reservoir Data

Pressure = 7100

kh = 1092.0

Skin = 16.00

Boqueron 02 (13march01)

Density = 4.000

Perf Diam = 0.50

Penetration = 8.00

Rate vs. Pressure

27-Mar-01 11:42:54

Depth (MD) = 17276

WHPres (psia) = 770

Tubing I.D. = 2.750 (s1)

Before:

Oil: 2200 bopd

WHP: 770 psiBHFP: 3660 psi

Skin: 16

After:Oil: 3100 bopd

WHP: 1050 psi

BHFP: 5000 psiSkin: 2

Oil(bopd) GOR(scf/bbl) WHP(psi) BHFP(psi) WHT(°F) H2S(ppm) GAS(mmscfd) APIGrav SepPress(psi)

Before 2200 2080 770 3660 187 10 4.3 31.5 420

After 3200 1830 1050 5100 198 10 5,92 31.3 200

?

Boqueron Field in Maturín - Venezuela Source – Jose Soto

Example of

a solvent

job.

8/25/2015 8 George E. King Engineering

GEKEngineering.com

Event Oil(bopd) GOR(scf/bbl) WHP(psi) BHFP(psi) WHT(°F) H2S(ppm) GAS(mmscfd) APIGrav SepPress(psi)

Before 2200 1950 770 3660 195 10 4.3 31.4 420

After 3100 1950 1050 5000 195 10 5.92 31.4 420

With correction of Separator pressure, the data becomes:

Treatment Summary

100 gal per foot perforated of 100% Xylene -> Total: 21,000 gals Soak time: 6 hours

Injection rate: 1,1 bpm w/ CT annulus pressure: 2000 psi.

Calculated Xylene penetration with 10% porosity @ 6,5 ft.

Estimated Cost Real Cost

$ 255,000 $ 191,500 8/25/2015 9

George E. King Engineering GEKEngineering.com

Problems with Solvents

• rubber/elastomer seal deterioration

• density problems (hard to get to and hold on bottom)

• getting reasonably pure solvents – ie., xylene b.p. is 138-144 C

– naphta not nearly as good

– just what is a xylene bottom? – no real definition

8/25/2015 10 George E. King Engineering

GEKEngineering.com

Solvent migration through a standing brine column

• Xylene will come back to surface fast (fast or faster than gas?)

• Migrates at 5 - 10,000 feet per hour in seawater.

• If you're soaking a pill on bottom, it won't stay there long.

8/25/2015 11 George E. King Engineering

GEKEngineering.com

Disposal

• Most solvents are sold with crude.

• Some aromatics may affect oil price, but may not be a factor in large oil volumes.

• Care must be taken not to expose personnel or the environment to returning solvent.

8/25/2015 12 George E. King Engineering

GEKEngineering.com