FreFLO J823.pdf

Reservoir Development – Fracturing Products

Section 620.10

Fracturing Products Manual - Additives

May 1991 Page 1of 5

FREFLO F PREFLUSH J823 1

SUMMARY ............................................................................................................................................2

2

FLUID DESIGN.....................................................................................................................................4

3

2.1

Limitations of Application...............................................................................................................4

2.2

J823 Prepared as a Batch Mix..........................................................................................................4

FIELD MIXING PROCEDURES ........................................................................................................4 3.1

Batch Mixing ...................................................................................................................................4

3.2

Special Precautions When Mixing J823 Components .....................................................................5

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1

Section 620.10

Reservoir Development – Fracturing Products

May 1991 Page 2 of 5

Fracturing Products Manual - Additives

SUMMARY

FREFLO* F Preflush J823 from Schlumberger is a solvent and surfactant blend designed to condition the formation and enable more efficient recovery of the fracturing fluid. The J823 quantity is 1 0% to 20% of the total fracturing fluid volume and is pumped as a prepad. TABLE 1 - PHYSICAL PROPERTIES AND HAZARDS Chemical Code

Product Name

Form

J823

FREFLO F Preflush

Colorless Liquid

Specific Gravity

Health Hazard+

Physical Hazard+

Flash Point (°F [°C])

pH

0.97

Inhalation

Fire

115 [46]

—

+

Only the principal, immediate hazards are provided here. Complete information on health hazards, protective equipment, handling precautions, environmental hazards, and disposal is provided in the Schlumberger Material Safety Data Sheet (MSDS) for this product. Additional safety information is provided in the Schlumberger Safety and Loss Prevention Manual.

J823 is formulated by combining a nonionic surfactant (EZEFLO* F75N Surfactant), a miscible solvent (Mutual Solvent U66), Methanol K46, KCl (Potassium Chloride M117) and water. Isopropyl Alcohol F3 may be substituted for the K46. This formulation cleans the particle faces by dissolving microscopic impurities, and then applies a surfactant coating on the cleaned surfaces. In this manner, the solvents act to retard the reaction of the surfactant for a more uniform application over a larger area. The coating reduces the surface and interfacial tension to the point where fluids will not adhere to the particle surface. This reduces the forces holding the fluids in the matrix and allows easy passage of the fracturing and formation fluids. Table 2 provides the surface tensions for various fluids. The K46 (or F3) also acts to stabilize the fluid at the formation face of the fracture, resulting in slightly better fluid-loss characteristics. TABLE 2 - SURFACE TENSION MEASURED AT 75°F (24°C) Fluid Type Surface Tension (dyne/cm) Fresh Water

69

2% KCl

75

J823

21

Testing has been conducted to compare API Brine, 2% KCl water and J823 on the basis of the formation water saturation limits and permeability associated with those limits. The tests were conducted by measuring the gas permeabilities of carbonate and sandstone formations as a function of the test fluid saturation levels. Figure 1 illustrates that cores treated with J823 retained less fluid, therefore allowing faster cleanup and higher relative permeability.

* Mark of Schlumberger

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Reservoir Development – Fracturing Products

Section 620.10

Fracturing Products Manual - Additives

May 1991 Page 3of 5

Figure 1 - Residual permeability of various fluids.

J823 can be used in conjunction with Waterfrac (WF) and water-base Widefrac (YF*) fluids. Since the formulation is nonionic, it can be used in all formations.

* Mark of Schlumberger

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2

Section 620.10

Reservoir Development – Fracturing Products

May 1991 Page 4 of 5

Fracturing Products Manual - Additives

FLUID DESIGN

J823 is pumped as a prepad. The quantity of J823 is 10% to 20% of the total fracturing fluid volume. J823 may be viscosified to improve the fluid-loss characteristics; however, crosslinking of the formulation is not recommended. Although the formulation contains F75N, a similar surfactant is still recommended in the fracturing fluid. 2.1 Limitations of Application J823 is compatible with most Schlumberger fracturing fluid additives. Delayed YF Fluids: Contamination of a delayed, crosslinked fracturing fluid with J823 can shorten the delay time. Laboratory testing for a specific fluid is recommended to determine the relationship of J823 contamination and delay time. 2.2 J823 Prepared as a Batch Mix Table 3 provides the recommended component concentrations required for the formulation of J823. TABLE 3 - RECOMMENDED J823 FORMULATION

3

Component

Concentration (per 1,000 gal)

Fresh Water

744 gal

M117

125 lb

U66

4 gal

F75N

2 gal

K46 (or F3)

250 gal

FIELD MIXING PROCEDURES

Table 3 provides the recommended component concentrations required for the formulation of J823. 3.1 Batch Mixing The general steps in a batch mix are as follows. 1. Determine water quality. The source water should be fresh water, ranging from 40°to 100°F (4°to 38°C), a pH ranging from 6.0 to 8.0, an iron concentration less than 25 ppm, and bacteria- and enzyme-free. 2. Add and dissolve the M117. 3. Add the U66 and F75N.

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Reservoir Development – Fracturing Products

Section 620.10

Fracturing Products Manual - Additives

May 1991 Page 5of 5

4. Add the K46 (or F3). The fluid temperature will increase 10°to 15°F (6°to 8°C) from the heat of dilution while adding the K46 (or F3). If foaming is encountered, add small amounts ( < 0.5 gal/1,000 gal) of Antifoam Agent D47 (only if absolutely necessary). 5. Continue to circulate the fluid at a uniform rate for at least one tank volume to ensure even tank mixing. Adding J823 Components to a Viscosified Fluid The components of J823 may be added to the fluid either before or after the polymer is added. Adding the M117 before the polymer may slow the hydration rate. 3.2 Special Precautions When Mixing J823 Components The presence of K46 (or F3) as an additive increases the treatment hazards by adding the factors of flammability and alcoholic poisoning. Special precautions must be observed when handling the K46 (or F3). 1. Review the Safety and Loss Prevention Standard Manual. Standard No. 5 provides instructions for the preparation and pumping of treating fluids containing flammable fluids. 2. Review the current Material Safety Data Sheet (MSDS). 3. Review any other pertinent information, i.e., “A Guide to the Hazardous Properties of Schlumberger Products.”

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