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AvaFulFlow System
The AVAFULFLOW system was specially formulated to solve the problem of formation damage in workover and completion drilling operations. The AVAFULFLOW system is composed of only one product, based on a special formulation of polymers and calcium carbonate with selected and controlled particle size.
- The addition of 150 kg/m3 of AVAFULFLOW in fresh or salt water, is sufficient to obtain a unique drilling, completion and non-damaging fluid. Only in rare cases (high permeability zones) is the addition of INTASOL F and INTASOL M recommended to increase the particle size distribution.
- The system is composed of only one product. AVAFULFLOW should be added at a concentration of 130 - 150 kg/m3 to fresh or salt water under high shear conditions to improve product dispersion. This concentration provides fluid properties adequate both for drilling and workover operations. If higher viscosity is required, XC polymer (VISCO XC 84) may be added. To reduce viscosity, dilute with fresh water or brine. Only in depleted, very high permeable sands is the addition of INTASOL suggested.
- The fluid is compatible with small amounts of bentonite and it can be easily weighted with calcium carbonate or soluble salts (NaCl, KCl, Potassium Formate, etc.). The inhibitive action of the system can be easily increased with additions of AVACLAYBLOCK or potassium salts such as potassium formate and potassium acetate.
- The lubricating properties of this system can be enhanced by adding 1 - 3% AVAGREENLUBE or ECOL LUBE.
HS&E:
- All additives that form the AVAFULFLOW system have a low environmental impact and are readily biodegradable.
- All the organic polymers contained in the AVAFULFLOW system are environmentally friendly.
| Product |
Concentration (kg/m3) |
| SPECIFIC GRAVITY |
As Requested |
| CAUSTIC SODA |
1.0 - 2.0 |
| AVAFULFLOW |
120 - 150 |
| VISCO XC 84 |
1.0 - 2.0 |
| AVACID F/25 |
1.0 - 2.0 |
| AVACARB / INTAFLOW |
As Requested |
| AVAGREENLUBE |
As Requested |
ADVANTAGES:
AVAFULFLOW is a mixture of special polymers and CaCO3 with selected particle sizes ranging between 3 and 500 micron. This formulation gives excellent bridging action, avoiding CaCO3 compaction and filtrate loss. The AVAFULFLOW system provides the following advantages:
- Prevention of Formation Damage: With the AVAFULFLOW system, the particle size distribution produces a very thin impermeable filter cake, easily removed when a very low backpressure is applied (5-10 psi). As a result, no modifications of rock permeability occur and the system gives excellent return permeability and reservoir productivity. These characteristics make AVAFULFLOW useful as an LCM, whereas other LCM products based on cellulose or CaCO3 required acid treatment or chemical washing to recover initial permeability.
- Hole Cleaning: When drilling pay zones, the system has rheological performances similar to XC polymer, i.e. very high viscosity values in low shear conditions, and exceptional yield/plastic viscosity (YP/PV) ratios that guarantee excellent hole cleaning and solids removal in directional and horizontal wells.
- High Penetration Rates: Due to its fragile gel structure, the AVAFULFLOW system has low viscosity in high shear conditions, improving penetration rates and avoiding problems breaking circulation.
- Shale Inhibition: The system shows a strong stabilizing action on troublesome formations such as unconsolidated clays, sandstones, gumbos and many types of water sensitive shale. The stabilizing action is derived from the: - formation of a polymer film on the wellbore; - chemical inhibition of drilled formations; - high quality filter cake minimizes formation fluid loss.
| Parameter |
U.M. |
Value |
Value |
| Avafulflow> |
kg/m3 |
140 |
190 |
| 600 rpm |
|
51 |
73 |
| 300 rpm |
|
39 |
56 |
| 200 rpm |
|
33 |
49 |
| 100 rpm |
|
26 |
39 |
| 6 rpm |
|
12 |
20 |
| 3 rpm |
|
11 |
18 |
| Gels 10" / 10' |
lb/100ft2 |
11 / 13 |
17 / 20 |
| Apparent Viscosity |
cP |
25.5 |
36.5 |
| Plastic Viscosity |
cP |
12.0 |
17 |
CASE HISTORIES:
Well #1: Libya - Offshore
- Formations composed of plastic limestone, friable and fractured.
- Avafulflow: 120 kg/m3
- Drilled deviated 30° well (KOP: 530 m): 17 1/2" and 8 1/2" sections
- Average ROP: > 8 m/h
| Parameter |
Programmed |
Actual |
| Specific Gravity |
1.15 |
1.15 |
| Plastic Viscosity |
Minimal |
13 |
| Yield Point |
18 - 22 |
18 |
| Gels 10" / 10' |
3-4 & 12-18 |
4-5 & 10-12 |
| API Filtrate |
<3 |
3.0 |
| HPHT Filtrate |
<12 |
11.0 |
Conclusions:
- Drilled Limestone formations without any problems
- No acid job required to gain initial permeability
- Gauge hole indicated by caliper logs
Well #2: Southern Appennines - Italy
- Drilled carbonate reservoirs (Apulian platform)
- Drilled Horizontal well up to 4,600 m
- Specific gravity: 1.05 g/cm3
- Treated system with 2% AVAGREENLUBE to reduce torque
Conclusions:
- No problems occurred during drilling
- No acid job required to start production
- Use of lubricant reduced friction up to 50%
- Gauge hole indicated by caliper logs
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