Experimental and Simulation Studies of Energized Fracturing Fluid Efficiency in Tight Gas Formations
Abstract
:1. Introduction
2. Materials and Methods
2.1. Sample Preparation
2.2. Rheology
2.3. Filtration Measurements
2.4. Simulation of Fracturing Treatment and Fracture Propagation
3. Results and Discussion
3.1. The Results of Rheological Tests of Non-Foamed and Foamed Fluids
3.2. Filtration Test Results
3.3. 3D Simulation Results
4. Conclusions
- Based on laboratory tests and simulations, it can be concluded that foamed fluids exhibit good rheological parameters and capability of opening a fracture (Figure 5 and Figure 6; Table 8) and proppant-carrying capacity, which is crucial during fracturing treatment. In general: similar geometries of the fracture and proppant concentrations are obtained for the non-foamed as well as for 50% quality nitrogen foamed fluids. At the same time, when using a fluid with a gas additive, the water content in fracturing fluid is reduced, up to 50%, which means the minimization of the negative results of the clay minerals swelling.
- When using non-foamed fluid, the fracture is slightly longer (4.7 m) and higher (6.4 m) compared to foamed fluid, while its width is smaller (0.3 cm less). When fracturing with the foam, the placement of the proppant in the productive horizon is much more beneficial in terms of the fracturing treatment performance. High concentration of the proppant, in the case of using a non-foamed fluid, is obtained only in the top part of the Rotliegend productive horizon, causing an irregular proppant distribution in the fracture (Figure 6 and Figure 7).
- The analysis of laboratory data (Table 8), and the performed simulations indicated that fracturing fluids foamed by nitrogen are a good alternative to conventional fluids (non-foamed), especially for the low-pressure reservoirs and with high sensitivity to contact with water.
Funding
Conflicts of Interest
References
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Non-Foamed Fluid | Fluid 50% N2 | ||
---|---|---|---|
Cw (m/min1/2) | Spurt (m3/m2) | Cw (m/min1/2) | Spurt (m3/m2) |
5.373·10−4 | 3.473·10−4 | 4.057·10−4 | 9.904·10−4 |
Fluid Type | Time (min) | n’ (-) | K’ (Pa·sn’) | Dynamic Viscosity at a Given Shear Rate (mPa·s) | ||
---|---|---|---|---|---|---|
40 s−1 | 100 s−1 | 170 s−1 | ||||
Non-foamed | 9 | 0.6000 | 0.2154 | 49.2 | 34.1 | 27.6 |
18 | 0.6006 | 0.2172 | 49.8 | 34.5 | 27.9 | |
27 | 0.5982 | 0.2224 | 50.5 | 34.9 | 28.2 | |
50% N2 | 9 | 0.4043 | 1.4727 | 163.6 | 94.8 | 69.1 |
18 | 0.4038 | 1.4840 | 164.5 | 95.2 | 69.4 | |
27 | 0.3964 | 1.5414 | 166.2 | 95.6 | 69.4 |
Fluid Type | Time (min) | n’ (-) | K’ (Pa·sn’) | Dynamic Viscosity at a Given Shear Rate (mPa·s) | ||
---|---|---|---|---|---|---|
40 s−1 | 100 s−1 | 170 s−1 | ||||
Non-foamed | 9 | 0.7674 | 0.0436 | 18.5 | 14.9 | 13.2 |
18 | 0.7496 | 0.0475 | 18.9 | 15.0 | 13.1 | |
27 | 0.7620 | 0.0445 | 18.5 | 14.9 | 13.1 | |
50% N2 | 9 | 0.5801 | 0.4111 | 87.3 | 59.4 | 47.6 |
18 | 0.5630 | 0.4618 | 92.1 | 61.7 | 48.9 | |
27 | 0.5652 | 0.4613 | 92.8 | 62.3 | 49.4 |
Stage No. | Treatment Stage Type | Elapsed Time (min) | Fluid Type | Volume of Liquid without Proppant (m3) | Proppant Concentration (g/L) | Proppant per Stage (kg) | Slurry Rate (m3/min) | Proppant Type |
---|---|---|---|---|---|---|---|---|
- | Wellbore Fluid | 2% KCL | 11.26 | - | - | - | ||
1 | Main frac acid | 1 | 15%HCl | 5.00 | 0 | 0 | 4.0 | - |
2 | Main frac flush | 4 | Non-foamed | 12.00 | 0 | 0 | 4.0 | - |
3 | Main frac pad | 14 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
4 | Prop slug | 19 | Non-foamed | 20.00 | 120 | 2400 | 4.0 | 100 mesh |
5 | Main frac pad | 29 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
6 | Prop slug | 34 | Non-foamed | 20.00 | 120 | 2400 | 4.0 | 100 mesh |
7 | Main frac pad | 44 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
8 | Main frac slurry | 49 | Non-foamed | 20.00 | 120 | 2400 | 4.0 | 30/50 |
9 | Main frac pad | 59 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
10 | Main frac slurry | 65 | Non-foamed | 20.00 | 150 | 3000 | 4.0 | 30/50 |
11 | Main frac pad | 75 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
12 | Main frac slurry | 80 | Non-foamed | 20.00 | 150 | 3000 | 4.0 | 30/50 |
13 | Main frac pad | 90 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
14 | Main frac slurry | 95 | Non-foamed | 20.00 | 200 | 4000 | 4.0 | 30/50 |
15 | Main frac pad | 105 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
16 | Main frac slurry | 111 | Non-foamed | 20.00 | 200 | 4000 | 4.0 | 30/50 |
17 | Main frac pad | 121 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
18 | Main frac slurry | 126 | Non-foamed | 20.00 | 250 | 5000 | 4.0 | 30/50 |
19 | Main frac pad | 136 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
20 | Main frac slurry | 142 | Non-foamed | 20.00 | 250 | 5000 | 4.0 | 30/50 |
21 | Main frac pad | 152 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
22 | Main frac slurry | 157 | Non-foamed | 20.00 | 250 | 5000 | 4.0 | 30/50 |
23 | Main frac pad | 167 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
24 | Main frac slurry | 173 | Non-foamed | 20.00 | 250 | 5000 | 4.0 | 30/50 |
25 | Main frac pad | 183 | Non-foamed | 40.00 | 0 | 0 | 4.0 | - |
26 | Main frac slurry | 188 | Non-foamed | 20.00 | 250 | 5000 | 4.0 | 30/50 |
27 | Main frac flush | 191 | Non-foamed | 11.00 | 0 | 0 | 4.0 | - |
28 | Shut-in | 221 | SHUT-IN | 0 | 0 | 0 | 0.0 | - |
Treatment Stage Type | Elapsed Time (min) | Fluid Type | Bottom N2 Quality (%) | Bottom Clean Foam vol (m3) | Bottom Proppant Concentration (g/L) | Proppant per Stage (kg) | Bottom Slurry Foam Rate (m3/min) | Proppant Type |
---|---|---|---|---|---|---|---|---|
1 | 1 | 15% HCl | 0 | 5.00 | 0 | 0 | 4.00 | - |
2 | 4 | Non-foamed | 0 | 12.00 | 0 | 0 | 4.00 | - |
3 | 6 | Non-foamed | 0 | 10.00 | 0 | 0 | 4.00 | - |
4 | 12 | Non-foamed | 0 | 20.00 | 120 | 2400 | 4.00 | 100 mesh |
5 | 22 | Non-foamed | 0 | 40.00 | 0 | 0 | 4.00 | - |
6 | 27 | Non-foamed | 0 | 20.00 | 120 | 2400 | 4.00 | 100 mesh |
7 | 37 | Non-foamed | 0 | 40.00 | 0 | 0 | 4.00 | - |
8 | 42 | Non-foamed | 0 | 20.00 | 120 | 2400 | 4.00 | 30/50 |
9 | 62 | Non-foamed | 0 | 40.00 | 0 | 0 | 2.00 | - |
10 | 73 | N2 50% | 50.7 | 40.56 | 74 | 3000 | 3.95 | 30/50 |
11 | 93 | N2 50% | 49.3 | 78.94 | 0 | 0 | 3.95 | - |
12 | 103 | N2 50% | 51.6 | 41.28 | 121 | 5000 | 3.95 | 30/50 |
13 | 118 | N2 50% | 49.3 | 59.20 | 0 | 0 | 3.95 | - |
14 | 135 | N2 50% | 52.3 | 62.90 | 162 | 10,200 | 3.95 | 30/50 |
15 | 150 | N2 50% | 49.3 | 59.20 | 0 | 0 | 3.95 | - |
16 | 167 | N2 50% | 52.4 | 63.01 | 167 | 10,500 | 3.95 | 30/50 |
17 | 182 | N2 50% | 49.3 | 59.20 | 0 | 0 | 3.95 | - |
18 | 199 | N2 50% | 52.4 | 63.01 | 167 | 10,500 | 3.95 | 30/50 |
19 | 205 | Non-foamed | 0 | 11.00 | 0 | 0 | 2.00 | - |
20 | 220 | SHUT-IN | 0 | 0 | 0 | 0 | 0 | - |
Layer Number | Top of Zone Measured depth (m) | Lithostratigraphy | Fracture Toughness (kPa·cm1/2) | Young’s Modulus (bar) | Poisson’s Ratio | Stress Gradient (bar/m) |
---|---|---|---|---|---|---|
1 | 0 | Overburden | 21,976.9 | 4.14 × 105 | 0.250 | 0.190 |
2 | 2343 | Salt | 10,988.4 | 2.40 × 105 | 0.440 | 0.190 |
3 | 2463 | Anhydrite | 16,482.7 | 5.20 × 105 | 0.300 | 0.180 |
4 | 2479 | Limestone | 5494.2 | 1.00 × 105 | 0.300 | 0.180 |
5 * | 2483 | Rotliegend | 10,988.4 | 2.00 × 105 | 0.245 | 0.170 |
6 | 2501 | Anhydrite | 16,482.7 | 5.20 × 105 | 0.300 | 0.180 |
7 * | 2503 | Rotliegend | 10,988.4 | 2.00 × 105 | 0.245 | 0.170 |
8 | 2510 | Anhydrite | 16,482.7 | 5.20 × 105 | 0.300 | 0.180 |
9 | 2512 | Sandstone | 10,988.4 | 3.45 × 105 | 0.200 | 0.180 |
10 | 2660 | Underlying rocks | 21,976.9 | 4.14 × 105 | 0.250 | 0.190 |
11 | 3000 | Underlying rocks | 21,976.9 | 4.14 × 105 | 0.250 | 0.190 |
Non-Foamed Fluid | Foamed Fluid | |
---|---|---|
Quantity | ||
15% HCl | 5.0 m3 | 5.0 m3 |
Linear gel 3.6 g/L | 743.0 m3 | 473.0 m3 |
N2 | - | 89,244.7 sm3 |
Proppant 100 mesh | 4800.0 kg | 4800.0 kg |
Proppant 30/50 mesh | 41,399.9 kg | 41,600.0 kg |
Average pumping rate | 4 m3/min | 4 m3/min |
Reservoir temperature in the perforation interval | 60 °C | |
Reservoir pressure in the perforation interval | 250 bar |
Parameters | Non-Foamed Fluid | Fluid 50% N2 |
---|---|---|
Fracture Length (m) | 206.8 | 202.1 |
Propped Length (m) | 206.8 | 202.1 |
Total Fracture Height (m) | 83.0 | 76.6 |
Total Propped Height (m) | 83.0 | 76.6 |
Fracture Top Depth (m) | 2453.1 | 2459.8 |
Fracture Bottom Depth (m) | 2536.1 | 2536.4 |
Average Fracture Width (cm) | 1.2 | 1.5 |
Average Proppant Concentration (kg/m2) | 1.5 | 1.7 |
Dimensionless Conductivity | 2.699 | 2.785 |
Total Clean Fluid Pumped (without proppant) (m3) | 750.8 | 750.1 |
Total Slurry Pumped (with proppant) (m3) | 766.2 | 765.5 |
Design proppant pumped (kg) | 46,200 | 46,400 |
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Wilk, K. Experimental and Simulation Studies of Energized Fracturing Fluid Efficiency in Tight Gas Formations. Energies 2019, 12, 4465. https://doi.org/10.3390/en12234465
Wilk K. Experimental and Simulation Studies of Energized Fracturing Fluid Efficiency in Tight Gas Formations. Energies. 2019; 12(23):4465. https://doi.org/10.3390/en12234465
Chicago/Turabian StyleWilk, Klaudia. 2019. "Experimental and Simulation Studies of Energized Fracturing Fluid Efficiency in Tight Gas Formations" Energies 12, no. 23: 4465. https://doi.org/10.3390/en12234465
APA StyleWilk, K. (2019). Experimental and Simulation Studies of Energized Fracturing Fluid Efficiency in Tight Gas Formations. Energies, 12(23), 4465. https://doi.org/10.3390/en12234465