3D Hydraulic Fracture Simulation for Injection in Plastic Shales
- Amr Mohamed El-Fayoumi (Advantek International Corp.) | Karim S. Zaki (Advantek International Corp.) | Ahmed S. Abou-Sayed (Advantek International Corp.)
- Document ID
- Society of Petroleum Engineers
- SPE Production and Operations Symposium, 27-29 March, Oklahoma City, Oklahoma, USA
- Publication Date
- Document Type
- Conference Paper
- 2011. Society of Petroleum Engineers
- 4.1.2 Separation and Treating, 3.2.3 Hydraulic Fracturing Design, Implementation and Optimisation, 6.5.3 Waste Management, 5.6.3 Pressure Transient Testing, 5.8.2 Shale Gas, 2.2.2 Perforating, 3 Production and Well Operations, 1.2.2 Geomechanics, 5.4.2 Gas Injection Methods, 1.6 Drilling Operations, 2.5.1 Fracture design and containment
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Injection and hydraulic fracturing in plastic shales can be a complex and problematic operation. Issues that accompany such treatments include shale swelling, plastic deformation, embedment's and perforation tunnel stability issues. Simulators that model fluid or slurry injection in plastic shale have always overlooked the plasticity issues associated with these formations. The approach has led to erroneous estimation of fracture extent and dimensions. Post injection shale deformation due to pore pressure changes can also lead to detrimental effects on productivity (fracture closure due to creep) and well/casing failure.
The current paper offers clear quantitative insights into the overall effect of injection in plastic shales. The experience is gained through drill cutting injection operations that have been taking place in highly plastic shales in an environmentally sensitive remote location. Fracture and slurry containment have been investigated using state-of-the-art 3D fracture simulator to provide assessment of the injection and to estimate out-of zone growth as well as shale plastic deformations and the effects on fracture vertical growth at different batch volumes. Analysis of historical pressure trends and pressure fall-off tests confirmed results from the 3D Simulation and the injection history. The results provide insights that have implications on the job design and implementation of hydraulic fracturing in plastic shale gas, particularly the Haynesville.
The results from the 3D fracture simulator and pressure transient analysis combine to accurately assess fracture vertical and lateral extents in similar formations, hence, minimizing the risks associated with injection and fracturing in these highly plastic shales.
Models of hydraulic fracturing that result from fluid or slurry injection into plastic shales have always overlooked the plasticity issues associated with these formation types. This can lead to erroneous estimation of the fracture dimensions and extent. For drill cuttings and slurry injection operations, assurance of a successful and environmentally sound long-term program requires accurate modeling, monitoring and periodic analysis of injection performance response [1, 2]. Modeling ahead of the injection operations serves as the baseline for the implementation process. Accurate modeling would lead to minimization of the operational risks since injection and fracturing in plastic shales can be a complex and problematic operation.
The paper demonstrates experience gained through drill cuttings injection operations that have taken place in highly plastic shales in a remote environmentally sensitive location. The state-of-the-art 3D fracture simulator provides accurate assessment of the fracture and slurry containment. The pressure transient response also confirmed fracture vertical and lateral extents. The combined analysis help in minimizing the risks associated with injection in highly plastic shales and generate out-of zone growth estimate as well as shale plastic deformations.
Results of the simulation of different batch injection volumes were used to determine the fracture vertical growth taking into consideration the effect of shale plasticity. Analysis of historical pressure trends and pressure fall-off tests were analyzed and used to confirm the results from the 3D Simulation and the injection history.
Hydraulic Fracture Models and Used Model Concepts
There is a lot of literature that dealt with the rock behavior and the hydraulic fracture models that is associated with them . These models can be summarized as follows
1. Elastic models
2. Incremental plasticity tangent models
3. Elasto-Plastic secant models
|File Size||1 MB||Number of Pages||7|