Optimizing Drawdown Strategies in Wells Producing from Complex Fracture Networks
- Ashish Kumar (The University of Texas at Austin) | Puneet Seth (The University of Texas at Austin) | Kaustubh Shrivastava (The University of Texas at Austin) | Mukul M. Sharma (The University of Texas at Austin)
- Document ID
- Society of Petroleum Engineers
- SPE International Hydraulic Fracturing Technology Conference and Exhibition, 16-18 October, Muscat, Oman
- Publication Date
- Document Type
- Conference Paper
- 2018. Society of Petroleum Engineers
- 0.2 Wellbore Design, 2.4 Hydraulic Fracturing, 2.5.2 Fracturing Materials (Fluids, Proppant), 4.1 Processing Systems and Design, 2 Well completion, 3 Production and Well Operations, 0.2.2 Geomechanics, 4 Facilities Design, Construction and Operation, 3 Production and Well Operations, 4.1.2 Separation and Treating
- Complex Fracture Network, Fractured Well Productivity, Choke Optimization, Fractured Well Performance, Fracture Closure
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- 898 since 2007
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In unconventional reservoirs, the presence of natural fractures coupled with high pore pressures leads to the creation of complex fracture networks. During drawdown, the fracture network experiences large changes in the stresses which can affect the fracture conductivity, and hence the production rate. We present a workflow to find an optimum drawdown strategy in which the fractures can remain conductive while maintaining a high enough drawdown to maximize production.
A fully coupled geomechanical reservoir simulator is developed to simulate production from complex fracture networks. Flow in the fracture and reservoir domains is solved in two separate conforming meshes which are coupled through matrix-fracture transfer indices. The complex fracture network is represented as an explicit discontinuity in the reservoir domain which is essential to capture the stress variations in the vicinity of the fractures due to reservoir depletion and fracture closure. The fracture closure process is modeled dynamically using the Barton-Bandis contact relationship, and the fracture conductivity is determined using the fracture width and proppant concentration. This model is used to study the impact of drawdown strategy on fracture conductivity and well productivity.
It is observed that the estimated ultimate recovery (EUR) from complex fracture networks depends upon the connected fracture conductivity and the applied drawdown. A conservative drawdown strategy maintains the fracture conductivity for a longer period but results in a lower initial production rate. As the drawdown is increased, the unpropped fractures close and can cause a large portion of the fracture network (the part behind the closed segment) to get disconnected from the wellbore. This reduces the available fracture area for production. Although an aggressive drawdown strategy results in higher initial production rates, it can lead to faster fracture closure, in turn resulting in a lower EUR. Impact of drawdown strategy on productivity is analyzed at different fracture closure rates.
We show that the optimum choke management strategy depends on the sensitivity of the fracture conductivity to stress. A coupled geomechanical reservoir model is presented that can simulate production with dynamic fracture closure in complex fracture networks to quantify this effect.
|File Size||1 MB||Number of Pages||14|
Barree, R. D., & Mukherjee, H. (1995). Engineering Criteria for Fracture Flowback Procedures. Society of Petroleum Engineers. doi: 10.2118/29600-MS
Bryant, E. C., Hwang, J., & Sharma, M. M. (2015). Arbitrary Fracture Propagation in Heterogeneous Poroelastic Formations Using a Finite Volume-Based Cohesive Zone Model. Society of Petroleum Engineers. doi: 10.2118/173374-MS
Fisher, M. K., Wright, C. A., Davidson, B. M., Goodwin, A. K., Fielder, E. O., Buckler, W. S., & Steinsberger, N. P. (2002). Integrating Fracture Mapping Technologies to Optimize Stimulations in the Barnett Shale. Society of Petroleum Engineers. doi: 10.2118/77441-MS
Fredd, C. N., McConnell, S. B., Boney, C. L., & England, K. W. (2000). Experimental Study of Hydraulic Fracture Conductivity Demonstrates the Benefits of Using Proppants. Society of Petroleum Engineers. doi: 10.2118/60326-MS
Hajibeygi, H., Karvounis, D., & Jenny, P. (2011). A hierarchical fracture model for the iterative multiscale finite volume method. Journal of Computational Physics, 230(24), 8729-8743. https://doi.org/10.1016/j.jcp.2011.08.021
Karantinos, E., Sharma, M. M., Ayoub, J. A., Parlar, M., & Chanpura, R. A. (2016). Choke Management Strategies for Hydraulically Fractured Wells and Frac–Pack Completions in Vertical Wells. Society of Petroleum Engineers. doi: 10.2118/178973-MS
Karimi-Fard, M., Durlofsky, L. J., & Aziz, K. (2004, June 1). An Efficient Discrete-Fracture Model Applicable for General-Purpose Reservoir Simulators. Society of Petroleum Engineers. doi: 10.2118/88812-PA
Monteagudo, J. E. P., & Firoozabadi, A. (2004). Control-volume method for numerical simulation of two-phase immiscible flow in two-and three-dimensional discrete-fractured media. Water resources research, 40(7). https://doi.org/10.1029/2003WR002996
Okouma Mangha, V., Guillot, F., Sarfare, M., San, V., Ilk, D., & Blasingame, T. A. (2011). Estimated Ultimate Recovery (EUR) as a Function of Production Practices in the Haynesville Shale. Society of Petroleum Engineers. doi: 10.2118/147623-MS
Robinson, B. M., Holditch, S. A., & Whitehead, W. S. (1988). Minimizing Damage to a Propped Fracture by Controlled Flowback Procedures. Society of Petroleum Engineers. doi: 10.2118/15250-PA
Rojas, D., & Lerza, A. (2018). Horizontal Well Productivity Enhancement through Drawdown Management Approach in Vaca Muerta Shale. Society of Petroleum Engineers. doi: 10.2118/189822-MS.
Sharma, M. M., & Manchanda, R. (2015). The Role of Induced Un-propped (IU) Fractures in Unconventional Oil and Gas Wells. Society of Petroleum Engineers. doi: 10.2118/174946-MS
Shrivastava, K., & Sharma, M. M. (2018a). Mechanisms for the Formation of Complex Fracture Networks in Naturally Fractured Rocks. In SPE Hydraulic Fracturing Technology Conference and Exhibition. Society of Petroleum Engineers. doi: 10.2118/189864-MS.
Shrivastava, K., & Sharma, M. M. (2018b). Proppant transport in complex fracture networks. In SPE hydraulic fracturing technology conference and exhibition. Society of Petroleum Engineers. doi: 10.2118/189895-MS.
Weng, X., Kresse, O., Cohen, C.-E., Wu, R., & Gu, H. (2011). Modeling of Hydraulic-Fracture-Network Propagation in a Naturally Fractured Formation. Society of Petroleum Engineers. doi: 10.2118/140253-PA
Wilson, K., Ahmed, I., & MacIvor, K. (2016). Geomechanical Modeling of Flowback Scenarios to Establish Best Practices in the Midland Basin Horizontal Program. Unconventional Resources Technology Conference. doi: 10.15530/URTEC-2016-2448089
Wu, W., Kakkar, P., Zhou, J., Russell, R., & Sharma, M. M. (2017). An Experimental Investigation of the Conductivity of Unpropped Fractures in Shales. Society of Petroleum Engineers. doi: 10.2118/184858-MS
Xu, Y., Cavalcante Filho, J. S. A., Yu, W., & Sepehrnoori, K. (2017). Discrete-Fracture Modeling of Complex Hydraulic-Fracture Geometries in Reservoir Simulators. Society of Petroleum Engineers. doi: 10.2118/183647-PA