Accurate placement of multiple horizontal wells drilled from the same well pad plays a critical role in the successful economical production from unconventional gas reservoirs. However, there are high cost and uncertainty due to many inestimable and uncertain parameters such as reservoir permeability, porosity, fracture spacing, fracture half-length, fracture conductivity, gas desorption, and well spacing. In this paper, we employ response surface methodology to optimize multiple horizontal well placement to maximize Net Present Value (NPV) with numerically modeling multistage hydraulic fractures in combination with economic analysis. This paper demonstrates the accuracy of numerical modeling of multistage hydraulic fractures for actual Barnett Shale production data by considering the gas desorption effect. Six uncertain parameters, such as permeability, porosity, fracture spacing, fracture half-length, fracture conductivity, and distance between two neighboring wells with a reasonable range based on Barnett Shale information, are used to fit a response surface of NPV as the objective function and to finally identify the optimum design under conditions of different gas prices based on NPV maximization. This integrated approach can contribute to obtaining the optimal drainage area around the wells by optimizing well placement and hydraulic fracturing treatment design and provide insight into hydraulic fracture interference between single well and neighboring wells. 1. Introduction The combination of horizontal drilling and multistage hydraulic fracturing technology has made possible the current flourishing gas production from shale gas reservoirs in the United States, as well as the global fast growing investment in shale gas exploration and development. Multiple transverse hydraulic fractures are generated when all wellbores are drilled in the direction of the minimum horizontal stress. Maximizing the total stimulated reservoir volume (SRV) plays a major role in successful economic gas production. The unprecedented growth of shale reservoirs has brought a new perspective and focus to the optimization of multiwell placement in the same pad. Drilling multiple horizontal wells from a single pad has increasingly become a common approach for developing shale reservoirs due to significant cost, time, and environmental savings. The surface footprint is reduced greatly by drilling multi-well from the same pad due to minimizing the number of surface locations required while increasing the bottom hole contact of the shale resource [1]. Zipper fracturing
References
[1]
J. L. Miskimins, “Design and life-cycle considerations for unconventional-reservoir wells,” SPE Production and Operations, vol. 24, no. 2, pp. 353–359, 2009.
[2]
G. Waters, B. Dean, R. Downie, K. Kerrihard, L. Austbo, and B. McPherson, “Simultaneous hydraulic fracturing of adjacent horizontal wells in the woodford shale,” in Proceedings of the SPE Hydraulic Fracturing Technology Conference, pp. 694–715, Woodlands, Tex, USA, January 2009.
[3]
M. J. Kaiser, “Haynesville shale play economic analysis,” Journal of Petroleum Science and Engineering, vol. 82-83, pp. 75–89, 2012.
[4]
S. L. Montgomery, D. M. Jarvie, K. A. Bowker, and R. M. Pollastro, “Mississippian Barnett Shale, Fort Worth basin, north-central Texas: gas-shale play with multi-trillion cubic foot potential,” AAPG Bulletin, vol. 89, no. 2, pp. 155–175, 2005.
[5]
M. Segatto and I. Colombo, “Use of reservoir simulation to help gas shale reservoir estimation,” in Proceedings of the International Petroleum Technology Conference (IPTC '11), Bangkok, Thailand, 2011.
[6]
S. Esmaili, A. Kalantari-Dahaghi, and S. D. Mohaghegh, “Modeling and history matching of hydrocarbon production from Marcellus shale using data mining and pattern recognition technologies,” in Proceedings of the SPE Eastern Regional Meeting (SPE '12), Lexington, Ky, USA, 2012.
[7]
M. Rafiee, M. Y. Soliman, and E. Pirayesh, “Hydraulic fracturing design and optimization: a modification to zipper frac,” in Proceedings of the SPE Eastern Regional Meeting (SPE '12), Lexington, Ky, USA, 2012.
[8]
O. C. Díaz de Souza, A. J. Sharp, R. C. Martinez et al., “Integrated unconventional shale gas reservoir modeling: a worked example from the Haynesville Shale, De Soto Parish, North Lousiana,” in Proceedings of the Americas Unconventional Resources Conference (SPE '12), Pittsburgh, Pa, USA, 2012.
[9]
J. Harpel, L. Barker, J. Fontenot, C. Carroll, S. Thomson, and K. Olson, “Case history of the Fayetteville shale completions,” in Proceedings of the SPE Hydraulic Fracturing Technology Conference (SPE '12), The Woodlands, Tex, USA, 2012.
[10]
H. Ramakrishnan, R. Yuyan, and J. Belhadi, “Real-time completion optimization of multiple laterals in gas shale reservoirs: Integration of geology, log, surface seismic, and microseismic information,” in Proceedings of the SPE Hydraulic Fracturing Technology Conference, pp. 691–705, The Woodlands, Tex, USA, January 2011.
[11]
S. Tavassoli, W. Yu, F. Javadpour, and K. Sepehrnoori, “Well screen and optimal time of refracturing: a Barnett shale well,” Journal of Petroleum Engineering, vol. 2013, pp. 1–10, 2013.
[12]
W. Yu and K. Sepehrnoori, “Simulation of gas desorption and geomechanics effects for unconventional gas reservoirs,” in Proceedings of the SPE Western Regional and AAPG Pacific Section Meeting (SPE '13), Monterey, Calif, USA,, 2013.
[13]
W. Yu and K. Sepehrnoori, “An efficient reservoir simulation approach to design and optimize unconventional gas production,” in Proceedings of the SPE Western Regional and AAPG Pacific Section Meeting (SPE '13), Monterey, Calif, USA,, 2013.
[14]
B. Rubin, “Accurate simulation of non-darcy flow in stimulated fractured shale reservoirs,” in Proceedings of the SPE Western Regional Meeting (SPE '10), pp. 19–34, Anaheim, Calif, USA, May 2010.
[15]
C. L. Cipolla, E. P. Lolon, J. C. Erdle, and B. Rubin, “Reservoir modeling in shale-gas reservoirs,” SPE Reservoir Evaluation and Engineering, vol. 13, no. 4, pp. 638–653, 2010.
[16]
R. D. Evans and F. Civan, “Characterization of non-Darcy multiphase flow in petroleum bearing formations,” U.S. DOE Contract DE-AC22-90BC14659, School of Petroleum and Geological Engineering, University of Oklahoma, 1994.
[17]
R. Schweitzer and H. I. Bilgesu, “The role of economics on well and fracture design completions of marcellus shale wells,” in Proceedings of the SPE Eastern Regional Meeting (SPE '09), pp. 423–428, September 2009.
J. P. Seidle and L. E. Arri, “Use of conventional reservoir models for coalbed methane simulation,” in Proceedings of the CIM/SPE International Technical Meeting (SPE '90), Calgary, Canada, 1990.
[20]
H. A. Al-Ahmadi, S. Aramco, and R. A. Wattenbarger, “Triple-porosity models: one further step towards capturing fractured reservoirs heterogeneity,” in Proceedings of the SPE/DGS Saudi Arabia Section Technical Symposium and Exhibition (SPE '11), Al-Khobar, Saudi Arabia, 2011.
[21]
R. H. Myers and D. C. Montgomery, Response Surface Methodology: Process and Product Optimization Using Designed Experiments, John Wiley and Sons, Hoboken, NJ, USA, 2002.
[22]
J. Kiefer and J. Wolfowitz, “Optimum designs in regression problems,” The Annals of Mathematical Statistics, vol. 30, no. 2, pp. 271–294, 1959.
