Fully-Coupled Numerical Evaluations of Multiwell Completion Schemes: The Critical Role of In-Situ Pressure Changes and Well Configuration

Nagel, N.B.; Sheibani, Farrokh; Lee, B.; Agharazi, Alireza; Zhang, F.

doi:10.2118/168581-ms

Cited by 14 publications

(11 citation statements)

References 11 publications

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“…The simulation results illustrate that the zipper fracturing has only a modest impact on the activation of natural fractures, but strong risk of screenout. Nagel et al (2014) extended the previous work by considering the effect of changing natural fractures pressure and concluded that the improvement in well stimulation using different completion strategies such as zipper fracturing is highly dependent on in-situ pore pressure, in-situ stress, natural fracture mechanical properties, natural fracture orientation, and initial aperture.…”

Section: Zipper Fracturingmentioning

confidence: 64%

“…Therefore, in an effort to increase the operational efficiency of hydraulic fracturing and reduce cost, several multiwell completion schemes, such as zipper fracturing and Љsimul-fracturing,Љ have been introduced. However, the productivity and return on investment from such fracturing schemes have seen mixed results (Nagel et al 2014). It is important, however, to account for various techniques to come up with the optimized completion technique.…”

Section: Introductionmentioning

confidence: 99%

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Reservoir Modeling for Pad Optimization in the Context of Hydraulic Fracturing

et al. 2015

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Multiwell pads have become a norm in unconventional reservoirs with wells having multistage, multiperforation-cluster configuration. The complex jungle of wells and horizontal laterals under the surface of the earth has raised the complexity of pad optimization and hydraulic fracturing to a next level. Modeling the hydraulic fracture systems correctly is key for optimizing well and stage locations. Even in the case of noncomplex, planar fractures, the interaction amongst the fractures, which is also known as stress shadow effect, can lead to uneven fracture growth. In the case of complex fracture networks, the fracture interaction can be even stronger due to typically higher fracture density. Therefore, stress shadowing is a key element in reservoir modeling for shale plays in the framework of hydraulic fracturing. The sequence of stage placement in the pad and their treatment can also have a significant impact on the reservoir contact.The zipper fracturing technique, involving the simultaneous and back-to-back stimulation of horizontal wells on a pad, has been rapidly adopted by multiple operators in the last few year across various shale plays in North America. The technique has achieved its popularity due to increased efficiency and reduced turnaround time for a multiwell pad. The method has been effective in saving tens of millions of dollars for operators by accelerating the pad development cycle. Apart from improved completion efficiency, pads that have run zipper fracturing have shown improved production from their counterparts in the same field that have been completed without zipper fracturing. The impact on hydraulic fracture growth due to stress shadow from offset wells' hydraulic fracture systems is a major contributing factor for this difference. Depending on the time spent between the stages, the extent and magnitude of stress shadow will change to dictate the growth of the offset well hydraulic fracture stage.Proper reservoir modeling can help optimize the well location and spacing, completion staging, and optimizing hydraulic fracture treatment designs as well as their sequence. This study reviews and discusses the application of stress shadow modeling for various treatment sequences for multiple wells in a pad-and use of numerical reservoir simulation for optimal pad development strategy. The results assess the impact of managing the fracturing sequence and accounting for the delay in time between stages, growth of hydraulic fractures and their interference amongst each other, distribution of proppants and fluids, and reservoir drainage through numerical simulation for unconventional reservoirs.

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Section: Zipper Fracturingmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Reservoir Modeling for Pad Optimization in the Context of Hydraulic Fracturing

et al. 2015

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“…The simulation results illustrate that the zipper fracs only have modest impact on the natural fractures activation but strong risk to screenout. Nagel et al 2014 extended the previous work by considering the effect of changing natural fractures pressure and states that the improvement in well stimulation using different completion strategies such as zipper fracturing is highly dependent on in-situ pore pressure, in-situ stress, natural fracture mechanical properties, natural fracture orientation, and initial aperture.…”

Section: Zipper Fracturingmentioning

confidence: 79%

“…In an effort to increase the operational efficiency of hydraulic fracturing and reduce cost, several multiwell completion schemes, such as zipper fracturing and Љsimul-fracturingЉ, have been introduced but with mixed results (Nagel et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Simulation Study of Zipper Fracturing Using an Unconventional Fracture Model

Qiu

Porcu

et al. 2015

Day 1 Tue, October 20, 2015

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In the past decade the industry has embraced unconventional resources; namely, shale oil and shale gas. After the initial drill-to-hold stage, multiwell pad drilling and stimulations are employed to exploit the acreage. Zipper fracturing is a technique that reduces the standby time (up to 50% reduction, when combined with the plug-and-perf isolation method). Because of this operational efficiency improvement, zipper fracturing has become one of the most common fracturing practices for unconventional reservoir stimulation. It has also been purported to increase production, which several authors have previously reported. There are also other studies showing no benefit of zipper fracturing on production performance.In this paper we have used a complex fracture network model, which we refer to as the Unconventional Fracture Model (UFM), to study zipper fracturing. The model simulates complex (branched) fracture propagation, associated stress shadows, fluid flow, and proppant transportation in the complex fracture network. The model solves the fully coupled problem of fluid flow in the fracture network and elastic deformation of the fracture. A key difference between UFM and the conventional planar fracture model is being able to simulate the interaction of hydraulic fractures with preexisting natural fractures (also referred as planes of weakness). The UFM simulates interwell and interstage stress shadows and honors both sequential fracturing and zipper fracturing scenarios' geomechanical interaction.In this paper, we present the results of a zipper and sequential fracturing study that includes the completion design optimization and the associated production performance in the Eagle Ford Shale. The study provides a workflow to optimize the completion and stimulation designs in pad development and to improve rate of return. The quantitative results show that zipper fracturing may not deliver a production benefit when compared with sequential fracturing and is a function of well spacing and perforation cluster spacing in a given area.

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“…Wang et al 2011;Daniels et al 2007;Le Calvez et al 2007;Nagel et al 2013Nagel et al , 2014. Although the complex fracture network provides key channels for gas flow, it also brings new challenges for shale gas development plan, which contains optimizing hydraulic fracture design and well productivity prediction.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Shale Gas Development Based on Complex Fracture Network Growth

Ye¹,

Yin²,

Li³

et al. 2014

SPE Energy Resources Conference

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Micro-seismic result has shown that compared to conventional reservoir, more complex fracture network will be generated in shale gas reservoirs after hydraulic fracturing stimulations, which provides key channels for shale gas to flow in economic rate. It is vitally important to recognize complex fracture network and model such complex system to better understand gas develop process, optimize hydraulic fracturing design, and determine development plans of shale gas reservoirs.Our proposed model enable realistic modeling of complex fracture network growth even with some uncertainty (SPE 157411), but it is possible to represent large-scale fracture network distribution in reservoir modeling and numerical simulation of shale gas development. In this paper, we used this proposed model to generate hydraulic fracture network distribution in shale formation, taking into account interaction between hydraulic fracture and actual large-scale natural fractures. Integrating hydraulic fracture network results and natural fractures in non-stimulated area, highly constrained unstructured gridding and a connection list are constructed, using the Discrete Fracturing Modeling (DFM) method. This model can effectively predict production performance. With real-world well data, the simulation system calibration is done, and the simulated well production performance has good agreement with real-world producing data. Using this simulation system, effective stimulated reservoir volume (ESRV) is also predicted.The proposed approach is capable of modeling complex fracture network propagation and predicting well producing rate, if information data on multi-scale pre-existing natural fracture is available. This approach provide one opportunity to predict well production performance and effective stimulated reservoir volume (ESRV), which is also significant for shale gas development plan.

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Fully-Coupled Numerical Evaluations of Multiwell Completion Schemes: The Critical Role of In-Situ Pressure Changes and Well Configuration

Cited by 14 publications

References 11 publications

Reservoir Modeling for Pad Optimization in the Context of Hydraulic Fracturing

Reservoir Modeling for Pad Optimization in the Context of Hydraulic Fracturing

Simulation Study of Zipper Fracturing Using an Unconventional Fracture Model

Numerical Simulation of Shale Gas Development Based on Complex Fracture Network Growth

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