New type curves for analyzing horizontal well with multiple fractures in shale gas reservoirs

Nobakht, Morteza; Clarkson, Christopher R.; Kaviani, Danial

doi:10.1016/j.jngse.2012.09.002

Cited by 52 publications

(11 citation statements)

References 28 publications

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“…Brittleness is one of the most important mechanical parameters of unconventional gas shale reservoir estimation when it comes to hydraulic fracturing (Gasparrini et al 2014;Holt et al 2015) and borehole wall stability assessment and gas preservation risk (Ingram and Urai 1999;Hu et al 2014;Zhou et al 2014). Brittle shales are more likely to be naturally fractured and will also be more likely to respond well to hydraulic fracturing treatments (Nobakht et al 2013). Natural fractures may provide some reservoir space for shale gas but also may result in shale gas leakage .…”

Section: Introductionmentioning

confidence: 99%

Burial depth interval of the shale brittle–ductile transition zone and its implications in shale gas exploration and production

et al. 2017

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Brittleness and ductility of shale are closely related to shale gas exploration and production. How to predict brittleness and ductility of shale is one of the key issues in the study of shale gas preservation and hydraulic fracturing treatments. The magnitude of shale brittleness was often determined by brittle mineral content (for example, quartz and feldspars) in shale gas exploration. However, the shale brittleness is also controlled by burial depth. Shale brittle/ductile properties such as brittle, semibrittle and ductile can mutually transform with burial depth variation. We established a work flow of determining the burial depth interval of brittle-ductile transition zone for a given shale. Two boundaries were employed to divide the burial depth interval of shale brittle/ductile properties. One is the bottom boundary of the brittle zone (BZ), and the other is the top boundary of the ductile zone (DZ). The brittle-ductile transition zone (BDTZ) is between them. The bottom boundary of BZ was determined by the overconsolidation ratio (OCR) threshold value combined with pre-consolidation stress which the shale experienced over geological time. The top boundary of DZ was determined based on the critical confining pressure of brittle-ductile transition. The OCR threshold value and the critical confining pressure were obtained from uniaxial strain and triaxial compression tests. The BZ, DZ and BDTZ of the Lower Silurian Longmaxi shale in some representative shale gas exploration wells in eastern Sichuan and western Hubei areas were determined according to the above work flow. The results show that the BZ varies with the maximum burial depth and the DZ varies with the density of the overlying rocks except for the critical confining pressure. Moreover, the BDTZ determined by the above work flow is probably the best burial depth interval for marine shale gas exploration and production in Southern China. Shale located in the BDTZ is semi-brittle and is not prone to be severely naturally fractured but likely to respond well to hydraulic fracturing. The depth interval of BDTZ determined by our work flow could be a valuable parameter of shale gas estimation in geology and engineering.

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Section: Introductionmentioning

confidence: 99%

Burial depth interval of the shale brittle–ductile transition zone and its implications in shale gas exploration and production

et al. 2017

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“…All shale gas reservoirs are not the same and there are no typical tight gas reservoirs (Kennedy, et al, 2012). Multi-fractured wells completed in shale gas reservoirs are difficult to analyse quantitatively due to a combination of unique reservoir properties (eg, non-static porosity and permeability, desorption, non-Darcy flow) and potentially complex induced hydraulic fracture geometries (Nobakht, et al, 2013). Conventional reservoir simulators cannot provide, without alteration, a reasonable production analysis for shale gas reservoirs (Xie, et al, 2013).…”

Section: Unconventional Gas Reservoir Uncertaintymentioning

confidence: 99%

“…Fundamentally, type curves are pre-plotted solutions to the [reservoir] flow equations, such as the diffusivity equation, for selected types of formations and selected initial and boundary conditions (Lake & Fanchi, 2006). Type curves, showing either flow rate over time or cumulative production over time is a common tool used to describe the performance of a reservoir in unconventional gas well (Nobakht, et al, 2013;Mingqiang, et al, 2016;Sugiarto, et al, 2015;Burgoyne & Clements, 2014;Aminian, et al, 2004;Baihly, et al, 2010;Karacan, 2013;Mavor, et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…Although attempts have been made to generate type curves from reservoir properties of unconventional resource (Nobakht, et al, 2013;Clarkson & Bustin, 2010), it is a large subject on its own and no attempt is made in this work to solve those challenges. This work is the first part in a larger investigation into surface facility designs against input boundary uncertainty, and proposes a synthetic type curve as a means to describe the input boundary.…”

Section: Introductionmentioning

confidence: 99%

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Developing synthetic reservoir type curve model for use in evaluating surface facility and gathering pipe network designs

Dennis

2017

Journal of Natural Gas Science and Engineering

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Please cite this article as: Dennis, M., Developing synthetic reservoir type curve model for use in evaluating surface facility and gathering pipe network designs, Journal of Natural Gas Science & Engineering (2017), doi: 10.1016/j.jngse.2017 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT AbstractSurface facilities and unconventional gas gathering networks are typically designed to collect gas from a large number of wells to a central location. The unit operations that make up the surface network need to be installed before the wells are producing and thus need to be sized on predicted performance rather than actual performance which is not known until production data is available. This means each reservoir's production profile which is based on uncertain input parameters and imperfect reservoir models forms the sizing basis for the surface facilities.In this study a method is developed to generate synthetic reservoir flow type curves based on a set of input parameters that is independent of reservoir parameters. The main qualitative characteristics of an unconventional gas reservoir type curve are described such as gas ramp to peak, peak gas flow and production decline, along with the discontinuities and variations from expected performance seen in operating trends. The synthetic type curve proposed in this work can be parameterised to mimic these characteristics, along with a well deliverability mechanism and subsurface communication between wells.The method of being able to describe a type curve by means of input parameterisation allows an unconventional gas surface facility of gathering pipe network and in-field booster compressors to be designed against many sets of synthetic type curves rapidly generated by randomisation of those input parameters.

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“…Multi-stage fracturing technology for horizontal wells can activate the pre-existing natural fractures and generate a complex fracture network called stimulated reservoir volume (SRV), which has become the most effective method to develop shale resources [1]. Generally, SRV is defined as the part of the drainage area impacted by hydraulic fractures and concomitant reactive fractures, where the productivity of shale gas well could be effectively improved [2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Hybrid Coupled Multifracture and Multicontinuum Models for Shale Gas Simulation by Use of Semi-Analytical Approach

et al. 2018

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Abstract:Combining the advantages of multicontinuum and multifracture representations provides an easy-to-use tool to adequately capture the characteristic of the multiscaled fracture system in shale gas reservoir. A hybrid model is established on the basis of simplified conceptual productivity assumption, where the matrix volume is divided into two sub-domains (triple-porosity model and dual-depletion flowing model) and the fracture volume is represented by discrete finite conductivity fracture. In addition, the mechanisms of instant desorption, viscous flow and dual-depletion in matrix are taken into account. The rate transient responses are then obtained by use of semi-analytical approach. Based on the model, type curves are plotted and verified by comparing with alternative reliable methods. Different flow regimes in shale gas reservoirs can be identified and detected. The Generalized Likelihood Uncertainty Estimation methodology, based on probabilistic aggregation theory, is employed to integrating those two productivity models together such that the production can be predicted more accurately. A field example is applied to validate the applicability of this new model. Finally, it is concluded that the proposed model can predict the rate and cumulative rate more easily and practically.

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New type curves for analyzing horizontal well with multiple fractures in shale gas reservoirs

Cited by 52 publications

References 28 publications

Burial depth interval of the shale brittle–ductile transition zone and its implications in shale gas exploration and production

Burial depth interval of the shale brittle–ductile transition zone and its implications in shale gas exploration and production

Developing synthetic reservoir type curve model for use in evaluating surface facility and gathering pipe network designs

Hybrid Coupled Multifracture and Multicontinuum Models for Shale Gas Simulation by Use of Semi-Analytical Approach

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