Suo, Yu (University of New South Wales) | Chen, Zhixi (University of New South Wales) | Rahman, Sheik (University of New South Wales) | Xu, Wenjun (University of New South Wales and Southwest Petroleum University)
Hydraulic fracturing is a significant way to improve the productivity of the unconventional reservoir with low permeability and porosity. Current hydraulic fracturing simulation models are mostly based on poro-elastic theory. However, for rocks such as shale, the viscoelastic feature has been observed in both field investigations and laboratory experiments. This paper presents a 3D numerical model for fracture propagation in viscoelastic shale gas formations using ABAQUS platform. The cohesive elements based on damage mechanics were adopted to simulate the initiation and propagation of hydraulic fractures. The model was used to investigate formation properties and treatment parameters on fracture geometry, especially the fracture behaviour when entering into the barrier formations. It is found that higher treatment pressure is required to initiate and propagate the hydraulic fracture and the fracture is wider but shorter in poroviscoelastic formation comparing to poro-elastic formation. The higher differential in-situ stress, tensile strength and Young modulus in barrier formations and lower fracturing fluid injection rate and lower fracturing fluid viscosity have positive effect on the controlling of fracture vertical growth and restricting hydraulic fracture within the pay zone. Results of this study will provide the industry a better understanding of hydraulic fracture behaviour in shale gas formations.
This paper was prepared for presentation at the Unconventional Resources Technology Conference held in Houston, Texas, USA, 23-25 July 2018. All information is the responsibility of, and, is subject to corrections by the author(s). Any person or entity that relies on any information obtained from this paper does so at their own risk. The information herein does not necessarily reflect any position of URTeC. Any reproduction, distribution, or storage of any part of this paper by anyone other than the author without the written consent of URTeC is prohibited.
Yuan, Yudong (School of Petroleum Engineering, University of New South Wales) | Rahman, Sheik (School of Petroleum Engineering, University of New South Wales) | Wang, Junjian (School of Petroleum Engineering, University of New South Wales) | Doonechaly, Nima Gholizadeh (School of Petroleum Engineering, University of New South Wales)
Characterization of flow processes in multi-scale porous system (nanopores to mesopores) in tight rocks, such as the shales, is challenging because of the coexistence of various flow regimes in the porous media. Although some methods based on dusty gas model (DGM) have been applied to determine the apparent gas permeability of shales (
This paper presents a new numerical model for analyzing transient pressure test data taken from naturally-fractured reservoirs. The model computes well pressures for a single well completed in a naturally-fractured reservoir. It models characteristic properties of naturally-fractured reservoirs including fracture orientation, fracture length, fracture density and fracture distribution. A single-phase, slightly compressible fluid flow is assumed. Fluid flow is modelled based on a hybrid approach which combines single continuum (block-based permeability tensor for small to medium fractures) and flow in discrete fractures (long fractures). A sensitivity analysis is presented to examine the effects of fracture density, fractal dimension and percolation probability. Then the model is validated against two worked examples reported in the literature. Results reveal that new model can predict transient pressure response of complex naturally-fractured reservoirs. Hence, it can be used to match pressure test data and diagnose characteristic properties of naturally-fractured reservoirs.
Pinczewski, Val (State University of Campinas (UNICAMP) - Brazil) | Maidla, Eric (State University of Campinas (UNICAMP) - Brazil) | Rahman, Sheik (Colorado School of Mines) | Taggart, Ian (Colorado School of Mines)
A goal was set - provide the necessary skills and training at the undergraduate level to enable the student to become an investigative petroleum engineer. Although untangible, some immediate steps were taken to assure marching in the correct direction.
A discussion was undertaken to try and improve on the educational process concerning the role of the petroleum engineer graduate in the industry today and how it will change throughout the years to come.
This is different than a discussion on the curriculum contents (that is also taking place).
It is well accepted that the basic undergraduate training should contain a balance between maths, physics, general science and petroleum oriented courses, that last ones including formation evaluation, reservoir, production, completions and drilling, and recently including topics on environmental engineering control and waste management.
The procedure undertaken here were to consider as a major priority, the industry's demands, stated simple and straightforwards as:
1) Sound technical skill to combine art and science in a way to achieve and sustain a competitive edge in a particular business.
2) Change and adapt to market demands.
3) Good human relation skills.
4) Good communication skills.
Historically, at the undergraduate level, we have partially attended the first demand. This was achieved by classifying the technical skills in areas (reservoir, drilling, etc.) which are taught by further subdividing them, once or twice (or as many times needed) and concentrating on a specific topic, i.e. well control, gamma ray log analysis, fluid displacements, etc.
This approach assumed that the student is able to solve problems by using the different tools be has mastered - this is typically a reductionism approach to the problem.
Evaluation of the topics addressed is also an issue since it normally concentrated in testing the student on a given subtopic in a way to produce a unique correct result.