Numerical investigation of a low-efficient hydraulic fracturing operation in a tight gas reservoir in the North German Basin

Conventionally, high-pressure water-based fluids have been injected for hydraulic stimulation of unconventional petroleum resources such as tight gas reservoirs. Apart from improving productivity, water-based frac-fluids have caused environmental and technical issues. As a result, much of the interest has shifted towards alternative frac-fluids. In this regard, n-heptane, as an alternative frac-fluid, is proposed. It necessitates the development of a multi-phase and multi-component (MM) numerical simulator for hydraulic fracturing. Therefore fracture, MM fluid flow, and proppant transport models are implemented in a thermo-hydro-mechanical (THM) coupled FLAC3D-TMVOCMP framework. After verification, the model is applied to a real field case study for optimization of wellbore x in a tight gas reservoir using n-heptane as the frac-fluid. Sensitivity analysis is carried out to investigate the effect of important parameters, such as fluid viscosity, injection rate, reservoir permeability etc., on fracture geometry with the proposed fluid. The quicker fracture closure and flowback of n-heptane compared to water-based fluid is advantageous for better proppant placement, especially in the upper half of the fracture and the early start of natural gas production in tight reservoirs. Finally, fracture designs with a minimum dimensionless conductivity of 30 are proposed.

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Microseismic Evaluation of Hydraulic Fracturing Completion Design in Tight Gas Reservoir in Oman

Sixth EAGE Workshop on Passive Seismic ◽

10.3997/2214-4609.201600001 ◽

2016 ◽

Cited By ~ 1

Author(s):

O. Al-Harrasi ◽

A. Briner ◽

J. Chavez-Florez ◽

Y. El-Taha

Keyword(s):

Hydraulic Fracturing ◽

Tight Gas ◽

Gas Reservoir ◽

Tight Gas Reservoir

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Development of a Novel Alcoholic Acid System for Removal Damage Resulting from Hydraulic Fracturing in the Tight Gas Reservoir

10.2118/86552-ms ◽

2004 ◽

Author(s):

Xugang Wang ◽

Honglan Zou ◽

Yandong Chen ◽

Fuxiang Zhang ◽

Jianxin Peng

Keyword(s):

Hydraulic Fracturing ◽

Tight Gas ◽

Acid System ◽

Gas Reservoir ◽

Tight Gas Reservoir

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3-D geomechanical modelling of a gas reservoir in the North German Basin: workflow for model building and calibration

Solid Earth Discussions ◽

10.5194/sed-5-767-2013 ◽

2013 ◽

Vol 5 (1) ◽

pp. 767-788 ◽

Cited By ~ 2

Author(s):

K. Fischer ◽

A. Henk

Keyword(s):

Stress Field ◽

Fractured Reservoirs ◽

Wellbore Stability ◽

Fe Model ◽

North German Basin ◽

Gas Reservoir ◽

The North ◽

In Situ Stresses ◽

German Basin

Abstract. The optimal use of conventional and unconventional hydrocarbon reservoirs depends, amongst others, on the local tectonic stress field. For example, wellbore stability, orientation of hydraulically induced fractures and – especially in fractured reservoirs – permeability anisotropies are controlled by the recent in situ stresses. Faults and lithological changes can lead to stress perturbations and produce local stresses that can significantly deviate from the regional stress field. Geomechanical reservoir models aim for a robust, ideally "pre-drilling" prediction of the local variations in stress magnitude and orientation. This requires a~numerical modelling approach that is capable to incorporate the specific geometry and mechanical properties of the subsurface reservoir. The workflow presented in this paper can be used to build 3-D geomechanical models based on the Finite Element Method (FEM) and ranging from field-scale models to smaller, detailed submodels of individual fault blocks. The approach is successfully applied to an intensively faulted gas reservoir in the North German Basin. The in situ stresses predicted by the geomechanical FE model were calibrated against stress data actually observed, e.g. borehole breakouts and extended leak-off tests. Such a validated model can provide insights into the stress perturbations in the inter-well space and undrilled parts of the reservoir. In addition, the tendency of the existing fault network to slip or dilate in the present-day stress regime can be addressed.

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A workflow for building and calibrating 3-D geomechanical models &ndash a case study for a gas reservoir in the North German Basin

Solid Earth ◽

10.5194/se-4-347-2013 ◽

2013 ◽

Vol 4 (2) ◽

pp. 347-355 ◽

Cited By ~ 29

Author(s):

K. Fischer ◽

A. Henk

Keyword(s):

Stress Field ◽

Fractured Reservoirs ◽

Wellbore Stability ◽

Fe Model ◽

North German Basin ◽

Gas Reservoir ◽

The North ◽

In Situ Stresses ◽

German Basin

Abstract. The optimal use of conventional and unconventional hydrocarbon reservoirs depends, amongst other things, on the local tectonic stress field. For example, wellbore stability, orientation of hydraulically induced fractures and – especially in fractured reservoirs – permeability anisotropies are controlled by the present-day in situ stresses. Faults and lithological changes can lead to stress perturbations and produce local stresses that can significantly deviate from the regional stress field. Geomechanical reservoir models aim for a robust, ideally "pre-drilling" prediction of the local variations in stress magnitude and orientation. This requires a numerical modelling approach that is capable to incorporate the specific geometry and mechanical properties of the subsurface reservoir. The workflow presented in this paper can be used to build 3-D geomechanical models based on the finite element (FE) method and ranging from field-scale models to smaller, detailed submodels of individual fault blocks. The approach is successfully applied to an intensively faulted gas reservoir in the North German Basin. The in situ stresses predicted by the geomechanical FE model were calibrated against stress data actually observed, e.g. borehole breakouts and extended leak-off tests. Such a validated model can provide insights into the stress perturbations in the inter-well space and undrilled parts of the reservoir. In addition, the tendency of the existing fault network to slip or dilate in the present-day stress regime can be addressed.

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