Mikhail Geilikman

Interaction of Multiple Hydraulic Fractures in Horizontal Wells

The technology of multiple hydraulic fracture stimulation in horizontal wells has trans‐ formed the business of oil and gas exploitation from extremely tight, unconventional hydro‐ carbon bearing rock formations. The fracture stimulation process typically involves placing multiple fractures stage-by-stage along the horizontal well using diverse well completion technologies. The effective design of such massive fracture stimulation requires an under‐ standing of how multiple hydraulic fractures would grow and interact with each other in heterogeneous formations. This is especially challenging as the interaction of these fractures are subject to the dynamic process of subsurface geomechanical stress changes induced by the fracture treatment itself. This paper consists of two parts. Firstly, an idealised analytical model is used to highlight some key features of multiple hydraulic fractures interaction, and to provide a quantifica‐ tion of ‘stress shadow’. Secondly, a new non-planar three dimensional (3D) hydraulic frac‐ turing numerical model is used to provide an insight into the growth of multiple fractures under the influence of subsurface geomechanical stress shadows. Attention is given to studying the height growth of multiple fractures.

The Geomechanical Interaction of Multiple Hydraulic Fractures in Horizontal Wells

The technology of multiple hydraulic fracture stimulation in horizontal wells has trans‐ formed the business of oil and gas exploitation from extremely tight, unconventional hydro‐ carbon bearing rock formations. The fracture stimulation process typically involves placing multiple fractures stage-by-stage along the horizontal well using diverse well completion technologies. The effective design of such massive fracture stimulation requires an under‐ standing of how multiple hydraulic fractures would grow and interact with each other in heterogeneous formations. This is especially challenging as the interaction of these fractures are subject to the dynamic process of subsurface geomechanical stress changes induced by the fracture treatment itself. This paper consists of two parts. Firstly, an idealised analytical model is used to highlight some key features of multiple hydraulic fractures interaction, and to provide a quantifica‐ tion of ‘stress shadow’. Secondly, a new non-planar three dimensional (3D) hydraulic frac‐ turing numerical model is used to provide an insight into the growth of multiple fractures under the influence of subsurface geomechanical stress shadows. Attention is given to studying the height growth of multiple fractures.

Integrated wellbore-quality and risk-assessment study guides successful drilling in Amazon jungle

Significant lost-circulation and wellbore-instability problems in the form of bit balling, stuck pipe, and adverse mud-shale interactions have been experienced in wells drilled prior to the study at three prospects in the Amazon jungle. An integrated borehole-stability and risk-assessment study has been carried out to enable successful drilling by optimizing borehole fluid pressures and predicting safe openhole times in various troublesome zones. The guidelines for hole-cleaning parameters and well-trajectory optimization have been obtained using improved fracture gradient and horizontal stress-anisotropy proprietary models based on special drill-cuttings data. Monopole and dipole sonic and imaging logs along with drilling data from the prospect wellshave been used to determine in-situ stresses, rock properties, andformation strength. These parameters have been utilized in borehole stability, hole cleaning, and open-hole time analyses for a comprehensive risk assessment and for selection of the optimum we...

New Model of Permeability of Tight Shale Gas Rock Based on Open-System Geomechanics

Finding an adequate description of permeability in shale gas is a challenging problem because of complexity of the rock which contains both organic and non-organic components. Due to small pore size, which is comparable with the mean free path of molecular motion, matrix permeability should include Knudsen and slip flow components as well as conventional Poiseuille one. If we assume as usual that permeability is a function of porosity, k(), then stress and pore pressure dependence of variation of permeability can be found as determined by porosity related effective (Terzaghi) stress, i.e. difference between confining stress and pore pressure (Carroll, 1980; Charlez, 1997):