P. A. Martynyuk

Assessment of stress state in rocks by deformation characteristic of borehole zone with hydrofracture

The authors propose the method of stress state assessment in permeable rocks. The method is numerically studied as the relationship between cross-section area of borehole length interval with a hydrofracture and the loading pressure on the borehole walls. The test data processing algorithm and the practical application of the method are considered.

Statistical Modeling of Rock Failure under Biaxial Compression. Part I: Shear Crack Interaction

The shapes and dimensions are determined for the regions of tensile stress concentration under the interaction of two shear cracks in the biaxial compression field. The statistical model for shear microcrack accumulation and main rupture formation is developed. The influence exerted by microcrack orientation and ratio of principal stresses on the direction of main rupture propagation is studied.

Trajectory of Crack Formed by Hydraulic Fracturing near the Contact of Productive Stratum with Enclosing Rocks

For the plain strain, the calculations are performed for developing the crack formed by hydraulic fracturing near the contact of oil-bearing stratum with enclosing rock. It is established that the external field of compressive stresses exerts a constitutive influence on the trajectory of crack propagation.

Statistical Modeling for the Failure Kinetics of a Solid in Tension

A statistical model is proposed for the kinetics of microcrack origination. Basic parameters are considered for development of a single main crack and the case of multiple failure. Dependences are found for grain size composition on the number of activized microcracks.

Growth of hydrofractures in an oil and gas stratum under impulse loading

It is analyzed how hydofractures grow from the circular hole boundary in the conditions of plane strain, as well as how amount of hydrofractures, their initial length, working fluid pressure and external compression parameters affect the fractured zone form, opening of the cracks and their volume. Depending on the basic parameters, development conditions are determined for two or more cracks.

Statistical Model of Rock Failure under Compression

Based on the analysis of the elastic stresses between two shear cracks in the biaxial compression field, the conditions of crack joining are determined. The simulated statistical model is proposed for the development of shear failure in solid body under compression.

Modeling fracture growth under multiple hydraulic fracturing using viscous fluid

Under computational investigation is the process of sequential growth of hydrofractures under conditions of plane strain. The working fluid is perfect and viscous. The authors analyze influence exerted on parameters and trajectories of growing fractures by spacing of the fractures, external compression field, fluid flow rate, fluid viscosity and leakage flow rate.

Hydrofracture growth in a compressed quasi-regular blocky rock mass

Effect of irregular structure of a compressed blocky rock mass on propagation of a hydrofracture is analyzed in the limit case when biaxial compression field is hydrostatic.

Propagation of hydraulic fractures in biaxial compression field, considering fluid leakage and viscosity

The authors analyze numerically propagation of hydraulic fractures from a circular hole boundary under viscous fluid injection in plane strain condition, considering influence of the fluid viscosity and elastic characteristics. The approximate solution is compared with the recent numerical calculations of exact formulated problem. Effect of configuration of incipient hydraulic fractures on development of the overall hydrofracturing pattern is analyzed, and stable growth conditions for several long fractures are found.

Analytical Model for Stochastic Development of Damage in Solid Body under Uniform Tension

The recursion relations are proposed for probabilities describing the simulating statistic model for kinetic process of microcrack coalescence and origination in modeling the failure of uniformly extended volume. It is shown that these relations make it possible to investigate the influence exerted by basic parameters of the model on the damage development with different laws of variation in radius of capture zone of interacting microcracks.