Advanced Drilling Induced Fracture Modeling for Wellbore Integrity Prediction

Abstract

We present a method for modeling drilling induced fractures dynamic growth through a porous medium in the near wellbore region. Understanding the early time fracture growth behavior, and related near wellbore stress state, can provide an effective tool to improve the treatment selection through parameters such as particle size distribution and ideal drilling fluid rheology. Also, it will help with field diagnostics for various lost circulation treatments and lost return events. ExxonMobil Upstream Research Company and SIMULIA® co-developed fully-coupled hydraulic fracturing modeling capabilities. The method is based on Cohesive Zone Modeling (CZM) elements, with pore pressure degrees of freedom, which were recently implemented into SIMULIA® Abaqus finite element package. The model was benchmarked with known solutions to analytical fracture growth regimes and validated with a laboratory scale experimental setup of hydraulic fracturing. The model allows for fluid leak-off from the wellbore and fracture faces into the porous medium, as well as an arbitrary injection schedule. Additionally, the physics of dynamic fracture growth and a variety of material properties and constitutive models for both the solid and liquid, are also captured in the model. The time-dependent fracture growth and interaction between the stress concentration region near the fracture tip and the wellbore result in a non-linear behavior of the near-wellbore stress state during early time fracture propagation, which was not possible to capture with static models. The model generation, execution, and post-processing are part of an automated workflow which requires minimal user time. This analysis allows for recommendation of optimum fracture width for maximum increase in wellbore integrity in the target formation. This is done by selecting the fracture width at the mouth, at which a necessary increase in the near-wellbore tangential stresses has been achieved as to prevent initialization of further fractures.

Wellbore shrinkage during drilling in methane hydrate reservoirs

“…[30][31][32][33][34][35][36] ABAQUS gets a rich material database to meet most engineering needs, and UMAT subroutines define arbitrary material properties autonomously. ABAQUS is a general purpose finite-element-analysis code that can analyze fluid seepage and mechanical problems in porous media and has been widely used for solving mechanical problems around a wellbore in recent years.…”

“…ABAQUS is a general purpose finite-element-analysis code that can analyze fluid seepage and mechanical problems in porous media and has been widely used for solving mechanical problems around a wellbore in recent years. [30][31][32][33][34][35][36] ABAQUS gets a rich material database to meet most engineering needs, and UMAT subroutines define arbitrary material properties autonomously.…”

Thermal effect on the compression coefficient of heavy oil reservoir rocks

“…In order to analyse the variation of reservoir compression coefficient around the well during steam stimulation, the Abaqus finite-element package is selected for numerical simulation studies of the variation law of temperature field around the well in the process of steam stimulation. Abaqus is a general-purpose finite-element analysis code that can analyse fluid seepage and heat transfer problems in porous media and has been widely used for solving problems around a wellbore in recent years [27][28][29][30][31][32][33]. This study mainly analyses the evolution law of reservoir compressibility at different distances from the wellbore during steam stimulation, and does not focus on the productivity of a reservoir.…”

Dynamics of fracturing saturated porous media and self-organization of rupture

“…Some solutions including inertia forces exist, however [22][23][24][25]. [22,23] show continuous fracture growth, [24] some pressure oscillations due to fracture toughness contrast between two adjacent layers, while [25] clearly exhibits stepwise behavior and pressure oscillations. This aspect will be addressed below and involves the use of algorithms which respect "self-organization of rupture".…”