4D Geomechanics Application for Successful Well Drilling Plan
Authors: Moid Farrukh , Hamid Osman 
Published: October 2023

4D geomechanics has an impact on a variety of hydrocarbon field operations, including exploration and development. 4D geomechanics modeling and analysis become more important when planning wells in difficult and depleted environments. This paper describes the application of 4D geomechanics modeling in a well drilling plan. The 4D geo-mechanics are used to understand subsurface behavior and plan wells in complex environments. Building a model that employs seismic inversion volumes to constrain geological facies and structural models is a part of 4D geomechanics.

The main goal is to analyze wellbore stability to predict mud weight window and best drilling practices to minimize drilling risks. The ultimate objective is to provide a stable and smooth borehole environment that meets the objectives and expectations of the completion and stimulation requirements to maximize hydrocarbon production. Constant collaboration and integration among all disciplines, including but not limited to Drilling, Geology, Geo-steering, Production Engineering, and Reservoir Management, is key to a successful well.

It is necessary to characterize stress redistribution throughout the field production lifecycle to avoid or reduce possible issues during drilling. To account for the variance in the rock properties, 4D geomechanics models were developed. A reservoir dynamic simulation model has been developed to account for pressure depletion in the reservoir during production. A 4D geomechanics model precisely aids pre-drill modeling for the upcoming drilling campaign. Pre-drill models suggest the right mud weight and drilling parameters for successful and safe well drilling.

Data from offset wells have been used to construct calibrated 1D geomechanical models; the 3D geomechanical models have been built by interpolation of the 1D geomechanical models, then the static model has been coupled by a simulation model for a number of years. A detailed geological model has been used for structural interpretation. The fracture and fault characterization has been used to determine the orientation of the horizontal stresses. Petrophysics and mineralogy were used to identify lithology, porosity, and permeability.

Identification of mechanical field integrity and production risks, such as reservoir compaction, subsidence, and sand production, were predicted with 4D geo-mechanical modeling. The model has also estimated wellbore strength before increasing weight and suggests bridging materials added prior to troublesome intervals. Collapse, pore, and fracture pressure have been predicted and used to ensure better wellbore quality. Post-drill analysis confirms maximum stress direction, and Image logs have shown excessive induced fractures. Bridging materials were added to strengthen the rock and reduce induced fracture effects. The comprehensive geological model results in smooth well drilling and stable borehole condition for future well evaluation and testing operations.

The 4D geomechanical modeling has been used to analyze and predict wellbore stability. Parameters affecting well stability include in situ stresses, pores pressure, rock strength, drilling fluid pressure, and drilling direction. The accuracy of geomechanics evaluation has been improved by the 4D geomechanics model that integrates a reservoir dynamic and static model. The model enhanced the analysis of bedding plane failures by using a simulation of the current stress profile, which revealed a greater mud weight requirement due to reservoir depletion. Following that, future planned wells can be drilled safely with minimal reservoir damage and no major wellbore instability issues thanks to an ideal mud weight program guided by the study's findings. A more thorough knowledge of reservoir dynamics can result from further integrating all reservoir dynamics models.