Geomechanical Characterization for an Unconventional Shale Reservoir With the Goal of Improving Drilling Efficiency and Sweet Spots Selection in a Field in Colombia

Medina, Leonardo Arias (Universidad de America, Bogota) | Lozano, Henry Andrey (Universidad de America, Bogota) | Mantilla, Hernan Dario (Ecopetrol) | Espinosa Mora, Carlos Alberto (Universidad de America, Bogota)

OnePetro 

SUMMARY: After the success of the drilling campaigns in unconventional shale reservoir in the United States, Ecopetrol wanted to replicate their success in Colombia as well. During the past years a drilling campaign encountered several unique issues for shale plays in Colombia. With the advances in electrical logging, petrophysics, geomechanical and geochemical analyses allowed understanding the shale plays in a basin in Colombia.

Geomechanics has been useful in providing the required information for the design of optimal well trajectories for efficient development of unconventional reservoirs. Additionally, extensive tri-axial and total carbon organic (TOC) tests in shales have been included in the study to calibrate the mechanical properties and TOC obtained from the electrical logs. The concept of critically stressed fractures has been included in the analysis of this geomechanical model in order to know the conductivity of the natural fractures in shale plays.

The present study displays a methodology for the design of a mud weight window as well as a geochemical analysis for the sweet spot selection in the shale plays. The geomechanical model considers transversal vertical anisotropy (TIV) with the use of Stoneley wave from sonic scanner tool necessary for the determination of the anisotropic mechanical properties and in-situ principal stresses. The present study includes conclusions and recommendations for unconventional shale reservoirs in Colombia.

1 INTRODUCTION

Oil companies have always wanted to drill wells in unconventional fields, but because of their complexity and limited technology in the time were an impediment.