Date of Award

January 2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Petroleum Engineering

First Advisor

Mehdi Ostadhassan

Abstract

Minimizing the costs and risks of drilling and achieving a maximum production rate are

technically and economically challenging, this becomes more crucial when drilling in tight

shale formations, an in-depth investigation of geomechanical behavior of the reservoir,

including elastic properties, and the in-situ stresses also known as Mechanical Earth Model

(MEM) is inevitable, which is studied by concept of Mechanical Earth Model (MEM). In this

thesis, the concept of the MEM is used to determine rock strength and elastic properties of the

wells in the Blue Buttes Field, Williston Basin, North Dakota. Blue Buttes is one of the major

oil producing fields from the Bakken Formation.

For this study, a 3-D MEM is constructed for the field. The input data includes wireline logs,

core, drilling reports and, geological properties of the field. For the study, analysis was done on

state of In-situ stresses, formation properties, and type of instabilities that occur around the

trajectory of the wellbore specifically in the Bakken Shale Formation by acquiring anisotropic

poro-elastic relationships to incorporate pore pressure and stresses in the field more accurately.

In the next step, safe mud weight window was determined the to avoid shear and tensile failure

during drilling, and mitigating other wellbore instabilities issues by controlling the sub surface

parameters and considering chemical properties of the shales and mud activities. The

constructed MEM model revealed how changes in pore pressure, stresses, and the overall

properties physiochemical of the shale can hugely impact the drilling process and production

from the field. which will minimize the unplanned well maintenance cost. Further it is helpful

in studies such as drilling in the deviated holes, hydraulic fracturing, sanding analysis and

perforation stability analysis.

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