Session: 11-01-01 Well Drilling Technology-1

Paper Number: 78659

78659 - Design and Evaluation of Wellbore Strengthening Materials for Fractured Reservoirs 

Fractured formations are commonly encountered while drilling. Drilling of fractured formations usually end up with lost circulation. In some cases, target zones cannot be reached due to lost circulation.

Fractures encountered before reaching target zones can be sealed off by using wellbore strengthening materials (WSM). WSM are drilling fluid additives which are specially sized and designed particulates. They are generally used to strengthen the wellbore and to prevent the occurrence of losses by propping and sealing the fractures. In this study, experiments were carried out to determine optimum concentration and particle size distribution (PSD) of WSM to seal off fractures.

A non-damaging water-based polymer drill-in fluid supported with acid soluble marble particle packages with different concentrations and PSD were used in this study. Plugging efficiency of different blends were tested using modified Permeability Plugging Apparatus by pushing WSM-imbedded drill-in fluid through fracture widths of 400, 800 and 1200 μm manufactured on metal disks. Different WSM blends were compared with regards to sealing time required to reach target pressure of 2000 psi and volume lost until the seal was achieved.

During the study, several tests were run to investigate the effect of different PSD, concentration, and fracture width. Results were interpreted to determine optimum WSM formulations for different fracture sizes by taking continuous particle addition strategy together with downhole tools limitations into account. Optimum WSM compositions applied in fractured zones which has the same fracture width in wells have been found to seal off these fractures widths successfully.

Presenting Author: UGUR GARGILI GEOS Energy Inc.

Authors:

UGUR GARGILI GEOS Energy Inc.
Ismail Hakki Gucuyener GEOS Energy Inc.
Ismail Durgut Middle East Technical University
Ahmet Ay GEOS Energy Inc.
Huseyin Ali Dogan GEOS Energy Inc.