Graduate Seminar: Rock Mechanics Center Feb 26

The weekly Rock Mechanics and Explosives Research Center (RMERC) Graduate Gathering is held in the  RMERC Building – 1006 Kingshighway, in the conference room (room 106)

From 3:30 -420 Fridays when  MS&T classes are in session.

Anyone is welcome to attend. Please also feel free to bring a friend.

Our presenter for this Friday, February 26, 2016  is as follows: Mr. Ahmed Alsubaih  MS candidate (Dr. Nygaard)

Paper Tittle :Shale Instability of Deviated Wellbores in Southern Iraqi Fields

ABSTRACT: Wellbore instability problems are the cause for the majority of nonproductive time in the southern Iraqi field developments. Although the geological structure isn’t very complicated, there are bountiful problems which have been encountered during drilling operations in the production zones. These drilling difficulties pose potential problems such as mud losses in weak or vugular formations, stuck pipe in shale or unconsolidated formations, flow of sulfurous water or gas flow in few zones. This paper focuses on the most severe problem in terms of effort and disbursement which is referred to pipe sticking in Tanuma shale formation. Admittedly, there is a considerable number of vertical wells which has been drilled throughout this zone successfully; yet stuck pipe has been frequently experienced during directional drilling operations. Examining the drilling data revealed that this phenomenon was mostly related to shear failure of the wellbore, which caused an immediate increase in the stand pipe pressure with no drilling fluid returns when circulating.  In this regard, a geomechanical analysis for southern Iraqi field was performed on field data from 45 deviated wells using the modified Mogi Column failure criteria, including thermally and chemically induced stress and the bedding related failure of the wellbore. The analysis identified the following areas of improvement. First, the mud weight being used was not changed properly with respect to variation in wells azimuth and inclination. Secondly, anisotropic effects of this shale formation caused by the bedding should be considered in wells trajectory design. Thirdly, the drilling practice of this problematic formation requires careful monitoring of drilling parameters. Due to the lack of published studies regarding wellbore problems in southern Iraqi fields, this paper could serve as an important case history for similar fields in that region.