A petrographic study of permeability, A petrographic study of permeability, porosity and clay content and their effects porosity and clay content and their effects

on reservoir quality in the on reservoir quality in the Bluesky Bluesky FormationFormation, Whitecourt Alberta, Whitecourt Alberta

IntroductionIntroduction

• My study area covers a portion of Northern Alberta from townships 62-58 and ranges 15-18.

• Study incorporates well log data from 605 wells and includes ideas and trends seen in some 1500 total wells.

• The Bluesky Formation is comprised of 2 main depositional facies: – Upper shoreface sands– Barrier bar sands

• These environments have been solidified by examination of drill core.

• Bluesky Formation is considered to be a tight gas reservoir.– A tight reservoir is a reservoirs of natural gas with an average permeability of less

than 0,1 mD

www.math.ualberta.ca www.spiritlakenation.com

Depositional EnvironmentDepositional Environment

• Inlet channel proximal to the coastal plain in an overall transgressive sequence, with pulses of regressive sand.

• Well log signatures:– Coarsening upward succession

interpreted as upper shore face.– Thick blocky sand interpreted as

barrier bar sands.– Other: a somewhat blocky sand

interlayed with mud drapes interpreted as possible estuary.

Why do people care???Why do people care???

• Well with oil and gas reserves decreasing the only way to keep pace with increasing demand for these products is to make new discoveries, and find new ways to recover what was previously uneconomical.

• Tight gas was previously not economic to produce so it has been largely untapped.

• If this study has a desirable outcome I may actually get a job out of it.

MethodsMethods

• Analyze thin sections and compare porosity and permeabitity and determine quartz %, grain size and shape, presence of micro-fractures, and type and degree of cementation.

• Using my data as well as the database data construct a framework of porosity and permeability pods in my area.

• Micro-probe analysis to determine clays present and determine their effect on drilling techniques and frac designs.

Work to DateWork to Date

• Well log analysis• Formation tops were placed for all of the 1500

plus wells with a TD that included the Bluesky Formation.

• Cross sections constructed• Isopach maps made at 3 and 6 percent cutoffs.• Logged drill core and core photographs taken.• Analysis of well production data.