Eagle Ford Geosteering
What we will learn
• Various methods of Geosteering and how they may be applied.
• What minimal subsurface 2D, 3D and drill cu@ng analysis required prior to perform geosteering
• Look at how the process of Geosteering is applied • Look at some of the piDalls of Geosteering and what can be
learned from these issues.
Geo steering tells us where we want to go
• DefiniFon & Purpose • What is Geo Steering?
Geosteering is the act of adjusFng the borehole posiFon (inclinaFon and azimuth angles) during the drilling process to reach one or more geological objecFves. These changes are based on geological informaFon gathered while drilling.
Reasons for Geosteering
– Land the well in a specific part of the reservoir that we believe has some specific properFes that will make the well more economic
– To guide the well through some geological barrier such as a fault or salt
– To guide the well through the reservoir in such a manner as to maximize or minimize hydrocarbon producFon
Methods used to Geo Steer
• Good Enough • Real Time
Good Enough
Mud logging • Lithology • Mineralogy • Hydrocarbons • Micro-‐paleontologists/ biostraFgraphy
ü Old School Geo Steering ü Takes experience and training ü At High ROP’s may not be possible to get good data ü Depends a lot on competence and judgment of mud logger ü “It may not be efficient but it is effecFve”
Real Time Geosteering
• MWD/LWD
– Gama DOI 1 to 6”
– ResisFvity
– Neutron
ü Dependent on the formaFon and depth of invesFgaFon, DOI.
ü More permeable and porous the formaFon the greater DOI
ü More DOI allows for be`er Geosteering results.
ü Need good offset data and Seismic input
ü Real Fme Geosteering is possible if the right people interpret the data
ü Remote real Fme informaFon
ü “real Fme informaFon that can double the speed of mistakes”
Proper Steps to Geo Steering
• Pre planning • Understand drilling constraints
– What type of BHA is being used – What type of bit – What is the expected ROP
• Real Fme Geo Steering implementaFon – Have a designated driver – Who makes the call – Communicate everything
• Post well evaluaFon – Adjust seismic – Re correlate Logs – Re draw maps.
Pre Planning
• Start with offset data – Very important
– Need as much offset data as possible
• E logs
• Mud Logs
• Seismic lines
• Cross SecFons
• DeposiFonal models
– Understand where you need to go
and then plan it
– See the well being drilled on paper
ExecuFon
• Have a designated driver
– Who makes the call?
• Timely CommunicaFon
– ROP
• Understand your Drilling Constraints
– BHA design
– Rig/ Pipe connecFon type
– DirecFonal tool types
• ABH motor and RS
– Casing Designs
• You can’t turn on a dime. 0ne degree of inclinaFon gives you 1.7 i verFcal movement per 100’
Aier Well Review – pat on the back or kick in the rear? ü What did we do well and what did we do poorly?
ü Did the well design match the geology?
ü Redraw maps and mark unseen faults
ü Check the hydrocarbon amounts encountered and compare to offsets
ü Don’t delay, get ready to do it right the next Fme!
ü When things go right we end up drilling a well that is ideally placed in the reservoir that produces the opFmum amount of hydrocarbons
Well 1
• Eagle Ford Well in South Texas • No 3D seismic • End of a 2D line migrated some Fme ago • Decided to drill a pilot hole • ConvenFonal AHM and Gama ray • We use a program that correlates Gama ray so Depth of invesFgaFon is small.
Case well no 1 Well drilled
Example 2
Example 3
The end
• QuesFons