😍 Thanks for all your support! I would be very happy to hear your experiences of evaluating residual oil - have you been caught out by temperature? - cold resistive rock looking like increased oil saturation?
Hi @davidanderson7389 thanks for the interaction! Well I have to be careful here, as I’m not an “Unconventional” kinda guy (“Unconventionals” is the term generally given to reservoirs that were previously considered as essentially source rocks!)…. In “conventional” reservoirs - these kerogen (organic) rich shale SOURCE rocks are buried to depth, heat up and generate oil and gas. This then flows (migrates) through porous and permeable carrier beds until it is trapped by a sealing formation in a porous reservoir rock. This presentation focusses on flowing oil out of these conventional reservoirs, and how much is left behind in our “sandstone sponge” if you like. We may also be interested in trying to evaluate the residual oil left behind in the carrier beds on the migration pathways - to try and prove and understand whether the rocks in the basin were at least generating hydrocarbons. Then “all we need to do” with our next well, is find a place where the oil may have moved to! Many a time a desperate geologist has tried to explain his/her near-miss exploration well…by being on a “migration pathway” or having a “leaky trap” - allowing the hydrocarbons to escape….if only we’d drilled the well 25 million years ago! So in unconventional reservoirs the hydrocarbons are generated in-situ by the organic shales themselves and have not really moved anywhere - so I guess by my definition here they wouldn’t be considered residual? However, we are interested in how much hydrocarbon we’re leaving behind in our commercial production schemes, when we rely on fractures to connect us to large-cross-sectional drainage areas….there will be a certain drainage efficiency (before we have to come back and re-Frac the wells). I’m aware of some Nuclear Magnetic Resonance (NMR) techniques to better evaluate the kerogen richness of the source- then we can estimate the hydrocarbon generation potential - then I guess the potential minus the production will give some estimate of the “residual” …..but I thought I had it tough in evaluating the “measurements” we make…….the Unconventional Dudes don’t even seem to have many measurements to evaluate….only differences in “estimates”? Sorry for the long rambling answer….perhaps some of the “Unconventional Folk” can provide more brevity and clarity!
😍 Thanks for all your support! I would be very happy to hear your experiences of evaluating residual oil - have you been caught out by temperature? - cold resistive rock looking like increased oil saturation?
I’m not a petroleum geologist/engineer but I am curious about residual oil in regards to the shale fields in the USA. Fascinating topic.
Hi @davidanderson7389 thanks for the interaction!
Well I have to be careful here, as I’m not an “Unconventional” kinda guy (“Unconventionals” is the term generally given to reservoirs that were previously considered as essentially source rocks!)….
In “conventional” reservoirs - these kerogen (organic) rich shale SOURCE rocks are buried to depth, heat up and generate oil and gas. This then flows (migrates) through porous and permeable carrier beds until it is trapped by a sealing formation in a porous reservoir rock.
This presentation focusses on flowing oil out of these conventional reservoirs, and how much is left behind in our “sandstone sponge” if you like.
We may also be interested in trying to evaluate the residual oil left behind in the carrier beds on the migration pathways - to try and prove and understand whether the rocks in the basin were at least generating hydrocarbons. Then “all we need to do” with our next well, is find a place where the oil may have moved to!
Many a time a desperate geologist has tried to explain his/her near-miss exploration well…by being on a “migration pathway” or having a “leaky trap” - allowing the hydrocarbons to escape….if only we’d drilled the well 25 million years ago!
So in unconventional reservoirs the hydrocarbons are generated in-situ by the organic shales themselves and have not really moved anywhere - so I guess by my definition here they wouldn’t be considered residual?
However, we are interested in how much hydrocarbon we’re leaving behind in our commercial production schemes, when we rely on fractures to connect us to large-cross-sectional drainage areas….there will be a certain drainage efficiency (before we have to come back and re-Frac the wells).
I’m aware of some Nuclear Magnetic Resonance (NMR) techniques to better evaluate the kerogen richness of the source- then we can estimate the hydrocarbon generation potential - then I guess the potential minus the production will give some estimate of the “residual” …..but I thought I had it tough in evaluating the “measurements” we make…….the Unconventional Dudes don’t even seem to have many measurements to evaluate….only differences in “estimates”?
Sorry for the long rambling answer….perhaps some of the “Unconventional Folk” can provide more brevity and clarity!