Dear Dr. Naderi,

Firstly, I would call the piercing diapir a salt stock if it is near circular or a salt wall with elongate planform. These two have discordant contact with the overdurden.

And let's call the non-piercing salt structure a salt pillow with near circular planform and salt anticline which is elongate in the map view. The salt pillows and anticlines have concordant contact with the overburden.

So, the impact of salt structures (e.g. stocks and pillows) on fluid flow within the overburden is not simple. A number of factors are important. I try to focus on salt pillow which is your concern.

For example, it is so important to distinguish the timing of the pillow growth because synsedimentary salt rise affecsts sedimentation pattern above and around the structure hence affecting the facies distribution. Facies distribution controls the fluid migration and trapping.

If the system is clastic, sands will tend to accumulate in the adjacent depressions, which of course depends on the water depth and the existence or ansence of topograghic relief above the pillow. The relief depends on the pillow growth rate relative to the local sedimentation rate. If the system is carbonate, and if the pillow has a relief near the photic zone, carbonate buildups form on top of the pillow and wedge out towards the flanks.

Because the salt pillows stop rising under thick roofs, subsequent tectonic deformation, mainly shortening, can reactivate them. Pillow shortening lifts, rotates, folds, and fractures the overlying roof strata. The prime consequence of roof deformation is to ease pressurized fluids flow up the dipping beds towatds the structural top. When the fluid column above the pillow is sufficiently large to generate a pressure exceeding the local least principal sttess, vertical migration of fluids occur towards the shallower lovals.

In addition, the fracture systems and faulting of the roof strata form migration conduits for fluids. However, faults are not always migration conduits. Some faults rather seal the fluids in the strata. The relationship of fault throws with respect to peremeable and impermeable beds affects the sealing or leaking behavoiur of faults above the salt pillows. Reactivation of pillows by tectonic shortening affects the sediments being deposited at the same time. This includes, again, controlling sediment distribution as well as local unconformities above and adjacent to the pillow. They may form stratigraghic traps at the pillow flanks.

Sorry for the long answer, but I hope this helps...

Regards

Jafar Hassanpour

Well,

https://gfzpublic.gfz-potsdam.de/rest/items/item_237203_1/component/file_237202/content

Hi Mehrangiz

if the diapir is in direct contact with the aquifer there will be reactions by the contact rock- water at the bottom of the aquifer layer. It is necessary to study the structural geology of the reservoir and the diapir thus a determination of faults in the area is also necessary. Also what is the area of the reservoir is it upstream or downstream because it is important as well as a hydrochemical analysis of the aquifer is recommended. Hope my idea is useful

Dear Dr Hussien,

Thank you for your consideration and sharing the paper. I reviewed the paper. But the case that I want to know about, is impact of non-piercing salt dome (salt pillows and anticlines) on the deep groundwater flow. I mean the  salt dome without any exposure to the geological layers and buried under rocks with 4 Km thickness. I'd like to know the impact of this kind of salt diapirs on deep fluid flow.

Dear Dr. Hassanpour,

Thanks your perfect explaniation. What I am getting from your answer is the fluid flow move up to structure top because of the deformation of roof formations. Since we talk about the change in present aquifer system so, the moving of the salt pillow toward the structure top is continuing in the present time. is it true?

Dear Hafidha,

Thanks for sharing your idea.

Actually it is impossible to study the salt diapir directly by using the borehole data because, the borehole was drilled to gas reservoirs just above the salt pillow. So we just know about the salt diapir based on seismic data and the shape of upper formations like an anticline. The salt pillow is located in downstream and under the gas and water bearing formations.