ﺑﺮرﺳﯽ ﺗﺎﺛﯿﺮ ﻋﻤﻖ و اﺧﺘﻼف ﻣﺪول اﻻﺳﺘﯿﺴﯿﺘﻪ ﺳﻨﮓ ﻣﺨﺰن ﺑﺎ ﻣﺤﯿﻂ در ﺑﺮﮔﯿﺮﻧﺪه روي ﭘﺪﯾﺪه ﻗﻮس زدﮔﯽ ﺗﻨﺶ

Investigation of The Effect of Depth and Elasticity Modulus Difference between Reservoir Rock and the Surrounding Rock on Stress Arching

ﭼﮑﯿﺪه در اﯾﻦ ﻣﻘﺎﻟﻪ ﻣﮑﺎﻧﯿﺴﻢ راﻧﺶ ﺗﺮاﮐﻤﯽ ﮐﻪ ﻣﯿﺘﻮان آن را ﻣﺮﺗﺒﻄﺘﺮﯾﻦ ﻣﮑﺎﻧﯿﺴﻢ راﻧﺶ ﻧﻔﺖ ﺑﺎ وﯾﮋﮔﯽﻫﺎي ژﺋﻮﻣﮑﺎﻧﯿﮑﯽ ﻣﺨﺰن داﻧﺴﺖ ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. در ﻣﺪلﺳﺎزي ﻫﺎي راﯾﺞ ﺗﻨﺶ ﻋﻤﻮدي ﮐﻞ ﺑﺮ ﻣﺨﺰن، ﺛﺎﺑﺖ ﻓﺮض ﻣﯽ ﺷﻮد. ﯾﮑﯽ از ﻣﺸﮑﻼت ﻣﻬﻢ اﯾﻦ ﻣﺪلﻫﺎ در ﻧﻈﺮ ﻧﮕﺮﻓﺘﻦ ﭘﺪﯾﺪه ﻗﻮس زدﮔﯽ ﺗﻨﺶ در ﺣﯿﻦ ﺗﺮاﮐﻢ ﻣﺨﺰن ﺑﻮده ﮐﻪ ﻣﻨﺠﺮ ﺑﻪ ﮐﺎﻫﺶ ﺗﻨﺶ ﻋﻤﻮدي ﮐﻞ ﺷﺪه و ﻫﻤﭽﻨﯿﻦ ﺗﻮزﯾﻊ ﺗﻨﺶﻫﺎي ﻋﻤﻮدي و اﻓﻘﯽ را ﺗﺤﺖ ﺗﺎﺛﯿﺮ ﻗﺮار ﻣﯽدﻫﺪ. در اﯾﻦ ﻣﻘﺎﻟﻪ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻗﺎﺑﻠﯿﺖ ﺑﺎﻻي ﻧﺮم اﻓﺰار آﺑﺎﮐﻮس در ﻣﺪلﺳﺎزي ﻋﺪدي ﻣﺤﯿﻂ ﻣﺘﺨﻠﺨﻞ، از اﯾﻦ ﻧﺮم اﻓﺰار ﺟﻬﺖ ﻣﺪلﺳﺎزي ﻣﺨﺎزن ﻓﺮﺿﯽ ﺑﺎ ﺧﺼﻮﺻﯿﺎت اﻻﺳﺘﯿﮏ ﻣﺘﻔﺎوت و ﻗﺮار ﮔﺮﻓﺘﻪ در اﻋﻤﺎق ﻣﺨﺘﻠﻒ اﺳﺘﻔﺎده ﮔﺮدﯾﺪه اﺳﺖ. ﺑﺮاﺳﺎس ﻧﺘﺎﯾﺞ ﺑﺪﺳﺖ آﻣﺪه ﺗﻔﺎوت در ﺿﺮﯾﺐ اﻻﺳﺘﯿﮏ ﻣﺨﺰن ﺑﺎ ﻣﺤﯿﻂ درﺑﺮﮔﯿﺮﻧﺪه و ﻧﺴﺒﺖ ﻋﻤﻖ ﺑﻪ اﺑﻌﺎد ﻣﺨﺰن ﻣﻬﻤﺘﺮﯾﻦ ﭘﺎراﻣﺘﺮﻫﺎي ﮐﻨﺘﺮل ﮐﻨﻨﺪه ﭘﺪﯾﺪه ﻗﻮس زدﮔﯽ ﺗﻨﺶ و ﻫﻤﭽﻨﯿﻦ ﭘﺎراﻣﺘﺮﻫﺎي ﺗﻌﯿﯿﻦ ﮐﻨﻨﺪه در اﻟﮕﻮي ﺗﻮزﯾﻊ ﺗﻨﺶﻫﺎ و ﺗﺮاﮐﻢ ﻣﺨﺰن ﻣﯽﺑﺎﺷﺪ. ﻫﻤﭽﻨﯿﻦ ﺑﺮرﺳﯽ ﺗﺎﺛﯿﺮ ﻗﻮسزدﮔﯽ ﺗﻨﺶ ﺑﺮروي ﻣﮑﺎﻧﯿﺴﻢ راﻧﺶ ﺗﺮاﮐﻤﯽ ﻧﺸﺎن داد ﮐﻪ رﺧﺪاد اﯾﻦ ﭘﺪﯾﺪه ﻣﯽﺗﻮاﻧﺪ ﺣﺘﯽ ﺗﺎﺣﺪود 50 درﺻﺪ ﺑﺎﻋﺚ ﮐﺎﻫﺶ ﺗﺮاﮐﻢ ﺣﻔﺮات ﻣﺨﺰن و در واﻗﻊ ﻧﺼﻒ ﺷﺪن ﻣﯿﺰان ﺗﻮﻟﯿﺪ ﻧﻔﺖ در اﺛﺮ ﻣﮑﺎﻧﯿﺴﻢ راﻧﺶ ﺗﺮاﮐﻤﯽ ﻧﺴﺒﺖ ﺑﻪ ﺑﺮآورد اوﻟﯿﻪ آن )ﺑﺪون در ﻧﻈﺮ ﮔﺮﻓﺘﻦ اﺛﺮ ﻗﻮس زﮔﯽ ﺗﻨﺶ( ﮔﺮدد. از اﯾﻦ رو در ﻧﻈﺮ ﮔﺮﻓﺘﻦ ﺗﺎﺛﯿﺮ ﻗﻮس زدﮔﯽ ﺗﻨﺶ در ﺗﺨﻤﯿﻦ ﻣﯿﺰان ﺑﺎزﯾﺎﻓﺖ ﻧﻔﺖ در اﺛﺮ ﻣﮑﺎﻧﯿﺴﻢ راﻧﺶ ﺗﺮاﮐﻤﯽ ﺑﻮﯾﮋه در ﻣﯿﺪاﻧﯽ ﺑﺎ ﻧﺴﺒﺖ ﻋﻤﻖ ﺑﻪ ﮔﺴﺘﺮش ﺟﺎﻧﺒﯽ ﺑﺎﻻ و داراي ﺳﻨﮓ ﻣﺨﺰﻧﯽ ﺑﺎ ﻣﺪول اﻻﺳﺘﯿﺴﯿﺘﻪ ﭘﺎﯾﯿﻦﺗﺮ ﻧﺴﺒﺖ ﺑﻪ ﺳﻨﮓﻫﺎي در ﺑﺮﮔﯿﺮﻧﺪه، اﻣﺮي ﺿﺮوري ﻣﯽﺑﺎﺷﺪ.

In this paper, the compression drive mechanism, which can be considered as the most related oil drive mechanism with the geomechanical properties of the reservoir, has been investigated. The constant total vertical stress on the reservoir and uniaxial reservoir compaction with zero lateral strain are two main assumptions in the conventional reservoir compaction modeling. These assumptions are not considering the stress arching which leads to a reduction in the total vertical stress. In this paper, due to the high capability of Abaqus software in numerical modeling of porous media, this software has been used to model the compaction of oil reservoirs with different elastic properties and located at different depths. Based on the obtained results, the difference in the elastic modulus of the reservoir with the surrounding rock and the ratio of depth to the dimensions of the reservoir are the most important parameters controlling the stress arching. Also, the study of the effect of stress arching on the compaction drive mechanism showed that the stress arching can reduce the compaction of reservoir pores by up to 50% and halve the oil production compared to its initial estimate by the compaction drive mechanism without considering the stress arching. Therefore, it is necessary to consider the effect of stress arching in estimating oil recovery due to compaction drive mechanism, especially in fields with a high depth to lateral expansion ratio and reservoir rocks with a lower modulus of elasticity than the surrounding rocks.