نوع مقاله : مقاله پژوهشی

نویسندگان

گروه حوضه‌های رسوبی و نفت، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران

10.29252/envs.18.4.219

چکیده

سابقه و هدف:
اجرای یک پروژه سیلاب زنی نیاز اساسی به مطالعات زمین­شناسی دارد. این درک نیاز به شناخت فاکتورهای زمین­شناسی محیط رسوبی، فرایندهای دیاژنتیکی و رفتار گسل­های مخزنی دارد تا درک مناسبی از خصوصیات سنگ/ آب/ نفت بدست آید. در این مطالعه به دلیل آبی شدن زود هنگام بعضی از چاه­های تولیدی غرب میدان اهواز و همچنین کاهش فشار مخزنی این ناحیه، تصمیم به انجام عملیات سیلاب زنی گرفته شد که تاکنون چنین عملیاتی در ایران بصورت عملی انجام نشده است.
مواد و روش:
لذا جهت مطالعه زمین­شناسی مخزن ایلام اهواز چاه ۱۱۶ از دیدگاه دیاژنز، تغییرات رخساره­ای و تکتونیک توسط ابزار­های میکروسکوپ پلاریزان، میکروسکوپ الکترونی، اطلاعات حاصل از داده­های مغزه، ارزیابی پتروفیزیکی و مدل مخزنی بررسی گردید.
نتایج و بحث:
از دیدگاه رسوب­شناسی، زون C1 مخزن ایلام اهواز از اجزای موجودات میکروسکوپی همی پلاژیک غالبا اولیگوستژینیده در محیط رسوبی دریای باز تشکیل شده است. چنین رخساره­ای که متشکل از گل آهکی میکریتی است، ذاتا باید تخلخل نداشته باشد. اما فرایند دیاژنز متئوریکی قبل از سنگ شدگی باعث افزایش کیفیت مخزنی آن گردیده است. بنحوی که در گستره مخزن شاهد ایجاد مخزنی از نوع آهک گل سفید (chalky) با  تخلخل از ۵  تا  ۲۷ درصد (در ناحیه غربی مخزن از ۱۵ تا ۲۷ درصد تخلخل) و تراوایی کلینکنبرگ ۱ تا ۱۰ میلی دارسی و گاها ۱۰۰ میلی دارسی شده است. همچنین شرایط ایجاد گلوگاه­های خلل و فرجی از ۲۰ تا غالبا چند دهم میکرون را نیز فراهم نموده است. اما دلیل توسعه دیاژنز متئوریکی متفاوت در گستره مخزن را باید در حوادث تکتونیکی زاگرس در دوران کرتاسه دنبال کرد. در دوران کرتاسه گسل­های پی سنگی کششی دوران مزوزوئیک فعالیت مجدد کرده و بر جغرافیای گذشته حوضه تاثیر می­گذارند. بنحوی که که در امتداد این گسل­های شمالی-جنوبی در زون C1 مخزن ایلام اهواز شاهد تفاوت در  فرایندهای دیاژنزی ناحیه غربی و نواحی دیگر مخزن هستیم. این تفاوت فرایندهای دیاژنزی کمی قبل از سنگ شدگی رسوب اتفاق افتاده است.
نتیجه گیری: تاثیر مناسب فاکتورهای زمین­شناسی (رخساره، دیازنز و تکتونیک) شرایطی ایده آلی را برای سیلاب زنی مخزن فراهم کرده است.

کلیدواژه‌ها

عنوان مقاله [English]

Effective geological factors (facies, diagensis and tectonic) for reservoir characterization of Ilam Reservoir zone C1 (Ahwaz oilfield)

نویسندگان [English]

  • Mehdi khoshnood kia
  • Mohammad Hossein Adabi
  • Mahboubeh Hosseini-Barzi

Department of Sedimentary and Petroleum Basins, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran

چکیده [English]

Introduction:
Geological studies is essential for running a water flooding project. So, understanding the geological factors is important such as sedimentary environment, diagenetic processes, and reservoir fault behavior to obtain a proper understanding of rock / water / oil properties. In this study, due to the early breakthrough of some wells in west of Ahwaz field as well as the reduction of reservoir pressure in this area, it was decided to perform a water flooding operation, which so far have not been practiced in Iran.
Material and methods:
Therefore, geological study have done in Ilam reservoir of AZ-116 in view of diagenesis, facies and tectonic. In this study were used polarizing microscope, electron microscope, core data, petrophysical evaluation and reservoir model.
Results and discussion:
From a sedimentological point of view, the C1 zone of the Ilam reservoir of Ahwaz is composed of components of frequently oligostegina hemiplegic microscopic organisms in the sedimentary environment of the open seas. Such a facies, which is composed of calcareous micritic mud, should not inherently have porosity. But the process of meteoric diagenesis before lithification has increased its reservoir quality. Chalky reservoir with porosity of 5% to 27% (in the western part of the reservoir from 15% to 27% porosity) and Klinkenberg permeability of 1 to 10 milli-darcy and sometimes 100 milli-darcy. It also provides conditions for the porethroats from 20 to often several tenths of microns. But the reason for the development of different meteoric diagenesis across the reservoir has to be follwed to the Zagros tectonic events of the Cretaceous period. During the Cretaceous, extensional basement crust of the Mesozoic period reactivated and affected the paleogeography of the basin. So that along these north-south faults in zone C1 of Ilam reservoir of Ahwaz, we see different diagenetic processes in west area incontrast to other part of reservoir, just before litification.
Conclusion:
Appropriate impact of geological factors (facies, diagensis and tectonics) has provided ideal conditions for water flooding operation.

کلیدواژه‌ها [English]

  • Diagensis
  • Facies
  • Tectonic
  • Ilam reservoir
  • Ahwaz oilfield

• Adams, T. D., Khalili, M., Khosravi-said, A., 1965: The strtigraphic significance of some Oligosteginid faunas from Lurestan to Khuzestan. Iranian Operation Oil Company, Reservoir Geology Division, Interior published report, 18p.

• Allen, M., Jackson J. Walker, R., 2004: Late Cenozoic reorganization of the Arabia Eurasia collision and the comparison of short-term and long-term deformation rates. Tectonics, V. 23, TC2008.

• Austad, T., Shariatpanahi, S. F., Strand, S., Black, C. J. J., Webb, K. J., 2011: Conditions for a Low-Salinity Enhanced Oil Recovery (EOR) Effect in Carbonate Oil Reservoirs. Energy and Fuels, V.26 (1), 569-575.

• Authemayou, C., Bellier, O., Chardon, D., Malekzadeh, Z., Abbassi, M., 2005: Active partitioning between strike-slip and thrust faulting in the Zagros fold-and-thrust belt (Southern Iran). Comptes Rendus Ge´osciences, V. 337, 539 –545.

• Azarpour, M., 2015: Structural Interpretation of 3D Seismic Information of the Asmari Reservoir of Ahwaz Block A. National Iranian South Oil Company, Reservoir Geology Division, Interior published report No.8475, 132p. [In Persian]

• Berberian, M., 1995: Master blind thrust faults hidden under the Zagros folds: Active Basement Tectonics and Surface Morphotectonics. Tectonophysics, V. 241, 193-224.

• Bolz, H., 1975: Stereoscan electron microscope (SEM) studies of a chalky limestone reservoir in the Bangestan Formation of Well Ahwaz 063, Oil Service Company of Iran, interior published report No. 1227, 112p.

• Bolz, H., 1977: Reappraisal of the biozonation of the Bangestan group (late Aptian- early Campanian) of southwest Iran Oil Service Company of Iran, interior published report No. 1252, 29p.

• Bolz, H., 1978: Core study in Bangestan reservoir of the Ahwaz field, Oil Service Company of Iran, interior published report No. 1276, 45p.

• Fabricius, I. L., 2007: Chalk: composition, diagenesis and physical properties, Bulletin of the Geological Society of Denmark, V. 55, 97–128.

• Fajrak, M., Khoshnoodkia, M., 2019: Modeling study of Ilam reservoir of Ahwaz field in line with water flooding project in western part of Ahwaz field: National Iranian South Oil Company, Reservoir Geology Division, Interior published report No.10012, 37p. [In Persian]

• Flügel, E., Franz, H. E., Ott, W. F., 1968: Review of elctron microscopic studies of limestones. Recent development on Carb. Sed. In central Europe, Springer, 85-97.

• Folk, R. L., 1965: Some aspect of recrytalization in ancient limestones, society economy, palantology, mineralogy, special publication 13, 14-38.

• James, G. A., Wynd, J.G., 1965: Stratigraphic nomenclature of Iranian oil consortium agreement area. American Association of Petroleum Geologists, Bulletin 49, 2182-2245.

• Khalili, M., 1974: The biostratigraphic synthesis of the Bangestan Group in southwest Iran. National Iranian Oil Company, Reservoir Geology Division, Interior published report No, 1219. 70p.

• Khoshnoodkia, M., 2018: Application of 3D Seismic atributes in Identifying Fracture Areas of Ahwaz Bangestan Reservoir and Integration with Reservoir Production Data: National Iranian South Oil Company, Reservoir Geology Division, Interior published report;; No.9698, 50p. [In Persian]

• Kord, M., Abdali, M., 2009: Analysis of reservoir rock properties in study of Bangestan reservoir of Ahwaz field: National Iranian South Oil Company, Reservoir Engineering Division, Interior published report, 64p. [In Persian]

• Lakzaee, A., 2015: Structural Interpretation of 3D Seismic Information of the Asmari Reservoir of Ahwaz Block B: National Iranian South Oil Company, Reservoir Geology Division, Interior published report No.8457, 97p. [In Persian]

• Mosavi, A., 2017: Modeling study of Bangestan reservoir of Mansuri field: National Iranian South Oil Company, Reservoir Geology Division, Interior published report No.9950, 97p. [In Persian]

• Moteie, H., 1993: Geology of Iran, Stratigraphy of Zagros, 1009p. [In Persian]

• Omidvar, M., Mehrabi, H., Sajjadi, F., Bahramizadeh-Sajjadi, H., Rahimpour- Bonab, H., Ashrafzadeh, A., 2014: Revision of the foraminiferal biozonation scheme in Upper Cretaceous carbonates of the Dezful Embayment, Zagros, Iran: integrated palaeontological, sedimentological and geochemical investigation. Revue de Micropaleontologie, V. 57, 97–116.

• Parchehkhare, Sh., 2009: Petrophysical evaluation of Ahwaz borehole 116 in Ilam and Sarvak formations: National Iranian South Oil Company, Reservoir Geology Division, Interior published report No.6595, 65p. [In Persian]

• Rahimpour-Bonab, H., Mehrabi, H., Enayati-Bidgoli, A. H., Omidvar, M., 2012: Coupled imprints of tropical climate and recurring emersions on reservoir evolution of a mid-Cretaceous carbonate ramp, Zagros Basin, SW Iran. Cretaceous Research, V. 37, 15–34.

• Rezaee, M. R., Jafari, A., Kazemzadeh, E., 2006: Relationships between permeability, porosity and pore throat size in carbonate rocks using regression analysis and neural networks. Journal of Geophysics and Engineering, V. 3, 370-376.

• Saadallah, N., Roustaie, M., Salehi, M. A., Najafzadeh, K., Edalat, A., Shojaee, S., 2019: Mansoorabad PSTM/PSDM 3D Seismic Interpretation Structural Modeling and Velocity Modeling Report. National Iranian South Oil Company, Reservoir Geology Division, Interior published report, 240 p.

• Schlumberger methods, 2017. Ahwaz G&G study Asmari Reservoir. National Iranian South Oil Company, Reservoir Geology Division, Interior published report, in press.

• Sepehr, M., Cosgrove, J, W., 2005: Role of the Kazerun Fault Zone in the formation and deformation of the Zagros Fold-Thrust Belt, Iran.Tectonics, V. 24, 1-15.

• Shabani, M., 2018: Modeling study of Bangestan reservoir of Abteymur field: National Iranian South Oil Company, Reservoir Geology Division, Interior published report No.9751, 89p. [In Persian]

• Sharland, P. R., Archer, R. Casey, D. M., Davies, R. B., Hall, S. H., Heward, A. P., Horbury, A. D., Simmons, M. D., 2001: Arabian Plate sequence stratigraphy. Geo Arabia, Special Publication 2, 371.

• Sherkati, S., Molinaro, M., Frizon De Lamotte, D., Letouzey, J., 2005: Detachment folding in the Central and Eastern Zagros fold-belt (Iran): salt mobility, multiple detachments and late basement control. Journal of Structural Geology, V. 27, 1680-1696.

• Speer, R. G., 1976: Review of the geology of the Bangestan reservoir in Ab Teymur and Mansuri fields. Oil Service Company of Iran, interior published report No: 3021. 35p.

• Speer, R. G., Baker, S. N., 1978: Ahwaz Bangestan reservoirs relationship between fracture distribution matrix porosity and well productions, Oil Service Company of Iran, interior published report No: 3458. 22p.

• Talbot, C. J., Alavi, M., 1996: The past of a future syntaxis across Zagros. Geological Society, London, Special Publications, V. 100, 89-109.

• Tiab, D., Donaldson, E. C., 2015: Petrophysics - Theory and Practice of Measuring Reservoir Rock and Fluid Transport Properties (4nd Edition), Elsevier, Gulf Professional Publishing, 918 p.

• Willhite, G. P., 1965: Waterflooding, SPE text book series vol. 3, 327p.

• Wynd, A. G., 1965: Biofacies of the Iranian oil consortium a greement area, Iranian Operation Oil Company, Reservoir Geology Division, Interior published report No. 1082. 137p.