نشریه علوم زمین خوارزمی

نشریه علوم زمین خوارزمی

تحلیل مقایسه‌ای توانایی روش‌های پتروفیزیکی و آماری در بازتاب شاخص‌های زمین‌شناسی سازند کنگان، بخش مرکزی خلیج فارس

نویسندگان
وحید توکلی 1
علی‌اکبر جهان‌پناه 1
مهدی نخستین مرتضوی 2
1 دانشگاه تهران
2 جهاد دانشگاهی
10.22034/KJES.2025.11.2.102062
چکیده
ناهمگنی مخازن کربناته ناشی از تغییرات سنگ‌شناسی، بافتی و دیاژنزی سبب می‌شود که رفتار جریان سیال درون این سنگ‌ها پیچیده و غیرقابل پیش‌بینی باشد. این پژوهش با هدف تحلیل توانایی روش‌های پتروفیزیکی و آماری در بازتاب شاخص‌های زمین‌شناسی سازند کنگان در بخش مرکزی خلیج فارس انجام شده است. در این راستا، داده‌های مغزه و مقاطع نازک مورد تجزیه و تحلیل قرار گرفت تا ارتباط میان ویژگی‌های زمین‌شناسی و نتایج حاصل از روش‌های پتروفیزیکی و آماری بررسی شود. داده‌ها شامل اندازه‌گیری‌های تخلخل و تراوایی، درصد اجزای سنگ‌شناسی و پارامترهای دیاژنزی شامل نوع و نرخ سیمانی‌شدن، فشردگی و دولومیتی ‌شدن بودند. برای طبقه‌بندی داده‌ها از چهار رویکرد استفاده شد که شامل روش‌های (1) وینلند، (2) شاخص منطقه جریان، (3) روش آماری جنکس بر پایه تخلخل و ترکیب تخلخل-تراوایی و (4) همچنین شاخص جدیدی با عنوان شاخص کیفیت زمین‌شناسی تعریف گردید که از ترکیب درصد دولومیت، تخلخل مفید و نرخ سیمانی‌شدن به عنوان کنترل‌کننده‌های اصلی کیفیت مخزنی، حاصل شد. نتایج نشان داد که در تمامی روش‌ها، روند افزایشی کیفیت مخزنی از گروه‌های پایین به بالا با افزایش دولومیت، کاهش سیمانی‌شدن و کاهش انیدریت همراه است. در روش شاخص منطقه جریان و جنکس بر پایه شاخص کیفیت زمین‌شناسی، جدایش سنگ‌ها از نظر ویژگی‌های سنگ‌شناسی و پتروفیزیکی منظم‌تر و قابل تفسیرتر از سایر روش‌ها بود. میانگین تخلخل و تراوایی از حدود ۸ درصد و ۳ میلی‌دارسی در گروه‌های پایین تا بیش از ۲۲ درصد و ۲۳۰ میلی‌دارسی در گروه‌های بالاتر تغییر می‌کند که بیانگر سازگاری قوی میان کیفیت مخزنی و فرآیندهای دیاژنزی است. روش وینلند مرزهای کلی را به‌خوبی تعیین کرد اما حساسیت کمتری به تفاوت‌های سنگ‌شناسی داشت. در مجموع، نتایج این مطالعه نشان می‌دهد که ترکیب داده‌های زمین‌شناسی با روش‌های آماری و پتروفیزیکی و تحلیل جنکس، می‌تواند تصویر دقیق‌تر و واقع‌گرایانه‌تری از ناهمگنی‌های مخزنی در سازندهای کربناته ارائه دهد و در مدل‌سازی مخازن پیچیده به ‌کار رود.
کلیدواژه‌ها
وینلند
شاخص منطقه جریان
روش آماری جنکس
شاخص کیفیت زمین‌شناسی

عنوان مقاله English

Comparative analysis of petrophysical and statistical methods for reflecting the geological characteristics of the Kangan Formation, Central Persian Gulf

نویسندگان English

Vahid Tavakoli 1
Aliakbar Jahanpanah 1
Mehdi Nakhostin Mortazavi 2
1 University of Tehran
2 ACECR
چکیده English

Heterogeneity of carbonate reservoirs resulting from lithological, textural, and diagenetic variations makes fluid flow behavior complex and unpredictable. This study was carried out to perform a comparative analysis of petrophysical and statistical methods in reflecting the geological attributes of the Kangan Formation in the central Persian Gulf. Core data and thin sections were analyzed to examine the relationships between geological characteristics and petrophysical and statistical approaches. Porosity and permeability, the percentage of lithologic components, and diagenetic parameters including the type and rate of cementation, compaction, and dolomitization have been used. Four approaches were employed for data classification, including (1) the Winland method, (2) the Flow Zone Indicator (FZI), (3) the Jenks statistical method based on porosity and combined porosity–permeability, and (4) a newly defined Geological Quality Index derived from the integration of dolomite content, effective porosity, and the rate of cementation as the main controlling factors of reservoir quality. The results showed that for all methods, reservoir quality increases from the lower to the upper groups and is accompanied by increasing dolomite, decreasing cementation and decreasing anhydrite. In the FZI method and in the Jenks method based on GQI, the separation of rocks in terms of lithologic and petrophysical characteristics was more orderly and more interpretable than with the other methods. Mean porosity and permeability vary from about 8% and 3 mD in the lower groups to more than 22% and 230 mD in the higher groups, which indicates a strong correlation between reservoir quality and diagenetic processes. The Winland method defined the overall boundaries well but was less sensitive to lithological differences. Overall, the results of this study indicate that combining geological data with statistical and petrophysical methods, can provide a more accurate and realistic representation of reservoir heterogeneities in carbonate formations and can be applied in modeling complex reservoirs.

کلیدواژه‌ها English

Winland
Flow Zone Indicator (FZI)
Jenks statistical method
Geological Quality Index (GQI)
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