بررسي پتانسيل توليد در سازند هاي منشا پابده (ترشياري) و كژدمي (كرتاسه پاييني) در منطقه دشت آبادان، جنوب غرب ايران

Investigating Hydrocarbon Generation Potential of Pabdeh (Tertiary) and Kazhdumi (Early Cretaceous) Source Rocks in Abadan Plain, Southwest Iran

مهم ترين سنگ هاي منشا كرتاسه و ترشياري در حوضه زاگرس كه بيشترين ميزان نفت و گاز منطقه را توليد كرده اند شامل سازندهاي گرو، گدوان، كژدمي و پابده مي باشند. در مطالعه پيشرو سازند هاي پابده (ترشياري) و كژدمي (كرتاسه پاييني) از نقطه نظر ژئوشيميايي آلي مورد بررسي و مطالعه قرار گرفته اند. تعداد 87 نمونه مغزه و خرده حفاري در سازندهاي مذكور از 22 چاه اكتشافي در 13 ميدان نفتي در منطقه دشت آبادان مورد آناليز راكـ ايول و اندازه گيري بازتابندگي ويترينايت قرار گرفته اند. نتايج آناليزها نشان مي دهند كه سازند پابده با TOC متوسط 25/1% و HI متوسط mgHC/gTOC 145 مي تواند به عنوان سنگ منشا متوسط تا خوب معرفي شود. درحالي كه سازند كژدمي با TOC و HI متوسط 8/1% و mgHC/gTOC 278 به عنوان سنگ منشا خوب تا خيلي خوب درنظر گرفته مي شود. نتايج ارزيابي بلوغ از قبيل پارمترهاي Tmax و بازتابندگي ويترينايت نشان مي دهند سازند پابده در كل منطقه دشت آبادان ناپخته بوده درحالي كه سازند كژدمي در ميادين غربي دشت آبادان نابالغ ولي در ميادين شرقي و مرز فروافتادگي دزفول در اوايل پنجره نفتي قرار دارد. نقشه هاي هم تراز TOC و Tmax در منطقه دشت آبادان نشان مي دهند كه پتانسيل و بلوغ سازندهاي پابده و كژدمي از دشت آبادان به سمت فروافتادگي دزفول افزايش پيدا مي كنند.

Skidding logs from stump to depot areas is the most important part of ground-based logging operations, which often leads to an increase in soil bulk density and decrease in soil porosity. In this study, woody slash and sawdust treatments with a weight of 10 kg m-2 were used to decrease soil compaction on skid trails during the trips of rubber-tired skidder Tof E655 in compartment of 29 in Bahramnia forestry plan in Gorgan, Golestan province. Soil samples were collected by steel cylinder from 0-10 and 10-20 cm soil depths after 2th, 6th, 10th and 16th skidder trips on treated and control plots. Bulk density, porosity percentage and moisture content were measured in laboratory. Results showed the soil bulk density of 1.05, 1.12, 1.18 and 1.2 g cm-3 at the depth of 0-10 cm in bare soil after two, six, ten and sixteen trips. On trails treated by sawdust protective layer, the soil bulk densities were 0.98, 1.02, 1.07 and 1.09 g cm-3. These values for slash treatment were 0.64, 0.98, 1.05 and 1.07 g cm-3, respectively. The soil bulk densities after two, six, ten and sixteen trips were 1.31, 1.38, 1.43 and 1.45 g cm-3 at the depth of 10-20 cm in bare soil. By using sawdust these values decreased to 1.22, 1.26, 1.31 and 1.32 g cm-3, whereas the use of slash resulted in 1.18, 1.21, 1.28 and 1.31 g cm-3, respectively. The results indicated better performance of slash treatment in reducing soil compaction compared to sawdust treatment. Moreover, soil porosity at the both depths of treated plots by woody slash was more than that of other treatments and was near to forest soil porosity. Furthermore, sawdust treatments could more retain the soil moisture compared to slash treatment. Using coverage material in skid trails was concluded to reduce of destructive effects of skidder transport.