The Mesopotamian Remote Sensing researches..

Using of Remote Sensing technique in Exploration for hydrocarbon microseepage in Nahr Umr oil field , Southern Iraq

Haider Mahmood Jasm
Geology Department, College of Science, Basrah University

[email protected]

Abstract

Satellite Images have been employed for the detection of hydrocarbon seepages at the Nahr Umr Oil field southern Iraq which lies  between the coordinates of  30^o5 0   -  30^o 35  N  and  47^o 45 - 47 ^o 35  ^  E  .

          The present study deals with the implementation of visual and computer processing techniques for satellite images, Directional analysis of lineaments and spectrometry reflectance ,bacterial and mineralogical analyses of soil samples .

          The first part of the study used remote sensing technique of satellite image type (ETM) , in order to get the best results of data processing. Supervised classification and computer processing techniques were used to determine seepage areas .This technique includes different three processes in order to determine seepage areas precisely. The first process is contrast enhancement which shows the effected and non effected areas by seepages and this was confirmed by spectrometry reflectance of plants which appeared in faint color and bright colors within effected. The second process represents by making of  three ratio images : TM2/TM3, TM4/TM3 and  TM2/TM3- TM4/TM3, these three images have been compined to generate a false   colors image   TM2/TM3, TM4/TM3,TM2/TM3- TM4/TM3 ((RGB) Red Green Blue) ,which indicated seepage areas distinctly  in magenta  color .

          The third process is the principal component analysis (PCA) using mathematical conversion of original data of satellite image and re arrange them according to various axis , the longitudinal axis represented a measure of data changes along ,whereas , the transverse axis represented a comparison between the original component and original bands of image . This technique identified seepage phenomenon by constructing a false colors image from the essential constituent within the bands ( pc3,pc4,pc5) ( RGB), then converting  the image to another one of (( IHS) Intensity – hue – Saturation) type which showed more distinct seepage areas characterized by bright green color .Also computer processing has been used to study mineral distribution in the studied area by making of  ratio images : TM2/TM4, TM3/TM1 and  TM5/TM7, these images  were combined to form false color image TM5/TM7,TM3/TM1,TM2/TM4 which showed the mineralogical distribution , Magenta color reflects the occurrence of the clay minerals and carbonate while ferric oxides were indicated by green color and the plants in red color.

   The second part of study include the directional analysis for lineaments . The results of structures analysis of basement rocks which have been drawn from geophysical information have been compared with the results of directional analysis ; the comparison results showed that the dominant linear structures in the studied area are into two main directions  North west – south east  and  North east – South West . These directions have been found to be parallel to the faults that effected the complex basement rocks .The direction of linear structures predict a new fault which is not determined in the previous geophysical studies.

The third part include soil analysis of spectrometry reflectance , Microbial analysis   and mineralogical analysis where , the  spectrometry reflectance reveals both high and low spectral reflection areas  which shows that this area was affected by hydrocarbon seepage ; Microbial analysis reveals the existence of living bacteria on hydrocarbons with various rates depending on the intensity of seepage . while The mineralogical analysis of soil showed the occurrence of the following mineral according to their amount in descending order : Calcite , Gypsum , Quartz , Dolomite , Feldspar , Ferric oxides , Halite  and Anhydrite . Also clay minerals have been identified the soil  such as  Kaolinite , Illite , Chlorite , Montmorrillonite  and Palygorskite .

The final stage of this research was applied the GIS technique produced one map which includes all the above mentioned information , This procedure was successful to determine two seepage areas precisely ; the first one considered as principal area which has detected through  the study methodology, while the second seepage area considered secondary site detected during the study .