Bitumen Deposits by Pyrolysis Method Southern Iraq Oilfields

Ali, Abdullah A.¹; Abdulsadah, Riyadh A.¹
(1) Geological Dep., South Oil Company, Al Basrah, Iraq.

Reservoir rocks samples from upper Cretaceous Formations of southern Iraq were selected in order to evaluate by new method (Pyrolysis). The method presented in this study is a technique which can be used on the site and then allows information to be obtained at an early stage of field appraisal. The main applications are Identification and quantification of tar deposits by analysis of samples and Determination of oil composition.

Tar-mat zones in the Upper Cretaceous (Mishrif, Sadi and Kasib) reservoirs of Amara Fields southern Iraq were identified. The new method parameters indicate tar-mat zones occurred in different intervals depth in study area. ). The distribution of Tars and heavy oil in Sadi and Mishrif Formation in study area is very similar although the differences of depth intervals for these reservoirs This result denoting the same formation origin these tar zones and same effects on oils such as biodegradation and water washing in reservoirs or during hydrocarbon generation.

Tar-mat zones in the Upper Cretaceous (Mishrif, Sadi and Kasib) reservoirs of Amara Fields southern Iraq were identified by new method (pyrolysis). The new method parameters indicate the following results:

Mishrif Formation has 10 meters of Tar-mat zone in Amara - Z well and Halfiayh - B well at the intervals depth (2929-2939) and (3045-3055) meter respectively.

Sadi Formation has one zone of Tar-mat, and it has thickness about five meters at the interval depth (2979-2984) in Hweiaza-A well, while in Amara-Z well, the Sadi Formation has Tar-mat zone about three meters at depth (2800-2803), finally, in Hf-B well the Sadi Formation has one Tar-mat zone about seven meters at the depth (2815-2822).

Kasib Formation has one zone of Tar-mat about six meters at depth (3118-3124) in Hweiaza-A well, while in Amara-Z well it has two zone of Tar-mat in intervals depth (2855-2870) and (2890-2894) respectively.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.