2011 YÜksek lisans tez özetleri

Geostatistical Evaluation of Oils in Different Rezervoirs of an Oilfeild-North Iraq

In the oil fields of northern Iraq, oil is generally produced from more than one reservoir. These reservoirs consist of Tertiary (one reservoir) and Cretaceous (two reservoirs) aged units respectively. In this thesis we tried to find out whether oil in different reservoirs is formed from a single rock or from different source rocks and is formed as a result of single or multi-phase migration.

In this study, Khabaz Oilfield is considered and the oil wells selected in this field are from both Tertiary and Cretaceous aged reservoirs. We used physico-chemical properties of the oils in these reservoirs such as specific gravity, API-gravity, the amount of asphaltene, the amount of sulfur, the amount of wax, the amount of ash, amounts of Ni-V and also chemical composition of reservoir water in order to achieve the research purpose.

Firstly, these parameters which were separately defined for each well and reservoir, were arranged as a data base. Then with the support of by using computer-based assessments and comparisons the data were compared with each other by the statistical methods such as correlation coefficient (R), factor analysis, and analysis of cluster similarity and we tried to determine similarities, proximities and differences between the reservoirs.

Considering the results of this study it will be possible to redefine the strategies and scenario to become much more effectively for petroleum exploration and production activities in the region. In this sense, results of the study can be contributed and applied in practice, directly.

Khabaz oil field is located in three separate reservoirs. These include: Tertiary (one reservoir), Cretaceous (Upper Qamchuqa) and Cretaceous (Lower Qamchuqa). According to the results of evaluation, all of the wells produce oil from a single structure in Khabaz oil field. Only Khabaz-2b is out of this structure. In this field the specific gravity of oil is high and contains a lot of asphalt. Produced oil is extracted from the same source rock (Chia Gara Formation). However, according to the result of statistical evaluation it is shown that there are two types (a,b) of produced oil in the Khabaz oil field.