Structural Study of the Late Oligocene-Early Miocene Sequence in Khabaz Oil Field, NE of Iraq

Abstract

Khabaz Oil Field is located in Kirkuk, about 20 Km southwest of Kirkuk City between Jambour and Bai Hassan oil fields. Tectonically, it is located on the Unstable Shelf within the Low Folded Zone (Zagros Fold Belt). Six wells in Khabaz oil field with two seismic lines (Line K8 and KK54) are used to conduct the geometric analysis, which include the description of fold and fault systems for the purpose of understanding the structural setting of Jeribe (Early Miocene) and Azkand (Late Oligocene) formations in this field. Khabaz structure is a double plunging positively inverted subsurface asymmetrical anticline influence the whole pre-Holocene sedimentary sequence. The interlimb angle of this structure ranges between 137º to 151º which is classified as a gentle anticline. The dip values of the axial surface range between 82 – 84º, so it can be classified as an upright fold with a general trend NW-SE. The core of the anticline is bounded by two high angle dipping reverse fault splay dipping toward each other. These faults pushed the core of the anticline upward with respect to the limbs of the structure. The Southwestern limb is affected by several high angle inverted faults that were possibly bifurcated from one or two major faults. The Northeastern limb is also influenced by a series of high angle reverse, some are dipping toward the core of the structure and few others are dipping toward the limbs. Some of these faults especially those influenced the southwestern limb of the anticline were inherited from the original normal faults that bounding the graben structure developed during the deposition of the Shiranish Formation. During the Late Plio-Plistocene contraction phase, the sense of slip on these faults were inverted and the faults migrated upward into the Tertiary sequence resulting in the formation of the positively inverted structure.

Microfacies analysis and sequence stratigraphy of Oligocene formations within Bai Hassan oil field, Northern Iraq

“…The influence on the climate in the study area was not rapid and not sudden changes, the evidence for this is the presence of Palani formation at the Daoud area, in the lower part of which an MFS (Figure 6) as a sequence boundary type three was distinguished at the end of TST stacking pattern, this boundary characterized by the accumulation of planktonic foraminifera, while this boundary did not appear at either Shashal or Kithka area respectively because Palani Formation is an absence at the two areas, also it should be noted that the basinal character formation from Kirkuk group appears at Kirkuk oilfield adjacent to the studied oilfield, as well as some of these formations disappear at Khabaz oilfield, which is an oil field adjacent to the Kirkuk Oil Field [38,40]. This evidence shows that the influence of the climate (Icehouse) was not significant at the early Oligocene in the study area, at least, but its effect on the sea level was very clear.…”

The geological situation in Abu-Jir Faults Zone, western Iraq: evidence from the radioactivity in Hit–Haditha area

“…The half-lives of 238 U and 235 U are 4.46×10 9 and 7.13×10 8 years, respectively. Thorium with a half-life of 1.39×10 10 years occurs naturally as the radioisotope 232 Th which gives rise to a decay series that terminates in the stable isotope 208 Pb.…”