3-D seismic interpretation of hartha formation at Nasiriyah oil field, South Iraq

This study deal with structural and stratigraphic analysis of the seismic reflection data for Hartha Formation at Nasiriyah field, the area of seismic data is about (1237) km2. Nasiriyah oil field is located in Dhi Qar Governorate, southern Iraq, and the oil field is located to the East of Euphrates River of about (38) km northwest of Nasiriyah city. which includes twenty-four (24) wells. In some wells there are oil evidences in Hartha Formation at Nasiriyah oil field, for this reason, Hartha Formation is studied. Two reflectors are picked (top and bottom Hartha) they are defined by using synthetic seismograms in time domain for wells (Ns-1, and 3). Time and depth of Hartha Formation are drawn using velocity data of reflectors. The structural interpretation shows top and bottom of Hartha Formation. The Nasiriyah structure appeared as several regular enclosures shapes, their general trend northwest-southeast. The structure has three enclosures situated on five wells. The general dip towards the northeast. Variance seismic attributes technique are used; instantaneous frequency, instantaneous phase and chaos are done to verify and confirm this structural interpretation . Two coral Rudist (mound) accumulations are determined and interpreted. In addition, flat spot phenomenon has been observed which is located in northeast of the well site Ns-4 which represents a Direct Hydrocarbon Indicator (DHI) that refers to the presence of hydrocarbons