The Hartha Formation reservoir was evaluated to be produced in the near future in Y oil and J fields, West of the Tigris River in northern Iraq. Due to geological data analysis of the Hartha facies and diagenesis could enhance oil production with minimized risks, this research tried to deal with data to support the oil production. The Hartha reservoir is subdivided into five-rock units, Har-1, 2, 3, 4 and 5. It is of Heterogenic facies limestone, dolomite, dolomitic limestone and argillaceous dolomite. The Hartha Formation is a clean carbonate; it has an effective porosity. It consists of lime mudstone-packstone skeletal grain. This conclusion is based on the lithology, core microfacies, cutting, thin section and log interpretation variability.   The study aims to characterize the depositional and diagenetic properties of the Hartha carbonate and their effects on the reservoir quality. This research indicated that the depositional setting is a gentle slope ramp including outer, mid and inner ramps. The dissolution and dolomitization in near-surface and marine environments formed secondary porosity types as a vuggy, cavern, and melodic. The fracture is a good reservoir in the upper part of the Hartha reservoir. The lower section is affected by other diagenetic processes  causing a destructive effect on porosity such as compaction, Neomorphism  and cementation. The measured and calculated porosity with an integration of the measured permeability in the Hartha Reservoir gave a good reservoir quality to the formation. These data are coming from the analysis of the primary and secondary porosity. The petrophysical cut-off provided an excellent result for the rock properties as the net to gross ratio of the most units of the Hartha Reservoir.

Afield development plan (FDP)  of the Y and J oil fields for cretaceous reservoir (Harth Formation) evaluation and the production of hydrocarbons in the near future in two Y and J oil fields. Open hole logs namely (Gamma ray, Resistivity, Sonic, Caliper and Density) logs were used to determine petrophysical parameters. The parameters determined are; volume of shale, porosity, water saturation, irreducible water saturation and bulk volume of water. The thickness of the reservoir varies between (40 and 120) m. Determining the porosity depending on the porosity of the log (16-28)%  and core  Average porosity (18-37)% values vary between; generally decreasing with depth. Average porosity 33.3%.test is flow crude oil 1000 bll /d.in J field basically water saturation calculation5-16%. And oil saturation (90-80) % and the oil were carried out at a rate of 1000 barrels / day in the complete test of well Y. The amount of the original oil storage OOIP (1039 * 10^6) standard cubic meters. This study provides an insight into reservoir quality prediction in the study area and other carbonate reservoirs undergone different the development of Hartha reservoir in south Mosul north Iraq as a new reservoirs in the study as Tertiary reservoir  producing as old  degassing stations enabling facilities from the 1950s are being" surface facility", This study's aimed at making available petrophysical data the computer processed interpretation(CPI) for Hartha reservoir.