Evaluation of oil reservoir of Hartha Formation in Y and J field, North Iraq

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. This work is licensed under a Creative Commons Attribution 4.0 International License. Journal of Petroleum Research and Studies PISSN: 2220-5381 EISSN: 2710-1096 Open Access No. 34 part 1, March 2022, pp.70-84 71


Introduction
In the current study, the name of the studied fields and four wells have been coded as Y and J fields and (A, B, C and D) wells respectively Fig-1. due to confidentiality. These fields were discovered at the beginning of the last century by the German team conducting a surface survey during the [1]. There cretaceous reservoir not produce oil until now.
The largest part of the Y Field is located in the western part of the Tigris river, about 60 km south of Mosul city, while J field is located about 50 km southern part of Mosul city. The Y field consists of two domes separated by an NW-SE saddle axis, while the J field consists of one dome northwestern Y field. The dome in the southeast is wider and more developed than the dome in the northwest, the latter being narrow and inconspicuous, and the dome in the southeast is 45 meters higher than the dome in the northwest. The first cretaceous well Y-1, drilled in 1982, penetrated into the Cretaceous reservoirs, while the J-1 well was drilled in 1933 [2].
Final Well Reports wells, A, B, C, and D.
According to the tectonic divisions of [3]. And team, the study area is z . The studied boundary of formation study Figure   (1) and within this study's aimed at making available petrophysical data the computer

Materials and Methods
Collect all information regarding Hartha reservoir formation, its literature review,

Aims of Study
The main objectives of formation evaluations based on Well logs and core analysis data which: -Petrophysical properties to determine. Lithology, porosity, saturation "oil and water", from well logging data analysis.    Reservoir rock typing is the most important part of all reservoir modelling. For integrated reservoir rock typing, static and dynamic properties need to be combined, but sometimes these two are incompatible [6]. with which water saturation, porosity and shale volume content were calculated, as shown in Figure {(2) A, B,C and D},

Figures (2) to (5).
According to the CPI results combined with facies associations interpretation, Formation evaluation plays critical role in resources assessment and is important in selection the best locations for wells as well as the best interval for perforation during the development phase of the oil fields [7]. [8].  and somewhat worse at well (J-D). Figures (4) and (5).

 Har-2 Reservoir unit
The unit (Har-2) is characterized by Inner ramp association, which is characterized unit is good at wells Y- (A, B), at a rate of (18-24) %, and somewhat decreases towards the J field at the wells J-(C, D), at a rate of (13) %. Figures (4) and (5).

 Har -3 Reservoir unit
The reservoir quality of unit (Har-3 ) is the third unit in Y field it is good (18-23) % and worsens in J field to become (14-17)% ,These properties are related to Shoal facies association, which forms the main facies component in unit A3 in all studied wells. Figures (4) and (5).

 Har -4 Reservoir unit
The unit (Har-4) is characterized by Middle ramp association , effect porosity It becomes medium at Y-(A,B) at a rate of (15-19) %and good in J-C at a rate of (25%) and is somewhat lower in J-D, where it is (14%) unlike the previous units ,water saturation in this unit is very good in the two wells (Y-B) (J-C), medium in well (Y-A), and very bad at well (J-D). Figures (4) and (5). The oil reserves of the Cretaceous Hartha reservoir in Y and J fields were calculated.
In respect to oil /water contact level, the oil reserves are calculated to be (6535.31) bbl.

Conclusions:
Based on the analysis of petrophysical parameters, it is established that in of Y and J of Hartha reservoir formations is displaying medium to very good hydrocarbon saturation, so these are reflected as likely to be economically cretaceous Hartha reservoirs.
-The Y field consists of two domes NW-SE axis separated by saddle, while the J field consists of one dome northwestern Y field.
-The Upper Hartha is evaluated as a good quality reservoir in along the axis and shoulder of structure and it exhibits rapid variations in latterly to dolomite s within the location of wells A and B and C).
-The first, second reservoir units are medium -good in wells A and B and C) and somewhat worse at well (D).
-The third unit becomes very good in wells (A and B) and (C) and gets somewhat worse at well (D).
-The fourth unit is very good in the two wells (B, C), medium in well (A), and very bad at well (D).
-The fifth unit is good at the area of the two wells (C, D) and medium at the two wells (A, B).
-The oil column in well C J field is the best petrophysical properties the best producing well -Volume and Original-Oil-in-Place, the oil reserves are calculated to be (6535.31) bbl.
-The interested zone for drilling new production wells in along axis of Y and J fields, near wells A, B and C.