Petrophysical Evaluation and the Effect of Shale Layers on Net Pay Zone Thickness in the Marun Oil Field, Iran

The Marun oil field is situated on the eastern part of Zagros, Iran. Aghajari Formation is cropping out on the surface. The Asmari formation, the Bangestan and Khami Groups are the Main reservoirs in this field and Asmari formation is the most important reservoir. Dolomitic carbonates are dominant lithology in the study well. Increasing of shale Layers in different layers caused to decrease of brittle property and this condition had investigated by petrophysical evaluation. According to this research, near to 29 percent shale has mixed with sandstone rock units in the study well which is comparable with maximum porosity there. Because, sandstone layers have shown the best porosity (near to 26 percent) in the study well. Also, good rocks based on water saturation and porosity are situated in sandstone units and poor rocks have existed in the limestone-dolomites. Therefore, facies changes in the Asmari formation can explain the observed variations in reservoir quality in the study area.

Petrophysical evaluation for reservoir properties of Lower Cretaceous sands in Sawan gas field, central Indus Basin, Pakistan

The Sawan gas field(SGF)is located in Pakistan's central Indus Basin in the Province of Sindh,Pakistan.Tectonically,it is part of the southeastern Jacobabad high;and geographically,it is part of the Thar Desert in the Khairpur district.In the present study,three wells,Sawan 01,Sawan 02 and Sawan 08,were analyzed for reservoir properties of the Lower Goru C sand interval,which has been drilled in the central part of the field.Petrophysical parameters such as effective porosity,the volume of shale,formation water resistivity,and water saturation of the studied basin were calculated.In terms of shale volume,Sawan 01 has 30%–35%of non-clean(shale)lithology,which is the highest of the three wells.The effective porosity of the three wells ranges from 12%–16%,while the average water saturation in the interval of C sand in these wells stands around 50%–60%.But there are zones with relatively lower water saturation values of approximately 30%–50%.These zones are considered better pay zones than the rest of the intervals.A very interesting phenomenon that may be termed the"Gas effect"is visible on cross plots,representing the neutron-density cross over on the E-Logs layout and representing the presence of lighter hydrocarbons in this reservoir zone.

Depositional Environment,Petrophysical Evaluation and Electrical Properties of Zeit Formation,Northwestern Shore of Gulf of Suez,Egypt

The Zeit sand reservoir is one of the most prolific formations at Northwestern side of the Gulf of Suez.In this research we will try to coordinate between electrical,petrophysical properties,depositional environment and facies discrimination in order to evaluate the hydrocarbon potentiality of studied Zeit Formation.The statistical parameters for potassium(K),thorium(Th)and Th/U ratio contents have a general increase towards northwestern parts,whereas uranium(U)content has a general increase towards southeastern parts.The sandstone facies is distinguished from the other facies by its thorium content>4 ppm.U has high carbonate content(U≥1 ppm).Rocks'electrical properties vary greatly depending on a number of factors.Electrical measurements were taken at frequencies range of(5×10^(-4)Hz-100 kHz)for fully saturated samples(clayey sandstone)with NaCl(20 gm/L).As salinity,clay content,and frequency increase,consequently does the electrical properties.The continental condition are present in northwestern part(back-sea)which is distinguished by high K percent,high Th,high Th/U ratio,and low U contents.Low K,Th,and Th/U ratio contents,with high U contents,characterize the marine depositional environment that existed around the east and southeastern parts(foresea coincide with the dipping of strata).Furthermore,the studied Zeit Formation has good petrophysical properties that coincide with marine conditions.The middle and eastern parts(around ISS-94 and CSS-288)is a good reservoir(porosity 36%-39%,shale content<15%,hydrocarbon saturation 71%-92%,and net pay thickness 17-63 feet).

New prospective gas plays in pliocene sands, offshore Nile Delta Basin: A case study from Kamose-1 well at North Sinai Concession, Egypt

The Pliocene sands in the offshore parts of the Nile Delta Basin represent significant gas reservoirs.Several targets have been recently discovered in different places along the offshore Nile Delta Basin.The present work focuses on the possibility of discovering new natural gas resources at North Sinai Concession through an integrated method between seismic and well logs data interpretations.A case study from Kamose-1 Well at Kamose Field,North Sinai Concession has been examined.The quantitative explanation for the well log data of Kamose-1 Well has revealed two zones expected to be gas-bearing zones.These intervals are located between depths;1174–1186 m(zone I)and between 1429 and 1503 m(zone II).The calculated petrophysical parameters for these zones exhibit low water saturation(24–43%),high effective porosity(30–31%),low shale volume(21–26%),high total porosity(37–38%)and low bulk volume of water(0.07–0.12).Zone II(74 m thick)shows a clear bright spot on the seismic profiles covering the study area,while,zone I is beyond seismic resolution(12 m thick).Several seismic bright spots have been outlined on the seismic data nearby Kamose-1 Well.The comparison between the newly outlined seismic bright spots with the drilled one in Kamose-1 Well exhibited a great similarity.Accordingly,these prospects are expected to be new targets for gas exploration in the Pliocene succession at North Sinai Concession.