--> Abstract: Quantitative Assessment of Hydrocarbon Generation in Qarun and Natrun Area, Western Desert, Egypt, by M. Tammam, M. Gad, and M. Tarafawi; #90937 (1998).

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Abstract: Quantitative Assessment of Hydrocarbon Generation in Qarun and Natrun Area, Western Desert, Egypt

TAMMAM, M., EGPC; M. GAD, EGPC; M. TARAFAWI, EGPC

Summary

The regional studies define that Gindi and Natrun areas embrace several basins/or embayments of Jurassic, Lower Cretaceous, Upper Cretaceous and Eocene (Figure 1).

The geochemical analysis confirmed the presence of vast thickness of rich source rock within Abu Roash “F” Member (Turonian), Alam El Bueib Formation (Barremian-Neocomian) and Khatatba Formation (Middle Jurassic). Abu Roash “F” Member (Turonian) have a prolific source rock richness (up to 4.5% TOC) within the carbonate layers, which contains mainly type I Kerogen (high HI, up to 800 mgHC/gm Toc). The Kerogen is capable for generating oil, where thermal maturity was reached (at vitrinite reflectance = 0.6%). The oil to source rock correlation reveals and supports that the Abu Roash “F” Member (Turonian) is the main sourcing for Qarun, WD 19 and Wadi El Rayan areas. This is indicated by pr/nc 17 and ph /nc 18 cross plot and gas chromatograms.

Khatatba Formation (Middle Jurassic) represents a good contribution for feeding the reservoirs sequences of the area, where the richness vary from 1.0 to 4.0 % TOC and contains what exceeds 7% coal. The shale layers of Khatatba Formation (Middle Jurassic) contains type II and III Kerogen. These Kerogen are chiefly restricted to delta front and delta (Figure 2).

The Khatatba sequence have coal which seems to be as type II Kerogen. The maximum thickness of the effective source rock is 600 feet at El Natrun area (close to T. 57 and G. Rissu-1 wells).

Concerning Alam El Bueib Formation (Barremian-Neocomian), the richness values range from 0.59 to 6.7 % TOC. It contains type II Kerogen in the basinal area and type III Kerogen in the margin of the basin. The maximum thickness of the effective source rock was 170 feet.

The maturity situation (vitrinite reflectance was indicative for the maturity) of Abu Roash “F” Member is immature on the margin of the basin while it reachs 0.8 % Ro in the depocentre of the Gindi basin. The maturity of Alam El Bueib is enough to generate oil and could be generating gas inside the basinal areas.

In the Khatatba Formation (Middle Jurassic), the maturity was variable, where it ranges from 0.7 to 1.2 % Ro and expected to generate oil, condensate and gas within the embayments areas (Natrun and Gindi).

The reflectance gradient reveals two thermal events, one occurred in Pre Cretaceous while the other occurred in Late Cretaceous. The top of oil window varies from area to another (Figure 3), this variation in the depth to oil window means larger areas are prospective.

The amount of oil and gas generated by each Kerogen type in the particular source interval of the previous formations were calculated based on its Kerogen content, the hydrogen index, the effective source thickness in each basin/or embayment and the results of oil and gas generated are shown in the table I and were distributed on a maps (e.g Figures 4 & 5).

The amount of expelled oil and gas from each type of Kerogen within the previous member/or formation was estimated as shown in the table 1.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah