Silurian Qusaiba Shale Play: Distribution and Characteristics
Mohammad Faqira, Abid Bhullar, and Abdelghayoum Ahmed
Saudi Aramco, Dhahran, Saudi Arabia
爱情黑名单>q2是什么意思The organic-rich shale of the Lower Silurian Qusaiba Member of the Qalibah Formation is one of the most prolific source rocks in the Arabian Peninsula. More than 90% of the Paleozoic light oil and gas accumulations are known to be sourced by this unit. The extensive regional prence of this unit is a major factor for the significant Paleozoic oil and gas rerves that have been discovered in the region. It is now under investigation as a potential shale gas play in veral basins in Saudi Arabia. It contains up to 8% of total organic content (Jones and Stump, 1999).
The Lower Qusaiba shale member was developed due to the global a level ri at the ba of the Silurian. This major transgression was recognized by Al-Laboun (1988) and others in the Middle East and North Africa. This event was recognized basin wide from Oman in the south to Turkey in the north and from Iran in the east to Morocco in the west. The Qusaiba member consists of a thin hot shale at the ba overlain by thick lean shale, ranges its thickness from 250m at the outcrop to over 1000m in the basin. The extensive regional prence of the hot shale across most of the Arabian plate suggests eoc
a flat basin coupled with a very rapid ri in the a level. This tting is reflected by the consistent development of the hot shale over all parts of the basin.
The subquent Hercynian deformation controlled the distribution of the Qusaiba source rocks across the Arabian Plate basins. This deformation eroded the Silurian source rocks from large areas over the Levant, Al-Batin, and Oman-Hadhramaut arches. This erosion is illustrated by the truncation of the ba Qusaiba ismic reflector along the flanks of the arches. The widespread erosion of the Silurian source rocks over the arches limits the Paleozoic hydrocarbon potential to the margins of Hercynian Basins. The deep burial of the Silurian source rocks in the Hercynian basins has extended maturation of the rocks into the wet and dry gas windows.才德
The hot shale is characterized by distinctive respon on wire line logs with incread gamma-ray and resistivity respons and an increa in sonic transit times. Increas in gamma-ray values often indicate elevated amounts of TOC where non-detrital uranium is associated with organic matter (Stocks and Lawrence, 1990).
法语学习培训班The basal Silurian hot shale produces a strong ismic reflector due to the sharp velocity contrast with the underlying and overlying diments. Regional amplitude mapping of the reflector can be ud to differentiate between areas where the hot shale is prent and tho where it is abnt.
The Lower Qusaiba Hot shale is Type II, and appears as oil prone kerogen at the early stage of maturation. With increasing maturity, the generated gas was stored in a “sorbed” state as well as in a “free” state in interstitial pore in the low clay and brittle intervals. Gas yields are expected to be high and consistent with organic richness and original hydrocarbon generation potential. Some gas and light oil has been lost from the Qusaiba system through late stage expulsion but a high percentage remains in the Qusaiba itlf as indicated by high mud gas readings measured in many wells that were drilled through it. Recent kinetic data and modeling indicated that the Qusaiba hot shale is more gas prone than typical type II marine kerogen. The richness and maturity of the Qusaiba hot shale offers favorable conditions for shale gas prospectively in the Arabian Peninsula particularly in the northwestern
专四成绩查询Faqira, Bhullar, Ahmed…Page 2 territory of the Kingdom of Saudi Arabia. In addition to the hot shale, the overlying thick lean shale can be a good potential for shale gas, which contains less clay, high quartz and maturity in the range of wet to dry gas. Overpressure conditions may occur where the bounding formations form a al against hydrocarbon migration and gas generation continues within the shale.All the properties play an important role in making it as a prospective shale-gas play. The adsorption capacity of the shales is not very well understood and it needs more work. In
prefixaddition, the desorption of gas might have occurred due to the uplift in the areas where Qusaiba had reached the gas window prior to the Hercynian uplift.英语口语学习心得
References
Al-Laboun, A.A., 1988, The distribution of Carboniferous – Permian siliciclastic rocks in the greater Arabian Basin. Geological Society of America Bulletin, v. 100, p. 362 – 373.
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Jones, P.J. and Stump, T.E., 1999, Depositional and tectonic tting of the Lower Silurian hydrocarbon source rock facies, central Saudi Arabia. American Association of Petroleum Geologists Bulletin, v. 83, p. 314 – 332.steve jobs 演讲
Stocks, A.E. and Lawrence, S.R., 1990, Identification of source rocks from wireline logs. Geological Society of London Special Publications, v. 48, p. 241 – 252.
