Lithologic characteristics and diagenesis of the Devonian Jauf sandstone at Ghawar Field, Eastern Saudi Arabia

Al‐Ramadan, Khalid; Hussain, Maaruf; Imam, Badrul; Saner, Salih

doi:10.1016/j.marpetgeo.2004.09.002

Cited by 54 publications

(31 citation statements)

References 18 publications

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“…Also, po ros ity is de creased by pore-fill ing illite and mixed-layer illite-smectite in sand stones units (cf. Al-Ramadan et al, 2004). Pore-fill ing illite and mixed-layer illite/smectite have a greater in flu ence on po ros ity loss in lithic-rich sand stone whereas pore-fill ing kaolinite and chlorite cause the great est po ros ity loss in quartz-rich sand stone.…”

Section: Authigenic Clay Mineralsmentioning

confidence: 98%

“…Pseudo matrix is of ten more im por tant for po ros ity re duc tion where lithic grains are ab sent in the Narra been Group (cf. Al-Ramadan et al, 2004). Grain re arrange ment is also an im por tant po ros ity re duc tion fac tor in the ab sence of lithic grains, par tic u larly in quartzose sam ples (Worden et al, 2000).…”

Section: Influence Of Diagenetic Alteration and Composition On Reservmentioning

confidence: 99%

“…These are or ganic ac ids, CO 2 and de hy dra tion of clay min er als (Zhang et al, 2007) in addi tion to in or ganic min eral and me te oric wa ter re ac tions (Chi et al, 2003). Dis so lu tion may oc cur as a re sult of the orig i nal pore flu ids but is more com monly as so ci ated with acidic ground water in va sion (e.g., Al-Hajri et al, 1999;Al-Ramadan et al, 2004). Pore fluid is also im por tant in the dis so lu tion of car bon ate cement, such as cal cite ce ment (McBride et al, 1996).…”

Section: Authigenic Clay Mineralsmentioning

confidence: 99%

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The influence of diagenetic alterations on porosity in the Triassic Narrabeen Group, Southern Sydney Basin, Australia

Gahtani¹

2013

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The in flu ence of diagenetic al ter ations on po ros ity in the Tri as sic Narra been Group, South ern Syd ney Ba sin, Aus tra lia Pe trog ra phy of the Tri as sic Narra been Group (South ern Syd ney Ba sin of Aus tra lia) was de scribed by thin sec tion, scan ning elec tron mi cro scope and X-ray dif frac tion tech niques. Sand stone com po si tion in cludes mostly lithic grains with mi nor quartz, feld spar, mica and heavy min er als; litharenites and sublitharenites are com mon and quartzarenites are rare. Quartz in cludes monocrystalline and polycrystalline grains while the feld spar in cludes both K-feld spar and plagioclase. Vol ca nic, sed i mentary and chert rock frag ments are pres ent. In thin sec tion po ros ity is vis i ble in all units, par tic u larly the coarse-grained de posits. Sec ond ary po ros ity is greater than the pri mary po ros ity. The diagenetic al ter ations in clude com pac tion, quartz overgrowths, authigenic clay min er als, car bon ate ce ment and authigenic feld spar. Com pac tion oc curred in all units dur ing diagenesis. Both early and late diagenetic car bon ate ce ment is im por tant in the Narra been Group. Pore-fill ing car bon ate cement re duced po ros ity whereas dis so lu tion of car bon ate re sulted in sec ond ary po ros ity. Authigenic clay min er als are widespread in all units fill ing pores and oc cur ring as grain-coat ings on de tri tal and authigenic grains. Where they coat quartz grains they pre serve po ros ity by pre vent ing growth of quartz overgrowths. Dis so lu tion of un sta ble feld spar and lithic grains pro vided sec ond ary po ros ity. In the Narra been Group, shale and siltstone are abun dant in the Wom barra Claystone, Stanwell Park Claystone, Bald Hill Claystone and New port For ma tion, form ing lithological seals and con fin ing lay ers. Mi nor sandstone beds oc cur in the Wom barra Claystone and con tain more po ros ity. Me dium-and coarse-grained sand stone is com mon in the Coal cliff Sand stone, Scarborough Sand stone and Bulgo Sand stone and shows low to mod er ate po ros ity. Thus, these sand stone units prob a bly con tain gas or wa ter.Key words: pe trog ra phy, diagenesis, pri mary po ros ity, sec ond ary po ros ity, quartz over growth, car bon ate ce ment. INTRODUCTIONIn the Syd ney Ba sin (Aus tra lia), the Narra been Group is the low er most of three Tri as sic rock units and is lo cated be tween the Up per Perm ian Illa warra Coal Mea sures and the Hawkesbury Sand stone (Ward, 1971a). Fine-grained sed i ment in the Narra been Group was pre vi ously stud ied by sev eral authors (e.g., Baker, 1956;Loughnan et al., 1964Loughnan et al., , 1974Goldbery and Hol land, 1973;Retallack, 1977). Ward (1972) noted quartzose, quartz-lithic and vol ca nic sand stones as the three sed i ment suites in the Narra been Group. Prov e nance mark ers of fore land ba sin-fill sed i ments were de ter mined by Cow an (1993). The com po si tion and tex ture of the Narra been Group were de scribed by McElroy (1954). De scrip tions of the pe trology in the N...

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Section: Authigenic Clay Mineralsmentioning

confidence: 98%

Section: Influence Of Diagenetic Alteration and Composition On Reservmentioning

confidence: 99%

Section: Authigenic Clay Mineralsmentioning

confidence: 99%

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The influence of diagenetic alterations on porosity in the Triassic Narrabeen Group, Southern Sydney Basin, Australia

Gahtani¹

2013

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“…It is considered that chlorite coating improves reservoir quality in most cases, especially in deeply buried sandstones (Dowey, 2012;Ehrenberg, 1993;Tayloret al, 2010;Worden & Morad, 2009). The presence of chlorite coating inhibits quartz overgrowth, as well as carbonates cement by changing the grain surfaces to be oil wetting and preventing the access of water to detrital surfaces, thus stopping cementations (Al-Ramadan et al, 2004). Sandstone reservoir quality is a function both of the depositional conditions and diagenetic processes (Ajdukiewicz et al, 2010).…”

Section: Paragenetic Sequencementioning

confidence: 99%

Diagenetic controls on reservoir quality of tight sandstone: A case study of the Upper Triassic Yanchang formation Chang 7 sandstones, Ordos Basin, China

et al. 2018

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Through a range of petrological techniques, the petrology, diagenesis, pore characteristics, and controlling factors on the regional variations of reservoir quality of the Chang 7 sandstones were studied. These sandstones, mainly arkoses, lithic arkoses, and feldspathic litharenites, were deposited in a delta front and turbidites in semi-deep to deep lacustrine. The detrital constituents were controlled by the provenance and sedimentary condition, which resulted in a spatially variable composition; e.g., high biotite and feldspar contents in the northeast (NE) of the study area, and high contents of rock fragments, especially dolomite, matrix, and quartz in the southwest (SW). Diagenesis includes intense mechanical compaction, cementation, and dissolution of unstable minerals. Diagenetic minerals which were derived internally include quartz, ankerite, ferrous calcite, albite, illite, kaolinite, and chlorite. Thus the original sandstone composition hadfirm control over the development and distribution of cement. Mechanical compaction and late-stage cementations contribute to the porosity loss of sandstones of Chang7 member. The dissolution porosity in major sandstone, slightly higher than primary porosity is principally dependent on the accessibility of acid fluid. The high content of plastic component facilitated the reduction of primary porosity and limited the mineral dissolution. The best reservoir sandstones are found in W, and partly from NE, M districts, with porosity are primary. The relatively high textural maturity of these sandstones reduces the impact of compaction on primary pores, and commonly existed chlorite rims limited the precipitation of pore filling quartz and carbonate cementation in late stage. A través de una gama de técnicas petrológicas se estudió la petrología, la diagénesis, las características de poro y los factores que controlan las variaciones regionales de la calidad del yacimiento de las areniscas Chang 7. Estas areniscas, principalmente arcosas, arcosas líticas y arenitas líticas feldespáticas, se depositaron en un frente deltáico mientras las turbiditas se depositaron en ambientes lacustres profundos y semi-profundos. Los componentes detríticos dependen de la procedencia y la condición sedimentaria, lo que resultó en una composición variable en el espacio; por ejemplo, altos contenidos de biotita y feldespato en el noreste (NE) del área de estudio, y altos contenidos de fragmentos de roca, especialmente dolomita, matriz y cuarzo en el suroeste (SW). La diagénesis incluye compactación mecánica intensa, cementación y disolución de minerales inestables. Los minerales diagenéticos que se derivaron internamente incluyen cuarzo, ankerita, calcita ferrosa, albita, illita, caolinita y clorita. Por lo tanto, la composición original de arenisca tenía un firme control sobre el desarrollo y la distribución del cemento. La compactación mecánica y las cementaciones de la última etapa contribuyen a la pérdida de porosidad de las areniscas del miembro Chang7. La porosidad de disolución en la pi...

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“…A statistic analysis of 46 core samples reveals that the exogenous carbonate cementation mainly took place in Chang 6 sandstone in Fuxian area and that the cementation degree increased from northeast to southwest. The exogenous carbonate cements formed in later stage of diagenesis because cements are high in content, exist as substrate cement with irregular shape, and fill in remaining pores of reservoirs [11,12]. Electron probe results indicate that that the chemical compositions of the exogenous cements are similar ( Table 1).…”

Section: Geochemical Features Of Exogenous Carbonate Cementsmentioning

confidence: 99%

Characteristics of carbonate cementation in clastic rocks from the Chang 6 sandbody of Yanchang Formation, southern Ordos Basin

Liu

Zheng

et al. 2012

Sci. China Earth Sci.

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Densification of reservoir is an important factor that restricts oil and gas exploration from low porosity and extra-low permeability reservoirs. Carbonate cementation was heavily developed in Chang 6 sandbody, a facies of underwater distributary channel in delta front, of Upper Triassic Yanchang Formation in Fuxian area, southern Ordos Basin, and the cementation is one of the major factors that affect quality of reservoir. Based on the macro-microcosmic petrology and geochemistry features, the genesis of densification of carbonate-cemented reservoir was systematically discussed. The carbonate cementation can be classified into endogenous and exogenous, and the essential differences between them are that they were formed in different fluids and in different diagenesis periods. With the aid of identification of thin sections, analyses on electron probe, trace and rare-earth elements, carbon and oxygen isotope, we propose that the endogenous fluid for cementation came from the rock itself during early diagenetic stage. The minerals related to endogenous fluid had good shapes. The reservoir property was enhanced with porosity increasing by 3%-8% because of later dissolution by endogenous fluid. The exogenous fluid might be water combining with CO 2 , likely released from organic matter-rich mudstone. Calcite cement, in form of substrate cementation, was precipitated from the fluid and filled in the remaining pores of sandstones in late diagenetic stage as variations of physical and chemical conditions. The exogenous cement reduced rock porosity, damaged reservoir property, affected some oil enrichment, and seriously caused Chang 6 reservoir densification. Some of the dense layers that formed on top of sandbody could have served as diagenetic traps, and thus the exogenous cementation area could be favorable for oil exploration. Upper Triassic Yanchang Formation, densified clastic reservoir, carbonate cementation, substrate cement, genetic mechanism Citation: Liu C Y, Zheng H R, Hu Z Q, et al. Characteristics of carbonate cementation in clastic rocks from the Chang 6 sandbody of Yanchang Formation, southern Ordos Basin.Carbonate cement is one of the important cements in clastic reservoir, and is produced by water-rock interaction while temperature and pressure changing [1,2]. Occurrence and content of carbonate cement in clastic reservoir greatly influenced reservoir properties and petroleum migration and enrichment because carbonate cement originates from different sources and its solubility is sensitive to fluid and surrounding rock [3].Chang 6 member of Upper Triassic Yanchang Formation comprises mainly underwater distributary channel sandbodies in delta front facies and is an important reservoir rock in Fuxian area [4]. On the basis of well core and thin section observation, petrology, and geochemistry, this article analyzes periodicity of carbonate cementation, discusses cementation mechanism and its influence on clastic reservoir, studies relationship between reservoir properties, oiliness and characteristics of...

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Lithologic characteristics and diagenesis of the Devonian Jauf sandstone at Ghawar Field, Eastern Saudi Arabia

Cited by 54 publications

References 18 publications

The influence of diagenetic alterations on porosity in the Triassic Narrabeen Group, Southern Sydney Basin, Australia

The influence of diagenetic alterations on porosity in the Triassic Narrabeen Group, Southern Sydney Basin, Australia

Diagenetic controls on reservoir quality of tight sandstone: A case study of the Upper Triassic Yanchang formation Chang 7 sandstones, Ordos Basin, China

Characteristics of carbonate cementation in clastic rocks from the Chang 6 sandbody of Yanchang Formation, southern Ordos Basin

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