Mesogenetic dissolution of the middle Ordovician limestone in the Tahe oilfield of Tarim basin, NW China

Jin, Zhijun; Zhu, Dongya; Hu, Wenxuan; Zhang, Xuefeng; Zhang, Juntao; Song, Yougui

doi:10.1016/j.marpetgeo.2008.08.005

Cited by 92 publications

(50 citation statements)

References 24 publications

(23 reference statements)

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“…Karst was well developed in Ordovician, so it can be preferable for reservoirs. Lunnan-Tahe oilfield is considered as the biggest one with Paleozoic marine carbonate reservoirs in China (Lü et al, 2007;Liang, 2008;Jin et al, 2009). Thick sediments in Mesozoic and Cenozoic became a good regional cap rocks, so that oil and gas had been well preserved.…”

Section: Introductionmentioning

confidence: 99%

Distribution and Implication of Adamantane in Crude Oils in Lunnan Area, Tarim Basin in China

Zhu

Jiang

Jin

et al. 2012

Energy Exploration & Exploitation

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According to the present research, the cage structure makes adamantane very stable to resist cracking even at a higher temperature, so its concentration will be increased with temperature rising. But adamantane quantitative analysis of oil in Lunnan area shows a poor correlation between its concentration and geotemperature. Instead, it has a good relationship with maturation parameters such as the content of C 29 ααα 20R sterane and C 28 triaromatic steroid 20R as well as Ts/Tm. The reason is that the oil and cracked products generated in deep zone upwards charged in oil layers in low maturity and then turned into mixed oil which had higher concentration of Ts, adamantine etc. So it makes the parameters such as Ts/Tm ratio and adamantine concentration elevate. The incorporation a great amount of low molecular hydrocarbons diluted C 29 ααα 20R sterane and C 28 triaromatic steroid 20R, which resulted in the parameters of the mixed oil to indicate a higher maturation. Oils with higher adamantane concentration are mainly distributed on Lunnan fault-host zone, Sangtamu faulthost zone and Jilake structure zone. Cracked oil generated in deeper bed migrated along fractures which acted as channels upwards into the reservoir, and so adamantane content of the mixed oil increased. The source of Paleozoic oils in Tarim basin is involved only in two beds: lower Ordovician-Cambrian and middle-upper Ordovician. But according to the data in this paper, there is no obviously difference in adamantane concentration of oils from the two layers.

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Section: Introductionmentioning

confidence: 99%

Distribution and Implication of Adamantane in Crude Oils in Lunnan Area, Tarim Basin in China

Zhu

Jiang

Jin

et al. 2012

Energy Exploration & Exploitation

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“…18 O values are typically 3‰ higher than those of C3, lying between −5.37 and −2.29‰ VPDB, with a mean value of −4.01‰ VPDB ( = 12), and the 13 C values on C4 are close to those of C3, ranging from −0.32 to 4.90‰ VPDB, with a mean value of 2.21‰ VPDB ( = 10).…”

Section: C4 Thementioning

confidence: 89%

“…To study the fluid nature of vug-filling calcite cement, in situ 13 C and 18 O measurements were conducted using an in situ SIMS (Secondary Ion Mass Spectrometry) Cameca IMS-1280 ion microprobe at IGGCAS. The analytical procedures were similar to those described by Rollion-Bard et al (2003).…”

Section: Methodsmentioning

confidence: 99%

“…The range of 13 C values on C2 fluctuates from −0.91 to 3.75‰, with a mean value of 1.55‰ VPDB ( = 11).…”

Section: C2 Compared With C1 Thementioning

confidence: 99%

“…For the Tahe Oilfield, the current main oil-gas production layer is the Middle Ordovician Yijianfang Formation and the Early Middle Ordovician Yingshan Formation, and considerable previous works have been done on these layers [12][13][14][15][16][17]. By contrast, carbonate rocks of the Upper Ordovician Lianglitag Formation are potential exploration strata, which have received little attention.…”

Section: Introductionmentioning

confidence: 99%

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Multiphase Calcite Cementation and Fluids Evolution of a Deeply Buried Carbonate Reservoir in the Upper Ordovician Lianglitag Formation, Tahe Oilfield, Tarim Basin, NW China

et al. 2017

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Oil and gas have been found in the Upper Ordovician Lianglitag Formation carbonates in the Tahe Oilfield, Tarim Basin, NW China. This study documents the origin of diagenetic fluids by using a combination of petrology, SIMS, fluid inclusion, and radiogenic isotope analysis. Six stages of calcite cements were revealed. C1-C2 formed in marine to early burial environments. C3 has relatively low 18 O VPDB values (−8.45‰ to −6.50‰) and likely has a meteoric origin. Meteoric water probably fluxed into aquifers during the Early Paleozoic and Late Paleozoic uplift. C4 has 18 O VPDB values typically 3‰ higher than those of C3, and probably formed during shallow burial. C5 displays relatively negative 18 O VPDB values (−8.26‰ to −5.12‰), and the moderate-tohigh fluid-inclusion temperatures imply that it precipitated in burial environments. C6 shows homogenization temperatures (up to 200 ∘ C) higher than the maximum burial and much lower salinities (<10.61 wt% NaCl), which may suggest that the fluid was deeply recycled meteoric water. The average 87 Sr/ 86 Sr ratios of fracture-and vug-filling calcite cements are much higher, indicative of incorporation of radiogenic Sr. Caves and fractures constitute the dominant reservoir spaces. A corresponding diagenesis-related reservoir evolution model was established that favors exploration and prediction.

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Identification of facies‐controlled eogenetic karstification in the Upper Cretaceous of the Halfaya oilfield and its impact on reservoir capacity

et al. 2018

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Penecontemporaneous dissolution has been considered as the dominant origin of reservoir formation, whereas epigenetic dissolution has also played certain roles in the improvement of reservoir capacity in the Upper Cretaceous Mishrif Formation in the Middle East. Here, we report a possible new reservoir origin based on a case study in the Halfaya oilfield of Iraq, that is, facies-controlled eogenetic karstification. The most representative evidence is that early selective dissolution is not only present in relative high-energy categories of rocks but also in low-energy ones in the cored intervals. Meanwhile, the occurrence frequency of karstification varies among different environments and associated lithologies. In grainstones and packstones, spongy-like dissolution pores and irregular karst channels are widely developed, with fillings and massive plastic breccias. In contrast, in wackestones, lots of high-angle karst channels are developed based on biological burrows, and the karst is more frequently observed in the shoal environment than in the low-energy environments. These characteristics are indication of eogenetic karstification.The model of this karstification can be attributed to a multiple superimposition of short-term exposure during the penecontemporaneous stage and the medium-term exposure after the shallow burial stage. The karst has impact on reservoir capacity, according to which 3 areas are divided in the increasing order, namely, the tight bedrock area, spongy-like dissolution pores area, and karst channels and vugs-filled area, among which the karst channels and vugs-filled area is the most favourable for oil accumulation. This understanding might be general to the Mishrif reservoirs in the entire Middle East.

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Mesogenetic dissolution of the middle Ordovician limestone in the Tahe oilfield of Tarim basin, NW China

Cited by 92 publications

References 24 publications

Distribution and Implication of Adamantane in Crude Oils in Lunnan Area, Tarim Basin in China

Distribution and Implication of Adamantane in Crude Oils in Lunnan Area, Tarim Basin in China

Multiphase Calcite Cementation and Fluids Evolution of a Deeply Buried Carbonate Reservoir in the Upper Ordovician Lianglitag Formation, Tahe Oilfield, Tarim Basin, NW China

Identification of facies‐controlled eogenetic karstification in the Upper Cretaceous of the Halfaya oilfield and its impact on reservoir capacity

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