Multi-layered ordovician paleokarst reservoir detection and spatial delineation: A case study in the Tahe Oilfield, Tarim Basin, Western China

Tian, Fei; Jin, Qiang; Lu, Xinbian; Lei, Yuhong; Zhang, Likuan; Zheng, Shao-Hui; Zhang, Hong-fang; Rong, Yuanshuai; Liu, Naigui

doi:10.1016/j.marpetgeo.2015.10.015

Cited by 99 publications

(35 citation statements)

References 31 publications

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“…(c) Cross Section A-A', showing the paleokarst system of the Tahe Oilfield. The main reservoirs are located in the northern part of the Tahe Oilfield in the Yingshan Formation (O1-2 years), which is at depths exceeding 5500 m (modified from [2]). See Figure 1b for the cross-section location.…”

Section: Geological Backgroundmentioning

confidence: 99%

“…One-fourth of the karst area on Earth is distributed in China, and one-half of the karst bare area is in northern China [16,19]. The Tahe Oilfield is the largest Paleozoic marine oilfield in China [1][2][3]14,16,[20][21][22], covering an area of 2400 square kilometers. The Tahe Oilfield is located on the southwestern slope of the South-Central Akekule Arch (shown in Figure 1b) in the North Uplift (Shaya Uplift) of the Tarim Basin (shown in Figure 1a) [17].…”

Section: Geological Backgroundmentioning

confidence: 99%

“…It is generally thought that the Ordovician fracture-cavity carbonate reservoir was formed by dissolution, with an extremely heterogeneous internal structure and non-uniform lithological properties [1][2][3]. Because of the burial depth of the Ordovician carbonate strata, which exceeds 5500 m [1][2][3][4], the seismic reflection signals of the non-conformable surface are weak and discontinuous, with a relatively low signal-to-noise ratio. Due to the irregular geometry, the associated extreme based on Matching Pursuit is used to extract the different single-frequency data volumes.…”

Section: Introductionmentioning

confidence: 99%

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Spectral Decomposition and a Waveform Cluster to Characterize Strongly Heterogeneous Paleokarst Reservoirs in the Tarim Basin, China

Shan

Tian

Fang

et al. 2019

Water

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The main components of the Ordovician carbonate reservoirs in the Tahe Oilfield are paleokarst fracture-cavity paleo-channel systems formed by karstification. Detailed characterization of these paleokarst reservoirs is challenging because of heterogeneities in characteristics and strong vertical and lateral non-uniformities. Traditional seismic analysis methods are not able to solve the identification problem of such strongly heterogeneous reservoirs. Recent developments in seismic interpretation have heightened the need to describe the fracture-cavity structure of a paleo-channel with more accuracy. We propose a new prediction model for fracture-cavity carbonate reservoirs based on spectral decomposition and a waveform cluster. By the Matching Pursuit decomposition algorithm, the single-frequency data volumes are obtained. The specific frequency data volume that is the most sensitive to the reservoir is chosen based on seismic synthesis traces of well-logging data and geological interpretability. The waveform cluster is then applied to delineate the complex paleokarst systems, particularly the fracture-caves in the runoff zone. This method was applied to the area around Well T615 in the Tahe oilfield, and a paleokarst fracture-cavity system with strong heterogeneity in the runoff zone was delineated and characterized. The findings of this research provide insights for predicting other similar karst systems, such as karstic groundwater and karst hydrogeological systems.

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Section: Geological Backgroundmentioning

confidence: 99%

Section: Geological Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spectral Decomposition and a Waveform Cluster to Characterize Strongly Heterogeneous Paleokarst Reservoirs in the Tarim Basin, China

Shan

Tian

Fang

et al. 2019

Water

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“…Episode III occurred between the deposition of the Ordovician Sangtamu Formation and Silurian strata. The Lianglitag Formation is mainly affected by Episode II [17]. The Lianglitag Formation carbonates were exposed to the surface and infiltrated by ground water, leading to significant dissolution of the carbonates and formation of dissolution vugs and caves with sizes from centimeters to meters (Figure 11(b)).…”

Section: Diagenetic Fluid Evolution and Its Influence On Reservoirmentioning

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%

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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Some evolutionary patterns of palaeokarst developed in Pleistocene deposits (Ebro Basin, NE Spain): Improving geohazard awareness in present‐day karst

et al. 2018

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Pleistocene detrital deposits in the central Ebro Basin frequently show deformation features due mainly to karstification in the underlying Neogene evaporites. In 123 cases, estimation of parameters of shape and minimum volume of materials involved was accomplished. Six of them were analysed in more detail to establish the main processes involved in their genesis and the succession of events. All the deformation features in the selected sites are synsedimentary. To achieve the objectives, intense fieldwork was made applying methods of sedimentology and structural geology. Usually, a complex evolutionary pattern was observed, with evidences of dissolution, sagging, collapse, gravity flow, suffosion, and plastic flow. In a schematic way, three main situations, independent of the age of the analysed deposits, can be distinguished: (a) slow subsidence, (b) collapse, and (c) temporal overlapping of both processes. In the first 2 scenarios, basins with smooth or abrupt borders, respectively, were generated on the land surface. In the third one, slow subsidence was followed by a collapse, located in the area of maximum flexure. These patterns are also observed in present-day dolines. Comparison of direct and indirect parameters between paleodolines and present-day dolines indicates a bigger size of the latter, probably caused by the different conditions of observation. This study helps to know the possibilities in the evolution of mantled karst features, to estimate the volume of material affected by karstification and to improve the knowledge of present-day dolines behaviour. Consequently, study of paleodolines must be considered to achieve a better urban planning in active karstic areas.

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Multi-layered ordovician paleokarst reservoir detection and spatial delineation: A case study in the Tahe Oilfield, Tarim Basin, Western China

Cited by 99 publications

References 31 publications

Spectral Decomposition and a Waveform Cluster to Characterize Strongly Heterogeneous Paleokarst Reservoirs in the Tarim Basin, China

Spectral Decomposition and a Waveform Cluster to Characterize Strongly Heterogeneous Paleokarst Reservoirs in the Tarim Basin, 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

Some evolutionary patterns of palaeokarst developed in Pleistocene deposits (Ebro Basin, NE Spain): Improving geohazard awareness in present‐day karst

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