Features and origins of massive dolomite of Lower Ordovician Penglaiba Formation in the northwest Tarim Basin: Evidence from petrography and geochemistry

Qiao, Zhanfeng; Zhang, Shaonan; Shen, Anjiang; Guang-hua, Shao; She, Min; Cao, Peng; Sun, Xuewei; Zhang, Jie; Guo, Ruixin; Tan, Xiucheng

doi:10.1016/j.petsci.2021.03.001

Cited by 13 publications

(3 citation statements)

References 50 publications

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“…While the Tarim Basin is rich in oil and natural gas reserves [ 1 , 2 , 3 ], its role in China’s energy structure continues to grow and expand. Most of the wells are ultra-deep wells [ 4 , 5 ], and the lithology varies greatly from top to bottom in the Keshen block [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

A Nano-Cleaning Fluid for Downhole Casing Cleaning

Song

Zhang

et al. 2023

Polymers

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In drilling and completion projects, sludge is formed as a byproduct when barite and oil are mixed, and later sticks to the casing. This phenomenon has caused a delay in drilling progress, and increased exploration and development costs. Since nano-emulsions have low interfacial surface tension, wetting, and reversal capabilities, this study used nano-emulsions with a particle size of about 14 nm to prepare a cleaning fluid system. This system enhances stability through the network structure in the fiber-reinforced system, and prepares a set of nano-cleaning fluids with adjustable density for ultra-deep wells. The effective viscosity of the nano-cleaning fluid reaches 11 mPa·s, and the system is stable for up to 8 h. In addition, this research independently developed an indoor evaluation instrument. Based on on-site parameters, the performance of the nano-cleaning fluid was evaluated from multiple angles by heating to 150 °C and pressurizing to 3.0 Mpa to simulate downhole temperature and pressure. The evaluation results show that the viscosity and shear value of the nano-cleaning fluid system is greatly affected by the fiber content, and the cleaning efficiency is greatly affected by the concentration of the nano-emulsion. Curve fitting shows that the average processing efficiency could reach 60–85% within 25 min and the cleaning efficiency has a linear relationship with time. The cleaning efficiency has a linear relationship with time, where R2 = 0.98335. The nano-cleaning fluid enables the deconstruction and carrying of the sludge attached to the well wall, which accomplishes the purpose of downhole cleaning.

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Section: Introductionmentioning

confidence: 99%

A Nano-Cleaning Fluid for Downhole Casing Cleaning

Song

Zhang

et al. 2023

Polymers

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“…The Tarim Basin has the richest deep hydrocarbons and deepest oil drilling in China. − The current development of new and advanced technologies and equipment, such as hydraulic fracturing, nanomaterials, and 12,000 m drilling rigs, are incentives for the petroleum industry to explore and develop deep-basin oil. However, as the theoretical understanding of DLOA lags far behind exploration technology, hydrocarbon drilling activity is prevented from expanding to deeper strata. , From the perspective of hydrocarbon accumulation dynamics, based on experimental and statistical analyses and by employing pore throat radius parameters, the critical condition of the DLOA of Lower Ordovician deep carbonate rocks in the Tazhong area of the Tarim Basin was quantitatively characterized, the genetic mechanism of the threshold of oil accumulation in carbonate rocks was revealed, and the deep oil exploration potential was forecasted in this study.…”

Section: Introductionmentioning

confidence: 99%

Critical Condition of the Depth Limit of Oil Accumulation of Carbonate Reservoirs and Its Exploration Significance in the Lower Ordovician of the Tazhong Area in the Tarim Basin

Wang,

Pang,

Wang

et al. 2023

ACS Omega

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Carbonate rocks typically constitute porous media, making the study of hydrocarbon accumulation in carbonate reservoirs an essential area of research. In the Tazhong area of the Tarim Basin, specifically within the Lower Ordovician stratum exceeding 7000 m, effective reservoirs and industrial liquid hydrocarbon accumulations persist. However, the existence of a depth limit of oil accumulation (DLOA) for oil accumulation in carbonate reservoirs remains unclear, posing a challenge for explorers. This study quantitatively characterizes the critical condition of DLOA in deep carbonate reservoirs from the perspective of hydrocarbon accumulation dynamics. Through comprehensive experimental analysis, statistical assessments, and numerical simulations, it also forecasts the potential for deep oil exploration. Based on the results of mercury injection experiments on 350 carbonate rock cores collected from 19 drilling wells in the deep Lower Ordovician, it was found that the reservoir is compact and exhibits significant heterogeneity. The driving force for oil accumulation is the capillary pressure difference between the surrounding rock and the reservoir. A greater capillary pressure difference indicates improved oil-bearing properties within the reservoir. When the capillary pressure difference between the reservoir and surrounding rock reaches zero, oil accumulation cannot occur, marking the critical condition of DLOA. The critical pore throat radius for DLOA in the deep Lower Ordovician carbonate rocks in the Tazhong area of the Tarim Basin is determined to be 0.01 μm, and the DLOA is estimated at 9000 m. This study confirms that the maximum depth for the embedded Lower Ordovician carbonate reservoir in the Tazhong area does not surpass this limit. Consequently, oil exploration in deep carbonate rocks within this stratum is both feasible and promising. The findings from this study hold significant importance in scientifically predicting favorable areas for oil exploitation in deep layers and offer valuable insights into understanding the oil flow in carbonate rocks.

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“…Clay and other clay-like materials such as dolomite and limestone powder have been widely used as supplementary cementitious material (SCM) in the modern construction industry [7,8,9]. Dolomites are subsurface cements and replacements that form below active phreatic zone reflux and mixing zones in permeable intervals flushed by warm to hot magnesium-enriched basinal and hydrothermal waters [10]. Dolomite is a natural mineral found in seabed and rock deposits among others.…”

Section: Introductionmentioning

confidence: 99%

Mineralogical, Physicochemical and Morphological Characterization of Okpella Clay

Salahudeen

Abodunrin

2021

Mining Revue

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Local clay mineral was mined from Okpella Town, Etsako Local Government Area of Edo State, Nigeria. Mineralogical characterization of the clay was carried out using X-ray diffraction analyzer. Chemical characterization of the clay was carried out using X-ray fluorescence analyzer and the pH analysis of the clay was carried out using pH meter. The mineralogical analysis revealed that the clay was majorly a dolomite mineral having 72% dolomite. The impurities present are 18% cristobalite, 4.1% garnet, 5% calcite and 1% quicklime. The pH analysis of the clay revealed that the clay was acidic having average pH value of 3.9. The pH determined for the 1:1, 1:2, 1:4, 1:8 and 1:10 samples were 3.61, 3.85, 3.85, 4.05 and 4.09, respectively.

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Features and origins of massive dolomite of Lower Ordovician Penglaiba Formation in the northwest Tarim Basin: Evidence from petrography and geochemistry

Cited by 13 publications

References 50 publications

A Nano-Cleaning Fluid for Downhole Casing Cleaning

A Nano-Cleaning Fluid for Downhole Casing Cleaning

Critical Condition of the Depth Limit of Oil Accumulation of Carbonate Reservoirs and Its Exploration Significance in the Lower Ordovician of the Tazhong Area in the Tarim Basin

Mineralogical, Physicochemical and Morphological Characterization of Okpella Clay

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