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Ge X.,China University of Petroleum - East China | Fan Y.,China University of Petroleum - East China | Cao Y.,China University of Petroleum - East China | Xu Y.,China University of Petroleum - East China | And 2 more authors.
Applied Magnetic Resonance | Year: 2014

The carbonate reservoir has a number of properties such as multi-type pore space, strong heterogeneity, and complex pore structure, which make the classification of reservoir pore structure extremely difficult. According to nuclear magnetic resonance (NMR) T2spectrum characteristics of carbonate rock, an automatic pore structure classification and discrimination method based on the T2spectrum decomposition is proposed. The objective function is constructed based on the multi-variate Gaussian distribution properties of the NMR T2 spectrum. The particle swarm optimization algorithm was used to solve the objective function and get the initial values and then the generalized reduced gradient algorithm was proposed for solving the objective function, which ensured the stability and convergence of the solution. Based on the featured parameters of the Gaussian function such as normalized weights, spectrum peaks and standard deviations, the combi-natory spectrum parameters (by multiplying peak value and normalized weight for every peak) are constructed. According to the principle of fuzzy clustering, the carbonate rock pore structure is classified automatically and the discrimination function of each pore structure type is obtained using Fisher discrimination analysis. The classification results were analyzed with the corresponding casting thin section and scanning electron microscopy. The study shows that the type of the pore structure based on the NMR T2 spectrum decomposition is strongly consistent with other methods, which provides a good basis for the quantitative characterization of the carbonate rock reservoir pore space and lays a foundation of the carbonate rock reservoir classification based on NMR logging. © Springer-Verlag Wien 2014. Source

Cui M.-W.,China University of Petroleum - East China | Cao X.-W.,China University of Petroleum - East China | Feng Z.-Y.,Research Institute of Shaanxi Yanchang Petroleum Group
Chuan Bo Li Xue/Journal of Ship Mechanics | Year: 2014

The failure pressure of oil and gas pipeline with different morphology of corrosion pits was analysed by using the nonlinear finite element method. The impact of the cross-section area of corrosion pit on pipeline failure pressure with the axial and circumferential corrosion was researched. The analysis showed that the cross-section area of corrosion pits seriously influenced the failure pressure of pipeline with axial corrosion, however, which was not enough to fully describe the effects of the morphology of corrosion pits on pipeline failure pressure. The research considered the effects of the morphology of corrosion pits by using the cross-section area of corrosion pit and form factor of corrosion pit to descripe on pipeline failure pressure, and proposed a new B31G correction formula. The results show that forecast error and the fluctuation range of the error are little using the formula. Source

Dong Z.,Northwest University, China | Wang X.,Research Institute of Shaanxi Yanchang Petroleum Group | Liu Z.,Northwest University, China | Xu B.,Northwest University, China | Zhao J.,Northwest University, China
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2013

This paper presented a series of anion-nonionic surfactants with different hydrophobic tails and hydrophilic head-groups. Changes in physic-chemical properties of these products and their influencing factors were carefully studied. The CMC (critical micelle concentration) ranges from 1.1×10-2 mass% for NPS-4 to 4.8×10-2 mass% in the case of NPS-10. The values (γcmc) of surface tension at CMC are from 31.62mNm-1 for NPS-4 to 44.50mNm-1 for AES-9. Maximum surface excess concentration (Γmax) was more than 0.73×10-6molm-2and minimum area per molecule at the water/air interface (Amin) was less than 2.270nm2 molecule-1. Results show that CMC and γcmc were efficiently improved, and the ability of reducing equilibrium interface tension (IFTeq) was weakened due to the increasing of repeat units. The study demonstrated that the detergents with the additional rigid group in the hydrophobic tail had a higher CMC than those with the alkyl chain. In addition, we figured out some IFTeq results of the surfactants solution under the influence of alkaline/salt. Ultra-low IFTeq can be obtained only when the concentration is greater than the optimal value of alkaline/salt. Dynamic interface tension (IFTdy) was analyzed and a hypothetical mechanism was used to explain the interesting phenomena IFTdy. © 2012 Elsevier B.V. Source

Yu B.,Research Institute of Shaanxi Yanchang Petroleum Group
Northwestern Geology | Year: 2016

In east-southern Ordos basin, the Styles of third-order sequence boundary in Upper Pa-leozoic strata within can be districted as seven styles, including regional unconformity, structural system transformation surface, regional regression surface, channel erosion surface, regional leakage surface, coal bed, overlay-style transformation surface between limestone bottom and strata. Based on the analysis of sequence boundary characteristic, the Paleozoic stratigraphy, from Benxi Formation to Shihezi Formation, can be divided into two second-order sequences, namely the one (SSI) includes Benxi Formation, Taiyuan Formation and Shanxi Formation, the other (SS2) includes Shihezi Formation. Every second-order sequence is dominated by tectonic, including regional transgression and regression cycles. The second-order sequence can be divided into 11 third-order sequences, that is two third-order sequences CSQ1 and SQ2) in Benxi Formation, one (SQ3) in Taiyuan Formation, two (SQ4 and SQ5) in Shanxi Formation, six (SQ6 and SQ11) in Shihezi Formation. In which, the sequences of SQ1-SQ5 are marine and marine-conti-nental sediments, while SQ6-SQ11 are lacustrine sediments on continental. With the characteristic of sequence stratigraphy, the sequence-filling model in east-southern Ordos Basin has been established in this paper, which has a guiding significance for further research in sedimentary system evolution, reservoir formation and gathering for gas. Source

Li S.-W.,Northwest University, China | Gao R.-M.,Research Institute of Shaanxi Yanchang Petroleum Group | Zhang R.-L.,Northwest University, China | Zhao J.-S.,Northwest University, China
Fuel | Year: 2016

A catalyst system designed by a kind of hybrid material POM@MOF-199@MCM-41 (PMM) was found by a one pot and POM template self-construction of MOF-199 in the pore of MCM-41. This catalyst was exploited to act as a stable heteropolyacid-based one in the direct oxidative desulfurization process with a feedstock of model oil under O2 as oxidant. Based on optimal conditions, the DBT conversion reached up to 98.5% and the PMM could be recycled ten times with a slight decrease, which was compared with heteropolyacid only based on MOF-199 and MCM-41, respectively. Additionally, the structure of ordered nano-sized pores of MOF-199 with POM encapsulated in was clear under crystal analysis, which offered strong evidences for the further movement into the MCM-41. © 2016 Elsevier Ltd Source

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