Reservoir-forming by lateral supply of hydrocarbon: A new understanding of the formation of Ordovician gas reservoirs under gypsolyte in the Ordos Basin

AbstractThere developed thick gypsum-salt strata in the Lower Paleozoic Ordovician in the Ordos Basin, particularly gypsum-salt in the 6th segment of the 5th member of Majiagou Fm (O1m56) in a wide distribution, serving as a good regional cap. Recent drilling and relevant studies have proven that the hydrocarbon-generating capacity of the marine-facies hydrocarbon source rocks under the Ordovician salt layers in the eastern Basin is poor on the whole, making it difficult to form ”self-generating and self-preserving type” commercial gas reservoirs under the salt layer in Mizhi salt subsag. However, further research on reservoir-forming conditions under the gypsolyte on the west side of the salt subsag indicates that the O1m57 – O1m510 strata near the east side of the palaeo-uplift contact directly with the Upper Paleozoic coal measure source rocks, forming a “hydrocarbon supply window”; the Yanshan Movement caused the tectonic inversion of the basin main body, resulting in the tectonic framework “high in the east and low in the west”, which is conductive to the further migration of natural gas generated by the Upper Paleozoic coal measures to the updip high position of the east side along the O1m57 – O1m510 carrier beds after entering the dolomite reservoir under the gypsolyte through the “hydrocarbon–supply window”. In addition, the facies changes in the dolomite rocks under the gypsum-salt provide favorable barrier condition for the regional gathering of natural gas. Therefore, it is concluded through comprehensive analysis that reservoirs may form beneath the Ordovician gypsolith in the central region of the basin on the west side of the salt subsag with hydrocarbon supplied from the Upper Paleozoic source rocks of coal measures, which is expected to open up a new situation of natural gas exploration under the Ordovician gypsum-salt layer in the Ordos Basin

Visual Cortex Inspired CNN Model for Feature Construction in Text Analysis

Recently, biologically inspired models are gradually proposed to solve the problem in text analysis. Convolutional neural networks (CNN) are hierarchical artificial neural networks, which include a various of multilayer perceptrons. According to biological research, CNN can be improved by bringing in the attention modulation and memory processing of primate visual cortex. In this paper, we employ the above properties of primate visual cortex to improve CNN and propose a biological-mechanism-driven-feature-construction based answer recommendation method (BMFC-ARM), which is used to recommend the best answer for the corresponding given questions in community question answering. BMFC-ARM is an improved CNN with four channels respectively representing questions, answers, asker information and answerer information, and mainly contains two stages: biological mechanism driven feature construction (BMFC) and answer ranking. BMFC imitates the attention modulation property by introducing the asker information and answerer information of given questions and the similarity between them, and imitates the memory processing property through bringing in the user reputation information for answerers. Then the feature vector for answer ranking is constructed by fusing the asker-answerer similarities, answerer's reputation and the corresponding vectors of question, answer, asker and answerer. Finally, the Softmax is used at the stage of answer ranking to get best answers by the feature vector. The experimental results of answer recommendation on the Stackexchange dataset show that BMFC-ARM exhibits better performance

Pore Structure of Surfactant Modified Montmorillonites

A series of organoclays with different surfactant arrangements were prepared by ion exchange. The resulting organoclays were investigated using a combination of characterization techniques, including XRD, FTIR, TG and N2 adsorption-desorption. In the present study, the pores within the organoclays were discussed on the basis of the microstructural parameters, including BET-N2 surface area, pore volume, pore size, surfactant loading and distribution. The results show that both BET-N2 surface area and pore volume decrease from low to high packing density of the surfactant as the average pore size increases. Two basic organoclay models were proposed for hexadecyltrimethylammonium bromide (HDTMAB) modified montmorillonites: 1) the surfactant mainly occupied the clay interlayer and 2) both the clay interlayer space and external surface were modified by surfactant. This study demonstrates that the pore structure of the resulting organoclays has a significant influence on the sorption efficiency and mechanism of p-nitrophenol onto the organoclays