| 2 | Lithofacies Characters and Significance of the Submarine Fan of the Liufengguan Group in Qinling显示文摘Field investigation and laboratory research on flysch of the Liufengguan Group in Qinling indicate the following:(1) Sandstone of the Liufengguan Group is categorized as feldspathic lithic graywacke with a minor amount of lithic graywacke in the QFR triangular diagram.Grain size≤0.3 mm.Bedding plane structures such as groove casts and suspected flute casts can be found at the bottom of the sandstone.It is inferred that currents may have come from the southeast during deposition.Bedding structures such as ripple marks,graded bedding,parallel bedding,small-scale cross bedding,climbing bedding,suspected convolute bedding,microlamination and sliding structures have also been observed,which are of indicative significance.It is thought that the Liufengguan Group has the sedimentary characteristics of bedding,bedding plane structures and lithological assemblages of deep-sea low-density turbidity current deposits.The vertical succession of the Bouma sequence in the inner fan subfacies zone is generally incomplete:the assemblage of Ta and Tabc is commonly seen;the succession of the middle fan subfacies zone is relatively complete;and divisions Te and Tb are common in the outer fan subfacies zone.(2) The flysh of the Liufengguan Group is a sequence of deep-sea argillaceous-arenaceous submarine fan deposits,in which the authors recognize the inner,middle and outer fan subfacies and also nine types of lithofacies:normal graded sandstone(A1),medium-to thick-bedded,fine-grained sandstone(A2),medium-to thick-bedded and massive siltstone(A3),thin-bedded,fine-grained sandstone and mudstone(B1),irregular interbeds of thin-bedded,fine-grained sandstone and siltstone(B2),thin-bedded,fine-grained sandstone(C1),very thin-bedded,fine-grained sandstone(D1),olistostromes(E1) and deep-sea mudstone(F).The inner fan consists of four microfacies:natural levee(A1),water channel(A2,A3) and olistostrome(E1);in the middle fan there also occur four microfacies,i.e.,branch channel(B1),branch channel(B2),interdistributary bay(D1) and olistostrome.The outer fan is made up of the branch channel(C1) and sheet sand(D1) microfacies,which alternate vertically with sediments of deep-sea plain subfacies(F).There occur fining-and thinning-upward channel deposits in the outer-fan subfacies zone of the submarine fan of the Liufengguan Group observed in this study.The quartz content of the graywacke of the deposits is all higher than 40% and may reach as high as 60%.Therefore,on the basis of the aforementioned features,this flysh should be formed in a passive continental-margin tectonic environment. | ZHENG Ning LI Tingdong YOU Guoqing ZHANG Shuanhou CUI Jiantang CHENG Muwei | 2012 | Acta Geologica Sinica(English Edition)2012,86,1: | 2 |
| 3 | Stress sensitivity of carbonate gas reservoirs and its microscopic mechanism显示文摘In order to evaluate the stress sensitivity of carbonate reservoirs,a series of rock stress sensitivity tests were carried out under in-situ formation temperature and stress condition.Based on the calibration of capillary pressure curve,the variable fractal dimension was introduced to establish the conversion formula between relaxation time and pore size.By using the nuclear magnetic resonance(NMR)method,the pore volume loss caused by stress sensitivity within different scales of pore throat was quantitatively analyzed,and the microscopic mechanism of stress sensitivity of carbonate gas reservoirs was clarified.The results show that fractures can significantly affect the stress sensitivity of carbonate reservoirs.With the increase of initial permeability,the stress sensitivity coefficient decreases and then increases for porous reservoirs,but increases monotonously for fractured-porous reservoirs.The pore volume loss caused by stress sensitivity mainly occurs for mesopores(0.02–0.50μm),contributing more than 50%of the total volume loss.Single high-angle fracture contributes 9.6%of the stress sensitivity and 15.7%of the irreversible damage.The microscopic mechanism of the stress sensitivity of carbonate gas reservoirs can be concluded as fracture closure,elastic contraction of pores and plastic deformation of rock skeleton. | CHENG Youyou GUO Chunqiu CHEN Pengyu SHI Haidong TAN Chengqian CHENG Muwei XING Yuzhong LUO Xiang | 2023 | Petroleum Exploration and Development2023,50,1: | 0 |
| 4 | A new-generation Embedded Discrete Fracture Model calibration workflow applied to the characterization of complex naturally fracture reservoir显示文摘Characterizing natural fractures has a decisive effect on production forecasts in fractured oil and gas reservoirs.Discrete Fracture Networks(DFN)constitutes the main modeling framework for fractured geosystems.However,myriads of uncertainties are enclosed prior modeling representative stochastic or deterministic DFN ensembles.This paper presents a novel methodology for DFN calibration and an efficacious field application,which incorporatesWell-testing interpretation,Embedded Discrete Fracture Model(EDFM)framework,and numerical reservoir simulation.The proposed workflow starts with the DFN generation from seismic data,imaging logging data and core data.After multiple DFNs are modeled,well-test analysis is employed to calibrate the intrinsic properties of fractures at different locations.Then,these fracture networks are characterized dynamically by EDFM,which promotes capturing the optimal fracture model quickly screened.Finally,pressure and production history match are reached for the DFN realization that honors the optimal fracture model. | Hongbing Xie Mauricio Fiallos Torres Penyu Cheng Wei Yu Yuzhong Xin Jijun Miao Muwei Cheng | 2022 | Petroleum Research2022,7,1: | 0 |