查看更多>>摘要：Over the last 10 years,the China Geological Survey has deployed 137 slim-hole shale gas geological exploration wells for coring entire wellbores.These wells are primarily located in new blocks and geological formations where neighboring well data are insufficient,beyond the scope of developed oil fields in China,or outside of oil and gas company mining-right areas.The drilling rig equipment,coring tools,and core drill bits of slim-hole shale gas drilling technology are different from those associated with traditional petroleum drilling.Many studies have been conducted on non-coring slim-hole drilling technology.This paper focuses on coring technology and drilling safety,summarizing a set of high-efficiency shale gas drilling equipment and technology systems based on geological drilling equipment and techniques(that can be used for solid mineral exploration).We report on:1)an improved vertical shaft drilling rig adapted to shale gas well control safety;2)high-efficiency core drilling techniques,focusing on coring tools,and techniques incorporating an inverted tower drilling tool combination,air circulation follow-through technology,and expanded casing technology;3)research progress on high-efficiency core drill bits,including non-planar tooth polycrystalline diamond compact bits and impreg-nated diamond core bits,along with their application effects.This research provides substantial advances in drill-core technology and improvements in exploration efficiency.Moreover,it provides a reference frame for well structural design and selection of construction technology for shale gas exploration drilling projects.
查看更多>>摘要：Enhancing oil recovery from clayey reservoirs is a significant challenge in petroleum industry due to complex interactions between fluids and rock surfaces,particularly clay swelling.This study presents the first empirical analysis of magnetic fields'impact on fluid flow in clayey porous media.Our core findings indicate that magnetic treatment of water increases oil recovery by an average of 15-30％in clayey media,with limited effectiveness in pure quartz media.Detailed experiments unraveled that improved recovery factor by magnetic treatment stem from both mitigated swelling and altered magnetic prop-erties at clay surface;introducing 30％clay to porous medium decreased the recovery by 32％compared to pure quartz sand.Heating the clay to around 1000 ℃ to reduce its swelling property improved the recovery by only 16％,suggesting magnetic treatment is not solely attributed to clay swelling mitigation.Treating ferromagnetic films at clay surface with HCl to produce non-magnetic FeCl3 resulted in a high recovery factor,similar to the clay-free medium.Moreover,it was determined that a magnetic field in-tensity of 43760-51740 A/m is optimal for fluid displacement in clayey media.Notably,the intensity of 47760 A/m increased recovery to 84.5％in a 30％clay medium,compared to 49.7％without treatment.Interestingly,it was observed that the maximum flow rate was associated with zero potential difference across the medium,providing a faster method to determine the optimum magnetic field intensity.Lastly,the concept of'Magnetic memory'was investigated,referring to the persistence of magnetic field's in-fluence after its removal.Our findings indicated that pressure build-up time stability lasted 10 days post-treatment,after which water behavior reverts,and clay swelling resumes.This insight into the temporal dynamics of magnetic field application provides a deeper understanding of its long-term impacts on fluid flow in clayey reservoirs.
Maria Juliana Martins de SouzaAntônio Heverton Martins SilvaJosé Ricardo Pelaquim MendesMarcelo Anunciação Jaculli...
472-480页
查看更多>>摘要：Permanent downhole monitoring systems are responsible for measuring pressure and temperature time series and enable uninterrupted reservoir characterization during the oil field production period,playing a key role in the oil and gas industry.Located in hostile pressure and temperature environments(i)close to the reservoir,in the case of the PDG(Permanent Downhole Gauge)sensor,and(ii)at the wellhead,in the case of the TPT(Pressure and Temperature Transducer)and PT(Pressure Transducer),its data are transmitted from the subsea environment to the Floating Production Storage and Offloading(FPSO),where the Master Control System(MCS)provides the information in engineering format.This infor-mation fulfills its function in the FPSO plant and finally is stored in an onshore data historian.Such complexity,importance,and maintenance difficulty of this system make it necessary to control and manage its reliability.Therefore,the objective of this work is to increase the availability and maximize the useful life of the downhole permanent monitoring system through the reliability calculation,using the Weibull estimate with 2 parameters,and the application of an index quality of statistical inferences.The proposed method for estimating reliability uses a database containing information from permanent downhole monitoring systems of the PDG,TPT,and PT type,from January 1st,2008 to January 9th,2014,and considers only the failures that occur until the arrival of the data in the MCS.From the reliability results,it can be observed that stratifications of this database could generate samples with a smaller number of observations,thus inferring reliability even with a small number of samples.The deepening of this method results in the definition of the minimum sample that allows removing reliability inferences without statistical significance and a quality index that allows classifying the reliability estimates of stratified sets of the largest sample of a database.It is worth mentioning here that both methodologies developed in this work are inserted in a well monitoring system that intends to contribute to increasing the availability of pressure and temperature data for the management of well operations.
查看更多>>摘要：Member 5 of the Upper Triassic Xujiahe Formation(T3X5)in central Sichuan Basin has made a break-through in exploration recently.However,this new stratum has not been investigated sufficiently with respect to basic geology,making its types and distribution of sedimentary facies unclear,which severely restricts its subsequent exploration evaluation.In this study,types of sedimentary microfacies in the first sand group of T3X5(T3X5)are clarified through core observation and logging interpretation using core,log and seismic data,and then distribution of sedimentary microfacies in T3X15 is determined according to seismic waveform features and seismic prediction.The results show that T3X5 in the Dongfengchang area is mainly composed of deltaic deposits of several microfacies,such as delta front underwater distributary channel,sheet sand,and interdistributary bay.On seismic sections,different microfacies are significantly different in waveform features,the underwater distributary channel is characterized by one trough between two peaks,while diversion bay exhibits chaotic reflections between T6 and T51.The sedi-mentary microfacies varied greatly during the depositional period of T3X15 in the Dongfengchang area,this is because that the sediment supply was mainly controlled by the southwest and southeast prov-enance regions.Three superimposed underwater distributary channels are developed in the Dong-fengchang area.The phase-1 superimposed underwater distributary channel in the northwest transition to sheet sand in the northeast,the phase-2 superimposed underwater distributary channel in the south extends shortly,the phase-3 superimposed underwater distributary channel in the northeast has a large development scale.These research findings are helpful to guide the subsequent exploration of T3X5 gas reservoir and also theoretically significant for investigating the depositional evolution of the Xujiahe Formation in central Sichuan Basin.
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