Abstract: In a method for statistical analysis of aggregate encrypted data with key-leakage resilience for smart grids, every user area is managed by a fog node which plays the role of data aggregation gateway and data relay. All the users' electricity consumption data sent by smart meters in the same user area are firstly aggregated by the fog node to generate a fog-level aggregate ciphertext. Then the fog node further generates a digital signature for the fog-level aggregate ciphertext and sends these data to a cloud server for long-time storage. The cloud server stores all the aggregate ciphertexts and digital signatures received from different user areas in its database, and provides data query and statistical analysis services for the control center of smart grids. On the premise of without violating users' privacy, the cloud server could provide enough information for the control center, enabling it to compute the sum, arithmetic mean and variance of all users' data in specified areas in a privacy-preserving way.

Abstract: A calculation system for predicting a proppant embedding depth based on a shale softening effect is provided, including a sampling test terminal, a scheduling module, a monitoring module, and a calculation module, wherein the scheduling module, the monitoring module, and the calculation module are connected in communication, and the monitoring module is connected to an external operating system through a wireless network, wherein the external operating system is configured to perform a hydraulic fracturing operation and receive a first control signal and/or a second control signal from the monitoring module. The sampling test terminal is configured to test the samples and obtain test data. The scheduling module is configured to determine a target construction parameter.

Abstract: A quantitative evaluation method for integrity and damage evolution of a cement sheath in an oil-gas well is provided based on a fractal theory, an image processing technology, structural features and failure mechanisms of a casing-cement sheath-formation combination. The method uses correlations among fractal dimensions of casing-cement sheath interface morphology, cement sheath microscopic pore morphology, particle morphology of an initial blank group, and macroscopic mechanical properties including a radial cementing strength of the cement sheath interface, a tensile strength, and a compressive strength to quantitatively evaluate the integrity of the cement sheath of the blank group.

Abstract: A patching construction method using a hydraulic variable-grade expansion tool for blocking during drilling is provided, which includes a conversion joint, a supporting central pipe, a supporting ring, an expansion pipe, pressure gradient piston subs, double female thread connection subs, T-shaped limiting subs, a tapered centering sub, double male thread central shafts, split supporting subs, an expansion cone, a piston sub with male and female threads, a T-shaped ball compressor, a lower U-shaped pressing sleeve, a ball-seat fixing sleeve, a reciprocating spring, a sealing ball seat, a sealing ball, a tapered guide sub, etc.

Abstract: The present disclosure provides a method for experimentally determining a critical sand-carrying gas velocity of a shale gas well. The method includes: collecting well structure and production data, calculating parameter ranges of a gas flow velocity and a liquid flow velocity; carrying out a physical simulation experiment of sand carrying in the shale gas well to obtain the sand holding capacity of the wellbore under different experimental conditions, and calculating a sand holding rate; by observing a change curve of the sand holding rate of the wellbore vs. the gas flow velocity, defining a turning point, and sensitively analyzing the influence of other experimental variables on the turning point, to calculate the critical sand-carrying production of the shale gas well under different conditions. Therefore, this calculation method is simple and applicable, and provides a theoretical basis for the optimization design of water drainage and gas production process.

Abstract: A method for predicting a size range of a lost circulation channel based on deep learning (DL) is provided. The method includes the following steps: S1: acquiring data of the lost circulation channel, and establishing a prediction dataset of the size range of the lost circulation channel; S2: preprocessing the prediction dataset of the size range of the lost circulation channel, and determining the size range of the lost circulation channel; S3: establishing a prediction model for the size range of the lost circulation channel; and S4: optimizing the prediction model for the size range of the lost circulation channel, and predicting the size range of the lost circulation channel. The method overcomes the shortcomings of conventional methods, for example, the prediction value of the size of the downhole lost circulation channel is single, inaccurate and not real-time.

Abstract: Disclosed is a method and device for determining characteristics of metallic casing and casing attenuation, the method includes the following steps: obtaining the ratio of first magnetic field with metallic casing and without metallic casing at DC mode; obtaining magnetic related parameter of the metallic casing; obtaining magnetic permeability of metallic casing; obtaining the ratio of second magnetic field with metallic casing and without metallic casing at AC mode; obtaining electrical related parameter of the metal casing through the ratio of the second magnetic field and the magnetic related parameter of the metal casing; obtaining electrical conductivity of metallic casing through the electrical related parameter; obtaining casing attenuation of metallic casing through the magnetic related parameter and the electrical related parameter. The beneficial effect of this disclosure is: this method can obtain characteristics and casing attenuation of metallic casing without measuring impedance.

Abstract: The disclosure relates to an omni-directional horizontally oriented deflecting tool for a coiled tubing, which includes an inner central pipe, an outer central pipe, a conical outer cylinder, a piston outer cylinder, an anchoring mechanism, a sealing mechanism, a reversing mechanism and a steering mechanism. The anchoring mechanism includes a cone, an O-shaped sealing ring I, a cone spring, a slip, a slip spring, a slip seat, a claw I and a pin shaft I, and the sealing mechanism includes a piston, an O-shaped sealing ring II, a claw II, a pin shaft II, an upper rubber cylinder seat, a rubber cylinder, a connecting cylinder, a lower rubber cylinder seat and a gasket.

Abstract: A a plant composite corrosion inhibitor for an oil field and a preparation method thereof belong to the technical field of preparation of oil field chemical agents. The plant composite corrosion inhibitor comprises a first plant ingredient, a second plant ingredient, a corrosion inhibition synergist and an organic solvent. The first plant ingredient is zeaxanthin and a derivative thereof obtained by supercritical CO2 extraction of marigold; the second plant ingredient is prepared from luffa leaves, guava leaves and eclipta according to a mass ratio of 5:8:9; the corrosion inhibition synergist is prepared by mixing potassium iodide, 8-hydroxyquinoline and sodium dodecyl benzene sulfonate according to a mass ratio of 3:4:2; and the organic solvent is ethanol with a mass concentration of 82%. The composite corrosion inhibitor has a good corrosion inhibition effect, and reduces harmful chemical ingredients in the corrosion inhibitor.

Abstract: A device for simulating carbon dioxide storage in a deep saline aquifer, including a CO2 gas source, first and second valves, first and second pressure pumps, first, second and third pressure gauges, a water storage tank, a simulation box, a first flow meter, a gas-liquid separator, a recycling tank, a microcomputer-display assembly, a structure plate, core holders, an injection pipeline, a connection pipeline, a baffle, a piezometer, a second flow meter, a heater, a lifter and an acoustic logging tool. The CO2 gas source, the first valve, the first pressure pump and the first pressure gauge for gas injection. The water storage tank, a second pressure pump and a second pressure gauge for water injection. The second valve, the third pressure gauge, the first flow meter, the gas-liquid separator and the recycling tank form an output pipeline.

Abstract: The embodiment of the present disclosure provides an imaging method for a dispersion energy spectrum of surface waves, an electronic device, and a storage medium. The imaging method includes: obtaining first surface wave data, and the first surface wave data corresponding to a space-time domain representation; processing the first surface wave data to obtain the second surface wave data, and the second surface wave data corresponding to a space-frequency domain representation; and processing the second surface wave data based on a preset algorithm to obtain a first imaging result, the first imaging result corresponding to a slowness-frequency domain representation.

Abstract: A high-frequency composite impactor including a high-frequency axial and a torsional impact assembly is disclosed. The high-frequency axial impact assembly includes an upper self-excited oscillation cavity, a lower self-excited oscillation cavity, an adjustment block and a lock nut. The torsional impact assembly includes an upper end cover, a reversing switch, a pendulum, a lower shell, a lower end cover, a nozzle, a connecting block and a retaining ring. The high-frequency axial impact assembly converts the flowing drilling fluid into a pulsed jet to achieve a high-frequency axial impact. The torsional impact assembly enables a torsional impact through a shunt, and finally enables a high-frequency composite impact, which can effectively reduce the stick-slip of the drill string, jump drilling and other downhole accidents. By reducing the friction between the drill string and the borehole wall, the impactor can reduce WOB loss, increase the ROP, and improve the drilling efficiency.

Abstract: A comprehensive geological-engineering classification evaluation method for low-permeability reservoirs, includes: constructing geological classification evaluation indexes of a reservoir: adopting gray correlation method to obtain main controlling factors of reservoir geology of the low-permeability reservoirs that affects fracturing effects; based on the main controlling factors of the reservoir geology, constructing the geological classification evaluation indexes of low-permeability reservoirs by principal component analysis; constructing engineering classification evaluation indexes of the reservoir: adopting gray correlation method to obtain main controlling factors of geomechanics of the low-permeability reservoirs that affects fracturing effects; based on the main controlling factors of geomechanics, constructing the engineering classification evaluation indexes of low-permeability reservoirs by an analytic hierarchy process; and according to classification limit values of the geological classificatio

Abstract: The present disclosure provides a particle size statistical method of granular minerals of shale, comprising: collecting shale samples; cutting the collected samples into the size of 1 cm×1 cm×1 cm; performing argon ion polishing; magnifying the samples by the field emission scanning electron microscopy, collecting 500-1000 images; using Adobe Photoshop to seamlessly splice the collected images; using ImageJ in combination with EDS energy spectrum to determine types of mineral particles, performing background subtraction, and setting a reasonable grayscale threshold to classify the particle minerals; performing binary processing on the images of selected mineral particle types; identifying edges of granular minerals, and using a Analyze Particles command to statistically analyze and measure particle sizes, and drawing a particle size distribution histogram.

Abstract: A method for quantitatively analyzing the reservoir formation of an ultra-deep evaporite-dolomite paragenesis system is performed as follows. A typical drilling core containing the evaporite-dolomite paragenesis system and a field section are observed. The logging data is subjected to single-factor analysis to determine the planar distribution regularity of the ultra-deep evaporite and the dolomite, and the analysis of sedimentary combination pattern and development evolution regularity is performed. The diagenetic system is determined, and the reservoir formation of the evaporite-dolomite paragenesis system is analyzed. Based on the above technical solutions, the property, the evolution path and the reservoir formation of sedimentation-diagenesis fluids in the evaporite-dolomite paragenesis system can be clarified.

Abstract: A supramolecular star-shaped polymer with ?-CD as a core and a preparation method thereof. The supramolecular star-shaped polymer with ?-CD as a core has a ?-cyclodextrin-modified branched monomer F-?-CD that serves as a core and is grafted with acrylamide, acrylic acid, hydrophobic monomers and surface-active macromolecular monomers to form a supramolecular star-shaped polymer. The hydrophobic monomer is one or more of N-benzyl-N alkyl (meth) acrylamide and N-phenethyl-N alkyl (meth) acrylamide; the surface-active macromolecular monomer is one or more of allyl polyoxyethylene ether, alkylphenol polyoxyethylene ether (meth)acrylate, allyl alkylphenol polyoxyethylene ether, alkyl alcohol polyoxyethylene ether (meth)acrylate and allyl alkyl alcohol polyoxyethylene ether. The method has cheapness and easiness to obtain raw materials, ease to control synthesis conditions, and high yield.

Abstract: A high-frequency composite impactor including a high-frequency axial and a torsional impact assembly is disclosed. The high-frequency axial impact assembly includes an upper self-excited oscillation cavity, a lower self-excited oscillation cavity, an adjustment block and a lock nut. The torsional impact assembly includes an upper end cover, a reversing switch, a pendulum, a lower shell, a lower end cover, a nozzle, a connecting block and a retaining ring. The high-frequency axial impact assembly converts the flowing drilling fluid into a pulsed jet to achieve a high-frequency axial impact. The torsional impact assembly enables a torsional impact through a shunt, and finally enables a high-frequency composite impact, which can effectively reduce the stick-slip of the drill string, jump drilling and other downhole accidents. By reducing the friction between the drill string and the borehole wall, the impactor can reduce WOB loss, increase the ROP, and improve the drilling efficiency.

Abstract: The present disclosure provides a TOC prediction method for shale gas reservoirs, including: determining by well-seismic calibration a top interface Ttop and a bottom interface Tbottom of the shale gas reservoirs, and performing layer tracking in the entire area; converting the pre-stack CRP gather into angle gather seismic data; performing spectral shaping processing on the pre-stack migration pure wave seismic data; establishing an initial model, and then performing pre-stack simultaneous inversion to obtain P-wave impedance, S-wave impedance, primary-to-shear wave velocity ratio and density data volume; obtaining a TOC inversion volume A through a post-stack inversion; obtaining a TOC inversion volume B by calculation; then adding the well data for correction, and finally determining a planar distribution law of TOC content. The method can eliminate the multiple solutions of pre-stack inversion and improve the accuracy of TOC content prediction of shale.

Abstract: The present invention discloses a sand control device for marine hydrate production, which comprises a top motor, a bottom motor, and an inner-layer sand control cylinder, an outer-layer sand control cylinder and an outer-layer sand control screen coaxially arranged from inside to outside, wherein the top motor and bottom motor are configured to control the inner-layer sand control cylinder and the outer-layer sand control cylinder to rotate reversely, and wherein a plurality of sand retaining balls are provided between the inner-layer sand control cylinder and the outer-layer sand control cylinder and between the outer-layer sand control cylinder and the outer-layer sand control screen. According to the present invention, the arrangement of the inner-layer sand control cylinder and the outer-layer sand control cylinder rotating reversely can effectively prevent formation sand from accumulating on the surface of a sand control screen pipe and blocking the sand control screen pipe.

Abstract: A method for detecting a borehole caving based on cuttings and elements logging data includes: integrating real-time elements logging data and real-time cuttings return data of a target well, and historical elements logging data and stratum evaluation data of an adjacent well; calculating a root mean square deviation (RMSD) ? of a relative content of each element of the target well and the adjacent well and a real-time cuttings return ratio; setting a threshold ? of the RMSD ? of the relative content of each element and a threshold range (a,b) of the real-time cuttings return ratio; and establishing an intelligent stratum identification model based on a support vector machine (SVM) for real-time determination of a horizon from which current cuttings are returned. The method can achieve effective borehole caving detection, such that on-site personnel can deal with borehole caving in time and prevent it from developing into a complicated drilling accident.