Research on attenuation rate correlation calibration method based on acoustic variable density logging.

In order to solve the problem of logging calibration without a free pipe in the process of acoustic variable density logging and the subjective problem of the free pipe calibration method, this paper studies an attenuation rate calibration method based on acoustic variable density logging. Using the developed acoustic wave probe response relationship device and the acoustic wave probe calibration device, the response consistency of the receiving probe of the acoustic wave instrument and the frequency of the transmitting probe can be calibrated in the laboratory, and the response consistency and frequency calibration coefficient can be obtained. Through this coefficient, the acoustic wave attenuation rate can be derived.

Experimental Investigation of a C-S-H Nanocrystalline Nucleus Modified with PCE Dispersant on the Early-Age Mechanical Behavior of Oil Well Cement Paste.

For the exploration and development of oil and gas reservoirs in shallow, cold regions and deep oceans, oil well cement (OWC) pastes face the challenge of slow cement hydration reactions and the low early-strength development of cement stone at low temperatures, which can cause the risk of fluid channeling and the defective isolation of the sealing section during the cementing construction process. To address the above challenges, a nanoscale hydrated calcium silicate (C-S-H) crystal nucleus, DRA-1L, was synthesized. Its application performance and action mechanism were studied.

Effects of Postweld Heat Treatment on Interfacial Behavior and Mechanical Properties of Joints Welded with Cu/Ni-Cr Alloy.

Welded cable composed of nickel-chromium (Ni-Cr) alloy and copper is a crucial component in the resistance heating technology used for heavy oil production. Tungsten inert gas (TIG) welding was employed to join the copper and Ni-Cr alloy using copper filler wire, and the stability of the welded joint was analyzed under high-temperature service conditions. We examined the changes in the microstructure and properties of the welded joint after postweld heat treatment (PWHT) at 600 °C for 3, 6, and 12 days.

Evaluation and Optimization of Cement Slurry Systems for Ultra-Deep Well Cementing at 220 °C.

With the depletion of shallow oil and gas resources, wells are being drilled to deeper and deeper depths to find new hydrocarbon reserves. This study presents the selection and optimization process of the cement slurries to be used for the deepest well ever drilled in China, with a planned vertical depth of 11,100 m. The bottomhole circulating and static temperatures of the well were estimated to be 210 °C and 220 °C, respectively, while the bottomhole pressure was estimated to be 130 MPa.

Modified guanidine gel fracturing fluid system and performance optimization for ultra-deep and ultra-high temperature oil and gas reservoirs.

The development of deep high-temperature oil and gas reservoirs gives rise to a rise in reservoir temperature along with the depth of the oil reservoir, thereby imposing higher requirements on the heat resistance of fracturing fluid. Guar gum fracturing fluid has difficulty tolerating temperatures exceeding 160 °C, thereby demanding the development of corresponding cross-linking agents, temperature stabilizers, and other additives to enhance the thermal stability of the fracturing system. Considering the distinctive characteristics of deep and ultra-deep reservoirs, such as extreme burial depth (exceeding 6000 m), ultra-high temperature (higher than 160 °C), and high fracturing pressure, an experimental modification of a guar gum fracturing fluid system was carried out, specifically tailored for ultra-high temperatures.

Constructing Hierarchical Zeolites with Highly Complete Framework via Controlled Desilication.

Desilication in alkaline medium has been widely used in construction of hierarchical zeolites for industrially relevant catalytic processes. The built of hierarchy in zeolites, especially with low aluminum stability or high Si/Al ratio, often suffers from uncontrolled destruction of zeolitic framework, accompanied by a significant loss of microporous domains and intrinsic acidity after desilication. Here, we report a novel and simple methodology for preparation of hierarchical zeolites with highly complete framework and minimum sacrifice of microporosity and acidity.

Molecular characteristics of organic matter derived from sulfonated biochar.

Sulfonated biochar (SBC), as a functional carbon-based material, has attracted widespread attention due to its excellent adsorption properties. The composition of biochar-derived organic matter (B-DOM) is a key factor influencing the migration and transformation of soil elements and pollutants. However, molecular characteristics of sulfonated biochar-derived organic matter (SBC-DOM) are still unclear.

Visible-Light-Mediated Ring-Opening Geminal Dibromination of Alkenes via Alkoxy Radicals Enabled by Electron Donor-Acceptor Complex.

An electron donor-acceptor complex was utilized to generate alkoxy radicals from alcohols under mild conditions using visible light. This approach was combined with a hydroxybromination process to achieve the deconstructive functionalization of alkenes, leading to the production of geminal dibromides. Mechanistic investigations indicated the intermediacy of hypervalent iodine (III) compounds.

Numerical Simulation Study on the Influence of Fracture on Borehole Wave Modes: Insights from Fracture Width, Filling Condition, and Acoustic Frequency.

Unconventional reservoirs, such as shale and tight formations, have become increasingly vital contributors to oil and gas production. In these reservoirs, fractures serve as crucial spaces for fluid migration and storage, making their precise assessment essential. Array acoustic logging stands out as a pivotal method for evaluating fractures.

Host-Guest Interaction Mediated Interfacial Co-Assembly of Cyclodextrin and Bottlebrush Surfactants for Precisely Tunable Photonic Supraballs.

Investigations of host-guest interactions at water-oil (w/o) interfaces are limited in single emulsion systems producing simple self-assembled objects with limited uses. Here, within hierarchically ordered water-in-oil-in-water (w/o/w) multiple emulsion droplets, interfacial self-assembly of (polynorbornene-graft-polystyrene)-block-(polynorbornene-graft-polyethylene glycol) (PNPS-b-PNPEG) bottlebrush block copolymers can be precisely controlled through host-guest interactions. α-Cyclodextrin (α-CD) in the aqueous phase can thread onto PEG side chains of the bottlebrush surfactants adsorbed at the w/o interface, leading to dehydration and collapsed chain conformation of the PEG block.

Pore Structure Evolution and Failure Mechanism of Limestone in the Taiyuan Formation of the Ordos Basin under High Temperature.

The study on the destruction of the limestone microstructure after high-temperature treatment has a significant value in the airtightness and safety of underground high-temperature geotechnical engineering. In order to truly simulate the influence of the underground high-temperature environment on limestone, taking seven groups of limestones of the Taiyuan Formation in the Ordos Basin as examples, we carried out a high-temperature (25-1200 °C) heating experiment of limestone in an argon atmosphere. The pore structure of limestone after the high temperature is studied based on scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), porosity, and permeability, and the change in the fractal dimension of the limestone pore structure was discussed based on the thermodynamic fractal theory, combined with X-ray diffraction (XRD) and thermogravimetry differential scanning calorimetry (TG-DSC), the variation of mineral composition with temperature is characterized, and the evolution mechanism of the limestone microstructure under high temperature is discussed.

Application of a Core-Shell Structure Nano Filtration Control Additive in Salt-Resistant Clay-Free Water-Based Drilling Fluid.

When drilling into a reservoir, the drilling fluid containing bentonite is prone to solid phase invasion, causing serious damage to the reservoir, and the conventional API barite suspension stability is poor, which makes it easy to cause sedimentation and blockage. Therefore, in order to avoid accidents, we use ultrafine barite to obtain a good suspension stability. More importantly, the method of modifying zwitterionic polymers on the surface of nano-silica is used to develop a temperature-resistant and salt-resistant fluid loss reducer FATG with a core-shell structure, and it is applied to ultra-fine clay-free water-based drilling fluid (WBDF).

Atomic Zn-Doping Induced Sabatier Optimum in NiZn Catalyst for CO Electroreduction at Industrial-Level Current Densities.

The Sabatier principle defines the essential criteria for an ideal catalyst in heterogeneous catalysis, while reaching the Sabatier optimum is still challenging in catalyst design. Herein, an elegant strategy is described to reach the Sabatier optimum of Ni electrocatalyst in CO reduction reaction (CO RR) by atomically Zn doping. The incorporation of 3% Zn single atom into Ni lattice leads to the moderate degrade of d-band center via Ni-Zn electronic coupling, which balances the bonding strengths of *COOH and *CO, resulting in a relative low energy barrier for CO activation while not being substantially poisoned by CO.

A New Method for Erosion Prediction of 90° Elbow Based on Non-Axisymmetric Ultrasonic-Guided Wave and the PSO-LSSVM Algorithm.

The non-axisymmetric exciting guided wave can detect the thinning section of the elbow, and the time domain energy value of the signal collected at the outer arch position of the receiving end displays a downward trend as the remaining thickness of the erosion area decreases. To address the difficulty in detecting the erosion degree of the elbow with high accuracy, this paper uses the linear frequency modulation (LFM) signal to excite a non-axisymmetric guided wave that propagates in the 90° elbow and collects signals through four PZT receivers. To predict the erosion degree, the corresponding relationship between the energy value of the four signals after fractional Fourier filtering and the degree of elbow erosion is established through the particle swarm optimization (PSO)-least squares support vector machine (LSSVM) algorithm.

The Effect of Polymer Elastic Particles Modified with Nano-Silica on the Mechanical Properties of Oil Well Cement-Based Composite Materials.

The integrity of oil well cement sheaths is closely related to the long-term production safety of oil and gas wells. The primary material used to form a cement sheath is brittle. In order to reduce the brittleness of oil well cement and improve its flexibility and resistance to stress damage, nano-silica was used to modify polymer elastic particles, and their properties were analyzed.

Chinese Few-Shot Named Entity Recognition and Knowledge Graph Construction in Managed Pressure Drilling Domain.

Managed pressure drilling (MPD) is the most effective means to ensure drilling safety, and MPD is able to avoid further deterioration of complex working conditions through precise control of the wellhead back pressure. The key to the success of MPD is the well control strategy, which currently relies heavily on manual experience, hindering the automation and intelligence process of well control. In response to this issue, an MPD knowledge graph is constructed in this paper that extracts knowledge from published papers and drilling reports to guide well control.

Toxicity of Nanoscale Zero-Valent Iron to Soil Microorganisms and Related Defense Mechanisms: A Review.

Soil pollution is a global environmental problem. Nanoscale zero-valent iron (nZVI) as a kind of emerging remedial material is used for contaminated soil, which can quickly and effectively degrade and remove pollutants such as organic halides, nitrates and heavy metals in soil, respectively. However, nZVI and its composites can enter the soil environment in the application process, affect the physical and chemical properties of the soil, be absorbed by microorganisms and affect the growth and metabolism of microorganisms, thus affecting the ecological environment of the entire soil.

Constructing N,S and N,P Co-Coordination in Fe Single-Atom Catalyst for High-Performance Oxygen Redox Reaction.

Single-atom catalysts (SACs) are promising electrocatalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), in which the coordination environment plays a crucial role in activating the intrinsic activity of the central metal. Taking the FeN SAC as a probe, this work investigates the effect of introducing S or P atoms into N coordination (FeS N and FeP N (x=1-4)) on the electronic structure optimization of Fe center and its catalytic performance. Attributing to the optimal Fe 3d orbitals, FePN can effectively activate O and promote ORR with a low overpotential of 0.

Efficient hydrodeoxygenation of methyl levulinate into pentanoic biofuels over Ru/USY catalysts.

Catalytic hydrodeoxygenation of neat methyl levulinate into pentanoic biofuels is one of the pivotal reactions in biomass valorization. A combined pentanoic acid/methyl pentanoate yield of 92% can be achieved for Ru/USY with a Si/Al ratio of 15 at 220 °C and 40 bar H. The superior performance of Ru/USY-15 for the efficient production of pentanoic biofuels is attributed to the optimal site balance between the Ru species and strong acid sites ( 1 : 5).

Boosting Methanol-Mediated CO Hydrogenation into Aromatics by Synergistically Tailoring Oxygen Vacancy and Acid Site Properties of Multifunctional Catalyst.

Even though the direct hydrogenation of CO into aromatics has been realized via a methanol-mediated pathway and multifunctional catalyst, few works have been focused on the simultaneously rational design of each component in multifunctional catalyst to improve the performance. Also, the structure-function relationship between aromatics synthesis performance and the different catalytic components (reducible metal oxide and acidic zeolite) has been rarely investigated. Herein, we increase the oxygen vacancy (O ) density in reducible Cr O by sequential carbonization and oxidation (SCO) treatments of Cr-based metal-organic frameworks.

Synthesis and Plugging Performance of Nano-Micron Polymeric Gel Microsphere Plugging Agents for Oil-Based Drilling Fluids.

As shale gas recovery progresses to deep layers, the wellbore instability during drilling in applications of oil-based drilling fluids (OBFs) becomes increasingly severe. This research developed a plugging agent of nano-micron polymeric microspheres based on inverse emulsion polymerization. Through the single-factor analysis with respect to the permeability plugging apparatus (PPA) fluid loss of drilling fluids, the optimal synthesis conditions of polymeric microspheres (AMN) were determined.

Molecular Dynamics Insight into the CO Flooding Mechanism in Wedge-Shaped Pores.

Because of the growing demand for energy, oil extraction under complicated geological conditions is increasing. Herein, oil displacement by CO2 in wedge-shaped pores was investigated by molecular dynamics simulation. The results showed that, for both single and double wedge-shaped models, pore Ⅱ (pore size from 3 to 8 nm) exhibited a better CO2 flooding ability than pore Ⅰ (pore size from 8 to 3 nm).

Kinetic Hydrate Inhibition of Natural Gels in Complex Sediment Environments.

Natural gels are emerging as a hotspot of global research for their greenness, environmental-friendliness, and good hydrate inhibition performance. However, previous studies mostly performed experiments for simple pure water systems and the inhibition mechanism in the sediment environment remains unclear. Given this, the inhibition performance of xanthan gum and pectin on hydrate nucleation and growth in sediment environments was evaluated via hydrate formation inhibition tests, and the inhibition internal mechanisms were revealed via a comprehensive analysis integrating various methods.