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As shallow resources are increasingly depleted, the mechanics’ theory and testing technology of deep in-situ rock has become urgent. Traditional coring technologies obtain rock samples without retaining the in-situ environmental conditions, leading to distortion of the measured parameters. Herein, a coring and testing systems retaining in-situ geological conditions is presented: the coring system that obtains in-situ rock samples, and the transfer and testing system that stores and analyzes the rocks under a reconstructed environment. The ICP-Coring system mainly consists of the pressure controller, active insulated core reactor and insulation layer and sealing film. The ultimate bearing strength of 100 MPa for pressure-preservation, temperature control accuracy of 0.97% for temperature-retained are realized. CH4 and CO permeability of the optimized sealing film are as low as 3.85 and 0.33 ppm/min. The average tensile elongation of the film is 152.4% and the light transmittance is reduced to 0%. Additionally, the pressure and steady-state temperature accuracy for reconstructing the in-situ environment of transfer and storage system up to 1% and ±0.2 is achieved. The error recorded of the noncontact sensor ring made of low-density polymer is less than 6% than that of the contact test. The system can provide technical support for the deep in-situ rock mechanics research, improving deep resource acquisition capabilities and further clarifying deep-earth processes.

Using pressure-preserved coring technique to determine in-situ gas content provides a more precise assessment of gas resource reserves and safeguard of mining safety in coal seams. How coring technique and depth affect the determination of gas content is unclear due to borehole zoning rupture caused by roadway excavation and drilling disturbance. To this end, a proposed coupling model of stress distribution and gas migration was simulated and validated by FLAC3D and COMSOL Multiphysics considering superposition effects of roadway excavation and drilling disturbance. The findings indicate that the roadway surrounding rock displays distinct zoning features including stress relief zone, stress concentration zone that is composed of plastic zone, elastic zone, and original stress zone; and the broken situations depending on the borehole peeping are consistent with the corresponding simulation results. On this basis, this study proposes a set of drilling coring depth calculation and prediction model for the gas desorption affected area under engineering disturbance. Optimal depth of coring drilling is not only approach to the in-situ coal bulk, but also can get the balance of the drilling workload and cost controlling. According to the typical mine site geological conditions and the numerical simulation results in this study, if the roadway excavation time is ∼1 year, it is recommended that the pressure-preserved coring depth should be greater than 17 m.

This article focuses on the problem of scaling on the inner wall of the drill pipe during the diamond rope coring drilling process, which affects the smooth salvage of the core. Based on the research results of predecessors at home and abroad, the main factors affecting the scaling on the inner wall of the drill pipe are sorted out systematically, and a calculation program that can calculate the scaling index I and critical diameter Dc conveniently and quickly is developed. The system can propose corresponding anti scaling and descaling measures based on the calculation results. It has been applied on site in engineering, providing useful scientific guidance for engineers to prevent scaling and ensure safe and efficient drilling.

Core samples play a very important role in understanding the characteristics and conditions of rock formation. The coring tool is the primary equipment used to obtain a core sample, which has been widely used in engineering, and oil and gas drilling, for example. In this paper, the models of conventional coring joints and special coring joints are established to study the mechanical properties of the two joints being subjected to makeup torque load. The results show that the design of the special coring tool with double shoulders effectively shares the force on the thread and has a good mechanical performance compared with the conventional single-shoulder coring tool.

A new drilling system was developed by the US Ice Drilling Program (IDP) to rapidly drill through overlying ice to collect subglacial rock cores. The Agile Sub-Ice Geological (ASIG) Drill system is capable of drilling up to 700 m of ice in a continuous manner. Intermittent ice core samples can be taken as needed. Ten-plus meters of subglacial bedrock and unconsolidated, frozen sediment cores can be drilled with wireline core retrieval. The functionality of the drill system was demonstrated in 2016–17 at the Pirrit Hills, Antarctica where 8 m of high-quality, continuous granite core was retrieved beneath 150 m of ice. The particulars of the drill system development, features and performance are discussed.

A novel temperature-preserved core chamber designed for depths exceeding 5000 m has been developed to enhance the scientific understanding of deep oil and gas reservoirs. This temperature-preserved core chamber employs an innovative vacuum layer for temperature preservation and is compatible with a temperature-pressure preserved coring system. The design principles and key parameters of the temperature-preserved core chamber were determined through static analysis. Numerical simulations assessed the mechanical properties of 70, 85, and 100 MPa core chambers under conditions of 120–150 °C. The results demonstrate that the temperature-preserved core chambers withstand the applied stresses without plastic deformation, and the vacuum layer maintains its integrity under these conditions. A 70 MPa class core chamber prototype was manufactured, and system integration tests were performed on a self-developed in-situ coring platform. The system demonstrated stable operation at 70 MPa for 120 min, with pressure fluctuations within 5%. Additionally, the integrated system operated without interference, enabling the successful extraction of cores with a 50 mm diameter. These findings provide valuable theoretical guidance and design recommendations for advancing oil and gas in-situ temperature-pressure preserved coring technologies in high-temperature and high-pressure environments.

Deep oil and gas reservoirs are under high-temperature conditions, but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability, resulting in distorted resource assessments. The development of in situ temperature-preserved coring (ITP-Coring) technology for deep reservoir rock is urgent, and thermal insulation materials are key. Therefore, hollow glass microsphere/epoxy resin thermal insulation materials (HGM/EP materials) were proposed as thermal insulation materials. The materials properties under coupled high-temperature and high-pressure (HTHP) conditions were tested. The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased; additionally, increasing temperature accelerated the process. High temperatures directly caused the thermal conductivity of the materials to increase; additionally, the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity. High temperatures weakened the matrix, and high pressures destroyed the HGM, which resulted in a decrease in the tensile mechanical properties of the materials. The materials entered the high elastic state at 150 °C, and the mechanical properties were weakened more obviously, while the pressure led to a significant effect when the water absorption was above 10%. Meanwhile, the tensile strength/strain were 13.62 MPa/1.3% and 6.09 MPa/0.86% at 100 °C and 100 MPa, respectively, which meet the application requirements of the self-designed coring device. Finally, K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100 °C and 100 MPa. To further improve the materials properties, the interface layer and EP matrix should be optimized. The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.

To understand the long-term climate and glaciological evolution of the ice sheet in the region bordering the Weddell Sea, the British Antarctic Survey has undertaken a series of successful ice core projects drilling to bedrock on Berkner Island, James Ross Island and the Fletcher Promontory. A new project, WACSWAIN, seeks to increase this knowledge by further drilling to bedrock on two further ice rises in this region. In a single-season project, an ice core was recovered to bedrock at 651 m on Skytrain Ice Rise using an ice core drill in a fluid-filled borehole. In a second season, a rapid access drill was used to recover ice chips to 323 m on Sherman Island in a dry borehole, though failing to reach the bedrock which was at an estimated depth of 428 m.

Rapid Access Ice Drill is a new drilling technology capable of quickly accessing the glacial bed of Antarctic ice sheets, retrieving ice core and rock core samples, and providing boreholes for downhole logging of physical properties. Scientific goals include searching for old ice near the glacial bed and sampling subglacial bedrock. During field trials near McMurdo Station on a piedmont glacier at Minna Bluff in the 2019–20 austral summer, we successfully completed a ‘top-to-bottom’ operational sequence in three boreholes by (1) augering through firn, (2) creating a borehole packer seal in non-porous ice, (3) establishing fluid circulation, (4) quickly drilling a borehole in ice at penetration rates up to 1.2 m min−1, (5) acquiring a short ice core at depth, (6) penetrating the glacial bed at a depth of ~677 m, (7) recovering a 3.2 m core of ice, basal till and subglacial bedrock, (8) optically logging the borehole on wireline, (9) testing hydrofracture potential by overpressuring the borehole fluid and (10) operating in an environmentally benign yet rapid field mode. Minna Bluff testing, therefore, demonstrates the effectiveness of this integrated system to drill rapidly through thick ice and penetrate across the glacial bed to take cores of bedrock.

For any commutative ring R, we show that the categories of R-coalgebras and cocommutative R-coalgebras are locally ℵ1-presentable, while the categories of R-flat R-coalgebras are ℵ1-accessible. Similarly, for any associative ring R, the category of R-corings is locally ℵ1-presentable, while the category of R-R-bimodule flat R-corings is ℵ1-accessible. The cardinality of the ring R can be arbitrarily large. We also discuss R-corings with surjective counit and flat kernel. The proofs are straightforward applications of an abstract category-theoretic principle going back to Ulmer. For right or two-sided R-module flat R-corings, our cardinality estimate for the accessibility rank is not as good. A generalization to comonoid objects in accessible monoidal categories is also considered.