Design and Verification of a Deep Rock Corer with Retaining the In Situ Temperature

Abstract

Deep rock is always under high-temperature conditions. However, traditional coring methods generally have no thermal insulation design, which introduces large deviations in the guidance required for resource mining. Thus, a thermal insulation design that utilizes active and passive thermal insulation was proposed for deep rock corers. The rationale behind the active thermal insulation scheme was to maintain the in situ core temperature through electric heating that was controlled by using a proportional-integral-derivative (PID) chip. Graphene heating material could be used as a heating material for active thermal insulation through testing. In regard to the passive thermal insulation scheme, we conducted insulation and microscopic and insulation effectiveness tests for hollow glass microsphere (HGM) composites and SiO2 aerogels. Results showed that the #1 HGM composite (C1) had an excellent thermal insulation performance (3 mm thick C1 can insulate to 82.6°C), high reflectivity (90.02%), and wide applicability. Therefore, C1 could be used as a passive insulation material in deep rock corers. Moreover, a heat transfer model that considered multiple heat dissipation surfaces was established, which can provide theoretical guidance for engineering applications. Finally, a verification test of the integrated active and passive thermal insulation system (graphene heating material and C1) was carried out. Results showed that the insulating effect could be increased by 13.3%; thus, the feasibility of the integrated thermal insulation system was verified. The abovementioned design scheme and test results provide research basis and guidance for the development of thermally insulated deep rock coring equipment.

Fidelity Performance Research of Coring Bits during Drilling and Cutting in Deep Extreme Environments

“…Wan et al addressed the limitations of insulated coring and proposed an innovative design of an active insulation system for accurate temperature retention in in-situ fidelity coring of deep rock formations [11]. He et al developed an in-situ fidelity coring system and designed pressure controllers for different coring formations to minimize disturbance during drilling [12][13].…”

Mechanical Characteristics and Macro–Microscopic Response Mechanisms of Cemented Paste Backfill under Different Curing Temperatures

“…With the depletion of shallow mineral resources on the Earth's surface, deep resource mining has become an inevitable trend for development [1,2]. China started deep mining metal ores relatively late, but its development rate has been fast [2,3].…”

“…With the depletion of shallow mineral resources on the Earth's surface, deep resource mining has become an inevitable trend for development [1,2]. China started deep mining metal ores relatively late, but its development rate has been fast [2,3]. Before the 20th century, China had only two metal mines with mining depths close to one kilometer: Tongling Dongguashan Copper Mine in Anhui Province, and Hongtoushan Copper Mine in Liaoning Province.…”

Experimental Study on the Effect of Freeze-Thaw Cycles on the Mechanical and Permeability Characteristics of Coal

“…Energy has been an enduring topic in the ongoing process of social and economic development. Coal, as a primary source of energy, has played an indispensable role from certain perspectives and continues to be a major global energy source [1][2][3][4]. As shallow coal resources are depleted, the geological conditions of deep coal seams become more complex.…”