A review of coring technology for unconventional geological energy

Abstract:

Against the backdrop of the global energy transition and the in-depth advancement of China''s carbon peaking and carbon neutrality goals， unconventional geological energy has become a core alternative resource， and drilling coring is an important means to obtain accurate physical property parameters of its reservoirs. In view of the complex physical properties of unconventional reservoirs， the specific coring challenges associated with different energy types， and the current situation of existing studies-most of which are classified by energy type and lack a systematic summary of technical commonalities-this paper focuses on technical methodologies， systematically sorting out five major technologies： pressure-retaining coring， shape-preserving coring， large-diameter coring， sealed coring， and downhole freezing coring. The core principles and the current status of domestic and foreign technical applications of each technology are elaborated. The study shows that China has established a coring technology and equipment system with independent intellectual property rights and achieved engineering breakthroughs in scenarios such as deep sea and deep earth. However， the existing technologies still have some challenges， including limited adaptability of a single technology， insufficient capability in responding to extreme environments， and difficulty in balancing efficiency and cost. This paper further analyzes the core challenges in technological development and puts forward the development directions of technical integration， intelligent upgrading， environmental adaptation， green and high efficiency， and in-situ testing providing a systematic reference for technological innovation and engineering practice in this field.