Techniques and Application of Gravity Survey with High Accuracy in People's Republic of China

摘要

Researches on high accuracy gravity survey have been fulfilled according to the System En-gineering principle by the Ministry of Geology and Mineral Resources in China since late 1970s. Great progress has been made in methods and techniques. The national gravity system has been set up. Anomaly precision was improved to tens times using aerial photography and GPS techniques, we have perfected the high accuracy terrain correction with multi-sections of numeric terrain in mountainous areas, evaluation for correction errors, iterative interpre-tation for 3D density model with multifacets, direct processing and interpretation over a 3D curved surface, microgravity prospecting, engineering survey, and gravity & models data base. Considering 'concepts* further, we discussed the colony effect of multi-density bodies, found out the constraint conditions of four types with three classes for inversion, and put forward the interpretation strategies for 3D fitting with multi-constraints and for synthetic geophysical models. The application effect on some fields are obvious. During the past ten years, we have surveyed for 6,900,000 km2and submitted corresponding gravity reports and maps. New ideas have been got in crust—mantle structure, geological structure units, regional ore-controlling factors, and direct or indirect prospecting. Results in oil and gas exploration are quite successful. Microgravity has been successfully adopted to predict oil reservoir under good conditions. Good effect on probing the holes and appraising the stability on some engi-neering bases has also been achieved.