Research status and development trend of fractures in carbonate reservoir

Abstract

Fractures have a great impact on the oil and gas production of carbonate reservoirs.Much previous research have been done on the classification, genesis, controlling factors, identification and prediction of fractures in carbonate reservoirs.It is concluded that the classification, nomenclature and the meaning of some non-structural fractures are still controversial.The causes of fractures include tectonism, diagenesis, abnormal high pressure, denudation and weathering.The mechanism of grain size and porosity on the development of structural fractures still needs further study.Sedimentary facies has a certain influence on the development of structural fractures, but the lithology of the same sedimentary facies is complex, thus it is difficult to accurately reveal the formation mechanism of fracture development.Direct study on the influence of lithology on fracture development is more significant to reveal the fracture formation mechanism.The study of fractures based on diagenetic evolution sequence provides a basis for further discussion of controlling mechanism of rock on the fracture development.The controlling factors of the development of non-structural fractures such as bedding-parallel fractures, stylolites, abnormal high pressure fractures and dissolution fractures need to be further studied.In recent years, seismic has made little breakthrough in the field of fracture identification, and acoustic far detection technology has become the most potential technology in the field of unconventional logging.Fracture identification by conventional logging has always been the hot issue, and more than 40 different methods have been proposed by previous workers.Fracture prediction by using logging and seismic has the best reliability and it is the mainstream fracture prediction technology at present.Standardizing fracture classification, sorting out fracture genesis, deepening the study of the formation mechanism of structural fracture, strengthening the discussion of controlling factors of non-structural fracture, improving the fracture recognition rate of conventional well logging and predicting reservoir fracture by integrating existing fracture prediction technology are the important development directions of fracture research in the future.

Keywords

• carbonate rock
• fracture
• classification and genesis
• main controlling factor
• identification and prediction