Logging engineering technology

Logging technology is the key technical means of oil and gas resources evaluation, and its core is reservoir effectiveness evaluation, oil and gas reservoir identification and reserve calculation. The serious heterogeneity, diversity of pore structure and low porosity and permeability of marine reservoirs dominated by carbonate rocks make traditional logging interpretation theories, methods and technologies face many challenges and become a worldwide problem in logging evaluation.

The complexity of rock composition and structure, multiplicity of pore space and extremely uneven random distribution of marine reservoirs dominated by carbonate rocks lead to strong heterogeneity, which is more complicated than sandstone reservoirs in petrophysics, seepage physics and even oil and gas distribution. Therefore, the traditional logging theory and many mature evaluation techniques based on homogeneous and isotropic formations often degenerate or even fail in marine oil and gas reservoir exploration. Further optimizing and updating the original logging interpretation theory and exploring new ideas and evaluation methods have become common concerns of logging circles at home and abroad.

The reservoir has low porosity and strong heterogeneity. The logging results of resistivity and porosity are seriously affected by the rock skeleton and pore structure, and the information reflecting the properties of reservoir pore fluid is weak. Due to the deep invasion of mud in fracture system, it is difficult to identify the properties of reservoir fluid.

Complex environmental conditions such as deep, high temperature, high pressure, slim hole and corrosive gas (such as hydrogen sulfide) in offshore oil and gas exploration increase the difficulty of matching logging technology and obtaining all accurate data, especially affecting the application of key technologies such as imaging logging.

The heterogeneity of reservoir, the complexity of rock composition and the characteristics of low porosity affect the accuracy of determining a series of reserve parameters (rock mineral composition, porosity, saturation, effective thickness, etc.). ) and increase the difficulty of reserves calculation, it needs to be optimized from logging interpretation theory and calculation method.

Therefore, we must make full use of the advantages of the development of modern logging technology, apply basic theory to study, optimize and update the traditional logging interpretation theory, and explore new ideas and evaluation methods to cope with the difficulties faced by logging evaluation of marine oil and gas reservoirs with carbonate rocks as the main body. The goal is to form a set of logging theory and method suitable for marine heterogeneous reservoirs, a set of relatively complete and effective reservoir evaluation techniques and instrument series, and improve the efficiency and benefit of marine oil and gas exploration.