Research on 3D Geological Modeling of in Strongly Heterogeneous Carbonate Water-Bearing Gas Reservoirs

Carbonate reservoirs are influenced by multiple factors such as differential karstification and complex gas water relationships, exhibiting strong heterogeneity and making it difficult to establish high-precision geological models. In view of this, taking the Cambrian Longwangmiao Formation gas reservoir in the Moxi 21 well area of Anyue gas field as the research object, a relatively systematic high-precision 3D geological model was established using static data such as rock cores, logging, and earthquakes. The reliability of the model was verified from two aspects: data error statistics and model distribution trends. The research results indicate that: (1) the physical properties of the gas reservoir show the characteristics of “superior on both sides and poor in the middle”, and the porosity and permeability model is basically consistent with the previous understanding of the gas reservoir; (2) The gas reservoir is an independent fault block that is high in the south and low in the north, with no obvious gas water contact. The gas saturation model shows the characteristics of good gas content in high areas and poor gas content in low areas; (3) The NTG model established based on newly produced NTG logging curves can effectively avoid the generation of a large number of invalid grids and better reflect the true connectivity characteristics of gas reservoirs. Based on the guiding principle of phased property modeling, and using methods such as reconstruction curves, double constraints, and stochastic simulations, the distribution trend of the geological model established is basically consistent with previous understanding. The error between the original data and the model data is less than 10%, and the geological model has a certain degree of reliability, which can provide a basis for future development decisions.