Abstract: A block in the South China Sea is a major development area for the eastern South China Sea Oilfield.Its principal reservoir-a Pre Paleogene buried-hill formation-presents complex geology,challenging stimulation,and limited research data.To improve development efficiency,an integrated geo-engineering research approach was adopted,combined with deep diagenesis theory on the existing geological model of the buried-hill reservoir.And an analysis was made on the deep diagenetic environment,stress-strain response characteristics,and geological-mechanical modeling research was conducted.A multi field coupled artificial fracture network model and an unstructured grid reservoir productivity simulation model were developed to simulate and analyze how engineering parameters affected the geometry of hydraulic fractures and production performance,allowing optimization of these parameters.The results showed that the geological mechanical modeling method based on deep diagenesis theory could effectively restore the reservoir′s true diagenetic environment and clearly quantify the relationships between injection parameters (injection volume,fluid volume, proppant concentration)and post-fracture well productivity.The optimal values were found to be a rate of 5-6 m³/min,a fluid volume of 600-650 m³,and a proppant concentration of 11%-15%.The integrated geo-engineering approach could fully and accurately recover the actual reservoir characteristics of this complex block,which has significant implications for stimulation and development of unconventional reservoirs.

Key words: buried-hill reservoir, integrated geo-engineering, unstructured network, fracturing, productivity, numerical simulation