Conglomerate oil reservoirs have reserves exceeding 2 billion tonnes in China and are one of the important replacement fields for oil and gas energy in China. However, conglomerate reservoirs contain a large amount of gravel, which is very heterogeneous mechanically and has significant differences in crack propagation paths. It is difficult to achieve balanced distribution of fractures in fracturing, and it is difficult to effectively explain using existing theories of uniform rock crack propagation. Therefore, it is necessary to explore relevant theories and methods applicable to conglomerate. In response to the characteristics of conglomerate reservoirs and the difficulties in development engineering, this article explores the difficulties and countermeasures in conglomerate development from five aspects:rock characteristics, research methods, mechanical characteristics, fracture propagation and hydraulic fracturing technology. Based on this, a multi-scale analysis method was proposed for comprehensive mesoscale, conventional scale, large scale model, meter scale, and field scale, and the laboratory research results were applied to oilfield sites through scale upgrading; Clarifying the gravel, mixed base, and cementation surface is the key to controlling rock mechanical parameters and fracture patterns. It is necessary to establish a weak cementation surface model to improve the accuracy of mechanical parameter prediction; It has been clarified that there are two modes of conglomerate fracture propagation:through gravel and around gravel, with obvious process zone characteristics. A fracture propagation model suitable for conglomerate can be constructed based on the double K fracture criterion to predict the initiation and propagation parameters; The compressibility evaluation should be guided by the integration of geological engineering, integrating rock fabric characteristics and multi-scale mechanical parameters to establish, and optimize fracturing plans.

The significant amount of oil and gas resources in the Taha oilfield is stored in natural holes. Acid-fracturing can establish fluid communication pathways between natural holes and wellbores, which can increase the development of carbonate reservoirs. An extended adaptive meshing technique was developed in this paper. The multi-physics coupling model for acid-fracture propagation was established using the phase-field method. The interaction between acid fractures and natural holes was simulated. The effects of in-situ stress, hole structure, and acid-rock reactions on acid-fracture propagation were analyzed. Two communication modes between acid-fractures and natural holes, direct communication and indirect communication, were summarized. The simulation results reveal the following conclusions: 1. the acid fracture model based on the phase field method solves the fracture propagation path based on the principle of energy minimization, which can simulate the acid fracture initiation and propagation under multi-field coupling conditions. 2. In-situ stress plays a dominant role in acid-fracture propagation.Natural holes affect the propagation of acid fracturing, and acid rock reaction assists in the propagation of acid fracturing. 3. The acid diffusion and etching capabilities result in indirect communication between acid fractures and surrounding holes, The oil and gas resources in the holes can enter the acid fracture through the acid-etched matrix. The identification of the holes distribution is the basis of improving the acid fracturing result. It is believed that this finding can offer information for acid-fracturing study in deep carbonate reservoirs.