Study On Energy Supplement Of Low Permeability & Tight Reservoirs With Fractured Horizontal Wells

Fractured horizontal well is one of the most effective technologies to develop low permeability and tight reservoirs. The fractured horizontal wells are widely used in many large oil fields to enhance oil recovery. Currently most of fractured horizontal wells were developed in elastic recovery. It is urgently needed to supply formation energy because of the fast production and pressure decline. In this thesis, based on a certain oilfield horizontal wells demonstration area of CNPC, physical and numerical simulations were both used to study the effectiveness of the energy supplement of three types of low permeability and tight reservoirs with fractured horizontal wells. The main research results are summarized as follows:1. Physical simulation of water and gas injection into fractured horizontal wells was established in this research. The fracture equivalent design makes the simulation more close to the development condition of the reservoirs with fractured horizontal wells. The time and money were greatly reduced by the optimization design of the experimental process.2. The effectiveness of water and gas injection into the Class II reservoir with fractured horizontal wells were analyzed and the experimental results show that the final recovery ratio of water injection was almost close to that of gas injection, however the injection pressure of water injection would be much lager than that of gas injection.3. Compositional simulator was used to evaluate the development effectiveness of three types of reservoirs with fractured horizontal wells by water injection, CO2 injection and WAG. The simulation outcome reveals that water injection is more suitable for class â…  and Class â…¡ reservoirs and CO2 injection is more suitable for Class â…¢ reservoir.4. Comparison was applied to evaluate the energy supplement effectiveness of three types of reservoirs with fractured horizontal wells and five reasonable suggestions were proposed. Studied the fracture distribution effect on energy supplement and analyzed the main factors of the gas breakthrough.