Case Studies of Gascondensate Field with Oil Rim Development:Search for Effective Methods of Oil Production from Thin Rims

摘要

The present work is dedicated to the problem of developing oil and gas condensate pools with thin oil rims for neocomian deposits in the Urengoy region,and to the search for effective methods of oil production from thin rims.The key problems in the development of thin rims are the low cumulative oil production per well,as a result-low profitability and oil recovery ratio.The reasons are known:a sharp decline in initial oil rate due to the rapid increase in water cut and growth of gas factor associated with the water and gas coning.The results of hydrodynamic modeling at early stage in the development of oil rims often lead to optimistic forecasts that are not confirmed in practice.The paper provides an analysis of the reasons for optimistic calculations,tuning up models for the results of the development and operation of oil wells with different completion relative to the GOC.Obtaining history-matched oil and gas production systems made it possible to obtain a more reliable production forecast for oil wells,to substantiate the preferred target subsea depth for the completed interval in the rim and the type of completion.Scenarios with the completion of the horizontal section at a distance of one third from the GOC and OWC,or in the middle between the contacts,have been considered and analyzed.A comparison of the calculated performance of the wells with the actual one had been made.An economic evaluation of the operational efficiency of wells drilled on thin rims shows that their profitability based on oil production is marginal.The closer completion intervals of the oil horizontal wells to the GOC the higher economic efficiency of their operation due to additional volumes of gas and condensate production from the gas cap.The use of double-wellbore and multi-lateral completion of horizontal wells in the oil rim increases the economic attractiveness of the project.The integrated approach proposed in the paper to the organization of production and oil and gas processing systems from such oil wells makes it possible to technologically efficiently operate wells and ensure almost full utilization of associated gas.The joint development of gas condensate pools with thin oil rims allows for the cost-effective development of the ones.