Integrated management and Application of Horizontal Well Water Flooding Technology in a Large-scale Complicated Carbonate Oilfield Containing High permeability Streaks

Abstract AD oilfield in Iraq is a large-scale complicated carbonate oilfield with mid-high porosity and low permeability, of which OOIP is 3.5 billion barrel. The lithology and property for the oilfield is featured with strong heterogeneity, especially high permeability streaks and dissolution existed partially. In Middle East fewer examples are successful in application of horizontal well water flooding technology for the similar oilfields. Integrated management is the fundamental for the application of horizontal well water flooding technology. The paper put forward an integrated management system of horizontal well water flooding technology for the complicated carbonate oilfield. Water breakthrough mechanism and injection timing for horizontal water injection are studied based on numerical simulation, pilots and laboratory experiments. Production management system has been established to evaluate productivity, analyze production law for ESP producers and the change for reservoir pressure, which also timely diagnosis abnormal condition for producers and injectors. Evaluation and optimisation system are put forward including multiple indexes evaluation model for horizontal well water flooding's development effect, classification charts for horizontal well with different changing law, cause analysis for abnormal water cut increasing, and optimization for pressure and production/injection parameters. The relevant optimization and adjustment measures have been recommended and implemented in time to maximize single well production through the integrated system. The production capacity has been constructed up to 7 million ton per year and achieved stable yield of 3 years continuously in AD oilfield, of which 6% was increased by horizontal well water flooding. The ultimate recovery factor of horizontal well water flooding has been predicted about 40%, nearly 2% higher than that of the overall field development plan in 2011. The integrated management of horizontal well water flooding technology will provide significant technical support for longer stable production with 70 million ton per year in AD oilfield. The application result has significant reference for the development of complicated carbonate reservoirs containing high permeability streaks in Middle East.