A New Hybrid Optimization Algorithm And Its Application In The Optimization Of Oil Field Development

One of the main tasks of a reservoir engineer is to develop a well-arrangement scheme and evaluate the profitability of different schemes when put into execution, and the best one will be selected for adoption. A rational scheme requires making use of the least well number to control the reserves by the greatest degree. The most hydrocarbon should be produced to obtain maximal profit within economic and natural limits. Therefore, we must design a rational well number, placement and mode. This is the most central problem involved in the oilfield infrastructure and an essential problem related to the future production effect.Optimal placement of oil, gas or water wells is a complex problem that depends on reservoir and fluid properties, type of drive, well and surface equipment specifications, as well as various economic parameters. Thus it is a multiple decision variables problem and each proposed scheme is relative to a wide set of decision variables. It is obvious that the choice of their values is an optimization problem. Since they can not deal well with this kind of problem of multiple variables, discontinuous and non-differentiable functions, traditional optimization technologies are usually not adopted. Furthermore, regular well pattern lacks flexibility and takes a risk in losing money in business.A new-style hybrid optimization algorithm that is based on standard genetic algorithm(GA), niching technology based on fitness-sharing model, and the simplex method is presented in this paper. The best advantages of this algorithm are that it has no function property requirements and can deal with large numbers of variables with a fast convergence speed and high precision. Thus it is especially fit for global-optimization problem on a large scale. This technology is applied in optimizing reservoir development in this paper. Firstly it is used for well placement optimization with the object of maximizing the cumulative production and then for well number optimization with the object of maximizing the net present value(NPV). This work provides reservoir engineers with a new idea and a new type of method in how to optimize well-arrangement scheme and increase economic profits.