A Dynamic Split Method to Predict Development Index in Heterogeneous Waterflooding Oil Field

Abstract

Considering the actual conditions of irregularity well arrangement and heterogeneity in reservoir, on the base of reservoir engineering theory, a method to predict residual oil distribution and dynamic development indexes has been proposed. The method first split the oil field into multiple units dynamically and each unit can be equivalent to homogeneous one, using the Buckley-Leverett waterflood theory to predict the dynamic development indexes of every unit and then calculate the entire reservoir development indicators. The oil saturation distribution was calculated by an interpolation algorithm.The new method is used in three examples to comprehensively analyze the reliability, which include a nine-point homogeneous reservoir and a five-point heterogeneous reservoir and a full-field heterogeneous reservoir with irregular well pattern. Numerical simulation method is also used as contrast experiment in this paper. The results calculated by the two methods are matched relatively well in water cut and oil saturation distribution. In addition, reservoir models of different sizes are established to test the computational efficiency of the new method. Compared with the numerical simulation method, the new method speeds up the procedure more than tens of times.The new method is of great significance to field application. Well placement optimization with stochastic optimization algorithms requires a large number of function evaluations, each of which entails a simulation run. The computational expense can be reduced by using the new method instead of the numerical simulation method to calculate objective function.

Research on Methods of Separate Stratum Injection Allocation in High Water Cut Stage

“…So Liumin developed separate stratum injection allocation tool and testing tool and resolved the separate stratum injection allocation and testing problems. In this paper,the suizhong 36-1 oil field is studied stratification by determining the injection-production ratio [2] , water injection well group and layer, and the separate stratum injection allocation results verified analysis and evaluation of the single well and the amount of the reasonable injection allocation well interval.…”

A prediction formula for ratio of injection–production control area in triangle well pattern

“…2). Because the waterflooding process is mainly affected by the parameters on mainstream line (Zhou et al 2016;Feng et al 2013), the parameters of each part are assumed to be equal to the average parameters of injector-producer line.…”

“…The ratio of injection-production control area acts as an important role in waterflooding reservoir, which is applied to evaluate the development effect (Siavashi et al 2016) and calculate oilfield development index (Song et al 2000;Feng et al 2013). The ratio of injection-production control area is influenced by permeability, oil saturation, injection-production pressure drop and injector-producer spacing (Jiang 2013).…”

“…Besides, considering the available parameters and expense, not all waterflooding reservoirs have the ability to conduct the streamline numerical simulation. For the empirical method, the angular bisector of two neighboring injectorproducer lines is used to divide the injection-production control area (Ji et al 2008;Feng et al 2013). This method is fit for the homogeneous reservoir and it is easy to be applied.…”

“…Therefore, this method is not fit for the heterogeneous reservoir. In order to deal with the ratio of injection-production control area in heterogeneous reservoir, Feng et al (2013) developed a dynamical split method. This method calculates the ratio of injectionproduction control area according to percolation resistance and displacement pressure.…”