A New Model to Predict Productivity of Multiple-Fractured Horizontal Well in Naturally Fractured Reservoirs

Abstract

In order to predict productivity of multiple-fractured horizontal well in fractured reservoir, flow models of reservoir and hydraulic fractures based on the volumetric source idealization are developed. The models are solved by utilizing Laplace transformation and orthogonal transformation, and flow rate of the well is calculated by coupling the two models. Compared to traditional point source functions, volumetric source function has many advantages in properties of function and programming calculation. The productivity predicting model is verified via an analytical ternary-porosity model. Moreover, a practical example of fractured horizontal well is studied to analyze the productivity and its influent factors. The result shows that flow rate of each fracture is different and inner fracture contributes least to productivity. Meanwhile, there are optimizing ranges for number, length, and conductivity of hydraulic fractures. In low-permeability reservoir, increasing surface area in contact with reservoir by increasing number and length of hydraulic fractures is the most effective method to improve the productivity.

Production performance analysis of fractured horizontal well in tight oil reservoir

“…It indicates the relative size of elastic storage ability of fracture system and matrix system . Resources exchanged between fractures and matrix blocks can be characterized by transmissivity ratio (k) which reflects how easy or difficult the fluid medium flows into fracture from matrix (Wang 2015).…”

“…Assuming the matrix block is divided into plats by secondary fracture (Fig. 2), the porosity of connected natural fractures is 100% and the system compressibility of secondary fracturing networks is homogeneous, x and k are defined as (Warren and Root 1963;Wang 2015):…”

“…Wang 2015). Due to the fact that the peak of hydraulic fractures may not be effectively supported by proppants, the original fracture length might be much longer than actual supported fracture length (X f derived from square root of time analysis).…”

“…As a validation, 2 simulated cases have been analyzed as well. In simulated cases, the synthetic data are provided by a semianalytical productivity prediction model for multistage fractured horizontal wells in naturally fractured reservoirs (Wang et al 2015;Wang 2015). This productivity model, which can be used to predict the productivity of MFHWs in tight oil reservoirs, is based on the volumetric source methods.…”

“…In this section, two multistage fractured horizontal well completed in this tight oil reservoir are simulated using a semi-analytical productivity prediction model for multistage fractured horizontal wells in naturally fractured reservoirs (Wang et al 2015 andWang 2015). Input reservoir parameters are the average values from this actual tight oil reservoir (Table 6).…”