The use of multilateral wells became significant in the recent years for both oil and gas development projects due to its maximum productivity resulting into fewer dollars per SCF development cost. However, there is a common mistake during the planning phase of these complex wells. They usually overestimate/underestimate the production from these complex well due to the lack of analytical well productivity estimation models in the literature which would require expensive numerical modeling. This paper investigates the effect of hydraulic fracturing on the productivity of this kind of wells and other factors like the anisotropy and lateral length as well as the fracture conductivity.

22 different scenarios were investigated to study the effect of different variables on the deliverability of the multilateral well. The base case scenario was built using ECLIPSE simulator. The effect of the lateral length and the number of laterals were studied then the fracture effect introduced to the base case starting from 1 stage fracturing up to 8 stage fracturing. Furthermore, the reservoir anisotropy and the fracture conductivity was explored. All these data sets were analyzed and combined using regression techniques to get one mathematical model that can predict the productivity in a simplified procedure. Vogel-type was used to get the final productivity model.

Based on the results, it was found that the most significant parameters that affect the study are reservoir anisotropy, and the fracture width. It was observed that changing the number of fracture stages is significant specially in the 8 laterals case as compared to the 4 and 6 lateral cases respectively. In addition, changing the number of lateral while holding the number of fracture stages constant showed small effect on 1 and 3 stage fractures compared to the significant effect in the 2 and 4 stage fracture. Changing the total length of the laterals plus the main horizontal stem also have great influence in the productivity. The effect of the fracture width and reservoir anisotropy which was found to be the most affecting parameter.

The mathematical model is simple to be used for quick estimation of the productivity relationship multilateral dry gas wells with very good accuracy in a way that save a lot of effort and time. And also can be implemented in simulator to save a great computational effort. The model was tested using different cases and found to give reasonable results with small average error.