A new and simple model for the prediction of horizontal well productivity in gas condensate reservoirs

Abstract

Horizontal wells are a proven and acknowledged technology to enhance well productivity through an increase in reservoir contact compared to that of vertical wells under the same conditions. In the last three decades, a considerable effort has been directed by many investigators to study flow around horizontal wells. In gas condensate reservoirs, in addition to the three dimensional (3D) nature of the flow geometry, the flow behaviour is further complicated by the phase change and the variation of relative permeability (kr) due to the coupling (increase in kr by an increase in velocity or decrease in IFT) and inertia (a decrease in kr by an increase in velocity) effects. Therefore, simulating such a complex 3D flow using commercial numerical simulators requires a 3D fine grid compositional approach which is very impractical, cumbersome and sometimes triggers convergence problems due to numerical instability. So far, none of these studies propose a method to deal with the complex multiphase behaviour of gas condensate flow around the horizontal well. Consequently, the introduction of a quick and reliable tool for long term productivity calculation in such a system is much needed. This paper presents a technique which was developed through a comprehensive study of the flow behaviour around horizontal wells in gas condensate reservoirs involving the creation of many in-house mathematical models using finite element and finite difference methods. An in-house simulator was developed to accurately model the multiphase flow of gas and condensate around horizontal wells. A large data bank was then generated covering the impact of a wide range of pertinent geometric and flow parameters on well performance including: well and reservoir geometries, reservoir and bottom-hole pressure, fluid velocity, gas oil ratio and fluid composition.Based on the results of the simulation, a new method has been proposed to predict the productivity of horizontal wells for the case of multiphase flow of gas and condensate. In this approach, the flow behaviour of gas and condensate around the well is quantified in terms of the effective wellbore radius of an equivalent open hole that replicates flow around the actual 3D system. The effective wellbore radius varies with fluid properties, velocity and interfacial tension (IFT), reservoir and wellbore conditions. The integrity of the new methodology has also been verified for various fluids and flow conditions.With this approach, a simple spreadsheet, without recourse to complex numerical simulation, can predict the horizontal well performance, significantly facilitating engineering and management decisions on the application of costly horizontal well technologies.

Effect of direct current on gas condensate droplet immersed in brine solution

“…An alternative technique for mitigating the effect of condensate banking involves drilling horizontal wells and hydraulic fracturing. However, this technique delays the onset of condensate banking and does not stop its occurrence (Behmanesh et al 2018;Ghahri et al 2018;Ghahri 2010;Hassan et al 2019;Hekmatzadeh and Gerami 2018;Wei Zhang et al 2019a, b). Hydraulic fracturing if not properly cleaned up can accumulate liquid within the fractures which affects the efficiency of the technique.…”

Selective Water Plugging Technology for Horizontal Well with Screen Completion

“…Czarnota et al [10] put forward the optimization method of horizontal well length under the quasi-steady flow condition considering wellbore pressure drop and described the change of reservoir pressure in the production process with the general material balance method. Ghahri et al [11] developed an in-house simulator to realistically simulate the multiphase flow of gas and condensate around horizontal wells. Based on these simulation results, a new method for predicting the productivity of horizontal wells in gas and condensate system was proposed, so as to do a dynamic prediction of horizontal wells, which greatly facilitated the application of engineering decision-making, and management decision-making to horizontal well technology.…”

Gas Production from Gas Condensate Reservoirs Using Sustainable Environmentally Friendly Chemicals

“…Drilling a horizontal well can increase the contact area between the wellbore and the reservoir. Then, the reservoir productivity will be improved, and considerable hydrocarbon can be produced [7]. Analytical and numerical models have been developed to estimate the performance of horizontal wells [8].…”