Case Histories of Improved Horizontal Well Cleanup and Sweep Efficiency With Nozzle Based Inflow Control Devices (ICD) in Sandstone and Carbonate Reservoirs

Abstract

Abstract This paper discusses the PLT-correlated results of two test wells completed during 2006; one in sandstone and one in a carbonate reservoir, with the new completion technology of nozzle-based passive inflow control devices (ICD) which improves performance of wells with reservoir challenges as described:In highly productive sandstone reservoirs, horizontal wells suffer from uneven flow profile and subsequent premature cresting/coning effects. In general, there is a tendency to produce more at the heel than at the toe of horizontal wells, which contributes to poor well cleanup at the toe. Additionally, excessively increasing the rate and/or horizontal well length can increase the risk of limiting sweep efficiency, resulting in bypassed reserves1.In carbonate reservoirs, permeability variations and fractures can cause uneven inflow profile and accelerate water and gas breakthroughs. Wells with early gas or water breakthrough have to be shut-in until remedial plans are decided and implemented, resulting in deferred production. The main reservoir objectives for applying passive ICD technology in the two test wells are:Sandstone: Decrease the influence of heel-toe effects and high permeability zones; hereby deferring water/gas breakthrough, improving well cleanup and sweep efficiency.Carbonate: Control flow rates from high permeability intervals and to limit production from each compartment based on lateral offset from the gas-oil contact to prevent premature gas breakthrough. The test well PLT-logs were correlated to static reservoir simulations. Analyses of the well performances show that the objectives of both completions were achieved. By having proper matches of the completions with ICD, the value over standard completions can be evaluated. Post-evaluation of the completion designs based on the PLT-log results has increased our understanding of the nozzle-based ICD performance. As a result several approaches for completing wells in both sandstone and carbonate reservoirs with ICD have been recommended in order to achieve optimized inflow performance. Introduction Two trial wells with nozzle-based passive ICD systems were designed and completed in 2006; one for sandstone and one for carbonate reservoirs. To evaluate and approve the new ICD completion, these wells were production logged and the results were carefully analyzed. The most important feature of the ICD completion is the self-adjusting effect of flow variations anywhere along the well trajectory and whenever they occur during entire well life. The key benefits are:Increased well life and reserves due to improved sweep efficiency.Delayed gas and water breakthrough.Decreased water/gas rates after breakthrough when water/gas mobility is higher than oil.Improved well cleanup.