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The need to produce oil and gas efficiently, economically and environmental-friendly has promoted the development of long extended reach horizontal and multilateral wells, which enable greater reservoir contact and lower draw-downs to achieve similar rates as conventional wells. However, this increased wellbore length has led to uneven drawdown distribution along such a well, often leading to early break-through of water or gas, and causing reduction in oil recovery and uneven sweep of the drainage area. The problem becomes more severe when a heterogeneous reservoir is involved.
To eliminate this problem, flow control devices have been used widely as a part of completion to control and optimize individual well or overall reservoir performance. The purpose of flow control devices is to equalize inflow along the length of the wellbore regardless of location and permeability variation, thus the entire length of the wellbore can contribute to the total production and thereby optimize hydrocarbon recovery. They also help prevent annular flow which can often lead to plugging and erosion of screens. Inflow control devices are choking devices that balance inflow by adding an additional pressure drop at the sandface. They are designed to apply a specific deferential pressure at a certain flow rate. The presentation will investigate how and when an inflow control device should be used. Two conditions that result in uneven flow distribution, wellbore pressure drop and heterogeneity of the formation, will be addressed. The focus will be on when and how an inflow control device can optimize production. Examples at field conditions will be used to illustrate that it is critical to understand the reservoir conditions and wellbore dynamics together when designing a well completion with inflow control devices. Since uncertainty of reservoir conditions always exists, backup plans and conservative designs are desirable. The observations from this study show that over-designed inflow control devices will not just increase the cost of well completion, but also impact the well performance detrimentally.
Ding Zhu is Associate Professor and holder of the W. D. Von Gonten Faculty Fellowship in Petroleum Engineering at Texas A&M University. She received a B.S. in mechanical engineering from the Beijing University of Science and Technology and M. S. and Ph. D. degrees Petroleum Engineering from the University of Texas at Austin. Dr. Ding Zhuís main research areas include general production engineering, well stimulation, and complex well performance.
Dr. Zhu is a co-author of more than eighty technical papers and the SPE book, Multilateral Wells. She has been a chairperson and a committee member for many Society of Petroleum Engineers (SPE) conferences and events, and a technical editor for SPE Production and Operations Journal.