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SPE 124677

Understanding the Roles of Inflow-Control Devices in OptimizingHorizontal-Well PerformancePreston Fernandes, Zhuoyi Li, and D. Zhu, Texas A&M University

Copyright 2009, Society of Petroleum Engineers

This paper was prepared for presentation at the 2009 SPE Annual Technical Conference and Exhibition held in New Orleans, Louisiana, USA, 4–7 October 2009.

This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not beenreviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, itsofficers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission toreproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright.

Abstract

Inflow Control Device, often referred to as equalizer, is a completion hardware that is deployed as a part of well completionsaimed at distributing the inflow evenly. Even though the detail structures vary from one design to another, the principle for 

different inflow control devices is the same - restrict flow by creating additional pressure drop, and therefore balancing or 

equalizing wellbore pressure drop to achieve an evenly distributed flow profile along a horizontal well. With a more evenly

distributed flow profile, one can reduce water or gas coning, sand production and solve other drawdown related production

 problems. In general, inflow control devices are not adjustable; once installed in the well, the location of the device and therelationship between rate and pressure drop are fixed. This makes the design of a well completion and inflow control devices

extremely critical for production. Inflow control devices can be either beneficial or detrimental to production, strongly

depending on the reservoir condition, well structure and completion design. Realizing that reservoir conditions will changeduring the life of a well, the impact of an inflow control device is a function of time. The inflow control devices sometimes

can be overlooked if the design is only based on reservoir flow simulation.

In this paper, we will investigate how and when an inflow control device should be used. An integrated analysis method

of inflow (reservoir) and outflow (wellbore) is used to generate the flow profile of a horizontal well, and additional frictional

 pressure drop created by inflow control devices will be considered. Two conditions that result in production problems,wellbore pressure drop and breakthrough of unwanted fluids, 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 condition always exists, backup plans and conservative designs are desirable. Theobservations from this study show that overdesigned inflow control devices will not just increase the cost of well completion,

 but also impact the well performance negatively.

IntroductionWith advances in drilling technology over the past 30 years, horizontal and multilateral wells have become a primary designtype to develop reservoirs, especially in unconventional resources. The need to produce efficiently, economically and

environmentally-friendly has promoted the development of 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 some problems in producing from such a well. Higher pressure drawdown around the heel sectionas a result of frictional pressure drop of fluid flow in the wellbore causes non-uniform fluid influx along the length of the

wellbore and higher production rates at the heel. This often leads to early break-through of water or gas, which causes a

reduction in oil recovery and uneven sweep of the drainage area. With longer contact between reservoirs and wellbore,heterogeneity is more likely encountered, and permeability contrasts along the wellbore can also result in the same

 phenomena because of unevenly distributed pressure along the wellbore.

To eliminate this problem Inflow Control Device (ICD) has been increasingly used in producing wells as a part of well

completion to control and optimize individual well or overall reservoir performance (Alkelaiwi and Davis, 2007, Krinis et al.,

2008, Emerick and Cunha, 2007). A completion with ICD is often referred to as a type of intelligent completion, with Inflow

Control Valve (ICV) as the other commonly used downhole flow control means. Intelligent completion can be a wellequipped with downhole monitoring systems, or downhole control devices, or both. It has been discussed before that ICVs

are more active control, and ICDs are passive control (Crow et al., 2006, and Birchenko et al., 2008). The purpose of ICDs is

to equalize inflow along the length of the wellbore regardless of location and permeability variation. These ICDs enable the