Horizontal wells have been widely used to significantly increase reservoir exposure in a wide range of conventional and unconventional oil and gas recovery applications, including tight-rock and multi-stage fracturing, offshore, primary and thermal heavy oil projects. In the heavy oil and bitumen reservoirs of the Western Canadian basin, horizontal wells have been extensively employed in Steam Assisted Gravity Drainage (SAGD) and Cyclic Steam Stimulation (CSS) in-situ recovery projects. In SAGD applications, the lateral sections of these horizontal wells are generally completed with various types of sand control systems, including slotted liners, Wire Wrapped Screens (WWS) and premium screens with a growing percentage incorporating some form of downhole injection or production Flow Control Devices (FCD). Given the relatively shallow depths, low reservoir pressures and high fluid rates of these applications, these horizontal wells are often constructed with relatively high build rates and large diameter tubulars. In an effort to improve project economics, well designs with increasingly longer lateral sections are being pursued.
In an effort to reduce potential damage during installation, engineering assessments are commonly conducted to ensure that the structural capacity of these liners exceeds the demand of the combined installation loads caused by liner-wellbore interaction and liner string buoyant weight, often with consideration of a suitable safety margin. To date, given the number of influential parameters, the complex nature of the analysis and corresponding computational demands, methods which employ significant simplifications, such as soft-string torque and drag (T&D) models, have been commonly used to assess liner installation loads. In addition, it appears that the current commercial soft- and stiff-string T&D analysis tools do not consider the nonlinear load capacity envelopes of the sand control liners in the evaluation to assess the potential damage under combined loading during installation. Advanced numerical methods, such as Finite Element Analysis (FEA), have also rarely been employed to evaluate the liner installation loads due to the complex nature of this problem.
This paper presents an advanced stiff-string T&D analysis approach developed using the commercial FEA program Abaqus. To demonstrate the application of this approach, several example cases are presented simulating the installation of the slotted liner design into a horizontal SAGD well. In these T&D analyses, wellbore and tubulars were modeled using pipe elements which accurately capture various geometric parameters and associated mechanical responses of the tubulars. Contact interaction and the clearances between the tubulars and the wellbore were modeled. Different friction factor (FF) values were assigned to the cased and open hole sections of the well. By incorporating the load capacity envelopes of the specific slotted liner design into the analysis, this paper demonstrates how this methodology may be applied to assess the load responses and potential damage risks associated with running large diameter liners into high build rate extended-reach horizontal wells. The approach presented in this paper may be expanded to various tubular, completion equipment and drill string running applications.
Author: Tao, G.
Year Published: 2016
Publisher: SPE Canada Heavy Oil Technical Conference
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