Abstract

Slotted liners are widely used in steam-assisted gravity drainage (SAGD) wells to control sand production and sustain wellbore productivity. The slotted liner can provide desirable performance when appropriately designed. A literature review indicates a limited number of studies that offer design criteria specifically for SAGD wells. Moreover, past criteria seem to neglect some key factors, which may lead to inadequate slot design. This paper proposes a set of graphical design criteria for slotted liners in SAGD production wells, using prepacked sand retention testing (SRT) data. The SRT is designed to incorporate several essential factors that are not present in the past design criteria, such as slot density, steam breakthrough, and particle size distribution (PSD). The proposed design criteria are presented graphically for normal and aggressive conditions, where the aggressive condition accounts for the potential occurrence of the steam breakthrough. It is found that the upper bound of the design window is substantially lower for the aggressive condition due to the higher sand production after the steam breakthrough. The design criteria also indicate that the slotted liner is suitable only for the formations with low fines content.

Highlights

  • As the third-largest proven oil reserves globally [1,2], the Canadian oil sands are exploited by the thermal recovery method using steam-assisted gravity drainage (SAGD) [3]

  • Past experimental works recognized a few factors that should be incorporated in the slotted liner design criteria, including slot size, slot density, fluid velocity, fluid phase and particle size distribution (PSD) [18,19,30,36]

  • The green color in the Traffic Light System” (TLS) means an acceptable slot size, in which the amount of sand production is lower than 0.12 lb/ft2, and retained permeability (RP) is greater than 70% [19,30]

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Summary

Introduction

As the third-largest proven oil reserves globally [1,2], the Canadian oil sands are exploited by the thermal recovery method using steam-assisted gravity drainage (SAGD) [3]. The SAGD consists of two horizontal wells, about 800–1200 m in length, with a horizontal injection well typically five meters above the horizontal production well (Figure 1) [4,5]. The operational temperature and pressure in the Alberta SAGD projects vary, depending on the depth. The typical operating temperature of the SAGD well is around 200–250 ◦ C [8,9]. Li et al [10] reported different injection pressures for various SAGD projects in Alberta, ranging from 2000 to 5000 kPa, depending on the reservoir depth. Schematic configuration of (a) steam‐assisted gravity drainage (SAGD) well pairs and (b)

Schematic
Limitation
Method
Sand‐Pack Samples
Sand-Pack
Injection Fluid Properties
Testing Matrix
Procedure
Testing Results
Sand Production
10. Produced
Retained Permeability
Design Criteria for Slotted Liners
16. TLS of DC-III
Comparison between Improved and Current Design Criteria
Findings
Conclusions
Full Text
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