Abstract

The emergence of downhole distributed temperature sensing (DTS) technology has led to much better instrumented wells, allowing operators access to real-time temperature data leading to better well control and more efficient field management.

This paper will use field examples to demonstrate the benefits of this technology in two different applications: fracture monitoring during open-hole frac-stage treatment and steam distribution during Steam-Assisted Gravity Drainage (SAGD) process.

The migration from conventional cemented liner plug-and-perf techniques to packer-only stage isolation in open-hole has had a significant impact on the economics and efficiency of shale completions operations. As in-pay horizontal lengths get longer and the desire for increased unit fracture density increases, the concern for effective frac stage isolation increases.

The SAGD process has been widely used in thermal recovery industry for its high recovery efficiency. Effective steam utilization requires proper understanding of steam distribution along the targeted horizontal section.

Examples shown in this paper demonstrate the following benefits afforded to operators with access to DTS data in real time:

  • Determine the effectiveness of open-hole frac-stage treatment during fracturing;

  • View the movement of frac-fluids downhole within the target frac stage during fracturing;

  • View the movement of fluids in previously fractured (lower) intervals during upper stage fracturing operations; and

  • Temperature distribution along the well paths (injectors and/or producers).

Collected DTS data can also be analyzed in real time using in-house software tools developed for DTS visualization and interpretation. Data analysis and lessons learned from field applications are presented in this paper and focus on following four areas:

  • Approximation of fracturing fluid distribution

  • Integrity of isolation packers

  • Improvement in understanding of steam distribution

  • Improvement of well integrity and identification of potential well completion breaches

Introduction

Distributed Temperature Sensing (DTS) is becoming an increasingly valued monitoring techniques when applied downhole in oil and gas applications. Acceptance has grown as a result of the increasing value that can be realized from such repeated, high-resolution well temperature profiles. Comparing with conventional production logging in horizontal wells, DTS technology is cost-effective and less risky. Unlike a conventional production log that provides only snapshots of the well performance, DTS can provide continuous real-time monitoring along the entire wellbore. Small temperature change can be easily detected by DTS. Such information can help operators to better understand their wells and reservoirs.

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