Modernizing Solutions for NextGen Coiled Tubing and Well Intervention

In previous features, the focus has been on what is new or reimagined. Therefore, I thought that, in selecting papers for this year’s feature, it would be useful to select ones that look at coiled tubing operations performed and that have been evaluated in one way or another.

Last year, this feature opened, almost inevitably, with comments on the effects the COVID-19 pandemic might have on our industry. Unfortunately, a year later, we probably have all experienced the effects, both personal and work-related.

One of these effects is that there has been re-evaluation of what’s important. To understand what is important takes some reflection and evaluation of the past. In previous features, the focus has been on what is new or reimagined. Therefore, I thought that, in selecting papers for this year’s feature, it would be useful to select ones that look at coiled tubing operations performed and that have been evaluated in one way or another.

From Bolivia comes a paper that reviews some 25 well interventions performed. Most of these operations are of a type that will be familiar to the reader. Also, some of the challenges that were faced in performing these coiled tubing operations will be familiar. These operations used a range of established types of coiled tubing operations and blended the techniques to meet particular operating conditions, especially location and logistics challenges. All conclusions and best practices that resulted, however, may not be familiar to all readers.

During the past few years, many coiled tubing papers have focused on the use of coiled tubing in multizone fracturing operations, especially plug milling. An area of coiled tubing use in fracturing operations that has had less of an audience recently has been the use of coiled tubing in annular fracturing operations. This activity is still routinely being performed, particularly in Canada. The question has long existed about how the pipe is being eroded. In the related paper in this feature, the authors explain how they have tried to answer that question and have shared some of their review insights.

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The complete paper discusses an advanced matrix-stimulation work flow that brings reliability and flexibility to the acidizing of tight carbonate water injectors and has delivered injectivity improvements tight carbonate onshore reservoirs in the Middle East.

The complete paper discusses an advanced matrix-stimulation work flow that brings reliability and flexibility to the acidizing of tight carbonate water injectors and has delivered injectivity improvements tight carbonate onshore reservoirs in the Middle East. The work flow leverages real-time downhole measurements and the presence of fiber optics in coiled tubing (CT) for telemetry, and relies on a high-pressure jetting tool, controlled with the help of real-time downhole pressure data, to enhance penetration of acid into the targeted intervals.

Introduction

Effective and long-term matrix stimulation of water-injector wells completed across tight carbonate reservoirs presents a significant challenge in the Middle East. Local practices for matrix stimulation of openhole horizontal carbonate water injectors consist of spotting hydrochloric acid treatment by CT along the uncased well section, using a specific fluid dosage per unit length of the pay zone. Thus far, that approach has delivered inconsistent results in wells completed across tight carbonate rock, most often leading to a rapid decline in injection rates following the treatment.

An alternative work flow leverages distributed temperature sensing (DTS) to evaluate the original water-injection coverage across the reservoir. Each section benefits from a customized treatment that increases injectivity and improves uniformity of injection. A high-pressure jetting tool, controlled with the help of real-time downhole pressure data, is key to this work flow because it enhances penetration of acid into the targeted intervals. 

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The complete paper discusses the systematic approach adopted by a service company to achieve the goal of safely abandoning wells offshore southwest Brazil with different completion types using light workover vessels.

The complete paper discusses the systematic approach adopted by a service company to achieve the goal of safely abandoning wells offshore southwest Brazil with different completion types using light workover vessels. Having determined the abandonment methodology, service company personnel developed processes and procedures to reach the objective that included advances in coiled-tubing (CT) rigup procedures and use of a real-time telemetry system.

Introduction

The use of a CT real-time telemetry system enables accurate setting of a through-tubing inflatable device system (T-TIDS) by monitoring the necessary downhole parameters in real time. The paper presents a case study wherein sensors [such as a casing collar locator (CCL) to perform depth correlation before setting the T-TIDS and placing cement plugs, a pressure sensor to monitor the T-TIDS setting, and a CT internal pressure sensor to help ensure all cement was pumped out of the CT] were used in real time to verify that well barriers were set in place, contributing to successful well abandonment. Real-time data collection proved to be the most-effective methodology for running critical equipment, thereby saving overall time and cost.

The decision for permanent abandonment of a well is not always easy. In ­Brazil, the National Agency of Petroleum, Natural Gas, and Biofuels (ANP) has established a compendium of rules for oil companies that extract and produce oil, gas, and derivatives. This involves a group of barriers known as CSB, which is a set of one or more elements with the objective of preventing the unintentional flow of fluids from the formation to the external environment and between intervals in the well considering all possible paths.
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This paper describes a coiled tubing gas lift (CTGL) technique successfully used to restart production from two pilot wells in a mature field in Pakistan that had been shut in since 2015.

This paper describes a coiled tubing gas lift (CTGL) technique successfully used to restart production from two pilot wells in a mature field in Pakistan that had been shut in since 2015. The project yielded production gains that resulted in a short payback period and verified that the technique represents an effective and economical solution to restart production in mature fields where conventional artificial-lift methods challenge well economics. The pilot results have encouraged the operator to further implement CTGL in Pakistan. According to the authors, suitable candidate selection, including data accuracy for nodal analysis and production forecast, and proper planning played fundamental roles in the project’s success.

Introduction

Exploration and production companies in Pakistan struggle with multiple challenges including pressure from regulatory bodies to increase oil and gas production to meet requirements of an energy-starved country in a period of historically low oil prices. With little new significant discovery, operators are challenged to produce economically from mature and declining fields. Several fields in south Pakistan have been forced to shut down because of uneconomical production rates. Most of the wells in these mature fields do not flow naturally because reservoir pressure is insufficient to overcome the hydrostatic column.

Existing techniques have their own challenges, including very high associated costs. Realizing these challenges, the government of Pakistan recently prioritized developing mature fields and optimizing production in declining fields.

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