Study on Cuttings Transport Efficiency Affected by Stabilizer's Blade Shape in Vertical Wells

In oil and gas drilling, cuttings transport related problems are a major contributor to well downtime and costs. As a result, solutions to these problems have been extensively researched over the years, both experimentally and through simulation. Numerous review articles exist, summarizing not only the research history but also the qualitative effect of individual case parameters such as e.g. pump flow rate, pipe rotation, rate of penetration on cuttings transport. However, comparing different studies is challenging, as there is no common reference basis defined in the form of typical and representative set of case parameters. In order to develop relevant and accurate cutting transport models, it is critical that both experiments and models are targeting flow cases, which are relevant for respective drilling operations. By developing a clear understanding of the industrial parameter space, as well as establishing critical benchmarks, the development of models and corresponding laboratory experiments will become much easier. Other industries have established such benchmarks (e.g. the "NREL offshore 5-MW baseline wind turbine" in wind power research), providing a standardized set of case parameters and profiles, readily available for use to researchers worldwide and resulting in straightforward benchmark and validation as well as faster project set-up and definition. For application to modeling of cuttings transport phenomena, we propose a methodology how to derive a well-defined and standardized set of geometrical, operational, and environmental case parameters describing various working points of actual drilling operations and procedures as well as simplified problems. The relevance and application of standard parameters is briefly discussed in the light of modeling, both experimentally and through simulations.

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Detailed Dynamics Modeling Helps to Assess the Effect of Stabilizer Design on Drill String Vibrations

Nguyen¹,

Mahjoub²,

Dao³

et al. 2023

Day 1 Tue, March 07, 2023

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Various stabilizer types are used in the industry, such as bladed stabilizers with straight or spiral blades, roller-reamers, and other emergent forms. Their designs are proved, via many in-field measurements, to have a significant impact on vibration levels. Although experimental data is extremely valuable to rank the available design options, testing the different stabilizers can be costly and sometimes risky. In addition, in-field conditions can be difficult to control making the comparisons between stabilizers even more complicated. Assessing the design impact using numerical simulations represents an interesting alternative to provide objective comparisons based on tests in a controlled environment. When a stabilizer is rotating, the contact forces between its different blades and the wellbore are transient. A static approach like torque and drag or directional models is then insufficient to properly investigate the stabilizer's design characteristics. Therefore, a time-domain dynamics approach is adopted in this work. A detailed modeling of bladed stabilizers including the blade geometry (number of blades, spirality, and blade width) and friction characteristics are introduced in an existing time-domain model. These characteristics are used to compute the contact forces between the wellbore and each individual blade. This numerical model is applied to quantify the effect of stabilizer design in terms of vibration, from straight blades to highly spiraled blades. First, a parametric study of blade design and wellbore inclination effects on stabilizer vibrations is presented by considering different stabilizers in straight well conditions. Simulations of an actual drill string configuration in an unconventional well is discussed. For vertical, curved, and horizontal sections, the acceleration levels, contact forces, and rotation speeds are investigated. These analyses can constitute guidelines about stabilizer design to minimize vibrations. The novelty of this work is to introduce the geometry details of the stabilizers in the time-domain dynamics to differentiate designs in terms of likelihood to trigger vibrations.

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Study on Cuttings Transport Efficiency Affected by Stabilizer's Blade Shape in Vertical Wells

Cited by 3 publications

References 10 publications

Well Annulus Cleaning While Using Stabilizer with an Experimental Flow Loop and its CFD Model

Well Annulus Cleaning While Using Stabilizer with an Experimental Flow Loop and its CFD Model

Cuttings Transport Modeling - Part 1: Specification of Benchmark Parameters with a Norwegian Continental Shelf Perspective

Detailed Dynamics Modeling Helps to Assess the Effect of Stabilizer Design on Drill String Vibrations

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