Casing Wear and Stiff String Modeling Sensitivity Analysis – The Contribution of DP Pipe-Body and Tool-Joint on Casing Contact

Vavasseur, D.; Mackenzie, N. F.; Nobbs, Benjamin; Brillaud, Loic; Aichinger, Florian; Dao, Ngoc-Ha

doi:10.2118/183388-ms

Cited by 8 publications

(1 citation statement)

References 6 publications

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“…In this situation, the contact of the wellbore wall with the jointed pipes is usually at the tool joints especially in curved wellbore sections. Tool joints cause casing wears due to torque and drag forces and buckling [6]. This results from interaction between the pipe tool joints and the casing string.…”

Section: Introductionmentioning

confidence: 99%

Drillstring Buckling Prediction and Its Impact on Tool-Joint Effects in Extended Reach Wells

Kerunwa¹

2020

OGCE

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The mechanism of buckling has been extensively studied in pipes and tubings. But these studies more often has been restricted to continuous or straight body pipes. In reality most pipes and other drillstring elements have end couplings or connections known as tool joint. Tool joint presence changes the annular geometry, hydraulics and stress distribution of the pipe or tubulars in the wellbore. Modelling drillstring in highly deviated wells with no regards to the tool joint effects has been a major source of error in many drilling mechanics analysis. This has often led to misleading information on buckling and bending of the pipe which could lead to drilling and completion problems and costly well interventions. Thus it becomes necessary to model tool joint effect in the drillstring as it is subjected to downhole forces and stresses. In this study, emphasis is made on the determination of tool joint effect on pipe buckling for highly deviated extended reach wells (ERWs). WellPlan T&D spreadsheet software was used for the simulation. The simulation was runned for pipe with tool joint and the same pipe with the tool joints removed. Results show that jointed pipes has similar buckling behaviour with continuous straight body pipes with buckling starting from sinusoidal buckling mode and gradually entering the helical buckling mode for both types of pipes. Furthermore, result revealed that tool joint presence increases the critical buckling force by an average of 28.9% for helical as well as (AWA) sinusoidal buckling modes.

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Section: Introductionmentioning

confidence: 99%

Drillstring Buckling Prediction and Its Impact on Tool-Joint Effects in Extended Reach Wells

Kerunwa¹

2020

OGCE

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Systematic Field Validation of New Casing Wear Quantification Process

Aichinger¹,

Dao²,

Brillaud³

et al. 2016

Day 4 Thu, November 10, 2016

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Casing wear predictions are necessary for a fit-for-purpose, cost efficient casing design. In order to achieve a reliable casing wear prediction from simulations, three objectives have to be met: (1) Accurate modelling of mechanical work, (2) accurate derivation of casing wear from mechanical work and (3) accurate wear factor calibration through MFCL (Multi Finger Caliper Log) interpretation. The paper presents a theoretical description of all three steps and their application on a representative field case, highlighting recent improvements and reducing uncertainties at each step with a focus on a newly developed MFCL interpretation methodology. To accurately derive the mechanical work an advanced stiff-string model(3) is used to simulate the history of side forces for each rotating operation, of each BHA, which was in contact with the casing. Accurate surveys and small calculation increments are vital. Operation parameters must be data mined with great care. To properly derive the wear from simulated mechanical work, a 3-D oriented wear model is used. This 3D mesh is able to distinguish the influence of different contact geometries on the wear groove shape and the location of thinnest wall thickness. Due to the usage of an advanced stiff-string model, drillstring body contact points are identified and therefore the wear model allows the input of different wear factors for different types of contacts (Tooljoint, Pipebody, Torque reducer)(12). Additionally, the model allows the application of linear and non-linear wear models. To properly calibrate wear factors, a reliable and robust MFCL log interpretation must be conducted. Wear is commonly measured by comparing the results of a MFCL to a base MFCL, which ideally was taken at the beginning of the section. In the standard process, the maximum measured diameters per joint of both MFCLs are compared. A more accurate single run-MFCL interpretation methodology will be presented, which relies on statistical analysis of the casing shape. It was found that the standard MFCL interpretation methodology may be the weak link in the chain. The standard methodology led to significant exaggeration of the wear factor(s), especially if the calibration was done based on mild levels of wear. Casing wear prediction remains a complex issue, due to uncertainties concerning wear and friction factor. The new MFCL calibration methodology, including a robust stiff-string torque and drag model, is capable of significantly reducing the levels of uncertainty. Overall the complete methodology is the basis for accurate wear prediction and reduces the need of casing over-engineering.

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Casing Wear Modelling: A Comparison between MFCL and 3D Stiff String Model

Aichinger¹,

Nobbs²,

Couliou³

et al. 2020

Day 1 Mon, November 09, 2020

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A stiff-string torque & drag & buckling model has been coupled to a 3D meshed casing wear calculation to model the effect of drilling operations on casing wall thickness reduction. Results of the numeric simulation are compared to MFCL for field cases and provide an understanding of possible well integrity issues during the well life cycle. A Hall wear model and 3D rigid stiff string model is used to predict casing wear. Using Wear Factor Coefficients obtained for several hard-banding, casing grade and mud-types, the process was tested against numerous field cases. For each field case, a history of drill string runs were modelled and filtered into operations in which the drill string rotates such as Drilling, Reaming, Back reaming and ROB. Initially, the calliper log was not analysed to ensure the results are non-biased using experimentally found Wear Factors. In a second phase, the Wear Factors were calibrated against the measured calliper log. This paper provides a methodology that was used to successfully quantify the effect of casing wear against numerous field cases. The 3D orientation of the casing wear was found from an un-calibrated MFCL. After calibration of the new Wear Factor, the casing wear can be predicted before and after well construction. When used as a post analysis tool, the methodology helps determine if casing wear was a root cause of loss of well integrity. This process also helps reduce the uncertainty in Wear factor as a major unknow in the contact force, is now properly modelled. When used in a post analysis process, the results where quantitative (groove depth vs 3D orientation) but also qualitative, providing a post-mortem description of the state of the well to operation's personnel. The methodology presented here can be used to both predict excessive casing wear and determine if excessing casing wear was a cause of failure. It can be used to help determine the state of well for workover operations or plug and abandonment operations. Accurate casing wear prediction at planning stage allows the anticipation of costly but fit for purpose mitigation means & measures.

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Casing Wear and Stiff String Modeling Sensitivity Analysis – The Contribution of DP Pipe-Body and Tool-Joint on Casing Contact

Cited by 8 publications

References 6 publications

Drillstring Buckling Prediction and Its Impact on Tool-Joint Effects in Extended Reach Wells

Drillstring Buckling Prediction and Its Impact on Tool-Joint Effects in Extended Reach Wells

Systematic Field Validation of New Casing Wear Quantification Process

Casing Wear Modelling: A Comparison between MFCL and 3D Stiff String Model

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