接箍锚定式井下节流器锚定机构性能分析及优化

Performance Analysis and Optimization of the Anchor Mechanism of Coupling Anchor Type Downhole Throttle

  • 摘要: 目前苏里格气田广泛应用的卡瓦式井下节流器在打捞时存在解卡工艺复杂、卡瓦咬死油管导致打捞成功率低等问题,为此研发了一种接箍锚定式井下节流器,依靠卡爪锚定于油管接箍槽间隙,具有易解卡、不卡死油管、不下滑和钢丝作业一趟完成打捞的特点。为了提高接箍锚定式井下节流器锚定机构的工作性能,利用ANSYS有限元分析软件,建立了锚定机构与油管接箍的有限元模型,模拟了锚定机构在锚定、打捞时的工作过程;利用中心组合设计法建立了节流器最小打捞力以及下击作业时卡爪所受最大应力与卡爪长度、卡爪厚度的数学模型,分析其影响变化规律,得出最佳卡爪长度、卡爪厚度分别为95.6 mm和2.9 mm,最小打捞力为1.9 kN,下击作业时卡爪所受最大应力为732 MPa,与原节流器相比明显提高。研究结果表明,接箍锚定式井下节流器锚定机构设计合理,在保证节流器锚定机构安全工作的同时,优化了节流器锚定机构的卡爪参数组合,为接箍锚定式井下节流器的现场应用提供了技术保障。

     

    Abstract: The slip-type downhole throttle widely used now in Sulige Gas Field has the problems of complex releasing process and low retrieving success rate caused by slip seizing tubing in throttle retrieving.Therefore,a new type downhole throttle was developed,which is fixed on the gap of tubing coupling groove by means of claw anchor,with the characteristics of easy releasing,without clamping the tubing tightly,no slippage,and retrievable in one run of wireline operation.In order to improve the working performance of anchor mechanism of the new type downhole throttle,ANSYS finite element analysis software was used to establish the finite element models for anchor mechanism and tubing coupling,so as to simulate the working process of the anchoring mechanism during anchoring and retrieving.The central combination design method was used to establish the mathematical models for describing the effect of length and thickness of the jaw on the minimum retrieving force and the maximum stress on the jaw while jarring it downward.Through analysis of the effect regularity,the optimum length and thickness of the jaw were determined as 95.6 mm and 2.9 mm respectively.In this case,the better anchoring performance was obtained,the minimum retrieving force was 1.9 kN,and the maximum stress applied on the jaw during jarring downward was 732 MPa,significantly improved the performance compared with that of the original structure.The research results showed that the anchor mechanism of the new type downhole throttle was reasonable in design,and the jaw parameter combination of anchoring mechanism was optimized while ensuring the safe operation of anchor mechanism of throttle,which can provide technical support for the field application of this new downhole throttle in the future.

     

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