Intervening in wells with challenging geometry is costly, often to the point that marginal producing wells may be prematurely shut-in. This paper details a novel, cost-effective approach taken when planning to intervene in a highly challenging well with the objective of bringing it back on-line after an extended shut-in period.

The methods used for conveying intervention tool string into oil and gas wells have developed significantly during the last forty years. As well geometry became ever-more-complex due to the adoption of directional drilling, it became apparent there very few options available in a toolbox to ensure delivery of intervention tool string to Target Depth (TD) in a cost-effective manner.

In response to this emerging challenge, a host of well service techniques and technologies have been introduced. One methodology that has delivered a real step-change, in terms of reducing well intervention expenditure and risk, has been the use of gravity-deploy mechanical roller systems. This lighter well intervention technique is now widely adopted by Industry and proven to reduce the use of more costly solutions such as wireline tractor and coiled tubing for pure conveyance reasons.

The paper details the impact of selecting a ‘next-generation’ gravity-deployed mechanical roller technology to undertake a remedial sand control well-intervention programme in a particularly challenging, highly deviated, dual oil producing well using slickline. The well had been shut-in for two-and-a half years with recent attempts to intervene using conventional roller tools proving unsuccessful.

The paper will inform the reader of technology selection based on the ability of a highly efficient rolling system to convey toolstring to target dept, containing no fastners, therefore reducing overall risk to asset. Other critical factors included pre-job conveyance modelling, tool string design and a highly-successful collaboration between well owner, service company and technology provider through their regional partner.

As well as significant challenges that were overcome to convey tool string to the high-deviation target, critical impact force was also delivered when in-situ, to ensure successful setting of sand screen assembly. Key to success was a willingness to rapidly adjust the well intervention plan by adopting industry best practice through lessons learned on a run-by-run basis. This resulted in successful setting of thru’ tubing sand screens in a cost-effective manner, ensuring that a valuable well was brought back on to production once again, delivering significant addition to recoverable field reserves.

The success of this intervention programme has led to wider adoption of next-generation conveyance technology using slickline methodology, before considering the use of wireline tractor or coiled tubing to undertake the same programme of work.

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