With today's oil and gas prices, the loss of well production creates a negative financial impact on operating companies, especially in an offshore environment.

One of the most common reasons for production loss is the development of scales inside the production strings, blocking the flow of the reservoir fluid to the surface facilities. Barium Sulfate (BaSO4) scale is among the toughest scales to remove, whether mechanically or chemically. Alternatives to remediate this problem are often quite costly.

Therefore, under this scenario, a cost-effective intervention mechanism to restore production to previous levels is imperative. One of these mechanisms is the deployment of coiled tubing intervention as it can be done while the well is still live, minimizing further loss of production.

The Namorado field in Campos Basin, offshore Brazil, has approximately 60 wells, with most of them presenting deposition of BaSO4 scale throughout their production history. Historically, in this field, the deployment of a down hole motor with coiled tubing has been effective, but limited to restoring the production path's diameter only to the outer diameter of the bit. Results with deploying a down hole motor have been satisfactory. On the other hand, chemical treatments have been extremely ineffective and are, therefore, seldom deployed.

This paper presents two case histories of successful Barium Sulfate scale removal from the production tubing by coiled tubing, utilizing a combination of mechanical and hydraulic tools. This process is different from the conventional method (downhole motor) as it provides faster cleanout rates and quicker production restoration. This combination is engineered through software that optimizes the velocity at which the coiled tubing string is run through the scale, as well as the configuration of the hydraulic tool with respect to the pump rate and selection of the jet angle.

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