Turnkey Development & Design of a Downhole Mechanical Shifting Tool

UMS Flowell


UMS Flowell are a product and service provider for the oil and gas sector. Their focus is on downhole completion equipment for wells that incorporate Electrical Submersible Pumps (ESP), as well as natural flow oil wells. Flowell design Oil and Gas products, such as Y-tools, which can be integrated in a variety of well setups, optimising ESP systems. An advantage and strong selling point of these tools is to provide operators with the flexibility and accessibility required due to the complex and arduous environments oil wells can provide. The design of these tools must consider many factors to reduce the opportunity for a failure downhole, however it is not always preventable.

The product that sparked the relationship between UMS Flowell and Armech Solutions was their Flow Management Diverter Valve (FMDV). The function of the well intervention sub-surface flow valve is to act as a bypass device that prevents backflow through the ESP, reducing exposure of well debris to the ESP.

The FMDV, when in bypass position, allows the well flow to bypass the non-operating ESP system. This protects the pump from unnecessary wear and exposure to large pressure drops. The FMDV can also prevent backflow, as the ESP powers down a flapper within the FMDV closes and ports to the annulus open to allow tubing contents above the diverter valve to drain into the annulus. A main advantage of this feature is the elimination of backspin on the ESP, which can break the shaft.

The FMDV will therefore carry out an important task in the completion phase of the well whilst being exposed to an onerous environment, including debris. While measures are in place to prevent the tool from getting stuck or operating incorrectly, a standby well intervention solution is required to be available to operators in these events.


Due to UMS Flowell’s engineering resources operating at full capacity on their core product lines, they decided to engage with Armech Solutions – specialists in development of downhole Well Intervention equipment – to develop a contingency product that would be able to remediate any FMDV operating issues. They drafted a design brief for a shifting tool with the following challenges:

  • Must be possible to deploy on either slickline or coil tubing, requiring only linear mechanical manipulation to operate.
  • Must allow the FMDV sliding sleeve to be exercised to facilitate removal of debris, and also allow the valve to be locked in the closed position.
  • Must allow flow through the FMDV when in use.
  • Must be retrievable using a standard OTIS GS pulling tool, using either coiled tubing or slickline.


Lost production time of producing oil wells is extremely costly for the operator, therefore, reliability of downhole equipment is paramount. The requirement for reliability is combined with an extremely arduous operating environment: high-pressure, high-temperature, chemical contaminants and debris are par for the course. Space is also limited by the diameter of the production tubing, and tools are being operated by a winch driver using only an encoder and tension measurement to operate and verify operation of downhole tools.

In combination with satisfying the functional requirements and environmental demands; Flowell specified that design-for-manufacture must also be paramount in the design process. The shifting tool should be field redressable and cost-effective with respect to both machining and time required to assemble and maintain.


Armech Solutions have an extensive background in the product design and development of downhole tools, particularly well intervention. Armech are therefore equipped with the expertise to undertake the turnkey development project and address the client’s challenges.

The project was required to be completed within a stringent time frame to ensure the tool was manufactured, tested and operational for deployment on a live well, if required. Armech approached the project with the following structure to ensure a time effective strategy.

UMS Flowell supplied their CAD model of the FMDV and outlined their specifications for the intervention tool. Armech are proficient and fluent in multiple CAD packages and therefore capable of undertaking the work in the package preferred by the client, in this case Autodesk Inventor.

Armech began to design a concept of the Shifting Tool by initially assessing the FMDV. This allowed a more in-depth characterisation of the restrictions presented by the FMDV geometry, which the Shifting Tool must operate within.

Following this, a set of feasible design solutions are created, and as per the project flow chart, submitted to Flowell for review and feedback. The design solutions varied from exercise only capabilities to latch and lock with a running tool. A concept report allowed Flowell to review each of the options and weigh them based on cost-benefit, selecting the option that would best suit their clients’ requirements. Following the selection of the most suitable design, Armech began the detailed engineering phase of the project to fully develop the bespoke Shifting Tool. This phase involved multiple iterations to optimise elements such as thread ratings and sizes, spring selection and collet calculations. At each functional phase of the Shifting Tool deployment process, the operators have control of the FMDVs position through a slickline jar via the shifting tool. During the deployment, the Shifting Tool is secured in a set position through shear screws and a locked collet. The shear screws are employed to provide operational control with each having a specified rating that will allow the FMDV to move into a subsequent stage. A jar down of the stipulated force, after deployment is completed, will shear the screws and allow the shifting tool to latch onto the FMDV through keys. This therefore provides the operators on the surface the ability to exercise the tool. This action can manually control the FMDV or assist in the clearing of debris. The running tool can be retrieved to the surface to allow well flow through the FMDV.

Through regular design reviews with UMS Flowell, progress updates were provided. Any new concepts devised during the detailed engineering phase could be discussed and approved during these reviews. This included an improved pulling arrangement which ensured the shifting tool could not exercise accidentally during retrieval of the system. The design was completed by creating detailed engineering drawings and delivering relevant calculations. Armech were involved in the manufacture and testing of the tool to ensure any modifications to the design were evaluated first-hand and efficiently carried out. 


The Shifting Tool was a resounding success with UMS Flowell.

They were able to concentrate on their core products during a busy period at the company while Armech Solutions took their project from concept to completion within the agreed time frame and exceeding expectations. Following the conclusion of the testing phase, Flowell requested the design of two further sizes of the tool to suit their fleet of FMDVs.

What Next

Following the Shifting Tool project, Armech Solutions and UMS Flowell relationship has grown which has
created the platform for further collaboration and projects.

Here is what Flowell had to say about our work a few months ago:

Having worked with Armech Solutions for over 2 years now, I have found their work to be excellent: exceeding expectations, delivered on time and on budget. I would absolutely recommend Armech Solutions.

Armech have no doubt that we will work with UMS Flowell team again in the near future and look forward to doing so.

If you are interested in finding out more about who we are and what we can do for you, please get in touch via the Contact Us page.

Browse our Website and LinkedIn page to see more of our projects.
Learn how to assess fatigue lifetime using FEA

Enter your email address and see how we combine FEA, the hotspot method, and DNV standards to assess a workboat davit