The global surge in demand for energy is pressurising oil and gas operators to enhance the efficiency of existing wells. As reserves deplete, the industry’s need for well intervention services is gathering pace. 

The West Coast of Africa provides a typical example of how the importance of well intervention is increasing when it comes to maximising the value of assets and optimising production.

Today, with oil reserves of 129.1 billion barrels, Africa accounts for an estimated 7.6 percent of the world’s proven reserves. On the Western Coast, which is home to the continent’s two largest producing countries, Nigeria and Angola, well intervention activity has been ramping up.  

The increase in activity in the region is due to a multitude of factors, including: regulatory imperatives, fluctuating market prices and technological advancements. In depleting reservoirs, when residual hydrocarbons are bypassed and trapped, initial well placement may not fully drain the reservoir. In some instances, only between 30-40 percent of the oil is recoverable.

In cases such as this, drilling new wells may not prove to be the best solution to extract additional barrels of oil. It’s for this reason that intervention specialists are so crucial. As a result, the employment of well intervention techniques, including well surveillance services, can enhance recovery rates.

Well intervention is undertaken in both onshore and offshore oil and gas wells and typically occurs around the five-year mark of production. It is often the result of reduced pressure, increased water cut or sand production, scaling or other common factors. Operators face a variety of challenges during workover, integrity and abandonment projects. It is widely accepted that very few wells will perform optimally, and produce an uninterrupted flow, from beginning to end. At some point during the lifespan of an oil and gas well, the completion will either require maintenance, repair or replacement.

When it comes to well interventions, there are two general categories: light and heavy. A light intervention will involve the lowering of tools or sensors into a live well, while pressure is contained at the surface. During a heavy intervention, the rig’s crew may need to completely remove the completion string from the well, allowing for major changes to be made to the well’s configuration. This requires production to be halted at the formation – a situation that can negatively affect the profitability of a business, impacting the bottom line. 

As operators look to serve the demands of the market, and maximise the output produced by their wells, it’s important that they deploy the latest, state-of-the-art technology to help them – ideally without having to resort to intervention techniques that require production to be halted.

As an example, Fotech’s DAS fibre optic monitoring technology can provide operators with a greater insight into the state of their assets. The fibre can be deployed in both vertical and horizontal wells, through a choice of methods, including: permanent installation, coiled tubing, carbon rod, slickline or wireline.

This can significantly improve the efficiency of reservoir management by enabling operators to run vertical seismic profile (VSP) surveys to review how well a reservoir is producing. In these instances, a permanently-installed fibre allows operators to run DAS VSP surveys while the well is still producing and acquire seismic data across the entire wellbore with the minimum of vibroseis sweeps.

In conjunction with the VSP, DAS may also be used to monitor production or injection, and can check for well integrity issues. The technology allows for multiple monitoring activities to take place simultaneously during one run in the well, saving on substantial rig down-time and lost production.

With the energy boom showing no signs of abating, maintenance to ensure operational efficiency and techniques that increase productivity and the rate of recovery are growing in importance. This has seen oil and gas operators the world over turn to employing the expertise of intervention specialists – and working collaboratively with them to drive solutions.

While investment in exploration projects is still forthcoming, in Africa and beyond, both regional and international operators are looking to technological innovations that will further reduce the cost of well interventions. The aim is simple: increase the productivity of operations in existing fields and plays.