What are the best water production risk mitigation strategies for oil wells?

Understanding reservoir dynamics through geological and reservoir studies helps in predicting and managing water production. Implementing water shut-off treatments and controlling reservoir pressure by managing the rate of production can prevent excessive water. Injecting chemicals such as polymer gels, relative permeability modifiers (RPMs), or other blocking agents can reduce water permeability in the reservoir. These treatments are designed to block the water pathways without affecting the oil flow.

In contrast to conventional shut-off methods that tend to be indiscriminate, blocking both water and hydrocarbon production, consequently resulting in costly workovers and long shut-in times, novel compounds have been developed that selectively target only the water phase of production stream. Being bullheaded or pumped through coiled tubing, these products used in conjunction with relative permeability modifier (RPM) components deform in the presence of oil, and minimize the restriction of the formation pore throat, allowing oil to flow uninterrupted. Alternatively, in the presence of water, the water-wetting polymer expands, filling the pore throats which increases the resistivity of water flow.

For the offshore oil and gas industry, approximately 75% of the produced water is treated and then discharged into the ocean, with the rest being re-injected. While onshore, roughly 90% of this water is reinjected, with the rest being treated and reused or discharged. With the development of shale oil and gas, and the demand for water for hydraulic fracturing, there is an increasing emphasis on flowback and produced water reuse.

The key to produced water management is to prevent water getting into the wellbore, and to minimize the water being brought to the surface. The use of online oil-in-water monitors can play an important role in the management of produced water. There are a significant number of technologies available on the market: UV fluorescence-based technologies are probably the most commonly used. Laser-induced fluorescence (LIF) technology has been gaining acceptance and market share. This is due to the availability of LIF-based probes, which can be inserted directly into the process pipeline. There are many benefits in using online continuous oil-in-water monitors, but particularly as they provide continuous information.

To mitigate water production risks in oil wells, altering the completion design is essential. One effective method is the Downhole Water Sink (DWS) approach. This technique uses a dual completion system, with one completion in the oil zone and another in the water zone. The water produced in the water zone is injected back into a suitable subsurface formation. Advantages: • Reduced Water Cut: Minimizes the amount of water reaching the surface. • Enhanced Oil Recovery: Controls water coning, leading to stable oil production. • Efficient Water Management: Treats and disposes of water underground, reducing environmental impact and costs. • Pressure Maintenance: Helps maintain reservoir pressure, supporting sustained oil production.

The most effective yet costly technology utilized by numerous operators worldwide to address water and gas issues is smart or intelligent completions, consisting of inflow control devices (ICDs) and downhole gauges. ICDs have served to alleviate these challenges for many years. However, they operate passively, requiring intervention through wireline or coiled tubing to open or close in the event of water or gas breakthrough in an oil well. On the other hand, Autonomous ICDs (AICDs) represent an active solution. These devices self-regulate and are more responsive in choking water and gas. Consequently, they prevent well flooding when unwanted fluids breakthrough, resulting in enhanced recovery rates and reduced water and gas productions.

Produced water is an inevitable by-­product of oil and gas production, but its discharge could potentially harm the environment. Management of produced water is critically important for the safe and economical production of oil and gas, which must involve multiple disciplines and use an integrated or holistic approach. With increasing water production from mature fields the oil and gas industry is facing a significant number of challenges to minimize the potential harm that can be caused by the discharge of produced water. Often water production becomes a limiting factor for continuing oil production economically for a specific field. How to best manage produced water in oil and gas production will therefore have a significant impact.

To mitigate the risk of water production,several key strategies can be implemented.Firstly,careful well design and completion techniques are essential.This includes choosing the right perforation strategies,using mechanical barriers&employing advanced methods like horizontal drilling to access oil while isolating water-bearing layers.Aslo,deploying downhole water sink technology can be effective.This involves a dual completion system draws down water away from the oil-producing zone,reducing water cut &improving oil recovery.Lastly,regular monitoring&surveillance are critical.Using logging tools and production data analysis helps detect early signs of water intrusion,allowing for timely interventions to manage water production effectively.