How Oil & Water Separator Optimization Improves Processing Performance

Limit the time spent on adjusting to unforeseen changes and upset conditions through investing in tools that help you identify changes in real time. Doing so, can help you better utilize the assets available in the production process plant. One of these assets, and perhaps the most important one is the oil and water separator.  

In order to put into perspective how important it is to optimize your separator process, this article will begin by briefly addressing the challenges and current developments that are happening within the industry. 

As this article is one of the more extensive ones we have published here at the Process System Performance blog, we have for your convenience, highlighted its content here:

1. An Industry in transformation

2. Poor Visibility (data) leads to delays and wrong decisions

3. Why is instrumentation such an important part of the solution?

4. What are your options (different types of instrumentation)?

5. Conclusion

1. An oil and gas industry in transformation

The oil and gas industry is in continuous development and transformation. As a result, new challenges, as well as opportunities are emerging. Here are the most important ones, that every instrumentation engineer should know:

1.1 Digital revolution

There are new powerful technologies increasing automation, productivity and safety, whilst at the same time reducing unit cost and labour force. The digital revolution is all about unlocking the power of data to generate value.

However, the main question you should ask yourself is how to get reliable and accurate data from the most inaccessible environment - such as from within the separator.

This is crucial, because if your initial data is wrong, it does not matter if you have the best software.

1.2 The easy oil is gone

Upstream E&P companies are facing the challenge of producing the more challenging hydrocarbons. These hydrocarbons might have been discovered years ago,but were not produced due to lack of technology.

We are only seeing the beginning of this trend.

With time, only the operators that are able to effectively utilize the most advanced technologies, will remain competitive.

1.3. Energy transition

New energy policies are taking effect around the world and there is a growing competition from renewable energies. As a result, a highly efficient production, with reduced downtime and costs, are no longer nice to have objectives, they are a must.

I encourage you to consider what these changes might entail. Take into account not only what you need today, but what you might need further down the road to ensure that you can remain a strong competitor.

But first, let’s take a short trip into our daily life.

2. Poor visibility (data) leads to delays and wrong decisions  

Have you ever gone for a hike in the mountains, and experienced a heavy layer of fog settle? It is not a fun experience. You cannot see further than a meter ahead and have no way of knowing if you are on the right track, or heading towards a steep cliff. You feel blinded.

The uncertainty of what lies ahead is unsettling, and in a situation like this it is best to stay put and wait for the fog to break up.  

However, picture that for every minute you stand still, you loose a big chunk of money. Suddenly you realize that waiting is not the best choice and you feel pressured to continue walking, despite the risks.

2.1 Dynamic digital twin & real-time monitoring  

In the oil and gas industry, planning and having a systematic approach in all processes are essential. Still situations occur where there is a combination of high degrees of uncertainty, and high level of expectations. Not surprisingly, it can lead to a lot of sleepless nights.

What are the causes of this? 

New expectations are emerging due to developments in the industry, and meeting these expectations is crucial to stay competitive. At the same time, any oilfield is naturally experiencing changes throughout its life span (like changes to the well stream in terms of flow rate, temperature, pressure, density, fluid composition and higher presence of by-products like water and sand, etc.), which creates production uncertainties.

The problem with such uncertainties is that they can easily develop into issues. Solving these issues can take time, and consequently you are left with delays, reduced or loss of production and increased production costs.

The factors mentioned above make it difficult to plan ahead and ensure optimal performance, as you cannot predict how things will change - all you know, is that they definitely will change. 

So, what can you do?

I recommend that you already in the early stages of a project, focus on removing uncertainties by investing in tools that help you identify changes in real-time.  

This can help you better utilize the assets available in the production process plant. One of these assets, and perhaps the most important one, is your oil and water separator.

Suggested reading: Why you need to select instrumentation for your oil and water separators during early phase design.

3 .Why is instrumentation such an important part of the solution? 

As mentioned in a previous article, the separator itself is a “blind” piece of equipment, with no flexibility at all. It is designed to receive a multiphase fluid stream, separate all its elements (oil, water, gas and solids) and dispose of the unwanted products (e.g. the water).  

However, the nature of any oil well is that the fluid stream changes over time. The complexity of multiple oil wells going into the same separator amplifies this challenge.

Instrumentation can help you get accurate and reliable data, from the most difficult place.  

Not knowing what is going on within the separator have consequences to the production rate; as adjusting to unforeseen changes or upset conditions takes time.

As you already are aware of, most oil fields loose approximately 6-7% of productivity a year. To remedy this, reduction techniques stimulating the field (water injection, chemical injections, polymer injections, steam injections etc.) are implemented.

Consequently, it affects the fluid stream from the well - meaning that a stream which produced little water, or had little to no problems with emulsion, might over time face these exact issues.

Suggested reading: How to increase oil production by utilizing your oil and water separator better

In a 3-phase separator, the instrumentation is applied to monitor the different aspects of the separation process. Thus, ensuring that the production of oil and gas goes according to plan.

Through selecting the correct instrumentation for your separator, you can help the operators stay on top of the situation by identifying when elements in the fluid change.  

Based on these identifications, the operator can then adjust the process accordingly and achieve a better separator performance. Put simply, the correct instrumentation allows you to deal with uncertainties, as well as avoid surprises through generating the most accurate measurements possible and in real time.

As a result, the separator performance is kept at a maximum and no need of spare capacity is required. 

However, choosing the correct instrumentation for your separator can be challenging. Let’s have a look at the different types of instrumentation and how they can help you with oil processing optimization.

4. What are your options? Different types of instrumentation: 

There are several types of instrumentation available on the market today. In essence, the ‘job to be done’ for instrumentation is to measure three different factors inside the separator: 

1. Temperature 
2. Pressure 
3. Level 

We can categorize temperature (1) and pressure (2) instrumentation as simple, cheaper and standardized technology.  

Instrumentation for monitoring levels (3) is a much more complex type of instrumentation, used in separators to measure single and multi-layer level of material (fluids). Level instruments are designed to sense, display, and transmit signals that corresponds to the levels measured within a vessel.  

The environment within a separator can vary (from vacuum to high pressure, and from low to high temperature), and the fluid density can differ from time to time. As a result, several types of sensors with different measuring techniques exist. Choosing the right instrumentation within this category is thus more challenging, than that of temperature and pressure ones.  

The fluids typically present within a 3-phase separator are water, emulsions, oil, foam and gas. The interfaces that are most crucial to monitor are those within the liquid phase - In particular, oil/emulsion interface and emulsion/oil interface. In order to maximize the utilization of your separator, it is therefore important that the level instrumentation is capable of monitoring both the various liquid interfaces, together with the various fluid levels. 

To help you make the right decision and optimize the separator performance, we will briefly outline the main two categories of level instrumentation in upstream production: 

• Category 1 - most advanced: Able to read all layers, within the 3-phase separator such as water, oil, emulsion, foam and gas. 
  
  
• Category 2 - medium advanced: The ability to read levels of oil, water and gas, but with limitations to measuring emulsion and foam. 

Note, that there is a third category consisting of less advanced technology (like Ultrasonic and Non Contact Radar), but these are rarely used for upstream production today. 

Naturally, the range of complexity affects the cost of the technology; advanced level instrumentation is expensive compared to simpler technology. However, in order to choose the right instrumentation for your separator, it is important that you consider more than just the features and price of the instrumentation. Additionally, examine how the instrumentation can help maximize the utilization of the separator during production, and continue doing so over time.

Suggested reading: Choose the Right Instrumentation For Your Oil and Water Separator

5. Conclusion

By comparing the capabilities of the different types of level instrumentation, as well as looking at industry trends, it is fair to say that choosing the more advanced level instrumentation will be more beneficial long-term. Yes, choosing the most advanced level instrumentation is arguably more expensive than choosing a simpler instrumentation. However, with the separator being the heart of the oil processing plan, optimizing its performance is a high priority. Without it performing at its best, the production will suffer, having a huge impact on both cost and revenue.  Thus, choosing the most advanced instrumentation is an investment that easily pays back manyfold over time.