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Cymric Oil Field—Surface Expressions

When fluids come to the surface

Over the last several decades, cyclic steam injection programs have encountered problems with surface expressions when pressurized steam breaks loose from the intended zone of injection. The goal of the cyclic steam injection is to mobilize the heavy oil and direct it and resulting wastewater up through the well during the production phase. However, steam injection has apparently interacted with the surrounding geology to create pathways to the surface… pathways that were not foreseen. These surface expressions can range from minor seepages to dangerously hot soils to violent eruptions that shoot rocks and material high into the air or send them flowing miles down creek beds. Cymric oil field has experienced a number of surface expressions. In 2011, a worker in another Kern County oil field died after falling into a sinkhole filled with hot fluids created by a surface expression. Let’s learn more about this challenge and what is being done to prevent these problems.1CalGEM. (n.d.). High-energy surface expressions. A Story Map.

The California Geologic Energy Management Division (CalGEM) summarized several facts to the public about the more recent surface expressions in the Cymric oil field.2CalGEM. (n.d.). High-energy surface expressions. A Story Map. The surface expressions are: 

  • Not near populated regions
  • Isolated from drinking water sources
  • Concentrated within oil field productive limits and within contained areas
  • Located within several lease areas operated by two different companies

The following figures are from GalGEM’s ArcGIS database.3CalGEM. (n.d.). High-energy surface expressions. A Story Map.

This map from CalGEM shows the locations and status of high-energy surface expressions in a number of oil fields in the San Joaquin Valley of California, including the Cymric oil field. Looking at the legend, you can see that at this scale most of the surface expressions are now inactive, although officials continue to closely monitor the area of previous outbreaks. You’ll notice from the map that there have also been high-energy surface expressions in the Midway-Sunset and McKittrick fields.

With this map, we’ve zoomed in on an area in the Midway-Sunset field. At the time this CalGEM map was downloaded, you can see that there was an active surface expression being addressed in the field.

Let’s look at information on one of the surface expressions from the Cymric oil field and see how long it takes to get these problems under control where they meet the regulatory requirements of CalGEM (the regulatory authority over these wells). We will highlight one of the surface expressions at the southeast end of the field as shown in this CalGEM figure:4CalGEM. (n.d.). High-energy surface expressions. A Story Map.

This image shows several surface expressions that have occurred at the southeast end of the Cymric oil field.

We can zoom in on the CalGEM map above and request information on the surface expression and see from the map below that the problem was first detected on June 23, 2019, and was finally resolved on July 21, 2019. An examination of a number of these surface expressions on the CalGEM map suggests that this is a fairly typical time frame – one month – to stop surface expression activity.5CalGEM. (n.d.). High-energy surface expressions. A Story Map.

This CalGEM image highlights several surface expressions that are no longer active in the Cymric oil field.

Image Credits: Courtesy of CalGEM ; Courtesy of CalGEM

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