Intelligent Plunger Lift: Digital and Cost-Effective Solution to Unlock Gas Potential in a Large Tight Gas Field in China

Abstract

The field is located in a large gas producing basin in China and has prominent characteristics such as thin formation thickness, low permeability and poor reservoir connectivity. Horizontal drilling associated with multistage hydraulic fracturing has proven to be an effective technique to produce the hydrocarbon in this field. As the gas wells matures, the production rate starts to decline due to the decreasing of the bottom hole pressure which will prompt a liquid loading issue. A trending gas production loss is up to 150 mmscf in a year due to liquid loading issue alone, which is equivalent to $1.8MM revenue loss. An analytical decline rate showed that the field is declining 3.4% to 4.6% monthly due to the descending of the casing pressure, superimposed with low backflow ratio after hydraulic fracturing, which create a technical and economic challenge to produce effectively. In addition, the location between well pads are remote and far apart. This creates HSE challenge for personnel to go to the well pads, especially during icy road in the winter. Solid soap stick had been tried as a deliquifications method, unfortunately the result is unsustainable without frequent injection. It is also very much relying on human intervention. Due to that, an alternative liquid lift loading system is introduced in the field. An intelligent plunger lift has been piloted in 12 wells in the field to reduce the liquid loading issue in mid 2021. Apart from the apparent advantages of plunger lift such as mitigation of liquid fallback, zero input energy and low operating/maintenance cost, this system is not desirable to fully close well at downstroke process which comes up with increment of gas production comparing to traditional plunger lift system. One of the major advantages is the real time production data surveillance to enable remote operations based on its intelligence flow control system and downhole sensor.