PerfECT is a niche tool to evaluate the effectiveness of perforations in a producing well. PerFECT, an acronym for Perforation Efficiency Calculation Tool, is based on an analytical model developed from the theory of step-rate testing in hydraulic frac jobs. Production data is the main input in the model; mainly flowing wellhead (tubing-head) pressures and hydrocarbon rates. Completion data along with well deviation survey and details of perforating guns is also required to initialize the model.

​

As most operators regularly record flowing pressures & production rates for wells, this dataset has the information of perforations efficiency. In simple terms, if production rates and pressure drop is declining in constant fashion, the change in pressure per unit & change in rate per unit can be used to evaluate how many perforation holes are contributing towards production. However, declining pressure & rates can be a result of multiple phenomenons such as liquid loading or declining reservoir pressure. Therefore following is assumed and required to use PerfECT effectively:

​

• Reservoir pressure data to quantify pressure depletion

• Atleast one pressure survey to calibrate wellbore hydraulics (VLP) model

• When perforations were conducted, all holes were open and contributing to flow. This is set as reference point.

​​

Although there are certain assumptions built into the model such as constant reservoir pressure over analysis time, because of the simplicity of tool and easy availability of data, PerFECT provides added insight towards possible reason for declining production. Further, in cases where other reasons for production decline are limited, PerFECT is very accurate in predicting decrease in efficiency causing decline in production. Once such case is a gas reservoir with constant reservoir pressure & no liquid production.  PerFECT has been extensively tested on actual field data, with wells ranging from shallow depths, darcy permeability sandstones to deep 10,000ft HPHT sandstone/carbonate 0.1 mD reservoirs. Often when PerFECT recommended a re-perforation to improve production, production increase was found in actual.

​

To request a copy or further information, please contact: software@propetra.com

​

Further Research

​

Similar to Pressure Transient Analysis, where recorded pressure data & its derivative can extract significant information regarding wellbore & reservoir, production data also contains a world of information regarding the reservoir, flow-path, wellbore etc. We at Oil & Gas Technologies are actively pursuing this research to integrate lift curves with perforation efficiency model. As the trend of change in flowing pressure & rate is different for perforation friction or liquid loading or scale buildup, etc. it should be possible to identify these unique markers and appropriately diagnose the cause of production decline. Our current objective is to utilize the extensive field production dataset to conduct a graphical trend analysis and outline empirical correlations.

​

If you are interested in this research, or want to be part of it, please contact: research@propetra.com

​

​

​