An advanced approach for well test and surveillance data analysis 

Convolution Explorer (ConvEx), is an innovative pressure transient analysis software that can be used with exploration/appraisal well test and with long term surveillance-type data. Developed by industry expert Michael Levitan, ConvEx allows an engineer to gain insights into the transient behavior of well data and determine if the well pressure and rate are consistent with the principle of superposition.  If in the course of analysis it is determined that the data are consistent with superposition it also converts the well data into a form of constant-rate drawdown pressure response. This function reflects the well completion and its geometry as well as the reservoir properties as manifested by the well location within the reservoir.  It is therefore a characteristic property of the well.

The drawdown response function is derived in the form of the Bourdet derivative plot with reservoir and well parameters (permeability, skin, fracture length, distance to a boundary, reservoir pore volume, and so on) estimated directly from that analysis plot using standard PTA methods.  The derived drawdown response function, which is a reflection of observed well behavior, can then be used to forecast future well rate performance for different scenarios of pressure constraints imposed on the well.

ConvEx is a multi-well application that allows engineer to account for well interferences. This is especially important for analysis of surveillance-type data that cover long term well production and are more likely to be affected by well interferences.

ConvEx can be used for well performance analysis of conventional and unconventional wells. As an approach that does not involve modelling it may prove to be especially useful for unconventional wells with their high degree of uncertainty regarding the well completion and the fracture network as it actually exists in the ground.

ConvEx has been presented at SPE and Well Testing Network meetings (incorporating well testing experts from leading companies including BP, Expro, ExxonMobil, Halliburton, Shell and Schlumberger).  The feedback was incredibly positive (see below)

“Whilst this technique appeared to provide clear benefits across the entire well range, its application to unconventional wells may prove particularly powerful.”


The ConvEx software is being marketed by OPC in co-ordination with our PTA services.  Contact Piers Johnson on 020 7428 1111 or email for more details.


Some recent convex

Successful well test management project
OPC has managed a successful well test project on an appraisal oil well offshore Mexico.  We were involved at all stages of the test which was completed 5 days ahead...
Well test planning, monitoring and analysis
OPC provided well test planning, modelling, monitoring and analysis services to an independent oil and gas exploration company drilling an appraisal well in the Norwegian North Sea. 
PTA and PVT review to determine gas caps
OPC undertook a review of existing PTA (Pressure Transient Analysis) data and existing laboratory PVT analyses from several wells in an offshore field in West Africa.
PTA utilising deconvolution and ConvEx
OPC undertook a Pressure Transient Analysis (PTA) study utilising deconvolution and ConvEx. The PTA connected volumes calculated were comparable with those from modelling and ConvEx was successfully used to help...
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