Is Well Test Analysis only about permeability and skin ? It is common to see some simple analysis when interpreting a well test or a pressure build-up test. This is sometimes called a “quicklook”. And the main results from this quicklook are permeability, skin and radius of investigation. The P* value can also be derived, [...]

Well test interpretation to re-evaluate the field potential Re-interpreting old well tests can help to re-evaluate the well and field potential or prepare for an EOR process (Enhanced Oil Recovery). By applying new techniques and tools (including Deconvolution), previous analysis could be re-visited to obtain a better understanding of the data and better describe the well [...]

To test or not to test? This is a common question these days... What are the worst possible nightmares in production? That the production wells quickly decline after start-up? Or to produce H2S or some other fluid contaminants when the new plant is not designed to handle it? What if the water injection wells are [...]

Production Flow Test or Well Test ?   In the North Sea, it is very common to call a production flow test a “well test”. In a production flow test, the well is flowed through a test separator or a multiphase flow meter MPFM. An average measured rate is reported, along with wellhead and bottom-hole [...]

Minimize well testing cost and reduce flaring Some special efforts in well test design and operations can be pursued to minimize the well testing cost and reduce flaring. Flaring less volume and for a less amount of time is not only good for safety and environmental reasons, but also cost effective. However, any effort to [...]

Real Time Well Testing   Whether you are comfortably sitting on your sofa at home or in the office onshore, you can have access to all the well testing data on a real-time basis during the operations, as if you were in the TDA cabin offshore. Pressure and temperature sensors are installed upstream and downstream of [...]

How many of the PBUs/PFOs do your team analyse on your production/injection wells?   When we ask this question, different answers come up: “how is this useful? Pressure build-up tests are for reservoir characterization with Exploration and Appraisal wells, not for production.” (moving on…) "We don’t analyse operations shut-ins. Sometimes when our reservoir engineer is not [...]

Nowadays, some companies not only tend to reduce the number of appraisal wells to a few in the best field locations, but they also give priority to MDT and mini-DST as the only fluid samples and dynamic data. These tools give some pieces of the reservoir puzzle, but they have a very small scale of investigation [...]

Some wells are tested with deliverability tests, instead of PBUs, to assess productivity. This could result in a misleading well and reservoir performance, in particular with low to mid permeability reservoirs. As a matter of fact, there is no other alternative to PBU/PFO tests so as to get KH and skin under transient behaviour. Complex deliverability [...]

Why is your PBU KH so different from the Core KH….? Let it be clear, we are talking about large discrepancy. Otherwise don’t worry about it. Core (or log derived) KH is not the same as PBU KH from well test analysis. Don't compare apples and oranges, both formation evaluation techniques do not measure the same [...]

In an attempt to save some data storage, pressure data from permanent downhole gauges are often processed and manipulated by some linear interpolation, commonly called “compression”. While big data management and data storage are sensible when looking at long term production trends, oil and gas processed data may no longer be suitable for pressure transient [...]

Deconvolution came up about 10 years ago and has become the driving tool in well test analysis. However, deconvolution is still not often used in well test design, operations and interpretation. Perhaps due to these 5 main misconceptions.   What is Deconvolution...? In a linear system with a single well, the well flowing pressure is [...]

Every PBU, every PFO, every shut-in contain some critical information about your well and your reservoir.    Every shut-in is an "information snapshot" of your well and reservoir.   Do you use every production shut-in as an opportunity to learn? Do you have the resources and expertise to do this for each of your wells?  [...]

Deconvolution in Well Testing  The Deconvolution technique transforms variable rate and pressure data into a constant-rate initial drawdown pressure response with duration equal to the duration of the entire test. Plotting this response and its derivative with respect to the log of Δt versus the test duration Δt on a log-log scale gives the deconvolved [...]

What is Well Testing ? After flowing a well over a stable period via a flow meter (test separator meter, orifice place, MPFM…), shutting-in the well with a surface or downhole valve for a finite time interval defines a well test. For a producer, pressure at the well builds up during a test: This is [...]

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