Dynamic data, acquired using wireline formation testing or well testing techniques, are used by operators to address uncertainties associated with reserve estimates and productivity, while rationalizing field development and production costs. However, these evaluation techniques provide dynamic data at different length scales, and with different environmental footprint, cost, and operational constraints.
To help reduce development risks, a Deep Transient Testing (DTT) technique was developed in response to an industry and customer need in 2015 and has been used since then by many oil companies. The method is a hybrid technique between wireline formation testing and Drill Stem Testing (DST) designed to meet local regulatory requirements to unlock reserves. It is based on innovations with higher resolution measurements, pumping of large fluid volumes on wireline at higher rates, extending testing time and circulating the produced fluids out of the well for safety and well control, without the requirement for surface flaring.
These features enable dynamic reservoir characterization in thicker formations, higher permeabilities and with much deeper volume of investigation than previously available. Pressure transient testing and sampling results from DTT technique is now becoming an important component in operating companies’ reservoir evaluation programs. The DTT technique is embedded in a digital framework to provide early reservoir fluids models and reservoir insights coupled to geological models, so that well deliverability and prospect commerciality can be evaluated. DTT also aligns with global sustainable development goals, by enabling reductions in CO2 emissions by up to 96% percent, and offering high operational efficiency compared with other wireline formation testing systems to significantly reduce energy consumption.
SPE Distinguished Lecturer: François-Xavier Dubost, Reservoir Technical Director at SLB
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