Integration of Conventional and Wireline Formation Testing for Improved Reservoir Characterization

Abstract

For many decades, well testing has been a valuable tool for reservoir characterization. It remains a standard practice today, while number of challenges have arisen, this including costs, time limits, safety, and environmental concerns. With safety as the top industry priority and the global shift towards a more sustainable energy future, these challenges must be addressed. In such cases, Wireline Formation Testing WFT (Mini-DST) may present a valuable alternative to conventional testing. In the case study presented, well-A was chosen. Four pretest stations were performed using an XLD probe over the same tested interval as the DST. The reservoir was found to be heterogeneous, with only one station showing a very good and unexpected mobility of 214.05 mD/cP. Pressure data from a ~35-minute Mini-DST buildup was gathered, organized, and interpreted using Kappa Saphir. A DST was then performed, and a buildup lasting 107 hours and 27 minutes was interpreted. Obtained parameters from both tests, such as permeability, skin, and wellbore storage were compared to assess the effectiveness of Mini DST and then combined to accurately characterize the reservoir. The plan was to use the WFT-PTA derived permeability to perform a nodal analysis by generating an IPR curve (Inflow Performance Relationship) and then estimate the layer’s deliverability. However, insufficient data was available to complete this step. The results showed that Mini-DST was able to support most of our assumptions regarding this reservoir being naturally fractured. Mini-DST was found to be an effective testing method that could be used to obtain a reservoir's parameters, estimate its potential (deliverability), and might be a valuable tool in the decision-making process as long as sufficient data is available. However, based on the testing objectives, Mini-DST may not be an alternative to conventional testing (DST) due to its small-scall investigation radius and the uncertainty of the reservoir's boundaries, and it should be seen as a complement rather than a replacement.