Evaluation of matrix acidizing job in a multi-layered gas-condensate carbonate reservoir using well test analysis combined with production logging interpretation

Acid matrix treatment is one of the key jobs to increase and maintain the long-term well productivity. Matrix acidizing of deep slanted wells in heterogeneous reservoirs is a challenging task. Thus, performance evaluation of pre- and post- stimulation job is of great importance. This study presents the analysis of well test data using deconvolution and also conventional pressure transient analysis (PTA), combined with the interpretation of surface well testing, data from production logging tool (PLT), and petrophysical logs to evaluate the performance of matrix acidizing and well deliverability improvement in a gas-condensate multi-layered carbonate reservoir. This evaluation can be used to optimize the acid matrix treatment strategy in offset wells and, consequently to perform an effective remediation in future wells. The diagnosis results using the surface data has indicated a successful acid matrix treatment job with having an improved total productivity index by a factor of three. Furthermore, it has shown that the wellhead flowing pressure has increased by 623 psi and drawdown has decreased to one third. Additionally, taking advantage of combining PLT and PTA analysis for multilayer systems, it has been found out that, the acid treatment has mostly affected the deepest reservoir layer with higher pressure. Hence, the unfavorable skin effect of different reservoir layers have not been removed uniformly, which needs to be considered in designing the future acid job for offset wells to control acid diversion in the reservoir towards less affected intervals.