Objectives/Scope
Wafra Joint Operations is a joint venture between Saudi Arabian Chevron and Kuwait Gulf Oil Company. Some of the wells in this area are completed by 7in casing and the artificial lift system is sucker road pumps. There is lack of production logging measurements due to the casing size constraint which is a barrier to use ESP with Y-tool to perform production logging surveys in these wells. Also, the determination of current water saturation behind these wells is challenging due to the low formation water salinity (formation water salinity is 4,000-20,000 ppm). Recently, the water-cut increased in these wells up to 100% and performing production logging is necessary to determine the water production source.
Methods, Procedures, Process
In this case study, Flow Jet pump technology was used to lift the well and perform combination of production logging and pulsed neutron-neutron surveys while flowing conditions as the first time in this area. This combination was successfully used to determine the contribution profile, the source of water production, and the current water saturation.
Results, Observations, Conclusions
The production logging measurements showed that all production is from two perforation segments and water hold-up is 100% across the two fluid entries. Crossflow was observed while shut-in conditions. Also, the pulsed neutron-neutron measurements showed high oil saturation against some of the non-contributing and some of the unperforated intervals. The active perforation intervals have been squeezed by cement, re-perforated some of the non-contributing intervals, and added some of the new intervals based on current saturation profile. The results of this well intervention showed a sudden drop in water-cut from 100% to less than 46% and high oil gain from the well.
Novel/Additive Information
The Flow Jet pump technology enabled the production logging and pulsed neutron-neutron measurements during flowing conditions. This will greatly affect the reservoir management and well-work plans.