Monitoring oil and water production from all wells is very important in any deep water field development, so to manage fluid movement and maximise hydrocarbon output. The use of Smart Tracers from a company such as oil inflow specialists Tracerco integrated into a lower completion, alongside the use of waterflood tracers, provides a number of advantages over traditional oil and gas inflow measurement technologies, at a fraction of the cost.
These advantages have been showcased in a recent application which required Tracerco to install 53 oil and water Smart Tracers into production wells of a subsea development. A number of interwell tracers also needed to be installed into seawater injection wells. The oil tracers’ primary use was to verify clean out and long term oil flow from each of the wells. Water tracers were used to detect the position of water breakthrough along each well and confirm whether the water source was from the formation or injected seawater.
Regular samples of oil were taken from the common flow line transporting fluids from all wells to the production facility throughout well start up and pressure build up tests. Analysis of tracer response allowed the measurement of average inflow across specific portions of each well. Comparison of reservoir quality acquired during drilling activities matched those inflow parameters measured using the Smart Tracers.
Once the onset of water breakthrough was established, samples of water were taken on a regular basis from the comingled flow line. These water samples were then analysed to look for the presence of tracers. Detection of tracers in samples and knowledge of their position in each of the production wells allowed an assessment of where the water was originating and whether it was injected seawater or formation water. Over time, as more water tracers were produced, comparison of water tracer concentration allowed a comparative map of water cut across all of the wells.
Waterflood tracer breakthrough was eventually detected, with this originating from one of the injection wells. In parallel with the detection of the waterflood tracer, it was noticed that an additional inflow Smart water tracer had simultaneously appeared. This well was shut-in for a short time period to verify that injection water was flowing into this well. During shut-in, the waterflood and smart tracer disappeared from sampled water confirming the relationship between the injector and production well.
Full details of this initial oil inflow study and how Smart Tracers can be used to maximise full field potential now and in the future, all at a dramatically lower cost than a standard PLT, can be found be reading this article.