Water management has always been a challenge especially in mature fields. Consequently, mechanical, chemical shutoff and other water reduction techniques have been developed and deployed to curb the menace in the hydrocarbon industry. However, poor diagnostic work can be a leading reason for the low success rate for any water control method. This paper introduces a holistic workflow to understand the candidate selection, filter the wells based on priority and determine the water breakthrough mechanism to eventually select the optimal remedial action.
In this paper, 7 wells are selected and prioritized to undergo a workflow to diagnose water breakthrough and characterize it. The first analytical tool is Chan correlation, which incorporates the water-oil ratio for determining the water signature. For determining the water entry zone, Production Logging Tool (PLT) will be used as the second investigative tool. Water source identification plays another major role in assessing whether the water is coming from an aquifer, nearby injector or native reservoir fluid, which can be determined by the frequent sample collection and lab analysis for ionic concentration. These three investigative tools will provide a basis to select the proper water management strategy.
The results of the diagnosis have revealed several facts regarding the aforementioned parameters. A number of the diagnosed wells have shown a steep increase in oil-water ratio and oil-water ratio derivative, which hints to a possible nearby thief zone according to Chan correlation. Reviewing the produced water ionic concentration suggests low salinity and that the water's chemistry is closer to that of an injected water than reservoir water. Finally, Production Logging Tool showed multiple water entries in the open hole section. According to the diagnosis, Inflow Control Device deployment for those wells are recommended. Couple of multilateral wells completed with Inflow Control Valves (ICV) showed rapid channeling of water, which can be caused by a thief zone or a lateral dominating the flow and contributing high water cuts. These wells were subjected to ICV optimization and it confirmed that a latera was dominating the flow with high water cut and was optimized. The water cut for those two wells dropped by 58%.
The workflow enables engineers to understand the water breakthrough mechanism in a timely-matter, which allows them to categorize the wells based on the different water signatures such as water coning, thief zone, and near wellbore breakthrough. The proposed workflow can be adopted and adjusted based on the water management problems associated to any field in order to find the optimal remedial action. This outcome played a role in the planning of placing and drilling new wells in the field.