New Model for Water Finding

Abstract

Find & Plug is defined as locating water zone in either vertical or horizontal well and shut it off. The most challenging job in a horizontal completion well is to locate the water producing zone, especially after a period of production over time. Once the water producing zone is precisely located, either mechanical or chemical isolation can be deployed to shut the zone off. PLT and donwhole monitoring such as fiber optical and downhole gauge are common technologies to locate the water zone. PLT log is somewhat risky and/or questionable to determine zones production profile when well relies on sucker rod for production or horizontal completed. Data is only for 6-12 hours duration which may not reflect the dynamic change of reservoir water influx. Fiber Optics can only measure zone pressure and temperature. To achieve the production profile, a mathematical model must be setup. Many parameters in the model are estimated and therefore the calculation or simulation of water producing downhole is overall questionable. Permanent gauges have to be deployed attaching onto tubing or casing. Wire has to go down to production zones thru the tubing or casing. It will take some rig time and is costly to deploy. This paper proposed a new model using polymer tracer to deploy with tubing alongside the production zones, either vertical or horizontal, with or without packers for isolation of each zone, to measure the liquid profile of interest zones at initial production and water profile of interest zones over a period of production. By deploying the polymer tracers near the production zones, the tracer sub will be installed atop or below the zones depending on where the ICV is located. When liquid and water produced from each zone, it must pass through the tracer sub where the tracers will dissolve into the produced water at initial stage and diffuse into produced water after the dissolution process is almost saturated. Surface samples of liquid and water will be taken by a designed sampling program and sent to lab for analysis. Analysis data will be interpreted by SHANIP and SHANWC model. SHANIP model is a mathematical formula which establishes relationship between produced tracers and zone liquid concentration at initial production. SHANWC model is a mathematical formula which establishes relationship between produced tracers and zone water concentration after the dissolution process is almost terminated. If packers are installed between interest zones to isolate the zonal production, SHANIP and SHANWC model can quantitative measure each zone liquid production and water concentration over a period of production. The period can be 6 months, 1 year or even longer depending on the amount of tracers installed and volume of water producing. If no packers are isolated between interest zones, a qualitative analysis to zonal water cut can be achieved. Those include major water producing zones, no production zones, low water cut zones, etc. With SHANIP and SHANWC models, clients and researchers in O&G can easily and economically evaluate the zones water cut at any time they wish. And no intervention is necessary except for the first tubing deployment.