FIELDWIDE DYNAMIC PRESSURE SURVEILLANCE WITH FPWD TECHNOLOGY

Abstract

Reservoir management utilizes time-lapse pressure data that is captured over years in order to monitor reservoir development. Several methods can be used to establish field-wide hydraulic lateral and/or vertical connectivity: well testing, monitoring of permanent downhole gauges, wireline and LWD formation testers. While a typical formation pressure survey provides information about reservoir depletion or charge (production or injection), in a field with several wells it is not clearly understood where the pressure disturbances are coming from, which can hamper further field development decision making in terms of infill well selection and drilling. A novel method is introduced where a Formation Pressure While Drilling (FPWD) tool is run in UKCS wells and used to acquire interference data while drilling. Initially reservoir pressures are acquired as soon as practically possible after drilling. Having established these benchmark pressures, nearby injectors and/or producers can be started or shut in one at a time. Drilling is then resumed and after a certain time has elapsed since the benchmark pressure acquisition (typically at least 12 hours), the pressure measurements are repeated using the FPWD tool to evaluate the influence of the created transients in order to prove or disprove either lateral or vertical hydraulic connectivity across reservoirs. This way, the influence of a single offset well is evaluated in real time over the reservoir being currently drilled. This helps in the determination of interference pattern whereby injector wells can be judged for selective zone injections and producers can be rated in terms of zonal contribution which can help in completion design. These direct pressure measurements can illuminate reservoir pressure complexity seen in mature fields and provide operators with the means to safely and effectively construct wells to develop brownfields. The pressure changes obtained are used not only by reservoir engineers as an additional source of dynamic data into the reservoir simulation model but also help geologists in refining the geological or basin model. Two applications of real-time interference testing using FPWD from a recent drilling campaign are shown. In the first application, communication between wells is tested to reduce the risk of accidentally completing a well in an area of the field that experiences insufficient injection support. In the second application, real-time interference testing is used to identify a specific zone in a multi-layered reservoir sequence in order to enable selective completion.