A useful spreadsheet based production prediction and surveillance program has been developed at the Vanyoganneft JV in Nizhnevartovsk, Russia. This paper will describe the program which will demonstrate application of fundamental petroleum engineering principles in a very practical, real time and hands on manner. As a result of this tool, real time reservoir management decisions are made, including production improvement opportunities.
This desk top surveillance program applies the fundamental principles of fluid flow with an understanding of rock properties. The program is regularly calibrated with surveillance data such as fluid gauges, pressure, logging data and sector material balance. The spreadsheet program also attempts to predict fluid flow behavior in wells with more than one producing zone. This feature has been particularly helpful in managing reservoir strategy and understanding reserve balance.
Use of the tool has helped engineers to establish a fundamental understanding of the reservoir, including reserve balance, monitor reservoir management strategy, and identify production improvement opportunities. We conclude that this tool does not replace reservoir simulation but helps with its appropriate application. It also, in a very practical manner assists in reservoir management strategy.
Within the Vanyoganneft organization, in western Siberia, a need was identified for a useful desktop reservoir surveillance tool. The surveillance needs were particularly recognized in view of many active wells; many operated zones and commingled production zones. The technical staff was also relatively young and new to many petroleum engineering principals. Therefore the surveillance tool was created to assist the staff in evaluating well performance, calculate the well and zone operational indices, estimate current and expected oil decline rates, predicted oil recovery factors within current completion zones, and evaluate for producing skin factors; The program also helps identify when skin was developed, thereby thereby serving as a real-time skin indicator and well stimulation identification tool.
The program is created in Microsoft Excel. The program consists of the many linked files, each of which is described below.
The first data file contained with the spreadsheet prediction program contains well gauge information. These files are created for each of the wells participating in calculations. Each file contains:
A complete gauge history (oil rate, fluid rate, water cut), of each well, and specific to the zones of completion within the wellbore.
History and prediction of formation pressure and GOR change within each well. The pressure record is either measured data which has been collected within the well or extrapolated data from regional wells. The reservoir pressure history is forecasted.
Additional surveillance data including: dynamic fluid levels, telemetry system data, annulus pressures, depths of ESP pumps installations, and directional survey data;
PVT data and estimated permeability data.