Over the past 18 months energy prices have declined more than 50%. This has placed significant constraints on energy companies who are experiencing major declines in operating cash flow while maintaining shareholder distributions. Increasingly, the response has been to cancel or delay capital-intensive projects while attempting to materially improve efficiency and reduce operating costs. Improving the efficiency of Base Production, defined as production from existing wells and fields, has been a particularly effective way for BP to improve or maintain production levels at relatively low cost. This is not without major challenges as Base Production includes fields/wells which are heavily depleted and/or liquid loaded. Offloading these types of wells requires specialized skills and simulation tools one of which is described below.
OLGA or Oil and Gas Simulator is a dynamic multiphase modelling tool which is used to simulate flow behavior of petroleum fluids from the reservoir to onshore gathering systems. It utilizes finite element analysis to divide the well or production system into elements which together create a mesh intersecting at nodes. After boundary conditions are introduced the simulation is completed in a series of several thousand time steps by solving system equations for each element with the outputs from one time step used as the input for the next one.
With this powerful calculation method, engineers are able to investigate the behavior of complex and irregular shaped systems, such as wells and networks, to determine the optimum range of pressures and temperatures to optimize production. For well offloading, dynamic modelling is used to evaluate the offload against various platform, well and reservoir parameters to understand and mitigate risks. Simulations are also completed to ensure new wells either have enough pressure energy to remove completion fluids and flow into the gathering system or to determine if a depressurized volume or reduced system pressures are required.
This approach has positively impacted wedge production delivery for the company as the Subsurface Team is able to better influence well offloading strategy at the early stages of planning therefore reducing instances of production downtime.