Water Handling and Disposal for a Rapidly Developing Field
Authors: Wilson Oliver 
Published: October 2012

Water handling and disposal comprises a significant expense in the drilling, completions, production, and operations disciplines of the oil and gas industry. With the rapid expansion of drilling, completions, and water flooding technologies, designing or redesigning water facilities to meet future conditions is vital.

The focus of this project concerned the Monument Butte field in the Uinta Basin of Northeastern Utah, where a five spot waterflood had been implemented and water trucking operations ran for fourteen hours a day. The operator in the region was drilling wells in just over three days, resulting in rapid area expansion. Consequently, water production increased substantially and current infrastructure forced inefficient means of transportation. This increased the lease operating expenses for the operator (LOE). With a limited amount of time, the goal of the project was to provide long and short term solutions to lowering the cost of transportation of water, while minimizing the spread of sulfate reducing bacteria (SRBs). This would then reduce the cost of all operations in the field.

Approaching the project involved analytical modeling and field data analysis, while maintaining a mindset to provide a safe environment for all operations. Using production data, a matrix map of deliverables was created to identify regions of high water production and consumption, and to display locations of current water facilities. Water injection wells required a constant flow rate. After daily trucking had concluded and the facilities had discharged all of the production water, fresh water was pumped as a supplement. Using mass balance calculations on the deficit facilities in the areas of high water production, it was possible to see how the addition of incremental stock tanks of varying size would increase the time until a facility reached capacity. This resulted in the trucking of water to other distant locations.

Temperatures in this area typically reached negative thirty degrees Fahrenheit in the winter, requiring the insulation and heat transfer calculated burial of truck offload pipes. These offload pipes directed water to the stock tanks. For safety purposes, new offload points were designed to prevent truck drivers from having to backup to unload water. Multiple offload points were needed at some facilities to reduce the wait times on locations. An in-house computer program was used to simulate pressure drops for different scenarios of multiple offload pipe combinations into the stock tanks to make sure the truck pumps would be able to discharge water against the hydrostatics of full tanks. Fail safe actuators were designed with solar panels for the facilities with no electricity or dry gas lines as a power source to ensure the tanks did not overfill.

The short term changes to the smaller facilities have shown improvements on trucking and freshwater costs. As a consequence, the advancements have successfully upset neighboring service companies who will be losing unnecessary business. The long term designs are currently undergoing implementation and have high expectations to dramatically reduce LOEs, which can then be delegated to further exploratory needs.