Key components in the economic evaluation of either production or development prospects are the capital requirements and operating costs of a brine disposal system. Many times, emphasis and attention are given solely to the potential and resulting cash flow from production. Proper planning requires that consideration be given to producing costs. A key component of producing costs is the cost of operating a brine disposal system and the required capital investment.

Several Issues must be addressed in order to gain an understanding of the true cost of brine disposal. Generally, in the oil and gas industry, brine is disposed into SWD wells via underground injection. The cost of disposal is dictated by the depth of the disposal interval, the formation characteristics (i.e., thickness, skin, permeability, pore pressure, frac gradient, porosity, injection area), tubular sizes and the maximum allowable wellhead injection pressure. The anticipated fluid volumes to be injected into each well, well life and the number of required injection wells are critical in assessing the true cost of managing an underground injection project. Unrealistic assessments initially can result in less than desired economic consequences.

This paper is a description of an underground injection cost model that will provide the capital and operating costs and optimize those costs based on hydraulic fracture design under specified reservoir conditions.

Generally, the process to develop brine disposal operating cost include the use of 3D reservoir, fracture and economic models. Various sensitivities must then be run and the results compiled in order to property estimate capital and operating costs. This model incorporates all key parameters and sensitivity analysis is done very quickly with a minimum of input. The model has correlations for many parameters that need to be estimated or calculated utilizing conventional models. This decreases the amount of design time, data required and familiarity with sophisticated models, and allows for easier parametric analysis. The model also allows for the user to input and modify additional parameters if the data is available.

You can access this article if you purchase or spend a download.