One of the principle concepts to understand any hydrocarbon field is the heterogeneity scale; This becomes particularly challenging in supergiant oil fields with medium to low lateral connectivity and carbonate reservoir rocks.
The main objectives of this study is to quantify the value of the heterogeneity for any well in question, and propagate it to the full reservoir. This is a quite useful specifically prior to conducting detailed water flooding or full field development studies and work, in order to be prepared for a proper design and exploitation requirements that fit with the level of heterogeneity of this formation.
The main tool used for these purposes is the application of the famous Lorenz coefficient method for calculating the degree of heterogeneity for any well. The starting point for this kind of complicated studies needs to start from the basics, in order to understand the big picture and be able to plan properly for the scope to be delivered, hence, utilizing analytical tools like the ones mentioned above becomes quite necessary, if not crucial, to the success of full field modelling and choosing an optimum water flood pattern and design.
This paper covers the methodology for quantifying and calculating the level of heterogeneity in a given reservoir (Majnoon Field/Hartha Reservoir) using three out of four original wells of this reservoir, and how this value impacts and directly feeds into planning for water flooding projects and selection of an optimum flood pattern.
This methodology has been tested successfully in the stated super giant oil field, in which the reservoir in question is a carbonate rock formation. It is important to note that the chosen reservoir is giant areally with moderate thickness. An example of this is covered in the paper. It was concluded that utilizing a heterogeneity calculation method before conducting a detailed reservoir simulation study can save a lot of time and effort by providing guidance to the path which needs to be followed, and sheds light on the critical elements to be looked after. This has also helped to uncover many insights on the reservoir itself, hence allowing the engineer to plan for the necessary voidage replacement and water injection rates to sustain the reservoir pressure and pattern development.
The suggested method, in combination with geological and petro physical information available, can be applied to majority of the reservoirs. This combination is paramount to ensure optimum time and planning is followed for each reservoir development study that involves water flooding.