#TITLE_ALTERNATIVE#

• Main Author: CAHYADI (NIM : 12214100), STEPHEN
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31091
• Institution: Institut Teknologi Bandung

The process of determining radius of investigation during pressure transient testing play a critical role in estimating the reserves of reservoir. Through that fact, it could determine the results of several important decisions in oil and gas industry. Various means to determine radius of investigation have been proposed since couple decades ago. However, those concept yield into different results of radius of investigation, and yet it still ambiguous and unclear. Recent study has shown better definition, and quantifiable radius of investigation, it also provide more general formula to calculate the radius of investigation in infinite-acting radial reservoir. Nevertheless, the formula was derived by approximating the exponential integral expression and it needed iterative technique in its calculation process. These could bring uncertainty and limitation of usage at some extent, moreover it would be inconvenient to use the formula in such manner. By using the definition of radius of investigation i.e., the location at given spatial coordinate and time, where the pressure change become observable, this paper proposed a new method to determine the radius of investigation in more sensible and convenient way. We established a relationship between the radius of investigation and parameters such as observable change of pressure, oil rate, permeability, reservoir thickness, and other parameters which have been included in conventional formulas by using a semi numerical approach, which incorporate pressure profile generated from ECLIPSE simulator, various observable pressure change, and linear regression. The relationship was then found and presented in a linear equation wherein it was applied to several case studies, where permeability, reservoir thickness, gauge resolution, and oil rate were varied. The results indicated that the dimension of radius of investigation can be either equal, higher, or lower than the ones that was calculated by using the conventional formulas, depended on the value of each parameters mentioned above. These differences would lead to different reserve’s estimation, and if not well recognized, it could mislead the decisions making process in the industry. By using the proposed method we can better quantified and recognized the limitation of radius of investigation calculation. Hence, it could provide more favorable consideration when several important decisions in oil and gas industry are being made.