Innovative Drilling Methodology by Integrating an Advanced Simulation Approach for Recovery Optimization of Horizontal Wells

Abstract

Abstract After the progressive advancement of the drilling technologies, such as mud motors and afterward rotary steerable systems, the successful execution of high angle wells became a common practice in the oil industry. Although the associtated costs have much superior magnitude when compared to the ones related to vertical wells, the production factor is normaly improved by multiple times, turning such trajectory design very suitable. However achiving the key performance objectives, e.g., consistent and effective net pay interval along the horizontal section, can be extremely difficult. There are many geological and geophysical reasons, such as the lateral discontinuities of the reservoirs and intrinsic seismic uncertainties. To overcome such challenge, Well Placement technique is used to interactively position the well based on geological and seismic criteria together with real time Logging-While Drilling data. Despite the fact of covering the technical disciplines of drilling, geology, petrophysics and geophysics, most Well Placement approaches rarely take into consideration reservoir engineering aspects when geosteering horizontal wells. Therefore the project objectives were to evaluate the impacts in the productivity generated by the geometrical changes in the trajectory through numerical reservoir simulation. The research work was then divided into two parts. The first one was the creation of a representative 3D synthetic reservoir model where numerical simulations were applied for each trajectory design. A detailed sensitivity analysis was made by comparing the results among the different trajectory cases in order to identify the relationship between well positioning and its productivity response. The second part consisted of a real geosteering case study. Around both planned and executed wellbores, it was created a detailed reservoir model enhanced by LWD inputs. Afterwards, reservoir simulations were performed in order to evaluate the impacts caused by trajectory variations, demonstrating the expected productivity results versus the actual. This research study shows that there is a productivity impact in all reservoir fluids when well trajectory is subjected to geometrical variations. Thus it reinforces that predictions related to reservoir production should not only be performed on planning stage, but most importantly during or after well conclusion using relevant inputs, such as the actual well path, LWD logs, and formation pressures while drilling, which all combined provides an enhanced reservoir model, and so a more accurate forecast analysis.