The nature of tight gas reservoir consists of heterogeneous sub-units separated by impermeable denses and various depletion level has become the greatest challenge on how to exploit this typical reservoir at its maximum. Despite maximum reservoir contact is the best method to deliver the highest well production, this paper tries to tell another success story about UBCTD applied in a triple lateral well which can deliver greater productivity than a normal overbalanced multilateral well. The study methodology begins with the evaluation of the current remaining potential sweetspots throughout the reservoir. The assisted history matching is used to generate 3 different model realizations: Low - Mid - High case that can map-out sweetspot distribution called Simulation Opportunity Index (SOI) map. SOI integrates 3 independent components selected from static and dynamic parameters: reservoir permeability-thickness, movable gas and reservoir pressure from a historically-matched dynamic model. One particular area is then selected and evaluated furthermore for the final new well and trajectory placement. The well was drilled as a triple lateral with one of the lateral was fully placed in prime sub-unit that likely holds the potential remaining sweetspot in the area according to SOI method with expectation to maximize its recovery. During the drilling, UBCTD technique was implemented because it offers several advantages such as reduction of formation damage, reduction of drilling fluid loss into formation, avoiding losses-related drilling problems and risk of differential sticking and creating cost saving for completion and stimulation requirements. Earlier study in the field signified that generally, the well productivity is strongly influenced by the type of the lateral and the geological structure. For instance, the triple lateral well located at higher structure normally gives higher productivity than the triple lateral well located underneath it. Theoretically, higher productivity will be given by the triple lateral compared to the situation if the same area is developed by dual lateral or even by the single lateral well. Currently, the implementation of UBCTD in this triple lateral well was confirmed to provide better productivity up to double exceeding a conventional overbalanced with the same well laterals. Greater initial gas production rate with high THP was evidenced during the well clean-up. UBCTD application in tight gas reservoirs is not only aimed to improve the initial well productivity significantly beyond the conventional overbalanced well but it is also expected to create more equal pressure drawdown distribution along the lateral drain because of many given advantages as stated above. At last, cost saving can be performed because the operating cost which is usually spent on normal wells for well stimulation can be reduced.

Reservoir X is a marginal tight gas condensate reservoir located in Abu Dhabi with permeability of less than 0.05 mD. The field was conventionally developed with a few single horizontal wells, though sharp production decline was observed due to rapid pressure depletion. This study investigates the impact of converting the existing single horizontal wells into single long horizontal, dual laterals, triple laterals, fishbone design and hydraulic fracturing in improving well productivity. The existing wells design modifications were planned using a near reservoir simulator. The study evaluated the impact of length, trajectory, number of laterals and perforation intervals. For Single, dual, and triple lateral wells, additional simulation study with hydraulic fracturing was carried out. To evaluate and obtain effective comparisons, sector models with LGR was built to improve the simulation accuracy in areas near the wellbore. The study conducted a detailed investigation into the impact of various well designs on the well productivity. It was observed that maximizing the reservoir contact and targeting areas with high gas saturation led to significant increase in the well productivity. The simulation results revealed that longer laterals led to higher gas production rates. Dual lateral wells showed improved productivity when compared to single lateral wells. This incremental gain in the production was attributed to increased contact with the reservoir. The triple lateral well design yielded higher productivity compared to single and dual lateral wells. Hydraulic fracturing for single, dual, and triple lateral wells showed significant improvement in the gas production rates and reduced condensate banking near the wellbore. A detailed investigation into the fishbone design was carried out, this involved running sensitivity runs by varying the number of branches. Fishbone design showed considerable increment in production when compared to other well designs This paper demonstrates that increasing the reservoir contact and targeting specific areas of the reservoir with high gas saturation can lead to significant increase in the well productivity. The study also reveals that having longer and multiple laterals in the well leads to higher production rates. Hydraulic fracturing led to higher production gains. Fishbone well design with its multiple branches showed the most production again when compared to other well designs.

The trajectory placement of a horizontal well that crosses a heterogeneous tight gas carbonate reservoir is one of the important elements that contribute to the success of well productivity. Proper placement can yield good production and vice versa improper placement may give low well productivity. An effort was studied to improve the well productivity from an existing single horizontal well that was initially placed in sub optimal location by implementing the Fishbones completion technology (work-over). In this paper, Simulation Opportunity Index (SOI) has been selected as a method to indicate the remaining gas sweet spot throughout the reservoir. SOI integrates 3 independent components extracted from static and dynamic parameters; reservoir permeability-thickness, movable gas, and reservoir pressure from a historically-matched dynamic model. By utilizing SOI, a map of the prospective gas sweet spots can be created; hence low performance existing wells are utilized to exploit the surrounding potential sweet spots using Fishbones completion, which consists of tiny short needles with a maximum effective length of 32 feet placed along the horizontal section. The study reveals that the Fishbones completion application on existing low-productive horizontal well can multiply the well productivity in multi-layer reservoir environment in addition to the significant production gain. Assisted History Matching (AHM) is used to explore the best scenario of Fishbones features combination, such as the number of Subs required as the container room to hold the needles, the optimum needles length, and the optimum lateral drain section to place the Subs and needles. Many sensitivities with the abovementioned variables are run at once, and the analysis is conducted to identify the most impacting parameter to bring the highest well recovery. The use of SOI method to scrutinize the best location of well candidatures for Fishbone application and the required Subs and needles placement is not only able to rejuvenate the performance of the problematic well, but it can aid in generating CAPEX saving and efficient project schedule to manufacture Fishbones with a proper number of Subs and needles compared to blind Fishbone technology installation. A combination of two techniques between reservoir simulation study to generate SOI with the new advanced completion technology called Fishbones applied on low-performance existing horizontal well is the real study integration with the final objective to increase the ultimate gas recovery in a tight gas carbonate reservoir. This is a breakthrough solution to optimize the development of tight carbonate gas fields in addition to the conventional development strategy with normal infill drillings.