Saudi Aramco is one of the pioneers in optimizing hydrocarbon production and reducing development cost using latest technologies aimed to increase gas production and enhance gas recovery. The case study discussed here shows results from an integrated approach used to drill wells in the minimum horizontal stress direction to create multiple transverse fractures during stimulation that helps enhancing production. The real challenge involved in drilling such horizontal wells is to maintain wellbore stability (especially in a transition zone from high porosity to low porosity and vice versa) mainly due to wellbore breakouts and differential sticking. Due to variably depleted reservoir pressures together with geological and structural complexities, pre-drill geomechanical models need to be updated in real-time, which require extra vigilance, in terms of optimizing mud weight while drilling, to address both formation breakouts and risk of differential sticking. If these problems are not addressed in a timely manner, initial signs of wellbore instability can aggravate with time leading to stuck pipe and loss of tool downhole. To address above issues, an integrated approach was applied during well planning and execution phases using prior drilling experience in conjunction with a geomechanical analysis to make recommendations for the planned well. While drilling, potential uncertainties in the geomechanical model due to formation heterogeneity and varying in-situ stresses, were further addressed by updating the model using real-time logging while drilling (LWD) data along with real-time drilling geomechanics (RTDG) support and advanced mud logging technology. In addition, advanced cutting return-monitoring technology was implemented which helped monitor proper hole cleaning and minimize the risk of stuck pipe due to compressional formation failure at the wellbore. Based on this analysis, revised drilling practices and recommendations were made to address the wellbore instability issues. The case study presents results from a challenging well using this integrated approach showing significant improvement in well safe delivery within planned drilling time and achieved the planned target gas rate.

Acid stimulation is an excellent method to increase hydrocarbon production and long-term formation drainage from carbonate formations. However, the stimulation effectiveness largely depends on pertinent placement method. Besides the necessity for optimized treatment design and fluid recipe, homogenous acid distribution is one of the most critical aspects for treatment success. For this purpose, a novel completion method has been deployed that allows for effective acid stimulation by maximizing formation contact in the openhole horizontal wellbore. An improved Multistage Stimulation System (MSS) that has been developed to distribute acid homogenously across the lateral is utilized, where multiple sleeves are deployed in clusters as part of a single stage, and opened with a single size ball without being limited to pump rate. It was considered imperative to have positive indications of the balls landing on the seats and the sleeves being shifted open within the zone of interest. The previous MSS system was based on severing part of the nozzles for fluid access which needed to be upgraded for better operational efficiency and production enhancement. The new completion technology is suitable for carbonate formations which are tight, heterogeneous and require stimulation to improve gas production and recovery. Wells drilled in the maximum horizontal stress direction to mitigate hole stability risks and geosteered to maximize the formation contact makes it difficult to stimulate effectively. Therefore, an improved MSS system is required to homogenously distribute the acid across the lateral during the stimulation. This novel MSS completion design was undertaken standardized, well established trial test procedure and was applied in a candidate well and included three stages where two of the stages utilized four sliding sleeves while the remaining stage was integrated with five sliding sleeves. Each stage was isolated by hydro-mechanical packers in the 5.875 in openhole. Each stage was then monitored using a new surface mounted real-time downhole monitoring system, an electronic device that enables live verification of completion operation events while being independent of pressure. The data gathered from different sources indicated that the sleeves functioned as per design. The production results exceeded the expectations. This paper describes a novel approach that enhances acid stimulation effectiveness and fulfills stimulation objectives using advanced openhole MSS completion technology. Evolution of the technology and comparison with its predecessor is discussed. It also demonstrates the use of a new surface monitoring system that supplies real time data during sleeve activations enabling clear and accurate detection of downhole events.