Stimulation Efficiency with Significantly Fewer Stages: Perforation Strategy Combined with Multimodal Diverters and Novel Nonintrusive Monitoring Algorithm

Abstract

Tight carbonate development is moving towards longer laterals requiring a higher number of fracturing stages to complete a given well. A higher stage count implies longer completion time and higher costs. Therefore, an engineered strategy using technology enablers is indispensable to reducing the number of stages while retaining the well performance objective. A 6,250-ft cemented lateral initially planned with 13 fracturing stages was analyzed for lithology and reservoir development to revise the perforation strategy to complete with more clusters per stage and reduced the number of stages to 5 stages. Clusters were designed to be very narrow to effectively divert the fracture fluids using chemical diversion. For a successful stimulation evaluation, a novel pressure monitoring technique was used to analyze the fluid entry points from the water hammers. Pills of multimodal particulate near-wellbore diverters were used across the lateral to stimulate the perforated clusters in only five fracture stages effectively. The multimodal particle distribution model allows for bridging and then creating an impermeable flow barrier to ensure diversion. Effective diversion was seen through a pressure increase when diverter entered the formation. Correlations were analyzed for diversion pressure dependence on pill volume and injection rate to improve diversion. A new algorithm for nonintrusive diagnostics was also deployed. The algorithm combines advanced signal processing with a tube wave velocity model based on Bayesian statistics and has no additional operational footprint. The program allowed a timely interpretation to evaluate the fluid entry points based on the water hammer events. This evaluation was compared to the intuitive stimulation sequence based on the lithology to explain the results. The comprehensive analysis demonstrated the lateral was stimulated effectively. Finally, the production performance was compared with two offset horizontal wells intersecting the same carbonate sublayer. Offset 1 was a cemented lateral completed with 12 stages, and offset 2 was an openhole packer and sleeve lateral completed with 7 stages. Analysis of the post-fracturing absolute production enhancement showed 11 to 15% improvement and production index (PI) improvement was 40 to 63% when normalized by stage count. The paper presents a rare and unique strategic integration of multiple technologies. This success paves the way for similar future developments to enhance operational efficiency and allow significant cost savings.