Validation of a Novel Beta Diversion Design Factor for Enhancing Stimulation Efficiency Through Field Cases and Near Wellbore Diversion Model

Day 1 Mon, October 03, 2022

Hansen

et al. 2022

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.

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

Day 1 Mon, October 03, 2022

Hansen

et al. 2022

Effective Well Engineering Approach for Completion Intervention, Stimulation and Flow Measurement to Enhance Efficiency and Production Performance

Alharbi

SPE Asia Pacific Oil &Amp; Gas Conference and Exhibition

et al. 2022

Well completion practices in high-temperature, high-pressure carbonates are challenging especially for long lateral horizontal wells intended for fracturing applications. An integrated approach involving intervention and fracturing design and reliable post-fracturing flow measurements is very critical to optimize the well performance. After initial intervention complexities due to wellbore accessibility in a 6,250-ft cemented lateral initially planned with 13 fracturing stages resulting in the loss of many operational days, a revamped engineering workflow was planned for Well-A. As a first step, Coiled Tubing (CT) was used for abrasive jetting perforations, cleanout, and acid squeeze functionalities with a novel bottomhole assembly (BHA). The BHA was equipped with a real-time telemetry to optimize intervention to a single run. Having real-time bottomhole parameters helped in perforating the desired zones accurately and enhanced the injectivity by creating cleaner perforation tunnels. Stages were reduced to five with an optimized perforation design based on rock typing approach, and short clusters were designed to divert the fracture fluids effectively using multimodal particulate diversion. Each fracturing stage was isolated with a mechanical plug. A novel high-frequency pressure monitoring technique that analyzes fluid entry points from water hammers was utilized during the fracturing treatments to analyze on-the-fly diversion efficiency and optimize further treatments. A multiphase flowmeter was utilized to enhance milling and flowback to minimize losses and manage the choke schedule based on actual well performance leading to better fracture cleanup and recovery. The production performance of Well-A was compared with two offset horizontal wells drilled azimuthally parallel, intersecting the same carbonate sublayer. The post-fracturing absolute production enhancement analysis showed 11 to 15% improvement, and productivity index (PI) improvement was 40 to 63% when normalized by stage count. The effective integration of multiple technologies was applied successfully on the candidate well, yielding enhanced operational efficiency with optimized production performance.

Comprehensive Design and Diagnostic Approach for Horizontal Completions in Carbonate Environment

Day 1 Mon, October 31, 2022

Al-Mulhim

et al. 2022

The development of tight carbonate reservoirs is moving towards drilling and completing wells with longer laterals. This leads to challenges of longer completion time, high number of fracturing stages, longer interventions, and eventually higher costs. Design cycle implementation is required to devise an engineered strategy to mitigate these challenges. Lateral landing was conducted based on the cross-section grid consisting of two offset horizontal wells completed with up to 13 fracturing stages. A longer lateral greater than 6,000 ft was drilled compared to 4,000 ft in offset wells to get the production potential. With a strategic design involving engineered chemistry and numerical simulation models, a cluster design was devised to reduce to stages. A mathematical algorithm employing tube wave velocity calculations was used as a diagnostic to ensure diversion success after each stage. The horizontal lateral was landed traversing the prolific layer. Stage reduction sensitivity simulations were conducted using multiphysics numerical models and novel beta factor workflows to evaluate the extent of stage reduction. The design was extended to plan for five stages only, with increased number of perforation clusters per stage. The reliable diversion chemistry utilized was accompanied by a revised perforation length as dictated by the beta factor workflow. A total of 39 clusters, 2-ft each, were distributed across 6,000 ft with four mechanical isolation plugs. A novel nonintrusive diagnostic model built on mathematical fundamentals of wave travel time was used with a Bayesian statistical approach after each diversion pill placement to ensure fracture fluid entry points and enough coverage in each stage. The high fluid viscosity and operating pumps during the water hammer events resulted in low signal-to-noise ratio in the input data. To overcome these limitations, the water hammer events were processed with a combination of two newly developed algorithms: predictive deconvolution and comb filter, which produced more robust results than the traditional approach. Consequently, the well production was analyzed to show equivalent or higher productivity index compared to the offset laterals with up to two times higher stage count. The paper presents a unique example in which an experiment was fully engineered from design to evaluation and monitored with reliable diagnostics. This example gives a blueprint for future completion designs.