The goal of the present work is to numerically simulate the effects of wellbore orientation on fracture initiation pressure (FIP). These simulations support the study of FIP sensitivity to arbitrary wellbore position and finding the orientations that correspond to the lowest FIP. A 3D numerical model of the fracture initiation from a perforated wellbore in linear elastic rock is used to model FIP. This model is based on the boundary element method (BEM) and maximum tensile stress (MTS) criterion. The data used were from different zones and blocks of a tight gas-bearing sandstone field in the Sultanate of Oman. The amount and quality of available data allowed comprehensive model development. The model is built for the four blocks of the main field, but can be applied to the other blocks and fields. Since the equations and correlations are not empirical and not field-specific, the model is applicable to a wide range of conditions. Some practical applications of the study include selection of the optimum perforated intervals intended for fracturing stimulation in deviated or almost horizontal wellbores where different parts of lateral sections are not exactly aligned with principal stresses. Drilling wells in a particular direction to the principal stresses for the specific reason to reduce the FIP has not been tested to date and is a subject to further discussion.• Stronger completions • Revised (reduced) safety margins for the pressure during fracturing • Use of heavy brine for formation breakdown • Different (so called hybrid) fracturing schedules

This paper discusses the first fiber-optic (FO) installation in a vertical high-pressure high-temperature deep gas well in PDO, Oman. A specially designed fiber-optic cable was successfully installed and cemented behind the production casing, which was subsequently perforated in an oriented manner without damaging the cable. This paper also describes how the fiber-optic cable was used afterwards to acquire Distributed Acoustic Sensing (DAS) and Distributed Temperature Sensing (DTS) data for the purpose of hydraulic fracturing diagnostics. Fiber-optic surveillance is becoming an increasingly important activity for well and reservoir surveillance. The added complexity of the fiber-optic installation will affect the well design, which is one of the elements that requires focused attention, especially when the fiber is installed behind casing. The impact on casing design, wellhead design, perforation strategy, and logging requirements will all be discussed. In order for a well to be completed with a permanent fiber-optic cable, a few critical procedures need to be followed, including: –modifying the wellhead design to include feedthrough ports for the cable;–optimizing the cement design;–imposing strict procedures to ensure the cable is installed behind the casing without getting stuck;–changing the perforation phasing to avoid damaging the cable;–mapping the location of the cable to allow the gun string to be oriented away from the cable. The fiber-optic cable itself needed to be designed to be protected in such a way that it would not be damaged during installation and completion (perf/frac) activities. Furthermore, the cable was also optimized to improve its detectability, to aid the oriented perforation. In deep gas wells, much more than in conventional shallow water injectors or oil producers, the well integrity aspect should be given special attention. Specifically, any risks related to unwanted gas leaks, either through the control line, poor cement, or because of other design errors should be avoided. In deep gas wells, high temperature and pressure will also play a big role in the expected lifespan of the cable. Finally, the well was hydraulically fractured in four stages, using the "plug-and-perf" technique, during which DAS and DTS data were acquired continuously and across all depths of the well. The data provided valuable information on the effectiveness of each of the frac stages, it could be used to analyze screen-outs and detect out-of-zone injection, and recommendations for the optimizations of future hydraulic frac designs could be derived. The fiber-optic data were also integrated with other open-hole data for improved understanding of the reservoir performance. The next step will be to acquire repeated time-lapse DAS and DTS data for production profiling, to gain more insights of how the long-term production performance is affected by the hydraulic frac operations.

In Oman, the unique geological properties of the reservoirs require different fracture strategies and technology deployment to make them commercially viable. Highly deviated wells, with multiple hydraulic fractures, have been identified as key technology enabler for the development of tight gas accumulations in Oman. The main objective of this study is to generate a 3D petrophysical and geomechanical view of the reservoir, to have a better understating of Hydraulic Fracturing for Horizontal and Highly Deviated Wells The comprehensive amount of data captured during the initial implementation phase of highly deviated wells covering reservoir characterization, fracture geomechanics as well as production logs in combination with the existent data captured in vertical wells, proves to be complex to analyze due to the volume of information and the multi variable nature associated with fracture and inflow predictions. A methodology was required where correlations and tendencies were identifiable at structural level, covering all target gas accumulations using all the static and dynamic captured data. The definition of a 3D Grid Visualization Block (3D-GVB) was introduced where all the captured parameters were distributed for analysis and interpretation. As a result of the appraisal and initial field development with vertical wells, it was possible to identify tight accumulations that will require dedicated highly deviated wells for its development. The initial phase of the implementation of highly deviated wells proves to be challenging, as the observed heterogeneities on geomechanical and petrophysical properties across the target gas accumulations, combined with differential depletion and the wells orientation to generate transverse fractures, creates a complex environment for fracture initiation and propagation, impacting not only fracture deployment but inflow deliverability of this wells. This paper will describe how the methodology uses a cycle of data analysis and interpretation to identify tendencies, that will lead to correlation and new algorithms that are retrofitted on the 3D-GVB platform, leading to optimization of well positioning at structural level, drilling and completion of this highly deviated wells. It will be described how this methodology is used for well positioning at structural level, to define well architectures oriented to enhance not only drilling, but also hydraulic fracturing and hydrocarbon deliverability on highly deviated wells.

The ultimate goal of hydraulic stimulation in terms of business value is "production", especially in those cases where the well is approaching the economic limit, is to increase the hydrocarbon flow, improve the ultimate recovery and make it profitable. During a sing stage fracturing operation, extensive data is produced. Unfortunately, less than 10% of the data are properly preserved. Finally resides in corporate repositories. Comparable is the case of knowledge, where just in few cases, previous lessons learned are taken into consideration when designing a new job. Data Quality and human talent dedication are not the exception; data completeness levels of just 40% has been estimated. While Production Technologist and Frac Engineers during a normal Frac design, dedicate nearly much of their time on searching for data. It was identified the need for having a centralized database, and avoid the dissemination of "local" customized spreadsheets to track the fracturing activities. At the same time, there were no fracturing workflow identified, instead, multiple version depending on each well/cluster approach. Hydraulic Fracturing Project emerged as a corporate initiative to support the HF evolution, and the vision to provide the business the best tools (knowledge, standard process, data, and technical resources) to get the maximum benefit from this broadly adopted technology. The paper discusses the analytical aspects, operational workflow and administrative and quality control for properly managing the Frac data, from pre-Frac (job design) to post-Frac (job performance evaluation), embedding Frac execution, and including workflow. The data base allowed efficient management of hydraulic fracturing operations, better identification of the fracture candidates, and better design of fracturing treatment, Hence, Frac Platform will improve efficiency, performance & delivery well targets that could essentially reduce resources in data management.

A detailed geomechanical study has been performed for a tight field in the Sultanate of Oman. This study included computation of fracture initiation pressure (FIP) applying the boundary element method (BEM) and maximal tensile stress (MTS) criterion using 3D numerical modeling. The goal of the present work is to numerically simulate the effects of wellbore completion type on FIP with arbitrary wellbore position and finding the conditions that correspond to the lowest FIP. The model is based on the BEM. Since the equations and correlations are not empirical and not field-specific, the model is applicable to a wide range of conditions. The data used for this project were from different zones and blocks of a tight gas-bearing sandstone field in the Sultanate of Oman. The amount and quality of available data allowed comprehensive model development. The model is built for the four blocks of the main field, but can be applied to the other blocks and fields. Two horizontal wells parallel to each other 400 m apart have been recently completed with different completion types, which allowed reasonable comparison of actual and modeled breakdown pressures for open and cased holes. Two vertical wells in different blocks have been completed with openhole sections with subsequent placement of hydraulic fractures. Discussion on the effectiveness of this completion type over the typically used cased and cemented completions in regards to breakdown pressure and overall well efficiency is provided. Some practical applications of the study include input for the decision on the completion type in vertical and horizontal wells.