Oman’s tight gas accumulations have been initially developed with fractured vertical wells, targeting up to 10 different hydrocarbon units, as well as with dedicated highly deviated to horizontal wells targeting the most tighter zones. The intrinsic geomechanical, petrophysical and lithological heterogeneities of these tight units, impact not only the fracture conductivity distribution, but the drainage efficiency of the fractured zones. This is observed when variations in the mobility of these units, impact their contribution once they are all commingled, with the areas of higher mobility dominating the total gas well production, as is observed for all wells architectures.

Differential depletion becomes a great challenge for the effective deployment of hydraulic fractures, for vertical and highly deviated wells in these unconventional tight gas accumulations. Key areas were identified, covering completion integrity, perforation strategy, fracture design, monitoring and diagnostics among others. Continuous mentoring and coaching was performed in parallel with the project objectives and deliverables, identifying best practices oriented to optimum fracture development while maximising investment.

This work was presented at the SPE Conference - Oman Petroleum & Energy Show -Muscat, Oman, March 2022, in a paper with the title “Deployment Strategies for Effective Hydraulic Fracturing Vertical, Highly Deviated and Horizontal Wells Across Challenging Differential Depleted Tight Gas Formations in Oman” (SPE-200073-MS)

High water production becomes a challenge for the continued development of mature heavy oil accumulations in Oman. Identifying appropriate technologies to control water inflow while maximising oil production is critical to economic viability. A rigorous and detailed technical analysis of the different suitable technologies led to the selection of the AICD technology (Autonomous Inflow Control Devices), and to the subsequent pilot field testing of some wells in these reservoirs.

The AICD completed wells showed initial water cut in the range 1% to 2%, which is significantly low in comparison to nearby analogues. The initial net oil rate resulted to be more than 2 times of the expected one, with an acceleration of ~10,000 bbls of net oil during the first month. After the initial production period, the technology is still delaying the aggressive water cut development usually observed in these fields, having provided 2 times the expected net oil rate during the first 3 months, with an acceleration of approximately 20,000 bbls of net oil over this period. It has been concluded that the application of the technology is successful and will be deployed as a baseline in all future horizontal wells drilled.

This work was presented at the SPE Gas & Oil Technology Showcase and Conference, October 21-23, 2019, Dubai, in a paper with the title “More Oil and Less Water: Heavy Oil Field Application of the Autonomous Inflow Control Devices AICD in Long Horizontal Wells - A Case Study from South Sultanate of Oman” (SPE-198554-MS)

• Introduction - Hydraulic Fracture, a holistic perspective with multiple disciplines interaction

• Subsurface characterization considering formation fluid composition, lithological, petrophysical and geomechanical properties, key elements for hydraulic fracture inflow prediction and hydraulic fracture design.

• Identification of target fracture length from an inflow perspective, using analytical and numerical approaches.

• Hydraulic fracture design considering identified target dimensions, subsurface characterization and dynamic inflow conditions.

• Completion integrity considerations under anticipated fracture loads and definition of pressure operating window.

• Perforation strategies considering fracture propagation behaviour and inflow performance of oil and gas accumulations in vertical, highly deviated and horizontal wells.

• Understanding Mini-Frac data acquisition and key tools for analysis.

• Impact of Minifrac data on Hydraulic Fracture deployment and key considerations for vertical, highly deviated and horizontal wells.

• Fracture monitoring considerations during deployment.

• Key elements of fracture diagnostics covering fracture propagation characterization, hydraulic fracture model calibration and inflow evaluation.

• Clean-up strategies to maximize fracture fluid recovery considering formation mobilities and pore pressure variability.

• Hydraulic Fracturing Implementation

• Re-fracture Operations

• Describing the challenges- Hydraulic Fracturing vertical, deviated and horizontal wells.

• Multi-stage hydraulic fracture strategies to optimize hydraulic fracture deployment.

• Advancements in design, implementation and diagnostics.