Engineered Perforation and Tubular Movement/Stress Modeling in Optimization of Complex Hydraulic Fracturing Application in Deep, Tight, Sour and HPHT Carbonates in North Kuwait

Day 3 Wed, November 17, 2021

Al-Otaibi

Al-Saeed

et al. 2021

The development of North Kuwait Jurassic gas assets has strategic importance for Kuwait's production strategy as the only non-associated gas-producing field in Kuwait. This paper demonstrates the benefits, challenges and lessons learned of the recent paradigm shift in Jurassic tight gas wells’ completion strategy from cemented liner to multi-stage completion. Successful expansion of Multi-Stage Completion (MSC) technology is achieved at the field level led by the integrated team efforts in 2020/21, despite challenging constraints of COVID-19. MSC's help to enhance overall well production potential, overcome reservoir and intervention operation challenges, and allow early production delivery, which is a key factor to achieve a strategic asset production target of 70-80% by 2024/25. Many technical and logistic challenges were experienced during first installations of which the relevant learnings will be shared in this paper. The Jurassic gas asset produces mainly from deep high pressure and temperature, conventional and unconventional tight carbonate reservoirs. The recovery from such complex heterogeneous reservoirs is extremely challenging if conventional development strategies are applied. Therefore, a dedicated full development plan applying integrated upstream and downstream technologies is important to achieve the strategic production target. Due to the excessive Jurassic carbonate reservoir tightness, permeability contrast and dual permeability effect (matrix and natural fractures), well productivity potential significantly depends on the effectiveness of subsequent stimulation treatments of such complex heterogeneous reservoirs to improve well productivity and potentially connect with natural fractures. Selecting proper well completion design is critical to overcome such reservoir challenges and ensure effective acid stimulation treatments for the mix of conventional and unconventional formations that need convenient diversion mechanism during stimulation to enhance the productivity of each individual reservoir flow unit and enable selective future flexibility of re-stimulation and reservoir management. The asset team has recently applied a step change in completion strategy to open hole multi-stage ball drop completions using state of the art MSC technologies including closeable frac sleeves, full 3.5-in monobore ID post frac sleeves milling and debris sub enclosure to protect the MSC string during casing tie-back operations. This is to overcome reservoir complexity, eliminate wellbore cleaning and decrease the challenges and risks that accompany multiple perforation intervention operations. As well as, eliminate cement quality risks and uncertainties, improve overall cost, and fast track well delivery to production to meet asset production targets by significantly reducing operation time from approximately one month for plug and perf techniques to less than one week when using continuous and less subsurface intervention operations. Recently, a total of 13 new MSC installations and subsequent multi-stage stimulations were achieved in seven months, fromQ3-2020 to Q1-2021, with positive overall production results, significant improvement of intervention operation efficiency and faster well delivery to production. This paper will describe the details of progress to date, and the plan forward for optimization and new technology trials to further improve well performance.

Paradigm Shift from Cemented Completions to Multi-Stage Completion Strategy for Managing Tight Gas Development Challenges

Day 3 Wed, November 17, 2021

Al-Otaibi

Al-Saeed

et al. 2021

First Time in Kuwait: Successful Hybrid Multistage Completion Accelerates Production of Najmah Unconventional Jurassic Gas Reservoir

Day 3 Wed, November 02, 2022

Bloushi

Al-Mutawa

et al. 2022

North Kuwait Jurassic Gas asset development has strategic value of gas independency for Kuwait as it is the only non-associated gas producing asset. This paper will share the experience, added value, challenges and lessons learned from the successful implementation of first ever Hybrid 15k Multi-Stage Completion in Kuwait across Najma unconventional gas carbonate reservoir commingled with lower cemented liner completion in conventional Middle-Marrat tight carbonate reservoir. This completion configuration enables acceleration of selective stimulation and testing of Najma unconventional production potential in existing wells, and simultaneous comingled production from both reservoirs to maximize well production potential. The development of North Kuwait Jurassic deep unconventional gas carbonate reservoirs is key to compensate the production decline from conventional producing Middle-Marrat reservoir and to achieve the production target of Jurassic gas asset. The recovery from such unconventional reservoirs is extremely challenging if conventional development strategies are applied. Therefore, a dedicated full development plan applying integrated upstream and downstream technologies is important to achieve commercial production. The NK field development team has initiated a study to test the potential of unconventional Najmah formation in existing wells to evaluate the production potential and accelerate production from such reservoirs. The typical completion of Jurassic wells include Najmah reservoir in the 7-5/8″ cemented liner section followed by the Marrat reservoir completed in 5″ or 4.5″ cemented liner section. The multidisciplinary team efforts have yielded an innovative hybrid completion solution of 15K rated cased-hole ball-drop multistage completion across Najma reservoir layers and cemented liner across Middle-Marrat reservoir layers that allows selective commingled production of Middle-Marrat and Najmah with ensuring full selective stimulation potential across Najmah reservoirs through the multistage completion. Many completion design, operations and installation challenges were resolved to ensure mechanical isolation of lower depleted conventional reservoir before perforation the upper unconventional reservoir and running the multistage across it. This is to mitigate the challenges of high differential pressure of approximately 5,000 psi between the two reservoirs in completion phase to avoid high formation damage to the depleted Middle-Marrat lower reservoir plus well control during rig operation. This innovative hybrid completion has been installed successfully in one well as first time ever in Kuwait. Najmah and Middle Marrat reservoirs have been selectively stimulated and tested individually then commingled production from both reservoir as first time in Jurassic gas fields and Kuwait. PLT showed positive production contribution from Najma open frac ports and no cross flow among open reservoirs. There is a plan to expand such Hybrid completion to other candidates. This innovative completion configuration can be used in similar application for commingling production to minimize cost of new wells for different reservoirs.

North Kuwait Jurassic Gas Experience of Expanding Multistage Completion Strategy for Managing Deep Tight Gas Development Challenges

Day 2 Tue, November 01, 2022

Al-Otaibi

Blushi

et al. 2022

North Kuwait Jurassic Gas asset has strategic importance for Kuwait production strategy as the only non-associated gas producing fields in Kuwait. This paper demonstrates the added value, experience, challenges and lessons learned of recent paradigm shift in Jurassic tight gas wells’ completion strategy from cemented liner to multistage completion. A successful expansion of Multi-Stage Completion (MSC) technology has been achieved on field level led by integrated team efforts since early 2020 to date. This helps to enhance overall well production potential, selective stimulation, overcome reservoir and intervention operations challenges, and early production delivery. The Jurassic gas asset produces mainly from deep high pressure and temperature, conventional and unconventional tight carbonate reservoirs. The recovery from such complex heterogeneous reservoirs is extremely challenging if conventional development strategies are applied. Due to the high reservoir tightness, permeability contrast among different flow units and dual permeability effect (matrix and natural fractures), well productivity potential significantly depends on the effectiveness of subsequent stimulation treatments of such complex heterogeneous reservoir to improve well productivity and connect the natural fractures. Selecting proper well completion is critical to overcome such reservoir challenges and ensure efficient acid stimulation treatments of such unconventional formations that need convenient diversion mechanism during the stimulation to enhance the productivity of each individual reservoir layer, and enable future flexibility of selective re-stimulation and reservoir management. The asset team has applied a step change in completion strategy to open-hole HPHT multistage drop-ball completions using state-of-the-art MSC technologies including closable frac ports, full 3.5in monobore post milling and debris sub to protect the MSC string during upper completion operations. This is to overcome such reservoir complexity, eliminate wellbore cleaning and multiple perforation intervention operations challenges and risks, eliminate cement quality uncertainties, improve overall cost, and fast track well delivery to production to meet asset production target by significantly reducing operation time from approximately one month of plug and perf technique to less than one week of continuous and less subsurface intervention operations. Total of 23 new Multi-stage completions were successfully installed in last 2 years including 4 systems in horizontal unconventional Najmah reservoir with overall good production results and significant improvement in selective acid stimulation (matrix and Fracturing), intervention operations efficiency and fast well delivery to production. Therefore, the asset plans to continue expansion in Multi-stage completion strategy. Based on gained experience, an integrated protocol for multi-stage candidate well selection, staging design and installation procedures workflow has been built by the integrated multidisciplinary team to ensure standard process across fields which can be used for application in other fields.