This paper demonstrates the production optimization methodology being used by Kuwait Oil Company Jurassic gas that added significant contribution of approximately 37% of total field incremental production gain in 2021. Production optimization is a continuous iterative process to improve production, especially in mature fields. The North Kuwait Jurassic Gas field’s team has adopted an integrated enhanced and structured process to identify opportunities for production optimization with a pro-active approach focusing on flowing wells and rig-less interventions to tackle production challenges and achieve production targets. The Jurassic gas asset has unique mature-field challenges. It produces mainly from deep (up to 19,000 ft MD) high pressure and temperature, conventional and unconventional tight carbonate reservoirs, highly deviated to horizontal wells, different completion configurations (4.5in monobore, 3.5in × 5in liner, and 4.5in Multi-stages completions), wellbore cleaning and accessibility, scaling and flow assurance, high heterogeneity and permeability contrast among different flow units and dual permeability effect (matrix and natural fractures), production decline due to pressure depletion, liquid loading, high H2S (up to 13 mol%), surface production facilities limitations (e.g. limited MP and H2S handling capacity). effectiveness of subsequent stimulation treatments of such complex heterogeneous reservoir to improve well productivity and connect the natural fractures. The recovery from such complex heterogeneous reservoirs is extremely challenging if conventional development strategies are applied and need for appropriate production optimization methodology outlined here. The Heterogeneity Index process is utilized to rapidly demonstrate production gain opportunities via quick screening method of identifying preliminary candidate wells with anomalous behavior (over/under performance) for further analysis. The results from this screening tool were utilized to identify the families of type productivity problems at field and well levels with solution categories for production enhancement. Representative wells were selected for detailed diagnostics based on the relevance and size of productivity impact and the potential of its well deliverability. Once a few "top potential" wells were identified, production engineering workflows were implemented to assess and forecast the potential of production increase and to determine and evaluate the best solution design and intervention action. Detailed production optimization process provided recommendations of various remedial intervention solutions to improve well production potential via productivity enhancement ranging from complex matrix and fracturing stimulation, additional and/or re-perforations, wellbore cleaning, flow assurance solutions, to choke management. Other advanced technologies were applied to improve various strategies, including completions, perforation, stimulation, and production control. The executions of recommended interventions added significant contribution of approximately 37% of total field incremental production gain in 2021. Such production optimization process, experience and lessons learned will be shared where it can be used in analog fields.

Jurassic Gas Field Development Group (GFDJ) of Kuwait Oil Company (KOC) completed the first ever CO2 foamed acid frac pilot campaign in three Jurassic sour HTHP wells. This innovative technology was utilized first time ever in the KOC history safely and effectively with exemplary well performances. GFDJ had been pursuing the CO2-foamed acid fracturing technology since 2019 with the objective of improving the stimulation and hydraulic fracturing efficiency in the Jurassic Middle Marrat formation. CO2-foamed acid fracs have several advantages over other stimulation techniques:CO2 is a miscible and non-damaging fluid blends in water and also mixes with hydrocarbons.Pumped as a liquid and slightly heavier than water, leading to lower treating pressures due to heavier hydrostatic head.Effective in treating lower-pressured/partially-depleted good KH carbonate reservoirs.Reduces water-based gels and overall frac-load volume by the percentage of CO2 pumped in the frac fluid system (40% by volume is utilized in this pilot).Energizes the frac fluid and stays in solution until it heats up to gas. This property ensures the frac load recovery is achieved throughout the flowback.Eliminates the need to activate the well after the frac with CT/N2 applications potentially saving time and money to KOC.Has potential to lighten up the heavier ends of the hydrocarbons due to its miscible properties, hence may help with better hydrocarbon inflow.Creates stable foam structure with the frac fluid, increasing the frac fluid viscosity hence has the potential to generate better frac geometry and higher "stimulated rock volume" or SRV. A three-well campaign was completed between September 2021 and February 2022. Three different monobore completion wells were fracture-treated using an average of 40% downhole quality CO2-foam pumped at an average rate of 30 bpm. Different service companies and their fluid systems, as well as their operational capabilities were utilized in operations with exemplary clean up and production test results that surpassed the expectations of the asset. Additionally, pumping cryogenic CO2 at high ambient desert temperatures of September in Kuwait, safely, and operationally effectively is a major milestone and achievement in itself. This paper summarizes the design, operational, well clean-up and production performance details of the CO2 campaign. Learnings of the GFDJ asset will be shared in order to benefit from the learning curve that KOC went through in implementing this strategic application. Success of novel CO2 stimulation technique is critical for the GFDJ asset to continue expanding its production capacity in next 2-3 years while maintaining the strong production plateau achieved in 2021. Future plans of the assets will also be discussed to ensure cross-boundary opportunity realization can be possible in the industry for the region.

The first ever CO2 foam fracturing new technology in Kuwait Oil Company (KOC) history was executed flawlessly in late 2021. Three treatments were executed. Co2 Foam Fracturing proved its significant added value of improving productivity in deep depleted tight carbonate Jurassic reservoirs, enhance flow back, reduce water consumption and carbon emission, and enable early production plus improving operation efficiency and cost saving. The stimulation operation has proven to be a huge success for all multidisciplinary teams involved as preliminary results showed over 50-70% production increase compared to offset wells. The main challenges of acid fracturing stimulation in depleted reservoirs are the need for extended formation cleanup to flow back the injected fluids via prolonging Nitrogen lift that add higher operational costs and intervention operations. Therefore, energetic high foam efficiency frac fluid becomes essential to assist flowback and retrieve pumped frac fluids from reservoir. To tackle these challenges, Carbon Dioxide CO2 is pumped in liquid phase as energetic fluid together with normal frac fluids. Due to CO2 liquid nature, high foam efficiency can be reached (40 – 50%) at much lower friction losses. So, it enables achieving pumping frac at high rates and high foam efficiency. The main benefits of CO2 Foam frac are better fracture cleanup due to expansion of the stored compressed gas in the liquid CO2, fluid loss control that is provided by foam, minimized fracture conductivity damage, and the increase in hydrostatic pressure while pumping that translates to lower surface pressures during injection. The selected pilot well is in depleted deep tight carbonate reservoir area of North Kuwait Jurassic gas fields. The executed acid fracturing operation required close planning starting from Q1-2021. Many challenges faced from logistical issues, lack of infrastructure and CO2 resources for the multi-faceted operation due to COVID-19 pandemic limitations. These challenges were tackled ahead with the integration of technical and operations teams to bridge the knowledge gap and to enable executing the operation safely. The pilot well's net incremental production gain is estimated at 50-70% compared to offset wells, with improved flowback and formation cleanup with less well intervention. The resulting time and cost savings as well as the incremental well productivity and better operation efficiency confirmed high perspectives for the implemented foam acid fracturing approach. Another two CO2 Foam acid fracturing wells were executed with good results too. This paper will demonstrate the value of CO2 foam fracturing in depleted reservoir and KOC experience post first application and its plans to expand CO2 Foam Fracturing application across KOC different fields.

Jurassic Gas Field Development Group (GFDJ) of Kuwait Oil Company (KOC) completed the first ever CO2 foamed acid frac pilot campaign in four Jurassic sour HTHP wells. This innovative technology was utilized for the first time in KOC's history safely and effectively with exemplary well performance. GFDJ had been pursuing the CO2-foamed acid fracturing technology since 2019 with the objective of improving the stimulation and hydraulic fracturing efficiency in the Jurassic Middle Marrat formation. CO2-foamed acid fracs have several advantages over other stimulation techniques: CO2 is a miscible and non-damaging fluid which blends in water and also mixes with hydrocarbons. Pumped as a liquid and slightly heavier than water, leading to lower treating pressures due to heavier hydrostatic head. Effective in treating lower-pressured/partially-depleted, good K.H (permeability-height function) carbonate reservoirs. Reduces water-based gels and overall frac-load volume by the percentage of CO2 pumped in the frac fluid system (40% by volume is utilized in this pilot). Energizes the frac fluid and stays in solution until it heats up to gas. This property ensures the frac load recovery is achieved throughout the flowback. Eliminates the need to activate the well after the frac with CT/N2 applications potentially saving time and money to KOC. Has potential to lighten up the heavier ends of the hydrocarbons due to its miscible properties, hence may help with better hydrocarbon inflow. Creates stable foam structure with the frac fluid, increasing the frac fluid viscosity hence has the potential to generate better frac geometry and larger stimulated rock volume (SRV). A four-well campaign was completed within 12 months period. Three different monobore completion wells and one 3-1/2″ tubing with 5″ liner completion well were fracture-treated using an average of 40% downhole quality CO2-foam pumped at an average rate of 30 bpm. Different service companies and their fluid systems, as well as their operational capabilities were utilized in operations with exemplary clean up and production test results that surpassed the expectations of the asset. Additionally, pumping cryogenic CO2 at high ambient desert temperatures of September in Kuwait, safely, and operationally effectively is a major milestone and achievement in itself. This paper summarizes the design, operational, well clean-up and production performance details of the CO2 campaign. Learnings of the GFDJ asset will be shared in order to benefit from the learning curve that KOC went through in implementing this strategic application. Success of novel CO2 stimulation technique is critical for the GFDJ asset to continue expanding its production capacity in next 2-3 years while maintaining the strong production plateau achieved in 2021. Future plans of the assets will also be discussed to ensure cross-boundary opportunity realization will be possible in the industry for the region.

NKJG area comprises of eight fields that are structurally complexcharacterized by high pressure & high temperature (HPHT) reservoir properties, critical or near critical nature of the reservoir fluids, high concentration of H2S & CO2 and multiple zones consisting of variations in carbonate formations. Tectonics, as well as the depositional complexities further complicate the trapping and distribution of hydrocarbons, leading the commingled completion and production challenges. Sabriyah field is the second prolific field in NKJG and is divided primarily into two parts; crestal part which is highly fractured and platform part is matrix dominated. Water breakthrough is observed in some of the wells located in the crestal part, and in general, two types of fluids are encountered (gas condensate & volatile oil). The pilot well where the new diversion technology was implemented is located in the western flank of the Sabriyah field. Limited natural fracturing occur across the 268 ft perforationinterval which is too long for effective stimulation in a conventional "bullheading" approach. Although the permeability is low, vertical permeability distribution ranges widelyacrossthe perforation interval (0.001- 10 mD). Nodal Analysis showed the possibility of tripling the production if all the perforation intervals were stimulated efficiently and contribute to flow. As a result, a sequence of operation was planned which included re-perforation of the current interval followed by stimulation to enhance well performance. Due to the operational complications, re-perforation was not completed as planned and the well was killed twice with heavy mud causing further damage. As a result, severe formation damage was created leading to significant loss of production, necessitating a robust stimulation treatment. An innovative "High Rate Matrix Acidizing (HRMA)"technique was designed to restore and enhance well production; where a Step Rate Test (SRT) was done prior to injecting main acid treatment to avoid unintended fracturing. In addition, different diversion strategies were usedin combination: one to divert across perforations and the other to divert stimulation inside the formation. All the chemical fluids that used in the HRMA was tested in the lab to confirm its compatibility and solubility with reservoirrock and fluid. Production was successfully improved after HRMA; where the wellhead pressure, oil and gas rate increased substantially as confirmed by the nodal analysis. During stimulation, there was clear indication of diversion with change in pressure, which confirmed the efficiency of the diverters, and possibility of treating all perforation intervals. Based on the success of this HRMA treatment, similar approach will be used to stimulate other low performers in the North Kuwait Jurassic Gas (NKJG)asset. This paper will provide the details of design, well results, and the overall learnings to address one of the key stimulation challenges in long-perforated deep HPHT wells of NKJG.