Sabiriyah Mauddud (SAMA) is not only a giant reservoir in North Kuwait with largest footprint it is also the most complex being carbonate. Presently, this reservoir is under waterflood which has helped to improve reservoir pressure and production performance. Production strategy of 1 million BOPD from NK reservoirs has brought focus on accelerated oil production by drilling new wells, good reservoir management practices and targeting difficult reserves. Possibility of early implementation of EOR has been considered as an option for SAMA. EOR screening studies were followed by extensive laboratory coreflood studies and sector model simulation study. In Lab, carefully designed recipe of chemicals (Alkali-Surfactant-Polymer) successfully addressed the critical issues of conformance control and adverse mobility ratio observed in SAMA to provide high displacement efficiency. Sector model was carried out to evaluate the different EOR processes like, gas, polymer and Surfactant-Polymer (SP). Encouraging oil recovery results were observed in lab and in sector model study with Chemical EOR which paved the way forward for testing it in reservoir. Success achieved through bench experiments and simulation study was transferred to the field last year when Single Well Chemical Tracer Tests with water and ASP recipe were conducted in three SAMA wells with successive improvement either in test procedure or in chemical formulation of the ASP. The result of the last test with ASP paid for all the hard work that was done with Sor brought down to 6%. Encouraged by these results, a small 6-acre inverted 5-spot pilot for Sabiriyah Mauddud is planned for 2016-17 success of which is a significant step for field wide implementation of EOR program.

This paper focuses on a chemical EOR feasibility study for Raudhatain Zubair (RAZU) reservoir in North Kuwait. The study describes a methodical approach to enable pilot location selection, and a fit-for-purpose modeling strategy to guide the Alkaline Surfactant Polymer (ASP) pilot design decisions. The objective of the pilot is to test in the field that ASP chemicals could mobilize remaining oil and drive it to the producers, where it is captured, produced and separated at the surface. A detailed study was conducted that focused first on mapping out the distribution of remaining oil in the Raudhatain Zubair (RAZU) sandstone reservoir, defining the subsurface uncertainties and identifying key decisions that needed to be addressed for the pilot design. Thereafter, a fit-for-purpose probabilistic dynamic model using a range of inputs based on available rock and fluid field data and ASP parameters from an in-house global Chemical EOR database was built. This model was used to predict the range of production outcomes and aid with pilot design decisions. Based on the stated objective of the pilot, an inverted 5-spot pilot pattern was chosen and a representative area was identified that spanned a reasonable average of field properties. An uncertainty analysis on the pilot pattern revealed that the residual oil saturation to both water and chemical and the remaining oil saturation at the commencement of pilot are the largest uncertainties governing the incremental oil recovery from ASP over water flood. Another significant uncertainty was the presence of an aquifer and the influence of active injectors near the pilot area. Depending on the aquifer strength and heterogeneity of the reservoir, fluid drift and can sweep the chemical slug away from the intended target region of the 5 spot pattern. On the design side, the chosen surfactant concentration in ASP slug, which affects the residual oil saturation to chemical, can result in lower than optimal oil recovery if surfactant losses (via adsorption or chemical consumption) are not adequately managed. Other important decisions are injection rate and pattern size since they affect the incremental recovery due to different swept pore volumes in the pilot pattern. Moreover, the model helped in steering important decisions for the pilot – e.g optimum time to switch to ASP injection after water flood. ASP sector models frequently suffer from being overly complex since they are not tailored to address practical questions that drive key pilot decisions in a timely manner. The unique practical modeling approach presented here focuses on identifying critical uncertainties and pilot design parameters while circumventing the need of detailed laboratory data and a full field model history match.

Ambitious leadership, integrated planning and availability of resources have seen unprecedented growth in development activities of North Kuwait reservoirs over the last 4-5 years. As a result of this production has significantly grown but so have production challenges. New ideas and ways to enhance production and reserve growths are being discussed and tested. In this context role of Enhanced Oil Recovery (EOR) has been critically examined and steps are being taken to have a pragmatic action plan in place to achieve strategic objectives.North Kuwait has been endowed with a mix of clastic and carbonate reservoirs of that are highly productive. These reservoirs are at different stages of depletion and their development plans are constantly tuned to enhance oil production and reduce water cut. KOC's approach to EOR plans is inclusive. It is looking at not only mature clastic reservoirs like Lower Burgan but also at Mauddud, Upper Burgan and Zubair reservoirs that are in middle stage of their development bypassing the conventional route post-secondary recovery.Considering previous work and recent developments in the field of EOR, chemical methods and miscible Carbon-Di-Oxide (CO2) processes were shortlisted for more in-depth investigations. Subsequent extensive simulation studies place incremental oil recovery estimates using the results of specifically customized Surfactant Polymer (SP) formulation for Sabiriyah Mauddud in excess of 25% over the CO2 WAG (Water Alternating Gas) process. SPE 167281In view of the significance of these results to North Kuwait's production plan EOR program is being fast-tracked. It is now at a point where a pilot is being planned in Sabiriyah Mauddud to field-test KOC's first SP flood in the next 1-2 years. Action plan is being finalized with all activities, milestones and deliverables. The project activities are being closely monitored to ensure timely completion of key tasks by different groups. For other reservoirs risk-opportunity matrix is being developed to understand the pitfalls and potential of shortlisted methods. It is expected that this work plan will enable KOC to realize its vision of getting first EOR oil from North Kuwait by the turn of 2016.

A downhole fluid analysis prototype module (MRPV) has been developed which measures both asphaltene onset pressure (AOP) and bubblepoint pressure (Pb). This manuscript describes one of many recent downhole jobs which were part of a study to characterize live crude oil in real time while sampling mobile oil in a permeable tar mat. These jobs support an enhanced oil recovery (EOR) study to understand the best way to extract bypassed oil (Fatma 2019). In this manuscript, downhole bubblepoint and AOP measurements made with the MRPV in well RA-0Y37 agree with those obtained in a laboratory with bottomhole samples. The effect of oil-based mud contamination on the AOP and Pb is examined during clean up while sampling. Water was present for all jobs, but the hydrophobic membrane blocked water from entering the MRPV, facilitating ease of interpretation of optical data. This manuscript comprises the first part of a two-part series (Tiwari 2020).

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