Abstract

High reservoir heterogeneity and tightness necessitate the application of new stimulation technology targeting good fracture conductivity and deep penetration for effective productivity and recovery enhancement. With efforts of multidisciplinary team, new Acid Fracture fluid, diverter and high leak off control technologies have been designed and executed successfully as first time ever covering multiple layers in Mauddud carbonate reservoir in Bahra field. Mauddud is heterogeneous, tight multilayer limestone reservoir especially in Bahra field which is still under exploration phase despite having initial production early 1975. Owing to the low reservoir transmissibility, production performance has historically been poor, even with Artificial Lift and conventional Stimulation. Therefore, full-scale commercial exploitation of the Mauddud/Bahra reservoir requires advanced technologies for productivity enhancement. One of the oldest Mauddud vertical wells in Bahra field was drilled in 1974

Abstract

The unconventional Jurassic Najmah carbonate-shale formation in northern Kuwait has been tested and found to be a prolific source rock as well as a producer of gas, condensate, and light oil in different wells. The flow-controlling system, given the very low porosity, is highly dependent on the presence of a natural fracture network. The Najmah kerogen member, formally known as the Najmah shale, is the source reservoir composed of highly organic-rich argillaceous and calcareous clay, represented by very high total gamma ray values associated with high uranium on spectral gamma ray logs. Average matrix porosity ranges from 2 to 6%, low permeability from 0.01 to 1.5 mD, and total organic content (TOC) from 7 to 12%. Identification and interpretation of fractures, bed boundaries, and borehole breakout from high-resolution images plays a crucial role in optimizing completion design. Using wireline has been a challenge in horizontal wells, making logging-while-drilling (LWD) acquisition pre

Abstract

Stimulation is a well-practiced technology in oil industry to improve productivity or injectivity of a well. Plasma Pulse Technology (PPT) is a special kind of stimulation technique where oil production enhancement occurs without formation damage and without using chemical agents. PPT is based on scientific research in the areas of Geology, petro-physics, blasting theory, acoustic, wave theory and resonance theory. Well RA-000A was identified for plasma application mainly to stimulate the very tight layer SID2 which otherwise difficult to produce through conventional perforation and to have positive production impact on nearby well RA-000B. Before application of this new technology, three intervals were perforated with last production rate @ 196 bopd with 90% water cut and closed for pressure. PNC log (sigma log)was recorded which shows that out of three perforated interval, the bottom COAL2-UCH layer having very high water saturation, the top of COAL2-UCH is having little water satura

Abstract

The Jurassic gas field is a high potential field which poses several challenges in terms of hydrocarbon flow optimization through highly varied carbonate intervals with low reservoir pressure support and reduced fluid movement. Due to this, the operative strategies have prioritized primary well completion using energized acid fracturing technology over regular stimulation. During fracturing, the acid system will form highly etched channels in the formation. Most of the fluid will flow into the path of least resistance leaving large portions of the formation untreated. As a result, the fracturing treatment options decline significantly, thus results are not optimum in each stage. Excessive fluid loss and achieving complete frac coverage for an entire interval is a challenge for any acid frac treatment performed in a multiple perforated well with variations in reservoir characteristics. Acid fracturing using Cohesive Foam Diversion (CFD) is performed using CO2 blend and self-degrading pa

Abstract

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 reserv

Abstract

Polymer flooding is a widely employed Enhanced Oil Recovery (EOR) technique, aimed at improving sweep efficiency and maximizing hydrocarbon recovery. Accurate monitoring of polymer concentration in production fluids is essential for optimizing EOR operations and assessing reservoir performance. However, the presence of contaminants, such as solid particles, oil droplets, and other contaminants makes polymer concentration determination quite challenging on production side. Main limitations of current quantification techniques are summarized below: • The bleach method might not be applicable to polymers containing 10% to 25 mol% or more ATBS and suffers from interferences with divalent cations. • The chemical oxygen demand method is sensitive to chloride content limiting its application to low salinity water. It also suffers interferences from oil contamination. • Refractometry requires stable water composition, free of oil. • Time resolve fluorescence is sensitive to salinity fluctuatio

Abstract

Directional wells through the 6-in. production-hole sections in the Marrat Reservoir of the Jurassic formations have traditionally required several wireline-logging and hole-conditioning runs for comprehensive petrophysical interpretation and completion design. As the planned well inclinations increase to maximize reservoir exposure and sweep efficiency, wireline deployment poses significant challenges due to the increased risk of losing the bottomhole assembly (BHA) in the hole. Over time, logging-while-drilling (LWD) tools have become preferable for the asset team, where the tools are run either in the drilling BHA or during a dedicated wiper trip after the section has been drilled to total depth (TD). Using LWD tools in this application also reduces well delivery times and costs. A comprehensive logging solution was required to drill the 6-in. reservoir section of a study well. The complex LWD string, consisting of gamma ray, resistivity, neutron porosity, azimuthal density, azimuth

Abstract

Drilling high angle wells into a heavily fractured, highly pressured, sour Jurassic reservoir may be the key to unlocking substantial reserves of light oil for Kuwait. One of the main risks to effectively developing this unconventional reservoir is the ability of wells to access a permeable, interconnected, vertical fracture network, without which the oil will not flow. Less than 50% of the vertical wells drilled to date have been successful due to a failure to intersect fractures or due to formation damage suffered during drilling. High angle or horizontal wells, while more technically challenging and expensive, will ensure fractures are encountered and will ideally penetrate multiple large, oil bearing fractures, to provide high productivity and reserves recovery per well. This paper discusses the challenges of designing a high angle well into the Jurassic which has so far proved difficult to drill vertically. These challenges can broadly be divided into three major categories - the

Abstract

Water dump flood is a non-conventional and cheaper alternative as compared to surface water injection commonly used to support reservoir pressure. The major costs associated with surface injection includes water treatment as well as sourcing of the water. The dump flood technique helps eliminate these costs thereby improving project and field economics. A dump flood technique eliminates the requirement of drilling an additional water producer well. In order for the dump flood technique to be successful, adequate production from the source and good injection rates into the target interval are key requirements. If either one of them are not met there is likely to be detrimental effects on the objective of the dumpflood. This paper details the risks and challenges identified for the subject well and the methods & technologies implemented to ensure the success of the project. As part of the water injection strategy in the subject field, water dump flood was deployed. These wells source wat

Abstract

A significant challenge in the tight Mishrif oil reservoir of the Minagish field is ensuring hydrocarbon flow through the complex and highly damage-susceptible carbonate intervals. In recent years, field development strategies have begun to prioritize multilateral well technology over vertical and deviated wells because of the advantages of maximized reservoir contact, higher production rates, and improved access to reserves (hydrocarbon in place). The downside of most unconventional multilateral wells is that laterals are open hole, completed with much complexity, and pose challenges for effective acid stimulation because of poor acid distribution over the long interval. The Mishrif formation in the Minagish field in west Kuwait is a challenging tight carbonate with poor reservoir quality, relatively low pressure, and no external pressure support. The stimulation methodology was highly modified as fit-for-purpose to address the unique challenges of multilateral well operations, format

Abstract

Quality Cementation across production sections consisting of depleted/weaker formations is the main challenge in Kuwait. Usage of conventional cement slurry over 15.8 ppg will lead to losses and poor zonal isolation. Newly designed 12.5 ppg enhanced compressive strength cement slurry was proposed to achieve desired zonal isolation and well integrity while avoiding losses and unnecessary remedial jobs. Strategy was formulated to minimize exposure of weaker formations for higher ECDs during cementation. Conventional 15.8PPG tail slurry was replaced with 12.5PPG Ultra high compressive strength (4000psi) cement slurry. New slurry design helped to carry out cementation job without any losses while achieving rapid compressive strength and excellent cement bond across production casing. The technology is based on three radical changes in the conventional way of designing cement Slurry of Substitution of part of the cement volume with inert agents of low specific weight, High packing density u

Abstract

The Greater Burgan field Kuwait is the second largest oil field in the world and the largest sandstone field. Greater Burgan is divided into Ahmadi, Magwa, and Burgan fields. This paper describes the result of the first Long Term Polymer Injecticity Test (LTPIT) in Magwa field targeting wara reservoir with inferior rock quality comparing with the previous LTPI tests implemented in Burgan Field. These multiple LTPI tests located in different areas of the Greater Burgan Field are aimed to de-risk fast-tracked phased commercial polymer-flooding deployment in pursuit of production acceleration, reserves growth and cost optimization. An existing water injector in Magwa field was selected and connected to existing effluent water plant. Down-hole pressure and temperature gauges were installed for real-time surveillance monitoring of the pilot operation. Effluent water was treated at specific criteria and then mixed with the dry polymer to form the mother solution. This solution was diluted wi

Abstract

High level multilateral technology can access multiple reservoirs with lateral junction integrity, increase drain hole lengths that can result in enhanced production from a single location and significantly lower construction cost. It can also access conventionally unreachable reservoir thereby recover bypasses oils and enhance production objectives. This paper focusses on successful deployment of TAML 4 systems in Kuwait field providing independent accessibility of both laterals during life of well for cleaning, stimulation, zonal isolation, selective production, data acquisition, etc. It also details challenges faces while installing high level multilateral system, drilling six horizontals including three through multilateral junction and accessing both main bore and lateral. Paper details on completion designs, drilling challenges in complex reservoir structure and also discusses challenges of individually accessing all six open hole laterals successfully with advanced Coil Tubing S

Abstract

This paper sheds light on the design and field results of a strategic Long-Term Polymer Injectivity Test (LTPIT) to de-risk phased commercial polymer-flooding in the largest sandstone field worldwide in pursuit of production acceleration, reserves growth and cost optimization. Effluent water with up to 170,000ppm TDS was used in conjunction with a pre-selected sulfonated polymer to evaluate injectivity at multiple rates and polymer concentrations under sub-fracturing conditions. Reservoir parting pressure was judiciously estimated to be around 2,500 psi. Polymer and water injected below parting pressure flowed into and through the Wara reservoir matrix as evidenced by the increase in downhole pressure with increasing injection rate in line with Darcy's law. Polymer solutions expressed in-situ viscosities of up to 2.75 cP when injected below fracture parting pressure while displaying pseudoplastic flow characteristics. Water on the other hand displayed Newtonian behavior. Polymer adsorp

Abstract

With the continuous production from Kuwait oil reservoirs, a clear decline in reservoir pressure is observed. Subsequently, the demand for artificial lift is increasing to sustain production. Maintenance of those wells requires frequent interventions and continuous presence of workover rigs, which affects overall cost of production. Change of the electrical submersible pump (ESP) deployment method represents one of the cost reduction initiatives undertaken by the operator to reduce well intervention time and improve asset utilization. To minimize deferred production generated by the ESP replacement operation, a novel rigless approach leveraging coiled tubing (CT) was introduced in southeast and west Kuwait. It reduces operating costs and eliminates disruptions to operations by enabling rigless retrieval and redeployment of a standard ESP assembly. To evaluate the efficiency of using CT as rigless ESP retrieval and conveyance method, two candidate wells were selected to recover and rede

Abstract

In recent years, North Kuwait has implemented advanced drilling practices by sidetracking existing wells and drilling long horizontal sections through the reservoir, which are completed with smart completions. These often include up to 20 stages, each of which is isolated using swellable packers. Management of production from these long horizontal sections through these complex completions is highly cost-sensitive and maintaining an optimum production rate is key to the economic success of these type of wells, especially in the current low oil price environment. In this case study the well was completed with 18 compartments with ICD's/sand screens and each isolated with swell packers(Fig-3). Production decline was dramatic and in three months since bringing the well on production, the gross production decreased by 50%. Quick diagnosis of the problem was crucial to understand the decline mechanism especially the production from each compartment along the horizontal section, determine wh

Abstract

Drilling the 16-in. section in Minagish field wells in western Kuwait is among the most challenging well sections. Challenges include drilling through severe loss conditions, destabilized shale, and deteriorating hole conditions. These conditions can result in hole collapse or lost in hole of the drill string that requires sidetracking. The objective of project presented in this paper was to develop an engineered solution to drill through the difficult zones, lessen nonproductive time, and reduce the total well cost. The solution proposed was to use casing-while-drilling technology with a drillable bit and drill through the fractured dolomitic limestone and sandstone formation while simultaneously setting casing. The drillable casing-while-drilling bit was specifically designed and engineered to conform to the formations in the field. The drillable casing-while-drilling bit is manufactured with a material that can be drilled out with either conventional roller cone or fixed cutter bits

Abstract

Critical Coning Rates reduce significantly as kv/kh → 1.0, therefore economically acceptable production rates in high-permeability reservoirs with Oil/Water Contacts (OWC) usually exceed their respective coning rates. Horizontal completions with Inflow Control Devices (ICD) have indeed provided some delayed water breakthroughs by significantly reducing the pressure drawdowns at higher production rates. However, when water breakthrough does occur in these ICD completions, the same significant oil production loss is experienced with no chance of acceptable restoration, since the water quickly moves laterally to flood adjacent compartments along the horizontal or high-angle wellbore. The Downhole Water Sink (DWS) technology, applicable only in vertical or moderately-deviated wellbores (<60°), is a technology that revolutionizes the development strategy of reservoirs with OWC's, and with partial to strong aquifers. The fundamental principle of this technology is to create an equivalent pre

Abstract

Greater Burgan Field has been producing from more than 70 years and brings many challenges with the maturing field. During the last decade almost all the new wells drilled were completed as dual completions to simultaneously produce from two different formations in Burgan. As the workover rig activity tremendously increased with the increased number of new wells per year, it has been a constant endeavor to carry out maximum well intervention jobs possibly by rig less operations to reduce rig related OPEX and well production down time during rig work over. One of the biggest long term challenges was to carry out well interventions in dual completions short tubing, which was used to be considered inaccessible due to presence of tubing long in the well bore. In view of above, most of the intended well interventions in tubing short were normally used to be proclaimed as work over candidate thereby increasing load on limited work over rigs. First time in Burgan a dual completion well was ca

Abstract

A hydrocarbon gas injection pilot was successfully conducted in a heterogeneous multilayered Oolitic carbonate reservoir in Kuwait. The pilot strived towards de-risking technical and commercial feasibility for field-scale deployment of miscible CO2 WAG EOR development. The aim was to generate reliable unambiguous pilot performance results on remaining oil saturation, inflow profile and sweep efficiency to better quantify risks and uncertainties. This paper describes design, execution, and results of this pilot and its challenges and opportunities. The pilot was an inverted four-spot, consisted of a pre-flush water injection phase (2016-19), drilling and coring two fiberglass cased observation wells, followed by a gas injection phase (2021-2022). The phases were carried-out sequentially in three target layers, injecting a range of pore volumes in each layer. The pre-flush surveillance program included Inter-well water tracer test (IWTT), time-lapse saturation logging, coring, PLT/ILT, V

Abstract

The Sabriyah field located in northern Kuwait primarily produces from the Mauddud and Burgan formations. The upper section of the Burgan formation is referred to as the Sabriyah Upper Burgan (SAUB) reservoir. SAUB reservoir consists of Cretaceous Albian age sandstones and spreads over an area of ~105 km2. This paper sheds light on the successful application of a long-term polymer injectivity (LTPI) test in the SAUB reservoir as a strategic milestone towards phased commercial polymer-flooding development. The main objective of the SAUB LTPI test was to evaluate injectivity at multiple injection rates and polymer concentrations under sub-fracturing conditions. Current EOR efforts target reservoir areas with unfavorable mobility ratio to improve oil recovery and unlock additional oil reserves. The location of the SAUB LTPI test was carefully selected to avoid faults and low channel thickness. Effluent water with TDS ranging from 150,000 to 200,000 ppm was used for polymer solution prepara

Abstract

The thickness and thermal maturity of the Najmah formation presents a favorable prospect for commercial exploitation of unconventional shale gas. Estimating reservoir storage volume is one of many formation-evaluation objectives when assessing an unconventional reservoir. The presence of kerogen has significant effects on several downhole logging sensor measurements. An operator used nuclear magnetic resonance (NMR) measurements to evaluate total fluid-filled porosity for a reliable estimate of the reservoir storage volume in source rock. While wireline NMR has historically provided a large segment of unconventional reservoir logging, logging-while-drilling (LWD) NMR provides an alternative method for assessing the total fluid-filled porosity within unconventional reservoirs. This paper provides a case study in the Najmah Shale Formation, where an operator used an LWD penta-combo system (gamma ray, electromagnetic wave resistivity, azimuthal bulk density, thermal neutron porosity, high

Abstract

The HPHT, sour, deep, fractured and not so fractured carbonate Jurassic formations within the North Kuwait cluster of fields present extraordinary challenges in driving towards an optimized field development that maximizes liquid recovery and meet the gas production aspirations for the state of Kuwait. The Middle Marrat reservoir has been developed to date with cased and perforated liner completions across the 500- 700ft pay. However due to the high permeability contrast between the different reservoir flow units, the low permeability zones are typically not contributing. This is further exasperated with the inability to effectively acid stimulate large proportion of the net pay with a single stage bullhead treatment especially when the contrast in permeability between the various flow units is higher than one order of magnitude. Key to successful reservoir management of the Middle Marrat whilst maximizing well capacity to meet the production aspirations is to implement a completion an

Abstract

In the north of Kuwait, developing a deep high-pressure/high-temperature (HP/HT) exploratory reservoir is challenging due to high H2S and CO2 concentration in the reservoir fluid. The studied field is located in North Kuwait, and the first well that showed commercial potential was in the middle Marrat reservoir. This paper presents a case study of the first well in this field where an openhole multistage completion was successfully installed and acid fracturing treatment was applied, achieving significant results. The well was successfully tested, which ascertains promising production potential in this area. The subject well is located in a strategic field in the north of Kuwait and it was targeting Middle Marrat formation to evaluate the reservoir production potential. It is a high angle deviated well (maximum inclination 57°) drilled to 19,000 ft (about 5.79 km) measured depth and close to the bottom of the Middle Marrat formation. Hydrocarbon shows were observed while drilling in th

Abstract

Jurassic's kerogen shale-carbonate reservoir in North Kuwait is categorized as a source rock exhibiting micro- to Nano Darcy permeability and is Kuwait Oil Company's focus in recent years. Although the challenges are significant (formation creep, fracturing initiation, etc.), the efforts toward producing from unconventional reservoirs and applying experience from both USA and Canada in this field are ongoing. As a step toward development, the gas field development group selected a vertical pilot well to measure the inflow of hydrocarbon from a single fracture while minimizing formation creep (flowing of particulate material and formation into the wellbore that blocks the production). This step was required prior to drilling a long horizontal lateral wells and completing it with multiple hydraulic fractures to confirm commercial production. A comprehensive design process was executed with the full integration of operator and service company competencies to achieve the three main objecti

Abstract

Proppant fracturing treatments in sandstone formations are routinely executed in Kuwait, however when carbonate formations are the target, acid fracturing is the preferred treatment method. It has been observed that acid fracturing delivers a high initial production however maintaining a sustainable production rate is a challenge in the tight cretaceous carbonate formations in Kuwait. A production enhancement technique needed to be identified in order to deliver more sustainable production and maximize recovery from these carbonate formations. Based on global experience it was proposed that proppant fracturing can deliver more sustainable production rate as compared to acid fracturing. Proppant fracturing had been previously attempted on two occasions in Kuwait, however both the attempts were evaluated as not being operationally successful. Hence prior to executing the first successful proppant fracturing treatment in carbonates in Kuwait a thorough study was undertaken to identify and

Abstract

Proppant fracturing treatments in sandstone formations are routinely executed in Kuwait, however when carbonate formations are the target, acid fracturing is the preferred treatment method. It has been observed that acid fracturing delivers a high initial production however maintaining a sustainable production rate is a challenge in the tight cretaceous carbonate formations in Kuwait. A production enhancement technique needed to be identified in order to deliver more sustainable production and maximize recovery from these carbonate formations. The first stage of the project focused on ascertaining the operational feasibility of proppant fracturing in a single layered Mauddud reservoir. This paper will focus on the operational implementation of multi-stage proppant fracturing in the multi-layered Tuba reservoir. (Nagarkoti, M., et al., 2018) Based on global experience it was proposed that proppant fracturing can deliver more sustainable production rate as compared to acid fracturing. A

Abstract

A new cutting element technology bit along with new drilling automation software provides a solution to drill the challenging 12 =" section in two fields in Northern Kuwait. The 12 =" section was drilled using directional BHA building the angle between 25 to 30 degrees. The formations are characterized to be interbedded limestone and reactive shale causing high downhole vibrations, high torque and stick and slip which affects the buildup capability of the directional tool and overall performance in this section. The main objective is to improve drilling performance by developing an integrated solution to eliminate the downhole tool failures and increase the rate of penetration. The engineering team incorporated a unique geometry into the bit cutting elements design and developed the Ridged Diamond Element (RDE) bit which has new cutting element technology and different geometry than the standard PDC cutters. The ridge shape cutter face helps to reduce the reactive torque generated thro

Abstract

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 unco

Abstract

Asphaltene deposition in production tubing is a major flow assurance challenge. Common strategies to mitigate Asphaltene deposition downhole include mechanical or solvent cleanouts and chemical inhibition. These are associated with production deferment, high job costs, HSE risks and operational issues. In a worldwide first, Kuwait Oil Company (KOC) has addressed this challenge using Fiberglass (GRE) Lined Production Tubing. This technology was implemented in two trial wells. This paper chronicles the different mitigation strategies employed by KOC and presents the findings of the above-mentioned successful trials. Tendency of scale to stick on smoother, non-metallic surfaces, is known to be less than on bare steel surface. KOC had trialed internal coating to mitigate Asphaltene deposition in tubing, but the experience was not satisfactory. KOC has been successfully using GRE lined tubing for corrosion protection and scale prevention in oil and water wells. Considering GRE's smoother su

Abstract

The journey of appraising unconventional reservoirs of North Kuwait Jurassic Gas (NKJG) fields achieved a significant milestone through the successful test in the first horizontal well completed in Najma Limestone (NJ-LS) reservoir in Bahra field. This accomplishment becomes even more remarkable given that none of the previous vertical wells' tests were successful. This paper will demonstrate the challenges faced in the well placement, completion and stimulation, as well as the implementation of new technologies to achieve Kuwait's highest ever initial gas production rate. This outstanding success in appraisal well has unlocked the potential of the NJ-LS reservoir and prompted a step-change in its development strategy. NJ-LS is a tight gas-condensate reservoir with typical porosity ranging from 2 to 9% and very low matrix permeability (~0.01mD) with primary production through natural fractures. To increase the chances of success in encountering fracture corridors, long drain-hole horiz

Abstract

The journey of appraising unconventional reservoirs of North Kuwait Jurassic Gas (NKJG) fields achieved a significant milestone through the successful test in the first horizontal well completed in Najma Limestone (NJ-LS) reservoir in Bahra field. This accomplishment becomes even more remarkable given that none of the previous vertical wells' tests were successful. This paper will demonstrate the challenges faced in the well placement, completion and stimulation, as well as the implementation of new technologies to achieve Kuwait's highest ever initial gas production rate. This outstanding success in appraisal well has unlocked the potential of the NJ-LS reservoir and prompted a step-change in its development strategy. NJ-LS is a tight gas-condensate reservoir with typical porosity ranging from 2 to 9% and very low matrix permeability (~0.01mD) with primary production through natural fractures. To increase the chances of success in encountering fracture corridors, long drain-hole horiz

Abstract

Traditional method of casing cutting takes long time as it requires two trips and there are risks associated due to long section of 9-5/8" casing that need to be retrieved. Furthermore, cutting casing in compression is not ideal in our case. Using cut and pull motorized system has an advantage in which surface verification for successful cut downhole can be observed on rig floor however one of the main challenges is to utilize a low specification mud motor 4-3/4" with flow rate range 150 - 250 gallon per minute (GPM) that can deliver approximately 4.45 K ft-lbs torque at 860 psi pressure differential across the tool. The one trip system consists of standard spear with spear stop sub, a spacer to accommodate the cutting depth, 8-1/4" hydraulic casing cutter with carbide inserts and 4-3/4" mud motor. The spear in the string helps to keep the casing in tension meanwhile the mud motor will deliver torque for the casing cutter knives to complete the job. The single trip cut and pull system

Abstract

The novel 6-inch slim Downhole Formation Tester (DFT) with its advanced Downhole Fluid Analyzer (DFA) sampling tool has been successfully implemented as first time ever worldwide in 6-inch open hole and as first time ever in Kuwait in Jurassic gas deep tight gas Middle Marrat carbonate reservoir. Downhole sampling was always being declined by the drilling team due to differential sticking risks associated with long sampling time using conventional downhole sampling tools in tight reservoirs. This paper will discuss the tool's first successful operation to overcome the formation evaluation and fluid sampling challenges and its immediate added value to subsequent completion and stimulation plan. The formation evaluation of North Kuwait Jurassic deep tight carbonate reservoirs is challenging due to the uncertainty of conventional log measurements and the oil-based mud filtrate (OBMF) invasion. The induction resistivity logging tool, which is based on formation conductivity, is known to ha

Abstract

The novel 6-inch slim Downhole Formation Tester (DFT) with its advanced Downhole Fluid Analyzer (DFA) sampling tool has been successfully implemented as first time ever worldwide in 6-inch open hole and as first time ever in Kuwait in Jurassic gas deep tight gas Middle Marrat carbonate reservoir. Downhole sampling was always being declined by the drilling team due to differential sticking risks associated with long sampling time using conventional downhole sampling tools in tight reservoirs. This paper will discuss the tool's first successful operation to overcome the formation evaluation and fluid sampling challenges and its immediate added value to subsequent completion and stimulation plan. The formation evaluation of North Kuwait Jurassic deep tight carbonate reservoirs is challenging due to the uncertainty of conventional log measurements and the oil-based mud filtrate (OBMF) invasion. The induction resistivity logging tool, which is based on formation conductivity, is known to ha

Abstract

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 r

Abstract

The flash point of hydrocarbons and petroleum mixtures is important safety-related data for processing and handling of these materials. In this paper, experimentally measured data on flash points of about 140 pure hydrocarbons and petroleum fractions were collected and used to evaluate existing methods for prediction of these data available in the literature. The errors for the available methods varied from 1.6 to 4.9% for pure hydrocarbons and from 3.7 to 11.1% for petroleum fractions. In these methods, parameters such as vapor pressure, boiling point, molecular weight, density, activity coefficient, and composition were used. On the basis of the available methods and simplified relations for vapor pressure prediction, it was found that the ratio of the flash point to the boiling point of hydrocarbon systems and their mixtures is a constant and a value of this constant is about 0.7 when both temperatures are expressed in absolute degrees. The average absolute deviation for this simpli

Abstract

The Deep carbonate reservoirs of North Kuwait are broadly divided into deeper assemblage consisting of diagenitically modified dolomitic layer and shallower fractured-laminated tight limestone and Kerogen units. It is a challenge to establish and quantify the known phenomenon of dynamic changes in the flow path characteristics and properties of the reservoir rocks, as the natural stability condition are altered by production of reservoir fluid. The parameters of the flow path characterization become more uncertain in case of deep HP/HT digenetically altered reservoirs and fractured-tight limestone with laminated kerogen, then similar to the North Kuwait deep reservoirs. In this study an integration of static data such as, borehole image, core and petrophysical evaluation with time lapse dynamic reservoir parameters like production, pressure data from buildup and pressure transient analysis was carried out to understand the flow path characteristic changes. A deterministic approach has

Abstract

[No abstract available]

Abstract

The year 2008 has witnessed unprecedented fluctuations in the oil prices.During the first three-quarters, the oil price abruptly increased to $140/bbl, a level that has never been reached before; then because of the global economic crisis, the price dramatically plunged to less than $50/bbl by the end of the year losing more than 64% of the maximum price in less than three months period. The supply of crude oil to the international market oscillated to follow suite according to the law of supply and demand. This behavior affected oil production in all exporting countries. Nonetheless, the demand for crude oil in some developing countries, such as China and India, has increased in the past few years because of the rapid growth in the transportation sector in addition to the absence of viable economic alternatives for fossil fuel. The rapid growth in fuel demand has forced the policy makers worldwide to include uninterrupted crude oil supply as a vital priority in their economic and stra

Abstract

Formation testing while drilling (FTWD) proved to be of great value to the asset team at Kuwait Oil Company (KOC) while recently drilling a deep, deviated well to target the Zubair sands. The deviated 8-1/2-in. hole section of the well had been planned to cut through more than 1,100 ft of true vertical thickness containing multiple reservoir units with varying pressures, lithologies, and formation characteristics, which posed a great risk for drilling operations and required the use of relatively high-density mud to maintain wellbore stability. The presence of highly depleted reservoir zones in this mature reservoir resulted in a challenging pressure overbalance in excess of 4,800 psi. Attempts to measure formation pressure in previous vertical offset wells in the same depleted zone in the same field/environment using wireline formation testers yielded either unsuccessful or erroneous results, indicating a tight formation, which conflicted with previous production and coring data avail

Abstract

The objective of this study is to perform forward stratigraphic modeling on the Kuwait Formation (also known as Kuwait Group) exposed stratigraphic succession along the Jal Az-Zor escarpment to explain the enigmatic occurrence of an elongated NW-SE geobody mapped from subsurface data at northern Kuwait. Outcrop measurements such as; stratigraphic successions, facies distribution, critical facies trends, and paleocurrent analysis have been collected along the 60 km length of the Jal Az-Zor escarpment. Such measurements were combined with thin section lab analysis to reveal the various sedimentary processes such as wave activity, grain size distribution, sediment supply sources, accommodation space, and erosional rates. These measurements were combined with subsurface data such as seismic attributes to reconstruct the paleography of the area and run a forward stratigraphic model simulation. The vertical succession was also utilized to reconstruct the relative sea-level fluctuation throug

Abstract

To better understand fractured reservoir behavior, geophysicists often rely on directional groupings of surface recorded seismic data that can be imaged and run through inversion processes to obtain fracture orientation and intensity attributes. We propose an innovative seismic imaging and inversion system carried out in depth, in which seismic data events are imaged and decomposed in the Local Angle Domain into two complementary full-azimuth angle gather systems with fully sampled directivities and reflectivities. The combination of the two angle gathers, together with the ability to handle the full-azimuth information in a continuous manner, enables the generation and extraction of high-resolution information about subsurface angle dependent reflectivity in localized 3D space. It expands our knowledge about both continuous structural surfaces and discontinuous objects, such as faults and small-scale fractures, leading to accurate, high-resolution, highcertainty, velocity model determ

Abstract

The Najmah/Sargelu reservoir of west Kuwait is a tight-carbonate oil reservoir in which porosity and permeability result from the fracture network. A multidisciplinary integrated approach combined geology [borehole-imaging (BHI) logs, cores, and wireline logs), geophysics [seismic facies analysis (SFA)], and reservoir-engineering data [production, production-logging-test (PLT), and well-test] to identify the main types of fractures, to predict their occurrence in the reservoir, and to determine the hydraulic properties of the different fracture types.

Abstract

Summary: This paper describes a multi-scale seismic approach for characterizing reservoirs affected by large scale fracture corridors (close to seismic resolution) as well as diffuse fractures (far below seismic resolution). To reach such objective, the method is based on joint use of three approaches: (1) post-stack discontinuity analysis, (2) azimuthal inversion and (3) lithology prediction using prestack inversion and characterization. This paper illustrates how these known approaches can be used simultaneously to provide a comprehensive description of the fracture network, calibrated at wells and validated against the conceptual fracture models.

Abstract

The emerging fracture induced exploration strategy can play an important role in the enhancement of porosity and permeability and can contribute to improved productivity in an otherwise poor reservoir facies environment. Seismic expression of such fracture related anisotropic effect can be generated through understanding of structure, fault and shear system by way of mapping and robust attribute analysis. Our focus here deals with the twin objective of (a)the understanding of the fault and other lineament network in both seismic and sub seismic scale along with their structural style and (b)the use of seismic and map based attributes integrated with well core and image data to provide valuable breakthrough in recognizing the zones of concentrated deformation linked to fracture development that are controlling the hydrocarbon play. The study was carried out in a reservoir at a depth of about 13000-16000 ft.

Abstract

An integrated fracture study was conducted to evaluate the fracture flow potential of the low permeability Mishref Formation, using electrical open hole logs, borehole images and production data from a horizontal well, and pressure transient analysis from a vertical well. Image logs show at least three stages of intense faulting and fracturing but the reservoir has only a limited fracture flow potential because (i) the early stage of NW/SE faults and fractures were all cemented. (ii) Although NE/SW fractures generated by recent tectonic episodes and very recent NW/SE fault rejuvenation are open and fluid conductive, faulting created fractures only within the brittle layers, which are a few inches thick and dispersed within thick low porosity and ductile units. Faults have wide fractured zones with flow potential only within a 2-5 ft thick brittle layer close to the reservoir top. The development of fracture permeability in a reservoir requires not only deformation and faulting but also

Abstract

Summary: Four azimuth-sectored 3D P-P volumes were pre-stack time migrated (PSTM) using the same velocity field. These high-fold data (4,000-5,000 traces were summed in each bin in each azimuth sector) of high S/N enable azimuthal analysis of amplitude, phase, frequency, and other seismic attributes. These high-fold azimuth-sectored PSTM 3D data enable us to make maps of azimuthal instantaneous phase (Top/Reservoir; Base/Reservoir) as well as to layerstrip instantaneous phase and remove the effect of the overburden, in order to see the properties of the reservoir interval. The E-SE natural fracture azimuths seen at Well A in the reservoir unit are also observed in the azimuth of the interval (layer-stripped) instantaneous phase, the sole attribute (so far) to tie well control.

Abstract

The search for fractured reservoirs is one of our exploration focuses in Kuwait. Our deep carbonate reservoirs in the Study Area are highly fractured reservoirs. Mapping fault/fracture networks is key to unlocking the resource potential. This abstract illustrates the workflow from fault/fracture mapping to fractured reservoir modeling. It was demonstrated that seismic attributes are useful for fault/fracture mapping. The combined post-stack inversion and neural network analysis improved the accuracy of porosity estimation. Lithofacies classification was carried out, as fracture density is dependent on facies types. Velocity modeling was the key step in transforming seismically-derived properties (e.g. porosity volume) from time domain to depth domain. Through detailed well-by-well image data analysis, it was observed that there are 3 sets of open fractures in the Modeling Area. A Discrete Fracture Network (DFN) model was built based on these 3 sets, further controlled by fracture densi

Abstract

Conventionally discovery to development of a heavy oil reservoir takes very long (Minimum 10-15years). However, significant volatility in the oil prices have required more collaborative workflows and strategies from operators and service companies to optimize cost and maximize efficiency and innovation. We present here a joint service integrated model between an NOC and a service company which was used in the fast track development of an unconventional heavy oil reservoir and resulted in discovery to production in record time. A conceptual field development plan was put in place for fast track development of the Lower Fars reservoir in the Umm Niqqa field after drilling and testing 26 exploration wells. The plan consisted of drilling and completing over 80 wells in conjunction with the construction and commissioning of an early production facility (EPF) to handle the sour heavy crude. Given the brief time and the unconventional nature of the reservoir, significant challenges were faced