This seminar will teach participants how to identify, evaluate, and quantify risk and uncertainty in everyday oil and gas economic situations. It reviews the development of pragmatic tools, methods, and understandings for professionals that are applicable to companies of all sizes. The seminar also briefly reviews statistics, the relationship between risk and return, and hedging and future markets. Strategic thinking and planning are key elements in an organisation’s journey to maximise value to shareholders, customers, and employees. Through this workshop, attendees will go through the different processes involved in strategic planning including the elements of organisational SWOT, business scenario and options development, elaboration of strategic options and communication to stakeholders.
Decisions in E&P ventures are affected by Bias, Blindness, and Illusions (BBI) which permeate our analyses, interpretations and decisions. This one-day course examines the influence of these cognitive pitfalls and presents techniques that can be used to mitigate their impact. Bias refers to errors in thinking whereby interpretations and judgments are drawn in an illogical fashion. Blindness is the condition where we fail to see an unexpected event in plain sight. Illusions refer to misleading beliefs based on a false impression of reality.
Tuba is tight carbonate reservoir and one of largest Upcoming Reservoirs in North Kuwait Sabriyah field and subdivided to three main reservoir units (upper, middle and lower). Tuba, though discovered in the 60's, is still relatively under-exploited presently with only ±10 active oil producer wells with very low total production rate compared to other major reservoirs in same field. High reservoir heterogeneity, tightness, and poor fluid properties necessitate the application of fracturing stimulation technology to maximize Conductivity and hence recovery enhancement. Recent technologies in multistage acid Fracturing executed successfully covering multiple layers as first time ever in one of existing two Tuba horizontal wells.
The well under study is highly deviated, completed as barefoot in the Upper Tuba reservoir, intersecting multiple sub-layers. Following the positive results of acid fracturing treatments in offset Tuba's vertical wells, the candidate well was selected for first multistage acid fracturing in horizontal wells, to setup the reservoir development plan ensuring high production potential with most cost-effective drilling and completion strategies. Rig-less 5-Stages Acid Fracture treatment was executed in flawless operation. Many technical and operational challenges were faced (Geo-mechanics, stages selection and design, cementing 7in liner) and properly handled within integrated teams with lessons learned are to be considered in next designs and executions. Initial post multistage acid Frack short term production showed productivity improvement by approximately 5 folds of pre-stimulation production. The well showed high decline in production rate within the first one-year production post fracturing stimulation. However, analysis showed that the decline mainly was caused by reservoir depletion rather than fracture conductivity deterioration. The well is under close monitoring for stabilization (rate and pressure). Horizontal PLT is planned to evaluate inflow profile from individual layers to improve next designs.
Despite the close results yilded from the multistage acid fracturing in two horizontal wells compared to the results from 7 vertical wells, it is still early to evaluate stimulation potential of horizontal against vertical wells. It needs more production history and more wells to evaluate long term sustainability.
Water-flooding is planned to support reservoir development and enhancing stimulation sustainability and by turn recovery factory. First pilot water flooding injector well was commissioned in early 2018, but comprehensive waterflooding analysis is not finalized yet.
The initial positive results of first multistage acid fracturing in Tuba reservoir had key contribution to setup Development strategy for the entire TUBA reservoir to expand drilling horizontal wells and complete it with initial multistage fract (MSF) stimulation to maximize reservoir exposure and enhance reservoior productivity that will contribute significantly to the NK production target. Two more horizontal wells were drilled and completed with MSF in late 2018 with initial encouraging enhanced productivity results during cleaning and lifting but were not put yet on production for more comprehensive analysis. ation to improve initial productivity.
This seminar covers the fundamental principles concerning how hydraulic fracturing treatments can be used to stimulate oil and gas wells. It includes discussions on how to select wells for stimulation, what controls fracture propagation, fracture width, etc., how to develop data sets, and how to calculate fracture dimensions. The seminar also covers information concerning fracturing fluids, propping agents, and how to design and pump successful fracturing treatments. As the industry wrestles with another price cycle, making sense of the world in which the oil and gas industry will operate is important to understanding the actions (by engineers, corporations, and governments) which must be taken today so that the oil and gas industry may prosper in the future. Hydraulic fracturing has been touted as a ‘new technology’ (though a misnomer) which is opening access to un-tapped value (in the USA) and lowering the cost of energy across the globe by shifting the balance between supply and demand.
Heikal, Amr (Kuwait Drilling Fluids) | El Banna, Mohamed (M-I Swaco a Schlumberger Company) | Manescu, Gabe (M-I Swaco a Schlumberger Company) | Al Mulaifi, Mohammed (Kuwait Oil Company) | Mohammed, Ibrahim (Kuwait Oil Company)
Objectives/Scope: A major Operator in Kuwait have used historically Non-Aqueous Fluid (NAF) to drill the buildup section through the challenging shale formations, mainly due to wellbore stability issues and lubricity requirements. As part of the operator's environmental improvement strategy, the operator and fluids provider team identified potentially fit for purpose High Performance Water Base Mud (HPWBM) as the most suitable, environmentally acceptable alternative to NAF's. Methods, Procedures, Process: A HPWBM system was designed and proposed based on extensive laboratory testing to overcome drilling challenges. Inhibition characteristics and formation sealing capabilities of conventional KCL polymer mud with sulphonated asphalt were enhanced by using a liquid polyamine based clay hydration suppressant and a co-polymeric nano-sized shale-sealing additive. A customized bridging package based on the pore size distribution was also introduced, using calcium carbonate and resilient graphite particles. The combination of effective bridging and sealing polymer helped in sustaining high overbalance to avoid differential sticking tendency, designed in laboratory conditions during the planning stage. Results, Observations, Conclusions: The field trial was a great success compared to the use of conventional fluid systems and methodologies. Using High Performance Water Base Mud, the operator successfully drilled and cased 12.25" and 8.5" sections as per plan with stable wellbore indicated by the smooth trips and no string stalling or sticking tendency.
Ranjan, Priya (Kuwait Oil Company) | Al-Qenae, Amna (Kuwait Oil Company) | El-Aziz, Sabry Abd (Kuwait Oil Company) | Al-Hashash, Awrad (Kuwait Oil Company) | Al-Ajmi, Hadi (Kuwait Oil Company) | Mofti, Mohamed (Halliburton) | Boueshi, Alaeldin (Halliburton) | Eid, Walid (Halliburton) | Sadeddin, Salma (Halliburton) | Allam, Ahmed (Halliburton)
The Tuba carbonate reservoir in the Sabriyah field, North Kuwait was deposited above the Wara shale and overlaid by the Ahmadi shale. It is divided into three stratigraphic units: upper, middle, and lower. This formation was considered to have limited opportunity for production enhancement. However, improved reservoir characterization along with developed pinpoint fracture acidizing technologies have provided new opportunities to improve recovery and increase pay zone productivity.
Pinpoint fracture acidizing technology, using drillpipe with a bottomhole pinpoint tool assembly, has helped to effectively stimulate pay intervals individually using acid fracturing treatments. This resulted in achieving multiple stimulation treatments in a single trip, where each treatment stage was tailored for the specific interval being treated. Moreover, this pinpoint technique increased the number of treated stages per well compared to conventional multistage fracture acidizing, which led to greater efficiency and greater production.
This technology has been successfully used for multiple zones in complex reservoirs to improve production and reservoir recovery. It provided an effective method to help boost production and injection from tight zones in openhole horizontal completions and completions where zonal isolation could be compromised. This treatment process helped optimize hydrajetting and acid fracturing technologies along with treatment design for individually placed fractures by using the dynamic fluid movement to divert fluid flow into a specific treatment point in the formation. This service required a different approach to treatment design by controlling and evaluating two primary fluid injection paths, which necessitates two separate pumping systems. However, a proper well candidate is important to the success of any stimulation treatment.
This paper discusses methodology and treatments applied on a recent well in the Tuba carbonate reservoir in a horizontal openhole completion. The technical approach taken during the design of the treatments is presented in detail, as well as the operational challenges encountered during the multistage fracture acidizing treatments. This stimulation technique was implemented successfully to perform a seven-stage acid treatment in a single lateral. The overall success of this project proves that there is a technical alternative to the traditional fracture acidizing methodology for wells of this type.
Pooniwala, Shahvir (Baker Hughes, a GE company) | Nagarkoti, Malvika (Baker Hughes, a GE company) | Alam, Anwar (Baker Hughes, a GE company) | Al-Enezi, Badriya (Kuwait Oil Company) | Aloun, Samir (Kuwait Oil Company) | Al-Haddad, Mohamad (Kuwait Oil Company) | Al-Harbi, Sultan M (Kuwait Oil Company) | Mubarak, Abdullah A (Kuwait Oil Company) | Al-Ibrahim, Abdullah A (Kuwait Oil Company)
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. (
Based on global experience it was proposed that proppant fracturing can deliver more sustainable production rate as compared to acid fracturing. A predominant issue in previous acid fracturing treatments done in the Tuba reservoir has been fracture containment between layers. Proppant fracturing was also identified as a solution to mitigate this challenge.
Proppant fracturing had been previously attempted in Kuwait, however the attempts were evaluated as not being operationally successful. The steps that lead to the recent first successfully executed proppant fracturing treatment in carbonates in Kuwait has been documented in Part I of this paper series.
The cretaceous carbonate formations in North Kuwait are relatively shallow and are known to be tight and highly ductile. Due to the ductility of these formations, proppant placement and reduction of the fracture conductivity due proppant embedment were thought to be significant risks. During the course of the project, detailed core analysis and testing was conducted using formation core samples to ascertain the severity of this risk.
Lessons learnt in the first stage of this project were implemented prior execution to ensure that the planned proppant fracturing treatment would meet or exceed operational expectations.
Successful execution of this hydraulic fracturing treatment was pivotal in order to plan the future production strategies for the Tuba formation. A cautious approach needed to be followed as proppant placement was of paramount importance. Different strategies were incorporated in the fracturing workflow to ensure the success of the treatment and to maximize data collection in order to optimize future treatments and well placement. Multiple mini-fracs, temperature logs and pumping of novel non-radioactive tracer proppant were some of the techniques utilized.
During execution various decisions were taken real-time to ensure success of the treatment. It was observed that all parameters were consistent with the results of the core and laboratory testing conducted during the initial phase of the project which lead to optimizing the proppant placement.
The success of this treatment has been a game changer resulting in more wells being identified as candidates for proppant fracturing in this field.
Once proppant placement was established in the first stage of this project, an attempt was made to optimize fracture designs, fluids and treatment schedules. The lessons from these optimizations will help further design implementations in the next phase of this project including fracturing of horizontal multi-stage wells which will help ascertain the future production enhancement strategy for this field.
This article exclusively relies on data from published literature.
The development of a foreland basin in the Mesopotamian Basin of South Iraq during the deposition of the Mishrif resulted in facies stacking patterns reflecting the development of a flexural bulge.
Paleogeographic reconstructions rely on carbonate facies as depth indicators, whereby rudist biostromes and coarser bioclastic debris define Shoal Complexes that separate restricted lagoonal deposits from open marine sediments. Ahmadi-Rumaila-Lower Mishrif sediments deposited into a N-S trending basin also showing evidence of precursory foreland basin tectonics: the increasing thickness of Lower Sequence deposits to E and NE reflects an increase of accommodation space in these areas. A disconformity separates the lower and upper Mishrif sequences, and represents the initiation of the flexural forebulge. The lower sequence (Mishrif mC, mB2) is characterised by a N-S oriented platform margin Shoal Complex, while during the upper sequence (Mishrif mB1, mA), a NW-SE orientation prevailed. The origin of the regionally deeper facies at the start of the Upper sequence reflects eustatic sea level rise, after which foreland basin tectonics significantly changed the paleogeography of the basin and enabled the rudist Shoal Complex to spread over a wider area. The Mishrif caprock at the top of the Upper Sequence represents a major regional exposure.
Alpine 1 tectonic activity, previously associated with the Khasib, Tanuma, Sadi and Hartha Formations in the region, actually initiated earlier, impacting the upper and to a lesser extent lower Mishrif sequences. The activity is interpreted in a foreland basin setting, with structural styles similar to but smaller scale than that seen later in the Alpine 2 Zagros emplacement.
Local structuration effects along pre-existing lineaments likely reactivated in different orientations due to the rotating stress fields. NW - directed push leading into Alpine 1 on N-S oriented structures may have resulted in transpressional strike slip related uplift. Such local uplift cannot however explain the observed facies stacking patterns, particularly in the Upper Mishrif.
Al-Othman, M. R. (Kuwait Oil Company) | Buhamad, A. A. (Kuwait Oil Company) | Al-Houti, N. B. (Kuwait Oil Company) | Ashkanani, M. S. (Kuwait Oil Company) | Al-Mehanna, H. S. (Kuwait Oil Company) | Al-Haddad, M. N. (Kuwait Oil Company) | Al-Dhafiri, A. A. (Kuwait Oil Company) | Al-Harbi, S. M. (Kuwait Oil Company) | Al-Ibrahim, A. A. (Kuwait Oil Company) | Al-Zuwayed, A. M. (Kuwait Oil Company) | Ahmed, A. M. (Kuwait Oil Company) | Al-Dousari, M. A. (Kuwait Oil Company)
In Kuwait, drilling and deployment plans focus mainly on drilling vertical wells through a wide range of reservoirs consisting of high- and low-permeability sandstones and carbonates, with varying crude types from medium-heavy to condensate. Since 1935, Kuwait has produced mainly from the types of reservoirs that keep its daily production as high as possible to accommodate the country's economic needs. With the aging of these mature reservoirs, reservoir pressure reduction and water production become a major challenge, in addition to the limited access to drilling resources. Accordingly, exploring different reservoirs and unlocking the potential of the existing low- to mid-permeability reservoirs through advanced fracturing technologies are considered the alternative plan to compensate for production decreases and to improve oil production. However, implementing such technologies requires a customized design and candidate selection process.
The plan involved a multidisciplinary well candidate screening and selection criteria for different reservoirs and fields. The criteria include different parameters such as bubblepoint pressure, minimum formation thickness, and rock mineralogy, in addition to the study of the previously applied production enhancement technologies. About 50 wells have been selected from different reservoirs and fields across Kuwait for the initial pilot plan to evaluate the potential of a wide range of reservoirs. Then, a customized fracturing technology design followed that included operational planning, execution, and evaluation.
Approximately 20 fracturing treatments were executed successfully, and the post-job evaluation showed two- to four fold gains in production. This changed the development strategy and allowed for further development plans for these reservoirs. These newer plans included the application of technologies such as channel fracturing for proppant fracturing and fiber-laden self-diverting acid system for acid treatments.
The well candidate selection criteria and customized design of channel fracturing technology for the sandstone reservoirs and fiber-laden self-diverting acid system technology for fractured carbonate reservoirs resulted in a total additional gain of approximately 15,000 B/D. The detailed engineering design from candidate selection to treatment and the application of optimized hydraulic fracturing technologies enabled production enhancement and additional recoverable reserves from the most challenging low-permeability and low-API gravity candidates for the first time in Kuwait where conventional stimulation techniques were not providing the expected results.
The Sabiriyah Tuba Reservoir has significant hydrocarbon resources in place with a high degree of reservoir rock and fluid heterogeneity. Until recently, it received marginal development attention, and was considered one of the ‘Minor Reservoirs' of North Kuwait with limited opportunity for production enhancement. Improved reservoir Characterization and the development of a 3D Static model, together with Horizontal Completion technology have now opened up new opportunities for an accelerated development strategy.
The Tuba formation represents a carbonate ramp with different lithofacies association from more proximal depositional setting to more distal environments. Even though the northern area of the field is represented by deeper facies, the reservoir quality shows comparable porosity and permeability trends. The porous and permeable aggradational and progradational carbonate of Upper & Lower Tuba respectively, constitute the main oil accumulations where reservoir quality is strongly controlled by structure, primary depositional fabrics, as well as extensive dissolution process.
It has a significant vertical and horizontal variation in oil quality ranging from low 11-18 API oils to better quality 23 API oils. Current performance of the producer wells indicates that Tuba has the potential to enhance dry oil production.
Tuba reservoir is divided into 3 main stratigraphic units, Upper, Middle & Lower and each unit is further subdivided into sub-layers. The geological layering based on sequence stratigraphy combined with 3D seismic data provided the framework for structural model. The high resolution model was achieved by generating 3D faulted grids and integrating all the components such as all the deterministic structure maps and petrophysical results in to one geo-cellular model applying different approaches and techniques. The model and visualization proved valuable in the interpretation of the primary depositional and secondary digenetic processes that left their imprints on Tuba rocks
The study helped accelerate the development of the Tuba reservoir, and led to new Drilling & Workover opportunities that converted to >500% increase in Oil production. Additionally, from this study, an estimated increase in recoverable reserves of >60% would now support a long term development plan and reserves growth for North Kuwait.
The Sabiriyah Tuba Reservoir is an Upper Cretaceous (Cenomanian) age belongs to the category of??Minor Reservoir?? in Sabiriyah field, North Kuwait (Fig-1). The Tuba reservoir is a part of North Kuwait resources and attempts were made to fully understand and develop the reservoir. Tuba with other minors reservoirs are expected to contribute significantly to the North Kuwait production target.
The tuba formation is a carbonate reservoir interpreted as a highstand and transgresive system which comprises dominantly skeletal mudstone , wackstones, packstones and rare grainstone / floatstone that can be rationalized into six facies associations (lagoonal, inner ramp ,shallow mid ramp, deep mid ramp, outer ramp & offshore).Tuba was originally divided into 3 major startighraphic units (Lower , Middle & Upper) . The sequence stratigraphy and reservoir layering scheme was carried forward from integrated open well log data supported by 8 wells with core data. These wells are centered to the north and one well in southern area of the Sabiriyah structure.