bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of Reservoir Pressure in Multi-Zone Well under Flowing Conditions Using Spectral Noise Logging Technique, Zubair Reservoir, Raudhatain Field, North Kuwait
Authors: Eldaoushy Ahmed S. , Al-Ajmi Moudi , Al-Shammari Maali , Aslanyan A. , Aslanyan I. , Prosvirkin S. , Farakhova R.
Published: November 2015

Monitoring the reservoir pressures throughout the production life of the field is considered as a cornerstone for reservoir management and optimization of the development plans. There are many challenges to have routine and proper pressure records. Multi-zone single completion wells are one of these challenges, where it is difficult to acquire the reservoir pressure for each zone through the conventional pressure gauges. In addition to that, deferring the production or injection of high rate wells for quite time to acquire downhole static pressure data is adding more to these challenges.

Raudhatain Zubair Reservoir is a layered reservoir with difference in reservoir pressure from layer to the other. Spectral Noise Logging technique has been utilized to estimate the average reservoir pressure for each perforated layer in a Multi-zone single completion oil producer. The noise logging survey has been carried out under flowing conditions and on different rates. The process of estimation the average reservoir pressure from Noise logging is based on quantification of the noise power under different rates. The signal recorded by SNL has two main parameters: amplitude and frequency. The frequency ranges widely from 8 Hz to 60 kHz, while the amplitude increases with differential pressure. The power of the acoustic noise signal generated by a reservoir fluid flowing from a particular unit is directly proportional to the product of differential pressure and flow rate. Nonlinear relationship between the noise power and bottom-hole flowing pressure has been utilized to estimate the average reservoir pressure which stays valid under monophasic flow conditions for the hydrocarbon to the wellbore.

The estimated pressures for each layer from this technique matched the RFT pressure data that have been recorded in the nearby wells and in also RFT data recorded in same well considering the production history. The noise profile has also indicated the effective sand thickness for each layer and investigated flow behind the casing from non-perforated reservoir to the existing perforations.

Utilization of the SNL logging to estimate the reservoir pressure is adding more to reservoir surveillance applicable tools that could mitigate some of the existing challenges and aiming to improve the surveillance process under certain circumstances.

This paper presents a case of applying the noise logging in an oil producer with the detailed job procedures, measured data, interpretation process, and the final results
Redevelopment of Brownfield in Malaysian Offshore Industry: A Cost-Optimized and Mitigated-Risk Approach
Authors: Lim Jit Sen , Muda Ahmad Ramudzan , Razali Wasli , Sidek M Saleh , Hashim Abdul Fattah
Published: November 2015

Brownfield redevelopment carries an amount of risk and cost (capital expenditure and operating expenditure). There will always be uncertainties on the remaining hydrocarbon in the reservoirs, and the estimated ultimate recovery. These uncertainties of production gain may undermine the economic feasibility, and restrict additional financial investment to redevelop the brownfield. This paper is a case-study of a 30-year-old brownfield redevelopment in Malaysia. The risks of redeveloping this brownfield were mitigated through subsurface studies, phased-development strategy, staged reviews, and risk sharing through alliance partnering. The costs were optimized by minimizing facilities modification, emphasizing on fit-for-purpose concept, applying low-cost alternatives, continuous improvement from lessons learnt, and having long-term plans to reduce the operating expenditure. A sustainable brownfield is defined by its ability to continue producing at an economical Unit Production Cost (UPC).
LWD Fluid Sampling, Tool Allows for Innovative Applications in Middle East Carbonate Reservoirs: A Case Study from a Gas Re-Injection Project
Authors: Al-Shehhi Noora , El-Hamawi Mohamed , Ateeq Budour , Smith Steve
Published: November 2015

The traditional way of acquiring reservoir fluid samples (prior to production) has usually involved running a wireline formation tester for several days or even weeks after drilling the well. This time delay between drilling and sampling has an adverse effect on obtaining high quality fluid samples because of long-term exposure to invasion. This effect becomes worse in low permeability formations where effective mud-cake build-up is poor, resulting in deeply invaded formations. In turn, this requires large volumes of filtrate to be pumped back out of the formation in order to collect low contamination reservoir fluid samples.

The ability to sample while drilling using LWD technology solves part of this problem by allowing the pump-out to start much earlier in the invasion process, thereby reducing the volume of filtrate required to pump out of the formation. In addition to cost-savings from reduced sampling time, there are other benefits to LWD sampling such as continuous circulation. This can be critical when multiple reservoirs are exposed, some of which may be depleted and pose differential sticking risks, which is often the case in the Middle East.

However, current LWD sampling technology is done with a probe which limits the inflow area thereby complicating the sampling process in low permeability formations. Many of the giant carbonate reservoirs in the Middle East are highly heterogeneous and have low average permeabilities (<1-5mD) making it difficult to sample with a standard probe in many situations (LWD technology cannot overcome all the challenges just yet). But viscosity is also critical and the overall mobility of gas reservoirs can be relatively high due to the low gas viscosity, thereby making gas samples a potential application for this new LWD technology in Middle East carbonate reservoirs.

Formation pressures and fluid samples were taken from such a reservoir. In this field there is known condensate banking and the project involves re-injecting the produced dry gas into the reservoir to help maximize the condensate recovery. Seven (7) samples were collected using an LWD sampling tool, and subsequent lab analysis on the samples confirmed condensate in the reservoir. This new technology is seen as a way to help maximize recovery and minimize costs.
Efficient Systems Completion Execution; The PNG LNG Experience
Authors: Richards D.J. , Perez V. , Lee Y.
Published: November 2015

The positive impact of a well planned, efficient and integrated Systems Completion program has a significant focus within ExxonMobil’s project portfolio. The recent publication of API 1FSC recommended practice for Facilities Systems Completion Planning and Execution which aims to standardize terminology across the industry is an initial step towards more consistently applied and accepted processes by contractors & clients alike. This paper discusses the continuous improvement measures of a successful Systems Completion implementation process and highlights the importance of the fundamental precursors for a successful project systems completion campaign. Through proper planning and alignment with all stakeholders, a project’s overall schedule to first production can be shortened and delays and downtime due to poor quality mitigated.

The Papua New Guinea LNG Project, LNG Facility located near Port Moreseby and operated by ExxonMobil was successful in its execution. One of the major factors was the proper planning and alignment across Company Project & Operations and Contractor organizations. The Project Team and EPC Contractor leveraged & improved upon jointly established processes from previous projects to capture further efficiencies. The turnover of the PNG LNG Plant Train 1 and Train 2 facilities were achieved ahead of schedule, with minimal punchlist and full alignment with the Operations Organization.
A Case Study of Integrated Seismic and Well Statistics in Modeling of Deep Reservoirs, Abu Dhabi, UAE
Authors: Hu Jialiang , Obaid Khalid , Witte Johan , Mahgoub Mohamed , Neves Fernando
Published: November 2015

Previously, the deep reservoirs of Middle Jurassic (Araej Formation), Upper Permian (Khuff Formation) and pre-Khuff (Berwath Formation) age in a salt-related field offshore Abu Dhabi were interpreted to be uneconomical due to their small GIIP volume which was based on limited data from only one exploration well. However, new geological studies including basin modeling suggest a much higher potential for deep gas in this particular field. In view of the increasing demand for gas in Abu Dhabi, ADNOC has initiated the re-evaluation of a number of deep gas reservoirs using updated geological models, integrating reprocessed 3D OBC seismic and all available well data.

The major challenge in modeling these deep reservoirs is lack of well control. It is challenging to calculate statistically meaningful averages for the lateral variations in reservoir characteristics with high confidence, only based on a few wells. On the contrary, reservoir property-related seismic attributes such as RMS amplitude and acoustic impedance from post-stack inversion of the 3D OBC seismic are laterally continuous datasets, providing the database for lateral statistics. In this study, geostatistics are combined with horizontal variogram modeling based on seismic and vertical variogram modeling based on wells, which bridges the vertical-lateral gap of resolution and continuity between wells and seismic. Variogram maps rather than a single variogram model are calculated from the average seismic attribute maps, which extend statistic control of lateral continuity to 360 degrees. In addition, variograms are mapped for each fault segment separately, which honors the reservoir behavior to the maximum. Statistically, seismic attributes show a similar trend in their probability curves and vertical distribution as reservoir properties calculated from well logs. Therefore the final reservoir property models are built using co-krigging sequential Gaussian simulation with seismic-well combined variograms.

As a result, the new geological model enlarges the area of deep-gas prospectivity and locates the primary deep gas target in the Upper Khuff and pre-Khuff around the crest of this field. The re-calculated GIIP with low, average and high cases now shows an economical gas volume in these deep reservoirs.

This integrated statistics and modeling approach, combining seismic and well data reduces uncertainty in reservoir characterization with limited well data. Considering the good coverage of seismic in Abu Dhabi, this approach can be applied to the other fields with lack of deep well penetrations.
In-Situ Tectonic Stress Measurement from Wireline Straddle Packer MicroFrac Testing: A Case Study in a Carbonate Reservoir (U.A.E.)
Authors: Al Shehhi Noora Saeed , El-Hamawi Mohamed , Moronkeji Dee , Franquet Javier , Smith Steve
Published: November 2015

Geomechanical modeling is important to understand in-situ stresses, reservoir stress path, stress contrast, wellbore stability, solid production, integrity of cap-rock and drilling vertical and horizontal wells. The knowledge of the in-situ stresses is critical for pre-drill and post-drill well planning as well as wellbore stability prediction and is needed throughout the life of a well. The uncertainty associated with this geomechanical modeling can be critical and costly if these uncertainties are not mitigated and, to reduce this uncertainty, it is important to have a calibrated geomechanical model. One important technology that can help with reducing the uncertainty is the wireline straddle-packer microfrac tests for in-situ stress characterization. It is an important technology that helps in the measurement of in-situ formation breakdown pressure, fracture propagation pressure and fracture closure pressure. It also helps with other important hydraulic fracturing design such as fracture containment assessment, horizontal stress profile and stress contrast to stimulate tight formation shale gas or oil, water disposal wells and for OBM cutting reinjection wells.

The microfrac testing procedure uses the pressure response measured during formation breakdown, fracture propagation, fracture reopening cycles and pressure fall-off cycles for overall stress measurement and fracture closure identification. The objective of this microfrac testing was to validate and calibrate the horizontal stress profile in various intervals of the target formations. This paper focuses on the microfrac testing methodology, the geomechanical principles governing the testing, the resulting interpretation and the geomechanical modeling for horizontal stress calibration in a vertical borehole onshore Abu Dhabi.
New Insights on the Mechanical Characterization of Kerogen-Rich Shale, KRS
Authors: Hull Katherine L. , Abousleiman Younane N. , Han Yanhui , Al-Muntasheri Ghaithan A. , Hosemann Peter , Parker S. Scott , Howard Cameron B.
Published: November 2015

In the past decade, chemical, physical and mechanical characterization of source rock reservoirs has moved towards micro- and nano-scale analyses, primarily driven by the fact that the representative elementary volume (REV) for characterizing shales is at the nanometer scale. Nanoindentation is now widely used in many industrial and university laboratories to measure both stiffness and strength and other mechanical properties of shales, such as anisotropic Young's Moduli and plastic yielding parameters. However, to date, tensile failures of shales have not been studied at the micro- or nanoscale.

In this work, a nanoindenter is used to bring organic-rich shale (preserved Woodford shale from a well site in Ada, Oklahoma) to failure in tension. Micro-cantilever beam geometries (~25 microns in length and ~5 microns in width) were milled and loaded to failure while monitoring in-situ via scanning electron microscopy (SEM). The force-displacement curves were analyzed in light of the high resolution images collected during fracture initiation, propagation, and ultimate failure. Complementary studies of the mineralogical composition, particularly at the failure faces, as well as the organic content were also performed. Failure planes and tensile fracture initiation in the micro-beam were associated with the various phases of the mineral and organic cluster components.

The micro-beam tests of this composite natural material demonstrate linear elastic behavior followed by plastic yielding before complete failure. This behavior was clearly observed to correlate with the amount of organic matter at the fractured surface. Energy dispersive X-ray spectroscopy (EDS) analyses were conducted at the post-failure stage on the resulting fracture faces and the relationship between mechanical behavior and composition was established. It was observed that when high mineral content was found at the faces, a brittle failure took place, while when the fixed support had high kerogen content the micro-beam failed in a ductile mode.

These results reinforce our growing understanding of the heterogeneous nature of shale and the importance of nano- and micro-scale analyses to understand our reservoir source rocks.
Mapping Geomechanical State of Unconventional Shale - A More Robust, Faster Lab Characterization Method
Authors: Pérez Héctor González , Ali Syed Shujath , Jin Guodong , Dhamen Ali Abdullah
Published: November 2015

Unconventional shale mechanical parameters are important for many applications such as reservoir stress-state determination, horizontal drilling and hydraulic fracturing design among other engineering design parameters. These parameters include Young's modulus, Poisson's ratio, cohesion, angle of internal friction, and unconfined compressive strength. Their determination is commonly performed on single-stage triaxial (SST) compression tests using three or more core samples at various confining pressures. For unconventional shale, this has been a practical bottleneck - it is very difficult to drill multiple plugs with good quality from a whole core because of its brittleness and complexity. An alternative procedure is the multi-stage triaxial (MST) compression test, which requires only one plug to be tested. However, its main problem lies in the practical difficulty in determining the failure envelope of the sample. Judgment must be made regarding the stress-strain state "immediately prior to failure". It is not uncommon that a wrong estimation of the failure state occurs when interpreting these stress-strain curves. The MST test uses one plug, which in itself could be a significant advantage.

This paper presents a robust modified method of the MST compression test that accurately determines the imminent rock failure through continuously monitoring the radial deformation. To test and validate the method, Berea sandstone and Mancos shale plugs are selected to perform a series of the SST and MST tests. For each rock type, at least four plugs are used, which are cut from the same whole core or have similar lithofacies. Experimental results show that the Mohr-Coulomb failure envelope can be generated perfectly from both the SST and MST tests. However, the failure parameters derived from the MST tests are lower than those from the SST tests. The difference may be attributed to the intrinsic heterogeneity of rock samples or the damage accumulated from the early stages in a MST test. The proposed MST method is an efficient alternative to generate the Mohr-Coulomb failure envelope when the availability of core samples with good quality is limited, especially in the exploration and development of unconventional reservoirs.
Mentor Book Based on Infographics Demonstration for Oil and Gas Companies
Authors: Ghazo S.
Published: November 2015

Description

One needs the proper guidance to develop his/her potential into tangible value and a role of a competent mentor is therefore crucial in that regard. Working in an organization, like ADCO, with 8037 employees (60.4% -4855 employees- of which are UAE nationals) and targeting 75% emiratization by 2017, the need for the right mentors becomes essential.

The main goals of publishing this paper are the following:

Application

Results and conclusion

Technical contribution
Architecture, Facies Distribution and Reservoir Properties of the Mishrif Formation (Zubair Field, Southern Iraq): An Example of Integration of Seismic Interpretation with Well Data
Authors: Miraglia Salvatore , Borromeo Ornella , Maragliulo Chiara , Rodrigues Juan , Sartorio Dario
Published: November 2015

With the aim of building environments of deposition (EOD) maps supporting the prediction of the reservoir quality in the Mishrif Formation investigated in the subsurface of the Zubair field, sedimentary facies distribution and reservoir internal architecture were defined through integration of 3D seismic interpretation with well data (core facies, biostratigraphy, petrophysical parameters and log-derived facies obtained extending the log character of the different core facies to the non-cored wells).

The workflow comprised the sedimentological core study, the seismo-stratigraphic interpretation tied to the well stacking pattern and the environment of deposition mapping including the interpretation of attribute volumes derived from seismic inversion (porosity and frame flexibility facies volume based on the internal Eni approach CaSRC -Seismic Reservoir Characterization for Carbonates- which put into relationship the rock physic parameters to the pore structure).

Mishrif Formation consists of shallow water, bioclastic carbonates deposited in a well-developed carbonate ramp system. Geometrical evidences observed on seismic allowed to depict the evolution of the ramp passing through a main phase of aggradation, a subsequent step of progradation and, finally, a stage of aggradation-progradation. For each identified system tract, thickness maps were computed and depositional settings distributed as inner, middle and outer ramp domains. Each domain is represented by a group of facies characterized by its own configuration of porosity and pore types. Porosity is excellent in rudist bearing shoal facies deposited in the middle ramp setting and poor in mudstone and wackestones of the outer ramp. The inner ramp domain is characterized by packstone with poor to moderate porosity, improved at the very top of the Formation by diagenetic alteration associated with subaerial exposure.

Once established the relationships between facies types, environments of deposition and porosity, the EOD maps were utilized to estimate the porosity distribution within each system tract. In this view, the interpretation of the volumes derived from the seismic inversion were included in the mapping process to refine the outlining of the boundaries between depositional domains characterized by different porosity configurations.

The approach proved to be very useful in predicting the distribution of facies and related reservoir properties in areas of the field poorly controlled by well-data.
Reservoir Facies Development and Depositional Models of the Mixed Carbonate/ Clastic Asmari Formation in the Northern Margin of Dezful Embayment
Authors: Afshin S. , Lotfpour M. , Chegini A.
Published: November 2015

The Oligo-Miocene Asmari Formation in the North Dezful Embayment of SW Iran is comprised of mixed carbonate/ clastic facies associations. The lower part of Asmari Formation is characterized by a variation of clastic facies and the upper part is dominated by carbonate shallow marine facies types. The main purpose is to investigate a regional reservoir facies changes (lateral and vertical facies variations) and also to define a relationship between sequence stratigraphy and reservoir facies quality among the three selected wells, which are located in the North magin of Dezful Embayment. During this case study, at least ten reservoir facies types were identified and classified in the study area using all available geological subsurface data. As well as, the six third-order depositional sequences (carbonate and clastic dominated cycles) have also been distinguished and correlated in the study area, representing particular sedimentary regime and relevant reservoir characteristics, which are controlled by local tectonic events and eustatic sea level fluctuations. Theses facies types directly make the significant aggraded to prograded systems tracts that can be separated by correlable surface boundaries, influenced by local disconformity events. The reservoir facies quality of these depositional sequences is drastically controlled by sedimentary regime, facies types and different diagenetic impacts on the reservoir. Local collisional tectonic events and relevant erosional features had a big role to influx the clastic sediments in the study area. The early and late diagenetic events generated the reservoir carbonate facies. The novelty of facies this case study is to define a new reservoir facies classification of the mixed Asmari reservoir stacks in the northern part of Dezful Embayment, which is affected by several influxes of the clastic sediments, multiple diagenetic events on the upper carbonate and tectonic events.
Brazilian Tensile Strength Test of Orgainc-rich Shale
Authors: Lai B. T. , Li H. , Liu H. H. , Zhang J. L. , Georgi D.
Published: November 2015

Tensile strength is a critical parameter for hydraulic fracturing, predicting crack initiation and propagation in reservoirs, especially in shale reservoirs with complex natural fractures and fissures. The tensile strength of conventional rocks, such as sandstone and limestone, has been well studied and documented. There are many studies of the tensile strength of laminated shale, which focus on scale effects, loading direction, and temperature effects; however, the studies on effects of mineralogy and the water content on tensile strength of organic-rich shales are very limited.

The objectives of this paper are to: 1) Critically review the key parameters that affect the tensile strength of shale; and 2) Experimentally examine the effects of water content, mineralogy and lamination on tensile strength. To do so, a rigorous workflow is followed: 1) Each 1 in. long shale sample is cut into two sub-samples, A and B, of similar length; 2) X-ray computed tomography scan is performed to diagnose pre-existing cracks and defects inside the core plugs; 3) Nuclear magnetic resonance (NMR) is then used to measure the air dry samples’ water content; 5) Sample A is placed on a load frame to measure the tensile strength; 5) Sample B is vacuumed and then saturated; 6) NMR is used to measure the water content after saturation; 7) Tensile strength of the saturated sample B is measured; 8) Samples are crushed, and X-ray diffraction (XRD), scanning electron microsope (SEM) and pyrolysis methods are used to estimate the mineralogy and total organic content (TOC).

A total of 70 Mancos and 48 Eagle Ford shale samples have been tested. The experiment results show that: 1) Bedding plane/lamination has a significant effect on Eagle Ford tensile strength, but no pronounced impact observed for the Mancos shale; 2) The imbibed water significantly reduces the tensile strength by 4.4% to 51.7% as water content increases from 4.45% to 11.7%; 3) Pre-existing detectable micro-fractures can significantly reduce the tensile strength by up to 66%; 4) Eagle Ford exhibits typical brittle hard rock failure configuration, with primary facture and secondary fracture being observed, while for the Mancos shale, only primary fractures are observed; 5) Acoustic velocity test results confirm that Eagle Ford is mechanically transversely isotropic, and Mancos is likely mechanically isotropic.
The First Successful 17½ in. Hybrid Drill Bit Run in Indonesia, Improves ROP and Saves USD 1.9 M in Arafura Sea Deepwater Operation
Authors: Mayendra A. , Pattinama J. , Tokuda N. , Waragai T.
Published: November 2015

A client operating in the deep water of the Arafura Sea faced a problem with drilling interbedded formations in a 17½-in. section. Previously, the section was drilled with a two-bit trip strategy because of various formation types and hardness; a tungsten carbide insert (TCI) bit for Tertiary limestone and interbedded sand, and a polycrystalline diamond compact (PDC) for Wangarlu shale and Puffin sand. Deepwater drilling is a high-cost operation. The new hybrid bit design is a solution to drill the section with one bit run and to save approximately 28 hours of tripping time. In addition, this run improves rate of penetration (ROP), especially in the "hard limestone" above Wangarlu.

The revolutionary PDC and roller-cone hybrid drill bit combines roller cone and fixed-cutter elements. The bit is designed to combine the best attributes of both bit types; the fast aggressive drilling action of the PDC and the smooth, low-torque action of the TCI. Hybrid bits are now being employed in difficult and challenging applications worldwide and are delivering a step change in performance and significantly lowering overall costs.

This paper presents the results of a field test in a deepwater application, and compares the performance of hybrid bits with conventional PDC and roller-cone bits used on offset wells. The interval was drilled in one run, saving USD 1M. Furthermore, the client saved an additional 23 hours, which is equivalent to USD 900,000, by achieving an ROP that is 45% faster than the best offset well.
First Cemented Completion in Egypt
Authors: Luna David , Bezbourah Pearl , Omar Mostafa
Published: November 2015

How can you achieve 20% well costs reductions with no flexibility on wellheads, casings or completion…and two months to do it. Impossible? In Bapetco we said: ″Why not?″ and we took on the challenge.

This paper tells the story of the first cemented completion executed in Egypt. It describes how Bapetco engineered and executed a cemented completion program in 46 days from concept to rig release. Achieving Best In Class performance, successfully cementing 4 ½″ pipe in 6″ hole and generating above 500 Kusd savings; setting new benchmarks for the field and opening up opportunities for the future. All this ensuring Process Safety and compliance with our Well Delivery Processes.

With limited time to develop a well concept, the processes need to be scaled down. To achieve this, an organization needs to ensure high levels of communication and team work.

For Sitra Cemented Completion, the story starts with the idea of cementing the completion to reduce well costs. This concept was endorsed during our Value Creation workshop – which acted as a catalyst. Without it, the decision and endorsement process would have taken months.

It was then up to the well engineers to design a cost effective well to deliver this 4 ½″ cemented completion. It was clear to us: the way to cut costs and remain effective was to drill small and fast.

The biggest limitation to drill a Slim well was the lack of fit for purpose wellhead equipment. So we went out of the box. We re-engineered the conventional well and the casing depths to allow the well to be finished in 6″. It was not the perfect solution, but perfect is the enemy of effective. For this pilot project, the compromised solution would allow us to test the concept and save costs on iron, fluids, bits and time.

None of this can be achieved without all groups deeply engaged, without communication, empowerment and, in some cases, compromises for the greater good.

Two wells have been drilled. Both drilled as Best In Class and both successfully cemented the completion in place. The results are astonishing, 15 days faster than the average of Sitra wells. And we have so much room for improvement, we are following a Technical Limit approach and with fit for purpose wellhead and equipment, the costs savings can grow as high as 1 MMusd per well, which is above 30% of cost reduced.
Enhancing Reservoir Surveillance and Production Sustainability Through Live Digital Slickline
Authors: Said M. Bou , Bilbeisi J. M. , Mansouri T. , Respecia B. S. , Assagaf M. , Cocagne M. , Ambo L.
Published: November 2015

Reservoir Surveillance is made increasingly difficult in mature offshore oilfields that contain a large number of wells with all associated infrastructure. While logging requirements are increasing in order to sustain production from the field and maintain well integrity, the production requirement is increasing and the operational cost has to decrease. These challenges are additional to the existing constraints due to resource limitations in an offshore environment: winch boats for equipment movement, slickline units for downhole safety valve retrieval and tubing checks as well as offshore living accommodation limitations are major factors any of which can cause a halt of rigless logging campaigns.

A new digital slickline unit was used to replace the conventional practice for rigless wireline logging operations in offshore fields (wellhead towers). The old method involved a slickline unit to perform the pre-job and post job work. That's in addition to the logging unit that performs the required production logging job. This process involved a lot of winch boat moves, personnel and shut in days resulting in loss of production between moves. This digital slickline unit combines the capabilities of a slickline unit and a logging unit. The type of slickline it uses allows sending commands to logging tools downhole and receiving data on the surface data acquisition system while logging.

The new approach had multiple operational, financial and HSE&Q impacts. Operationally, performing production logging operations using this digital slickline unit minimized logistics compared to conventional production logging (4 lifting loads Vs. 14 lifting loads). It has also reduced the operation time and trips to and from wellhead towers which resulted in reducing production losses. It also helped achieving the increasing annual logging and slickline KPI's without compromising data QC. Furthermore, HSE&Q was addressed by providing a solution for some integrity concerns related to wells being left with no downhole safety valves between slickline and logging unit movements. Moreover, the probability of incidents caused by improper handling of equipment and tripping/slipping hazards was reduced and most importantly, the option of Medevac by chopper became available in emergency cases due to the reduction in the occupied tower area.

This breakthrough in logging operations from offshore wellhead towers enhanced the operational quality and reduced cost. It represents a part of the continuous efforts to reshape the concept of production and reservoir surveillance (which includes well testing, pressure surveys, etc) by applying new technologies and following new approaches to allow fulfilling larger requirements without making compromises on HSE&Q, production requirement and cost efficiency.
Enhancing Oil Spill Consequence Management Through Satellite Technology
Authors: Ayasse Rob
Published: November 2015

Objectives/Scope

The paper will have four objectives: to outline how satellite technology can enhance oil spill monitoring and therefore consequence management even at mid-latitudes; to explain the technical challenges of using satellite technologies at mid-latitudes, such as in the Arabian Gulf; to showcase studies of how satellite-based oil spill monitoring has been done successfully at mid-latitudes elsewhere in the world; to outline how collaborative satellite monitoring could be adopted by countries around the Arabian Gulf, patterned on Norway and the European Maritime Safety Agency's multi-stakeholder approach.

Methods, Procedures, Process

The presentation will begin with an explanation of the key benefits of using satellite technology for oil spill monitoring and enhanced consequence management, as well as the identification of likely polluters; outline the challenges posed by doing so at mid-latitudes, such as the Arabian Gulf; use the case study method to demonstrate how it has been done successfully elsewhere under similar conditions; provide a vision of how collaborative satellite oil spill monitoring and polluter identification could be used to great effect in the Arabian Gulf, modeled on examples from the Norwegian Clean Seas Association for Operating Companies (NOFO) and the European Maritime Safety Agency's (EMSA) multilateral monitoring program.

Results, Observations, Conclusions

The results of the paper will be two-fold. Drawing on the example of successes in the Gulf of Mexico and French Guiana, that there are two keys to successfully using satellite technology at mid-latitudes for oil spill monitoring and enhanced consequence management. First, that a multi-mission satellite provider is required because one single satellite will not offer sufficient daily coverage close to the equator to provide oil and gas operators, or regulatory authorities, with adequate actionable information. Second, that the satellite provider must be suitably equipped in its service delivery chain to offer near-real time service, meaning delivery of oil spill detection reports in under 2 hours. Against the background of these results, a conclusion will be drawn, which is that significant benefits would accrue from the countries in the Arabian Gulf adopting a collaborative oil spill monitoring program based on effective satellite technologies. This challenge is particularly pressing given that an oil spill at one end of the Gulf will inevitably threaten beaches and delicate marine eco-systems at the other end. And when it comes to effective oil spill detection and consequence management, the most valuable commodity is time, making genuinely actionable information vital, not optional.

Novel/Additive Information

The potential, challenges and solutions of using satellite technology for oil spill monitoring and enhanced consequence management are not well known in the petroleum industry. This presentation aims to address that knowledge gap and showcase novel solutions to a key, pressing, HSE challenge for the petroleum industry.
Stimulation Feasibility Study Based on 3D Geomechanical Modelling on Thin and Tight Reservoir with Thin Cap Rock
Authors: Syofyan S. , Sirat M. , Kumar R. , Sumaida S. A. , El Gazar A. L. , Salahahuddin A. A. , Al Shabibi T. A. , Zhang X. , Vantala A. , Chen Y. , Mohamad A. A.
Published: November 2015

The field is located near the UAE capital, Abu Dhabi, with a tight oil and gas bearing carbonate formation. Rapid pressure drop observed, indicates slow charging from reservoir. Typically a tight reservoir like this is developed by hydraulic fracturing. However there is concern of fracture containment and placement. This study was conducted to construct a 3D reservoir geomechanical base model to optimize the completion strategy and production performances for the tight reservoir.

176 laboratory tests/measurements on cores were performed to determine the mechanical properties and petro-physical properties at different intervals in 5 wells over the field. Eight 1D mechanical earth models (MEMs) were constructed to characterize the mechanical properties and stresses along the well trajectories, and the laboratory test results were used to calibrate the mechanical property profiles of the 1D MEMs. A 3D geomechanical model was constructed using seismically-interpreted horizons and faults; mechanical property population and boundary stresses were based on the 1D MEMs. Present-day stresses within the formation and surrounding formations were simulated, and stress evolution from 2011 to 2095 was predicted. Preliminary fracture modelling was performed at two wells to understand feasibility. The major concern is to control fracture containment within the reservoir section, particularly avoiding downward growth. The results indicate that there is tendency of fracture growth downward at one well. However, the downward fracture growth at the other well is not expected. The average upward stress barrier is around 400 psi over the field and the average downward stress barrier is around 800 psi. However, the magnitude varies from location to location. Five completion methods were compared in terms of geomechanics. Acid tunnel and fishbone completion have a very low risk in horizontal well stability. Multilaterals completion has a low risk in horizontal well stability and junction integrity. Acid fracturing and proppant has a relative high risk in fracture placement and containment. It is recommended to perform further completions feasibility study to review the feasible well location, productivity enhancement, economical aspect and operational constraints.

This study reveals that the heterogeneity in the carbonate reservoir has a significant impact on the selection of completion methods. There is a high uncertainty to decide an optimal completion strategy based on 1D geomechanical study results because the large variations in the in-situ stress and mechanical properties. Therefore, a 3D geomecanical study is necessary for the completion selection for heterogeneous carbonate reservoirs, particularly for tight thin plays.
Field Development and Optimization Plan for Compartmentalized Oil Rim Reservoir
Authors: El Gazar Ashraf Lotfy , Alklih Mohamad Yousef , Sumaidaa Saleh A. , Al Shabibi Tariq Ali
Published: November 2015

This work illustrates field development plan and optimization studies conducted on a Middle-Eastern carbonate reservoir. The field lies in an onshore area where increasing urbanization is complicating the field development with regard to safety, accessibility, and drilling sites. The reservoir exhibits relatively fair to poor reservoir characteristics and variable oil water contacts due to faulting, suggesting the presence of 5 different reservoir compartments. A total of 10 wells had penetrated the reservoir out of which 8 wells tested oil and suggested a huge initial gas cap while 2 others penetrated water leg.

Six years of early production scheme (EPS, 4 producers, 1993 to 1998) data in addition to production testing, core (2 wells), MDT (3 wells), PVT (4 wells) data were gathered in order to identify the main uncertainties and test the feasibility of the full field development. EPS indicated production decline coupled with severe increase in GOR and water cut in some wells, after which the producing wells and facilities were P&A due to safety concerns and low productivity.

A number of parameters were addressed and optimized during the full field development plan. These include formation evaluation and modeling parameters based on EPS findings, the limited available data, and pressure support mechanism. Several development scenarios were constructed, consisting of various combinations of horizontal producers and injectors and considering natural depletion, WI, GI, and WAG scenarios targeting the proven reserves. The dynamic modeling suggests that an ultimate recovery of 70% can be achieved by the different injection scenarios. However, considering the complexity of the surrounding environment and the size of the prize, it is recommended that the field development would be economically viable for a period of 10 years under natural depletion, provided the most effective development strategy in terms of number, location, orientation and horizontal reach is adopted.
Application of Micro-Proppant in Liquids-Rich, Unconventional Reservoirs to Improve Well Production: Laboratory Results, Field Results, and Numerical Simulations
Authors: Dahl Jeff , Calvin James , Siddiqui Shameem , Nguyen Philip , Dusterhoft Ron , Holderby Eric , Johnson Bill
Published: November 2015

This paper discusses a study of condensate-rich Barnett Shale stimulation treatments with designs incorporating a micro-proppant (MP). By placing this proppant early during treatment, it can enter into the narrow natural fracture network where proppant even as small as 100 mesh cannot access. A description of the MP, area regional formation and fracture modeling, stimulation designs, reservoir simulation production results, and production comparisons to offsets are presented.

In present day shale plays, maximizing communication between natural fracture systems and the wellbore while also avoiding any damage to those natural fractures are two pillars of optimized stimulation. Increased proppant volume in primary fractures and helping ensure the near-wellbore (NWB) area of these fractures is open are two important stimulation concepts. Further improvements depend on:

Communicating with a greater number of natural fractures. Enhancing the number of secondary fractures opened. Increasing the number of these secondary fractures that remain open for the long term.

Of these three items listed, the third is probably the most challenging. This paper presents a study of MP use with the goal of propping natural fractures in a liquids-rich area of the Barnett, wherein the first and second items listed have already been addressed and provided significant production improvement. A well-to-well comparison of MP use revealed another step-change in an otherwise optimized drilling and completion program. Production history matching using advanced discrete fracture network (DFN) simulations of hydraulic fractures with the complexity of natural fractures included helped provide insight into how relatively small conductivity improvement to the natural fractures significantly improved well productivity. A new complex fracture design simulator successfully predicted the most favorable method within the fracturing design to include a MP entering these narrow natural fractures and thus improving conductivity. With the understanding gained from these new modeling tools, the MP was then field tested and proven to enhance production response.
Challenges of Permanent Downhole Water Cut Measurement in Multilateral Wells
Authors: Arsalan Muhammad , Ahmad Talha J. , Black Micheal J. , Noui-Mehidi Mohamed N.
Published: November 2015

This paper addresses the need and challenges associated with the permanent downhole water cut measurement in multiphase flow at an individual lateral level for efficient and reliable water cut management in a multilateral horizontal well environment. Furthermore, it reviews the available water cut measurement techniques and evaluates their suitability for permanent downhole deployment in multilateral horizontal wells. A comprehensive analysis of the state-of-the-art water cut measurement techniques is presented for the first time in this paper to evaluate their suitability for permanent downhole deployment. Downhole water cut measurement challenges are described in detail and a table is presented comparing various techniques against a set of requirements suitable for permanent downhole water cut measurement.
Effect of Surfactants and Water on Inhibition of Asphaltene Precipitation and Deposition
Authors: Subramanian Deepa , Firoozabadi Abbas
Published: November 2015

Asphaltenes are the most polar component of crude oils and lead to problems such as well-bore and pipeline clogging during extraction and transportation of crude oil. Previous works have successfully used ionic and nonionic surfactants to delay and prevent asphaltene precipitation. It has also been shown that water in pipelines, delays deposition. In this work, the effect of combining water and brine with ionic and nonionic surfactants are investigated in two Middle Eastern crude oils. Results indicate that water and brine do not change the amount of asphaltenes precipitated. The dispersing action of a nonionic surfactant BA, which acts on a colloidal scale to lower aggregate size and truncate asphaltene growth, is not altered by water / brine. The addition of an ionic surfactant, dodecylbenzene sulphonic acid, which molecularly solubilizes the asphaltenes via electrostatic interactions, acts antagonistically when water / brine is present, and destabilizes the crude oil. The above effects are attributed to changes in the electrostatic interactions between the surfactant and the asphaltenes, in the presence of water / brine.
Practical Recommendations for Successful Application of the MPS Facies Modelling Method
Authors: Riou Jeremy , Höcker Christian
Published: November 2015

As part of creating a user-friendly interface for Multiple-Point Statistics functionality in a reservoir modelling package, it has been investigated which strategies and workflows are more likely to satisfy the typical success criteria of oil and gas reservoir modelling purposes. Success criteria would encompass basic requirements such as the ability to honour hard and soft data while creating anisotropic patterns that are more realistic than those of dual-point statistic methods, all with reasonable computation times.

Examples are shown where an MPS recipe, a combination of a training image with certain parameters for training and simulation phases, has given successful results for common depositional settings that have been difficult to model with other techniques. In contrast to common assumptions about training images, it is argued that simplicity may not be a deficiency but a positive feature of a training image as long as generated models satisfy rules of sedimentation and sediment preservation.

Recommendations cover topics such as how to avoid excessive runtimes, how to optimise common parameters and how to handle non-stationary conditions caused by lateral variations in depositional energy or by crossing the interface between facies belts. It is demonstrated that auxiliary variables are a powerful enabler for fast and successful MPS simulations in simple and complex cases. They also facilitate nested, multi-scale simulations by communicating information from larger scale results to subsequent more detailed modelling passes, as is required for extremely complex cases like modelling meander point-bar deposits