bluuebunny/crossref_metadata_2025 huggingface dataset:
Intercept Method - A Novel Technique to Correct Steady-State Relative Permeability Data for Capillary End-Effects
Authors: Gupta Robin , Maloney Daniel Riney
Published: December 2014

In laboratory measurements of relative permeability, capillary discontinuities at sample ends give rise to capillary end-effects. End-effects influence fluid flow and retention. If end-effect artifacts are not minimized by test design and data interpretation, relative permeability results may be significantly erroneous. This is a well known issue in unsteady-state tests, but even steady-state relative permeability results are influenced by end-effect artifacts. This work describes “The Intercept Method,” a novel modified steady-state approach, in which corrections for end-effect artifacts are applied as data is measured.

The intercept method requires running a steady state relative permeability test with several different flow rates for each fractional flow. Obtaining multiple (3-4) sets of rates (Q), pressure drops (DP), and saturation data allow for assessment of capillary end effect artifacts. With Darcy flow, a plot of pressure drop versus total flow rate is typically linear. A non-zero intercept or offset is an end-effect artifact. To correct for the effect, the offset is subtracted from measured pressure drops. Corrected pressure drops are used in permeability calculations. The set of saturations from measurements at the target fractional flow are used to calculate a corrected final saturation. Because corrections for end effects are made during the test rather than after the test is over, any discrepancies can be resolved by additional measurements before moving on to the next fractional flow. Rates are then adjusted to yield the next target fractional flow condition and the same protocol is repeated for each subsequent steady-state measurement. The method is validated by theory and is easy to apply.

Introduction

Relative permeability is a fundamental input parameter for reservoir engineering. It describes multiphase flow and retention characteristics that are important for production forecasting, reserves estimates, and ultimate recovery predictions. Relative permeability versus saturation functions are typically obtained by conducting multiphase flow tests on reservoir rock core plugs in the laboratory. By nature of the laboratory multiphase flow set-up, there is a capillary discontinuity (end-effect or boundary effect) at the outlet end of the sample where fluids pass from the rock into the end-piece and tubing. In the rock, capillary pressure is related to saturation and saturation history. In the end-piece and tubing, capillary pressure vanishes. The discontinuity yields an accumulation of the wetting phase at the sample end which influences saturation distribution and pressure drop across the length of the sample.
Impact of Imbibition Mechanism on Flowback Behavior: A Numerical Study
Authors: Almulhim A. , Alharthy N. , Tutuncu A. N. , Kazemi H.
Published: December 2014

Horizontal drilling and multi-stage hydraulic fracturing are among key technologies that enable the oil and gas industry to unlock unconventional resources. Water-based fracturing fluids are commonly used in massive volumes to hydraulically crack shale formations and transport proppant to keep open the newly created fractures. After hydraulic fracturing implemented to stimulate a well, the clean-up process takes place by flowing back the well. Most shale reservoirs tend to trap and retain the fracturing fluid (water) in the small pores and microfractures ending with a water flowback which typically not exceeding 50% of the injected volume. The water imbibition mechanism by capillary forces can help explaining the reason behind the retained water in the shale matrix and the dynamic water saturation re-distribution during the shut-in time.

This paper investigates various effects, such as rock wettability, well shut-in time, capillary pressure and natural fracture intensity on the flowback behavior and the ultimate production performance. The specific emphasize was given on brine imbibition as a vehicle to improve gas permeability and the overall gas recovery. It was shown that spontaneous capillary imbibition in strong water-wet formations forces water into the matrix and eliminate water blockage in the fractures while in weak water-wet formations, more water stays in the fractures causing a delay in gas production.
Optimizing Well Bore Safety in the Mishrif Formation by Installing Bi-Directional Downhole Barrier Valves
Authors: Wickramasinghe Tharinda , Aliyev Aslan , Chen Igor
Published: December 2014

This paper describes the challenges faced when completing wells in the Mishrif formation of Southern Iraq, where well control concerns increase post acid stimulation of the reservoir due to the unpredictability of the formations behavior.

One of the biggest challenges faced when drilling and completing in this formation is to manage a natural hydraulic balance of the reservoir to avoid the well switching from losses to kicks without warning. While this challenge is being addressed by carefully selecting drilling and completion fluids of specific densities, it has not been fully mitigated as wells have shown signs of switching state arbitrarily specifically post acid stimulation operations. In light of this challenge Weatherford had proposed a completion design that would incorporate a downhole bi-directional barrier valve which would ensure that the well bore would be secure upon installation of the lower completion. It was envisaged that this technology would help overcome any dynamic changes of the reservoir that may lead either to fluid loss, risking damage to the reservoir or kicks risking a catastrophic blow out.

A typical production well architecture in the Mishrif formation of the West Qurna-2 field would consist of 9-5/8″ production casing to surface and an 8-1/2″ Open Hole section that would be completed with either 7″ slotted or perforated liner. Well trajectories could vary from vertical to a maximum deviation of 60 degrees in most cases. The proposed design was to complete a few of the early phase wells using 9-5/8″ × 5-1/2″ mechanical ball valves incorporated into the lower completion which would therefore serve as a bi-directional barrier once installed and shifted closed.
Combining Development with Environmental Friendly Solution (GASCO Artificial Islands)
Authors: AL Hosani Jasem
Published: December 2014

The paper presents a case study from Abu Dhabi, UAE where a new navigation channel needed to be dredged to satisfy the growing demand of a Sulphur Handling terminal. The project is located in the UAE where the creation of a navigation channel was needed to satisfy the demand of a Sulphur Handling terminal. The creation of the channel required the dredging and disposal of approx 19 million m3 of dredged material.

This paper presents a case study of the decision making process and design phases that were performed to ensure that the channel can be created in a fast, efficient and environmentally friendly way.

The UAE has gained international recognition due to the large scale and rapid construction of its massive projects in coastal and marine areas. With Abu Dhabi's ever growing oil and gas industry, new terminal, ports, navigation channels and jetties are constantly being developed, creating design, environmental and construction challenges.
Simulation of Miscible Gas Injection in a Fractured Carbonate Reservoir using an Embedded Discrete Fracture Model
Authors: Panfili P. , Cominelli A.
Published: December 2014

A large proportion of world's oil reserves resides in naturally fractured reservoirs. Implementing IOR and EOR processes in these reservoirs is a high risk/high reward activity. For instance, on one side water/gas may rapidly break-through along fracture corridors and then jeopardize the IOR/EOR scheme results. On the other side, fracture networks may effectively promote gas-oil gravity drainage or spontaneous imbibition. Accurate and efficient simulation of fractured media is a recognised challenge for reservoir simulators.

Various approaches, with different balance between efficiency and accuracy, have been proposed in literature. Up to now the most diffused methods to deal with fractures, have been the adoption of a Dual Porosity/Dual Permeability (DPDK) formulation in a logically structured grid, or the use of unstructured grids.

In this work EOR processes in a fractured reservoir were modeled using the Embedded Discrete Fracture Model (Li and Lee, 2008). EDFM represents a practical and efficient compromise between DPDK and unstructured gridding, combining a corner point geometry grid for matrix and an unstructured network for fractures. EDFM was implemented using commercial simulators.

The target of the work was sour gas reinjection in a carbonate reservoir characterised by a matrix dominated platform and a fractured rim, with some transition between these two environments. The input of the study was a discrete fracture network, developed using seismic curvature lineaments, and a geological model for the matrix. EDFM and DPDK models were first compared. Then, the new approach was used to investigate fracture impact as a risk for premature gas break-through. The results indicated that the containment of the injection inside the platform, possibly far away from the rim, is an effective way to control the EOR process.
Automatic Subsea Deduction Well Testing for Increased Accuracy and Reduced Test Time
Authors: Idsø E. S. , Sperle I. L. , Aasheim R. , Wold M. S.
Published: December 2014

High quality well tests are important for allocation, updating of reservoir models, daily production planning and optimization. Increased accuracy of well tests can enable production optimization at gas- or water-limited fields. An automatic deduction well testing method developed in collaboration between the asset and Statoil RDI (Research, Development and Innovation) is presented in this paper.

Subsea wells without a dedicated test flow line are normally tested by manual deduction well testing; i.e. the test well is choked back, and the resulting change in the common flow line is used to calculate the contribution from the test well. During the test, the flow rate from the other wells on the common flow line should be as constant as possible. As the total flow rate reduces, the back pressure for the other wells on the same flow line is reduced, and, if no other action is taken, the flow rate from the other wells on the test line will increase. The manual procedure to compensate for the pressure change is to adjust the well head chokes so that the well head pressure, and hence the flow from each well, is kept close to their initial values. The manual test method has about 10% deviation in actual flow, is time consuming and demands high attention from operators.

This paper describes development and application of an automatic deduction well testing method to improve well testing. The method was implemented and tested with good results at the Midgard and Mikkel subsea fields, tie-ins to the Statoil-operated Åsgard B production facility, in December 2012. In the automatic method, the well head pressure, and hence the flow rate from the other wells on the test line, are kept close to constant. The accuracy was improved to less than 1% deviation in actual flow, the test duration was reduced by 20–30%, and the operator work load was significantly reduced. The automatic deduction well testing method has been successfully repeated at the field every six months since the first test, and is currently being implemented at several other Statoil operated fields.
Successful Deployment of new Extended RockstrongTM Coring System: Record Coring Delivery and Recovery Achievement in ADCO Exploration well – UAE case History
Authors: Akinlosotu A. O , Reyami M. , Tipu I. , Said I. , Mahmoud G.
Published: December 2014

This paper presents how extensive pre-job planning and proper utilization of new technology led to actualizing the coring objective of a well safely including successful coring through the hydrogen sulphide (H2S) rich Habshan 1 and 2 formations in an onshore field of the Abu Dhabi Company For Onshore Oil Operations (ADCO) in the United Arab Emirates.

Well AK1 is part of a wider field appraisal plan to be used for data gathering and building a conceptual field development plan. The challenges were multiple, not only from the planning and coring bottom hole assembly (BHA) design point of view, but also in terms of effective health, safety and environment management during execution posing environmental and technical challenges to the desired data gathering objective.

The appraisal well AK1 well design required 12 conventional coring BHA runs over a 27days duration including coring with an 8–1/2" coring BHA through a 12–1/4″ hole section. With detailed forward planning, use of new extended coring technology, operational focus and health, safety & environment (HSE) consciousness at the forefront, 6 continuous cores in 15 rig days with a record total core length in excess of 1,300 ft was successfully cut with 100% recovery factor through Shilaif, Mauddud, Top Nahr Umr, Unit 22a, Unit 22, Habshan, Habshan 1, Habshan 2 and Dense below Habshan 2 formations with H2S contents way in excess of safe limits saving 12 days rig time and almost $1m USD of planned well cost in the process.

This paper aims to share how this was recently achieved highlighting some of the challenges faced in terms of planning and sharing the experience gained from successful execution of well AK1, including coring through H2S bearing formations, with respect to optimized core acquisition and handling for the benefit of other operators in the region.
Steerable Drilling Liner Technology Successfully Mitigates Formation Stability Issues
Authors: Eidem Morten , Grindhaug Gaute , Spreckelmeyer Niko , Regener Thorsten , Clemmensen Carl C.
Published: December 2014

The Steerable Drilling Liner is an integrated drilling system that combines the advantages of rotary steerable drilling- and logging-technology with the liner drilling concept. This allows drilling complex 3D wellpaths with the same logging and directional capabilities as a conventional drill string, enabling operators to drill and secure the wellbore with a liner in one continuous operation. The technology has been successfully applied in several drilling operations and has been recognized as a method to overcome stability challenges in unstable formations.

The technology offers the following benefits compared to conventional drilling:

Reduced initiation of formation instability due to: – Reduced hydraulic surge (no tripping in open hole) – LBHA/drill-string always tripped in cased hole also when a bit trip is required – Reduced mechanical load on borehole wall – Low rotational speed (~30 rpm) and fully centralized liner with "non-rotating" centralizers prevent mechanical interaction between pipe and borehole wall. – Low shock and vibration effects due to low rotation speed reduce risk of tool failures Reduced time consumption and open hole time: – Remove time between drilling and lining of formation. Wellbore secured before collapse processes start – Reduced operational time as reaming, back-reaming, wiper trip or general wellbore conditioning are not required for successful liner installation

This paper will elaborate on the Operators Steerable Drilling Liner technology experiences. Focus will be on the mechanisms why Steerable Drilling Liner is an enabling technology when used in unstable/troublesome formations, compared to conventional drilling methods. It will also describe expected future utilization and applications and finally touch upon the next generation SDL system, which currently is under development.
Capillary Pressure and Relative Permeability Assessment on Whole Core Samples from a Giant Middle Easteren Carbonate Reservoir Utilizing Digital Rock Physics
Authors: Koronfol Safouh , Grader Avrami , Suhrer Michael , Toelke Jonas , Mu Yaoming , Dernaika Moustafa , Pratap Mahendra , Al Hamadi Mohammad , Al Ratrout Ahmad , Kalam M Zubair
Published: December 2014

Digital Rock Physics (DRP) has significantly evolved in the last few years and added invaluable contributions in improving core characterization and in providing high quality advanced SCAL measurements, emphasized through various studies/papers (SCA-2012–03 Kalam et al). This paper represents a unique DRP SCAL study that includes primary drainage capillary pressure (Pc) as part of Swi establishment and relative permeability (Kr) measurements done on four whole core (WC) samples from two different carbonate formations with a stylolite layer in between. The aim of the study was to evaluate how DRP results would compare with physical SCAL measurements done – on the same WC samples as a composite, as well as on plug samples from the same formations/layers – in a leading international core analysis lab in USA. The DRP results were up-scaled to the individual WC level and compared with the SCAL results from the corresponding layers. The DRP technology in this study also provided the capability of up-scaling the results to the WC composite which was used by the lab to assess the effect of the stylolite layer on the water flood. The comparison showed excellent matches between the physical and DRP-derived Pc and Kr data. The paper outlines the DRP methods used to determine the SCAL properties of the three formations. The laboratory measurements of SCAL properties took six years while the DRP work that followed blindly (without any knowledge of the laboratory results) was completed in six months. This demonstrates the effectiveness of the DRP technology in providing high quality SCAL data in a timely fashion regardless of sample size. Impact of possible wettability changes and sensitivities on one of the WC composite constituent component was also easily established unlike the high risk laboratory tests. This is the first water-oil displacement validation study results on reservoir whole cores of four inch diameter at full reservoir conditions using DRP.
Innovative and Cost-Effective Coring Technique Extended Coring for Long Intervals of Multiple Zones with World Record – Case Histories from the UAE
Authors: Hegazy Gehad Mahmoud , Salem Adel M. , Shedid Shedid A. , Aftab Muhammad N. , Ali Muhammad , Al Riyami Mazin , Hazem Wahab , Mohamed Farouk
Published: December 2014

Continuous core acquisition across formations of interest to perform quantitative and qualitative analysis is extremely important for exploration geologists and reservoir engineers. Measurements performed on cores are typically calibrated against well logging data for accurate and better reservoir interpretations. However, the coring cost is directly proportional to coring technique, core length and a significant part of coring cost is associated with rig time. In deep formations, the coring cost becomes extensively high due to multiple trip times required after each conventional coring run (90 ft). The best way to minimize the coring cost is to reduce the rig time efficiently achieved by reducing the number of trips required to acquire core.

Abu Dhabi Oil Company for Offshore Oil Operations (ADCO) has recently investigated different coring scenarios and technologies to optimize the coring operation time. An innovative and cost effective solution was developed and applied as a result of this investigation by Extended Coring (Long Barrel) which meets ADCO's objective of continuous coring across formations of interest. This procedure reduced number of trips, rig time and eventually drilling cost. The extended coring (Long Barrel) can be run in lengths from 120 ft to 810 ft with proper timing and planning for the jobs.

This paper describes ADCO's new strategy of extended coring (long barrel) acquisition based on formation's geological description. The case histories of extended coring in different formations in 8 ½" and 6" hole size sections, the core handling procedures applied and lessons learned in a continuous iterative process to optimize drilling cost in future operations are presented and analyzed.
Information Technology Applications in Construction and Oil and Gas Projects Management Performance – Future Vision
Authors: El Ghandour Wael
Published: December 2014

In recent years more and more construction projects used information technology applications to support execution and management tasks. However, construction companies in the world and accordingly in UAE still wrestle with information technology applications in construction (ITC) and how they could be effectively applied on their specific projects. One main reason for this struggle is that an account about how ITC have been used in the past or could be used in the future is missing. This research aims to provide new impetus to UAE's growth and competitiveness in construction engineering and management areas.

The paper presents some areas that ITC could be applied in oil & gas construction sector of UAE. It offers practitioners such an account of the application areas of ITC technologies including the purposes for which these technologies have been applied. The paper qualitatively aggregates the results of more than 200 papers to show how ITC have been applied to address different projects challenges. The paper presents samples of key practical areas for simulation modelling applications in construction industry that are proposed by author for oil & gas projects. The main finding of this analysis is that ITC could play significant role in controlling key indicators of oil & gas construction projects performance including, but not limited to, schedule, cost, safety, quality, team work, and scope management. It could help project managers solving critical concerns such as claim analysis, cash-flow optimization, resources optimization, camp management, and many others.
Risk Based Inspection Implementation for Upstream Offshore Operator: Case Study
Authors: Matthews Steve , Al Jaberi Manea Saeed , Mundyath Devadas
Published: December 2014

A risk-based inspection (RBI) programme, covering ZADCO's offshore production and onshore processing facilities, has recently been completed. The scope of work, which included over 25,000 items of static pressure equipment, piping, relief valves and pipelines, had key objectives of reducing the risks to personnel, the environment and to the business through compliance with a regional, corporate Code of Practice for the identification and integrity assurance of health, safety and environmental critical equipment and systems (HSECES).

The RBI programme for static equipment and piping, which comprised over 80% of the total equipment count, was carried out in two phases: Phase 1, a screening phase, comprised qualitative risk assessments at the system level; system risk was based on the worst-case combination of failure likelihood and loss of containment consequence applicable to that system. Equipment and piping within low risk systems were allocated generic inspection plans, consistent with equipment type and materials of construction. Phase 2 comprised semi-quantitative risk assessments of the remaining equipment and piping within medium and high risk systems. All credible degradation mechanisms were separately risk ranked and inspection plans were allocated, based on relevant degradation mechanisms, equipment type, accessibility, materials of construction, internal lining/cladding and insulation status. Both phases of the RBI implementation were backed-up by a series of multi-disciplinary workshops during which the initial assessments were subject to rigorous challenge and review.

This approach has enabled ZADCO to fully implement RBI in a timely and efficient manner, with the screening phase, in particular, facilitating appropriate focus on current and emerging integrity threats to the facilities. A key element of the programme was the development of an RBI methodology and configuration of software to integrate much of ZADCO's existing integrity management practices with an innovative, efficient approach to risk assessments and inspection planning.
Multi-Lateral Wells with Downhole Water Control and Disposal in Heavy Oil Reservoirs with Bottom Water – A Case Study
Authors: Alblooshi Younes A. , Wojtanowicz Andrew K.
Published: December 2014

In heavy oil reservoirs with bottom water drive, water coning severely hampers well productivity and oil recovery, due to excessive water production. Moreover, conventional enhancement techniques such as thermal and/or gravity-assisted production methods do not solve the problem of handling and processing large volumes of produced water. In this paper, we study feasibility of a new well completion and production technique using Multi-Lateral Water Loop (MLWL).

MLWL wells are multi-functional installations that feature three horizontal legs on the same vertical plane and at different depths. The top leg drains the oil payzone, the middle one controls water cresting by draining the aquifer beneath the oil-water contact (OWC), and the bottom leg injects the drained water deeper into the same aquifer. The top horizontal lateral provides maximum reservoir contact (MRC), low pressure drawdown and high production rate thus enhancing recovery. The middle lateral makes the oil production water-free, while the bottom lateral keeps the water underground without lifting it to the surface.

Using a reservoir simulation model of MLWL and a conventional horizontal well in a West African heavy oilfield, we study MLWL well design and operation that would make the technique superior to conventional horizontal well production in this oilfield. The results demonstrate the MLWL potential for increased production rate and ultimate oil recovery and the economic advantage of handling formation water in-situ. The study also explains how the MLWL system improves the recovery mechanism by mobilizing oil throughout the whole drainage area rather than in the well's vicinity. Furthermore, optimum operation conditions for water looping system are identified where economic limit is met and inverse coning avoided. The results show superiority of wells with downhole water drainage over conventional wells. Morover, the MLWL wells have additional advantage of prolonged economic life and, therefore, high profitability.
Scale-Up and Transient Operation of CO2 Capture Plants at CO2 Technology Centre Mongstad
Authors: de Koeijer G. M. , Aasen K. I. , Hamborg E. S.
Published: December 2014

The CO2 Technology Centre Mongstad (TCM) is the world's largest facility for testing and improving technologies for post-combustion CO2 capture. The knowledge gained will prepare the ground for full scale CO2 capture initiatives to combat climate change. TCM is a joint venture between the Gassnova, Statoil, Shell and Sasol. It is located at the West coast of Norway, north of the city Bergen. This paper will discuss the scale-up and transient operation of amine based post-combustion CO2 capture plants in general, and presents some typical results. Scale-up and transient operation are typically among the last topics to be assessed in the technology development process because it requires bigger plants. Results were used from the monoethanolamine (MEA) campaign that was executed in fall/winter 2013/2014. The discussion on scale-up showed that emissions to air, material choice, construction method, vapour/liquid distribution and reclaiming are important technical aspects. Normalized transient data were presented for 7 important variables during a controlled plant stop-and-restart and a sudden stop-fast restart case. Stable CO2 product flow could be obtained after 3–4 hours, while stable emissions and CO2 product temperature took 1–2 hours more. NH3 emissions showed a peak after restart due to accumulation in the solvent during the stop. It was concluded that amine based CO2 capture plants should be able to follow their power plants without significant additional CO2 emissions.
Induced Fracture Modelling and Its Integration with Pressure Transient Analysis: Study for Shallow-water Offshore Field, South-East Asia – Part 1
Authors: Anand A. , Subrahmanyam S. G.
Published: December 2014

Numerous studies have been done on the design and analysis of hydraulic fractures. However, the study of induced fractures is still a maturing subject especially, with regards to the predictive capabilities of the fracture simulators and, it soon becomes a challenge when it comes to the acquisition of meaningful field data and their interpretations to validate the forward modelling results of the fracture simulators.

The paper is a step forward to fill the gap between the model predictions and the field observations for water injectors in the context of induced fracture propagation. The study was done for a field, located offshore South-East Asia.

The content of this study will be presented in two papers based on the key domains stated above – "field observations" and "model predictions". The current paper (Part 1) addresses the first subject where field data have been analyzed to get an understanding of the induced fracture growth in the water injectors. This comprises of "Pressure Transient Analysis (PTA)" of "Pressure Fall-Off (PFO)" tests done on the water injectors. The paper will present a workflow to interpret a PFO for fracture analysis using two approaches. The first approach is based on the standard PTA models where no explicit fracture mechanism has been invoked. We will introduce an analytical technique which uses the compliance value obtained from the standard model analysis to determine the fracture size. The second approach is based on the "Injection Fall-Off (IFO)" model, a dedicated Shell plug-in to Ecrin, used for fracture characterization. The workflow will be first illustrated elaborately through a stepwise interpretation of an example PFO test. We will demonstrate, afterwards, the application of the above methodology for analysis of a number of field tests using both approaches.

The paper will conclude with a consistent picture of fracture growth interpreted from both techniques. Significance of geological set-up wrt the fracture growth will also be highlighted. We will also highlight some limitations with the modelling and ways around it.
From Static Model to Asset Action Plan: A Field Case Successful Journey With Innovative Modeling Approach
Authors: Amor Faical Ben , Amari Mustafa , Sharifzadeh Ahmad , Dashti Qasem , Al-Saffar Ali
Published: December 2014

A hybrid natural fractured reservoir static geomodel using a wide range of 2D/3D seismic, geometrical and petrophysical attributes has enabled a reasonable 3D representation of three sets of fractures in the SA field, part of North Kuwait Jurassic Complex (NKJC). Based on well and seismic data, the three sets are fracture corridors associated with geophysically interpreted faults; medium scale layer-bound geomechanically controlled fractures; and folding-related fractures. The new hybrid fracture model, which is made of a discrete fracture network (DFN) and an implict fracture model (IFM), was calibrated using production logging tool (PLT), modular formation dynamics tester (MDT), and pressure buildup (PBU) data from 27 wells.

The calibrated hybrid fracture model has shortened the process of the history match significantly, requiring only very small adjustments/alterations to the initial static model. Achieving a smooth and timely history match resulted in significant CPU time gain and an optimized well count that went into the Asset Action Plan.
Time-Lapse Data Acquisition of Passive Seismic and Active Seismic at the Same Time
Authors: Takanashi Mamoru , Kato Ayato , Kasahara Junzo , Hasada Yoko
Published: December 2014

Microseismic analysis plays a key role in hydraulic fracture monitoring for developing shale plays and avoiding unwanted fracture development. Meanwhile, active seismic (or 4D seismic) monitoring is widely used for delineating temporal change associated with fluid injection and production. For continuous analysis of both passive and active seismic at the same time, we introduce an approach to simultaneously aquire seismic signals from microseismic and from active seismic sources ACROSS (Accurately Controlled, Routinely Operated Signal System). We perform test data acquisition with two ACROSS sources in Kashiwazaki, Japan to obtain high signal-to-noise ratio (S/N) of ACROSS data and passive seismic signals after the suppression of ACROSS data.

The ACROSS source was operated with sweep cycle of exactly 200 seconds and with frequencies ranging between 5 and 50 Hz. Permanent geophone data at 1.5 km and 5.5 km from the ACROSS sources confirmed highly repeatable ACROSS signals with 2 hour stack and 1 day stack, respectively. The results indicated that the transmittability of ACROSS signal is sufficient enough for daily-basis active-seismic analysis. On the other hand, motions related to ACROSS source were clearly suppressed by subtracting "weight-averaged" ACROSS data, and subtle motions from passive seismic were uncovered. The ground motions of lower than 50 micro kines (5 X 10-7 m/s) were extracted at just 70 m away from the ACROSS source. Since continuous microseismic observation is possible at most of the receiver locations, our proposed technicque should provide opportunities for passive and active seismic surveys at the same time and may be highly beneficial for shale or other tight reservoir characterization.
Clad Through Clad: A Mechanical Water Shut Off Solution for Commingled Production from Multilayered Reservoirs
Authors: Bourgoin Sebastian , Sobirin Muhammad , Mahardhini Antus , Jones Mike
Published: December 2014

A casing or tubing clad is a metal sleeve that can be run by several intervention means into a well to isolate an area of interest, be it to provide a permanent seal over splits, holes, or perforations in tubing and casing or for water shut off. Once it is on depth, the clad or metal sleeve is expanded out against the tubing or casing wall to form a seal.

Taking the example of water shut-off isolation, conventional clad technology only permits a ‘bottom up isolation’, the current technology does not have the ability to pass through an expanded clad of the same size thus it is not possible at a later date to install a second clad below an existing clad.

To resolve this issue, in 2006 TOTAL instigated the development of a "Clad thru Clad" technology through a JIP (Joint Industrial Program) Water Management R&D Project with Maersk, Statoil, Chevron, and BP as partners. Meta was selected to develop the clad through clad technology. The project objective was to design an electric line conveyed clad able to pass through other similarly sized clads previously installed in a well incorporating a metal-to-metal interference fit with elastomer seal against the 5-1/2″ production casing or tubing wall.

In addition to the dimensional, pressure rating (5000 psi absolute, 2000 psi differential) and temperature rating (125 degC) constraints, one of the major challenges was to achieve sufficient collapse rating for the clad once expanded.

The Internal Clad™ is deployed using a hydraulic expansion system. The setting tool consists of a standard electric line cable head, an electronic section (consisting of gamma ray (GR), a casing collar locator (CCL), a motor control module and pressure sensors), a down-hole reservoir, hydraulic module (consisting of motor, a pump, an intensifier and valves), and the setting tool itself.

The first trial was performed in Total Indonesia's Peciko field; well C, a gas well producing from a multilayered reservoir. The field trial was SUCCESSFUL although a number of improvements for future operations were identified.
An Effective Approach to Enhance Safety Leadership, Behaviour and Accountability
Authors: Scataglini Luciano , Salvador Carlo , Gigli Riccardo , Giusto Manfredi , Catalano Roccantonio , Petrone Annamaria
Published: December 2014

HSE statistics reveal that unfortunately the vast majority of incidents are of occupational nature and still occur as a consequence of violations of safe working practices (the so called Safety and Health Golden Rules).

This paper deals with some initiatives, developed within our Company, focusing on the best way to ensure that the Management Walkthroughs and the Workers' Attitude are conveyed to the same objective: constantly improve Behaviours and create a common Company Culture where personal beliefs, values and targets (life, family, health) inspire the way to do the job. A Manager shall lead this process, and give due recognition to all those who behave accordingly. This is our Company Vision. To improve personal engagement of Managers in this cultural growing process, a Leadership Toolkit has been developed and applied; on the other hand, to facilitate the workforce involvement in implementing the Company Policy, a Behavioural Based Safety (BBS) program has been developed and tested.

The effectiveness of these tools is monitored via a well established set of Key Performance Indicators; results are encouraging and a "step forward" has been planned.
Faults and Fractures Network Prediction: Stress/Strain Modelling from Outcrops Analysis to Seismic Characterization
Authors: Magistroni C. , Meda M. , Corrao A.
Published: December 2014

The comprehension of the fracture network at different scales is mandatory for understanding and developing a sub-surface fractured reservoir. The different scales of fractures are investigated using several approaches and then integrated in the final fracture distribution model.

For example the micro-fractures (from cm to meter length) are analyzed, for characteristics and distribution, from oriented cores and well logs, instead faults (macro-fractures, more than hundred meters length) are interpreted and mapped from seismic. The meso-fractures (tens to hundred meters length) are the most problematic since it is impossible to analyze them with direct tools as they are hard to be detected and described in the seismic volumes. This type of fractures, also called sub-seismic fractures, is extremely important for fractured reservoir permeability characterization.

We have developed a workflow which integrates data from analogous outcrops/cores and an automatic detection of structural features in seismic volumes enhanced by attributes as continuity or positive/negative curvature.

The seismic attribute volume is scanned and lineaments are detected and collected. The resulting dataset is statistically analyzed for length distribution (histograms), for strike (rosette diagrams and fracture sets detection) and for density (P21 and P20 maps or 3D grids).

The comparison with the fault network coming from seismic interpretation allows the detection of different fractured domains or fractures corridors related or not to the faults and to better constrain the structural evolution of the studied reservoir.

It is also possible to use these lineaments to compute probabilistic fracture surfaces that can be easily imported in a DFN (Discrete Fracture Network) model for the reservoir characterization.

The results are finally checked taking into account the stress/strain evolution through time of the studied area.

This workflow was successfully applied on the main fractured reservoir operated by eni as: Kashagan field (Kazakhstan), Perla field (Venezuela), Val d'Agri field (Italy).
A Novel Anti-Foam Chemical Application As Contributor To The Successful Start-Up Of The Majnoon Oilfield
Authors: Grutters Mark , Pandya Sunil , Turner Ian , Ames Simon , Khalil Sayf , Korosoglou Elias
Published: December 2014

The Majnoon oilfield in Southern Iraq, one of the largest in the world, recommenced production in September 2013. The field was developed by the Iraqi South Oil Company in the 1980s and originally produced around 50,000 BOPD. As result of Iraq's second licensing round a consortium of Shell, Petronas and Missan Oil Company worked closely with SOC and redeveloped Majnoon to increase its daily production from 50,000 BOPD to more than 175,000 BOPD.

Over a period of several days the production increased from 15,000 to 40,000 BOPD, when several plant trips occurred due to excessive liquid carry over from the separators into the flare system. At first this was attributed to unstable flow and tuning of the production facilities. However, more plant trips followed while ramping up to more than 100,000 BOPD as debris accumulated in the flare system which resulted in multiple blockages. A root-cause analysis was carried out by a team from production chemistry, operations and production support before piloting an anti-foam chemical solution which proved to be an immediate success and production stabilised within hours.

After three days the pilot project was converted into a permanent solution and since the introduction of the anti-foam chemical Majnoon hasn't suffered any further plant trips due to liquid carry over. In fact, the chemical has allowed production to be increased by at least 15,000 BOPD through improved flow through the separators.

This paper will explain the theory behind foaming and highlight the process of fluid testing. We will present the results of the plant trips root-cause analysis and describe in detail how the anti-foam trial developed. A novel monitoring program has been developed that allows for immediate correction in case of changes to production or chemical injection, which has greatly contributed to the safe and successful Majnoon start-up.
Fracture Characterization of Carbonate Reservoir with Integration of Dynamic Data
Authors: Caetano Hugo , Niculescu Elena , Hozayen Magdy , Radwan El Sayed , Farooq Umer , de Joussineau Ghislain , Games Federico , de Haeck Thomas
Published: December 2014

Characterization of naturally fractured reservoirs is challenging because of variable properties and high heterogeneity. One of these examples is the complex fractured carbonate reservoir of Upper Cretaceous Maastrichtian age present in a field located in onshore of Abu Dhabi.

A detailed study was conducted to accurately characterize and model fracture networks occurring in the reservoir, in order to control early water breakthrough problems caused by fracture connections to aquifer and resulting in reduced oil production and bypassed oil issues.

The workflow involved a full interpretation of the seismic dataset and fault networks, concluding that faults are short and discontinuous, with frequency increasing with depth.

A second step included a fracture network characterization using: Core, Borehole image, 3D seismic and dynamic data. Core description showed that reservoir is dominated by short diagenetic and stylolite-related fractures, with only rare tectonic fractures. Borehole image analysis confirmed core observations and concluded that fracturing is dominated by corridors related to faults, with thicknesses of 50 to 300 ft. No small-scale diffuse fracturing was detected. Seismic attributes were combined into fracture index maps to detect large-scale fractured zones at keys levels. Good relationship was found between the faults and lineaments from seismic and large fracture clusters seen on borehole image data.

Dynamic analysis using production, pressure, PLT and well test data showed that production is mainly controlled by matrix. Moderate Kh and productivity enhancement was detected at proximity with corridors (around 100 m), and water production behavior was locally explained by corridors. No evidence for small-scale fracturing flow was found.

Finally, a fracture model integrating all fracture characterization results was built and allowed computing equivalent fracture properties (fracture K in x, y, z, fracture porosity and matrix block sizes), in order to optimize new well location and trajectories for increased field production and delayed water breakthrough.
Pressurisation of Plant Using Sweet Gas
Authors: El Thany Ezzat
Published: December 2014

Abu Dhabi Gas Liquefaction Company (ADGAS) operates LNG production facility, Offshore Associated Gases facility and Integrated Gas development facility, in Das Island. They comprise of LNG Trains 1&2 processing LP Gases and HP Gas to produce 180 T/Hr of LNG each, LNG Train-3 processing only HP Gas to produce 384 T/Hr of LNG. Together they produce around 7 million tons of LNG in addition to LPG, Prafanic Naphtha, Liquid Sulphur per year.

The OAG facility processes LP Gases and involves compression of the LP Gases, Dehydration and despatch of 211 mmscfd of Gas & Condensate through marine pipeline to GASCO facility at Habshan, where NGL is recovered.

The Integrated Gas Development Project (IGD) comprises of three Trains capable of delivering 900 mmscfd of dry compressed HP Gas through marine pipeline to GASCO facility at Habshan along with the gas from OAG, where NGL is recovered and lean gas sent to the sales Gas header.
Developing Effective Site Safety Leaders in the Oil and Gas Industry
Authors: Johnston Stuart
Published: December 2014

Being a supervisor or manager in the oil and gas industry is challenging under the best of circumstances. Responsible for multiple priorities, but with limited time, many site leaders find it difficult to include safety tasks in a meaningful way. Yet, these leaders are influencing safety all the time through their decisions and actions. This paper discuss the specific ways oil and gas leaders are already influencing safety and how they can integrate concrete practices to improve safety and operational performance right now. This paper also outlines key safety activities for supervisors, how these activities are directly related to the leadership practices that drive safety, and how to leverage them for supervisory development and organizational safety improvement.
Optimized Approach for On-Bottom Stability Analysis of Subsea Cables
Authors: Azouz A. M. , Hakim M. Abdel , Yehia M.
Published: December 2014

On-bottom stability analysis of subsea cables is commonly carried out in accordance with the leading industry practice for subsea pipelines "DNV-RP-F109". Similar to pipelines, the analysis method typically used is F109's Generalized Lateral Stability Method. However, this method is considered to be overly conservative for small diameter cables in shallow water applications such as the Arabian Gulf. Consequently, costly additional stabilization measures such as vast quantities of concrete mattresses are normally required.

Given the flexible nature of cables, dynamic on-bottom stability analysis is considered to be a rational approach for optimizing the stabilization requirements. Dynamic on-bottom stability analysis is a known approach for subsea pipelines; however, its application is normally limited to extreme cases of environmental conditions where concrete coating requirements exceed practical limits.

Hence, ADMA-OPCO has initiated a study to develop an FE model for dynamic on-bottom stability analysis of subsea cables. The outcome of ADMA-OPCO's study demonstrated that dynamic on-bottom stability represents the best approach for achieving cost-effective stabilization solutions for subsea cables. Hence, it is envisioned to become the norm for on-bottom stability analysis of subsea cables. The key features of the FE model are presented as well as general guidance for dynamic on-bottom stability analysis of subsea cables.