bluuebunny/crossref_metadata_2025_split huggingface dataset:
New-Generation Ultrasonic Measurements for Quantitative Cement Evaluation in Heavy Muds and Thick-Wall Casings
Authors: Thierry S. , Klieber C. , Lemarenko M. , Le Calvez J.-L. , Brill T. M. , Barrou T. , Hayman A. , Mege F. , Van Os R. 
Published: September 2016

In this paper, we describe major improvements to ultrasonic logging techniques used for cement evaluation. Specifically, we explain engineering solutions developed to tackle known limitations such as logging in heavy (ultrasonically attenuative) muds, and very large and very thick pipes.
On the hardware side, new heavy mud/thick casing transducers are presented together with dedicated large-diameter logging heads for both pulse-echo and pitch-catch (flexural attenuation) techniques. On the processing side, we present a novel pulse-echo inversion scheme, based on real time inversion using accurate 3D models for metrology accuracy and a new scheme that does not require a priori knowledge of mud properties (specifically its acoustic impedance, Zmud). Through this, Zmud becomes an output parameter of this novel processing and we present field examples of such logs where we now image features such as mud deposition and segregation in deviated pipes. This new processing enables easier and more accurate interpretation of the cement sheath together with critical information on the logging fluid. The validity of the measurement across the operating range is demonstrated in this paper through results from both high precision laboratory measurements and several logs acquired during the last few years' field test campaign. Together with the fundamental sensor and processing improvements, we present engineering changes to the logging platform, enabling up to three times faster logging and accurate well site logs delivered right after rig down. Finally, we demonstrate that the combination of the pulse-echo and pitch-catch techniques, with its high azimuthal resolution, can probe the annulus up to the cement/formation or cement/second casing interface, making it a powerful technique for cement evaluation.
Previous limitations (such as mud weight, casing size and thickness) have been overcome and this has been fully demonstrated in both the laboratory and the field. Thus ultrasonic cement evaluation techniques now enable accurate and critical decisions to be made–from well construction to plugging and abandonment–in all conditions, casing sizes, and mud and cement types.
A New Method to Estimate Cementation and Saturation Exponents From Dielectric Dispersion Data
Authors: Venkataramanan L. , Donadille J. M. , Reeder S. L. , Van Steene M. , Gkortsas V.-M. , Fellah K. , Ramsdell D. , Al-Rubaiyea J. A. , Al-Ajmi F. A. , Al-Houli M. , Wilkinson P. , Bajunaid H. 
Published: September 2016

Abstract
Petrophysical models are applied to wireline dielectric dispersion measurement to estimate water saturation, water salinity, and the water phase tortuosity mn. The parameter mn (which is also referred to as "MN" in other sources) combines the effects of pore-space tortuosity (cementation exponent m in Archie's equation) and distribution of water and hydrocarbons in the pore system (saturation exponent n). We present a new method to separate these effects and obtain Archie's m and n exponents from this water phase tortuosity mn. The method described in this paper makes it possible to fully utilize dielectric dispersion log data to estimate key petrophysical parameters in situ, whereas these parameters were previously only available through expensive and time-consuming core analysis. Together, m and n may be used to infer wettability and estimate water saturation more accurately and reliably in the uninvaded zone.
When m can be estimated by nuclear magnetic resonance (NMR), borehole images, or core resistivity measurements, the dielectric parameter mn can be used to estimate n, which can be used to infer wettability. In the absence of capillary pressure hysteresis, mn obtained in the invaded zone by downhole dielectric tools may be used to estimate water saturation in the uninvaded zone by using deep resistivity tools and Archie's law. Practically, these applications are very limited in their scope. The new method assumes that the parameters m and n from the Archie equation are constant for depths with similar rock types. For each rock type, the parameter mn is plotted against a variable combining porosity and water saturation. The data are then fit with a linear function that yields Archie's m and n when the variable takes the values of 1 and 0, respectively. The fit is more heavily weighted towards data points with lower uncertainty.
We demonstrate via simulations that Archie's m and n exponents can be accurately and reliably estimated by the new method. This is supported by our study of several limestone cores in various stages of brine/oil saturation in the laboratory where we find that the predicted linear model fits the data reasonably well and can be used to estimate both m and n. We have also applied this method to several wells of a carbonate field. Rock types in each well are determined based on factor analysis of NMR data. The dielectric data for each rock type across all the wells are then analyzed with the method described here to yield values of m and n for each rock type, together with an evaluation of the uncertainty on these parameters. The results are then compared with m and n data from special core analysis (available in two wells of the field). We find that the new method's results fall within the uncertainty of the core analysis results.
Multiphase Analytics in a High Water-Cut Environment
Authors: Gannaway Gregory R. , Ibrahim Mazher , Pieprzica Chester 
Published: September 2016

Abstract
Historically, Rate Transient Analysis (RTA) has been performed to characterize the reservoir properties associated with multi-fractured horizontal wells (MFHW), using single-phase linear flow models (Clarkson et al., [2014]). This paper purposes a different look at RTA, by applying traditional diagnostics to more than one producing fluid phase. These RTA techniques can yield substantial insight into reservoir characteristics and performance, and simultaneously help one understand the true reservoir being accessed by the wellbore. By incorporating multiphase RTA techniques, the strategic development of some high water producing unconventional targets can be optimized through section spacing design and reduced offset fracture communication.
The premise behind this paper is centered on the extremely high water cut seen in wells within the Wolfcamp and Bone Spring formations, located in West Texas's Delaware Basin. As a wells produced fluid gains substantial proportions of water, traditional single phase analytic techniques need adjustment to allow for accurate fluid flow modeling and reservoir characterization.
This paper evaluates an 8 well case study of actively producing wells in the lower 3rd Bone Spring formation. This case study provides insight into the RTA workflow for multiphase analytics, evaluating the oil and water fluid constituents, both independently and together. This approach yields more accurate characteristics of producing reservoir geometry, completion properties, stimulated formation permeability and inter-well fracture communication.
Successful Use of Sophisticated Flow Modelling in the Planning and Operational Phase of Drilling, Liner Running and Cementing Operations: All in Managed Pressure Mode
Authors: Barr Aas I. , Skjerve K. , Haaland L. E. , Svendsen M. , Rommetveit R. 
Published: September 2016

Abstract
The managed pressure drilling (MPD) technique was chosen to drill a well on the Gullfaks A platform as a risk mitigating factor. In addition, the MPD technique gives accurate flow measurement, provides the potential to handle pressure variations quickly, and determines the drilling window. This paper presents the successful implementation of a sophisticated hydraulic model during planning and execution of a MPD operation in Gullfaks Well A-10B.
MPD service was delivered by a major service company with equipment coupled to a third-party real-time advanced transient hydraulic model. This model was used to calculate upstream choke pressure during MPD. It was also used in the planning stage to ensure operation was feasible within the pressure window with the selected fluids and drilling parameters. The system was run in automatic mode. Initially, only one section was planned for drilling in MPD mode. However, because of the losses observed and bottomhole pressure (BHP) flexibility provided by the MPD system, it was decided to drill the next section in addition to running and cementing the liner.
When the well was completed, three sections were drilled and two liners were run and cemented using MPD. The use of an automatic MPD system with a sophisticated hydraulic model helped ensure the well delivery was achieved according to plan without any major issues. The losses that occurred were detected and reduced significantly only by reducing the bottomhole target pressure. Dynamic drawdown tests in addition to a dynamic formation integrity test (FIT) confirmed the drilling window before drilling the second section. During the planning of cement job, a close working relationship between all parties was established in order to find the best possible solution for the well and achieve a delivery of a successful well. The planning tool used is a sophisticated hydraulic model that calculates a constant dynamic well pressure during the simulation of the cement job. The simulations were verified during the cementing job, with a good cement job as the result. Both liners were run and cemented with full returns and rotation.
This paper presents the challenges involved during this well project, how these challenges were handled by thorough planning, and finally the operational phase itself with focus on the MPD system, including the advanced flow model.
Visual Data Analytics: Morphological Image Processing Approach on the Evaluation of Foamed Cement Quality
Authors: Ding Bingjie , Samuel Robello 
Published: September 2016

Abstract
Foamed cement is widely used during cementing operations in which lightweight slurries are necessary. Foamed cement helps prevent gas migration and is often used in high-stress environments. A stable foamed cement has a uniform distribution of distinct bubbles, which helps ensure the gas will not break out of slurry. An unstable cement can result in gas coalescence with uncemented sections caused by channeling in the well and density inhomogeneity. Evaluation of foamed cement is necessary before use.
This paper proposes a methodology for evaluation of foamed cement quality using two-dimensional (2D) images and an efficient k-means clustering algorithm under image processing. A combination of image-processing techniques is applied to segment bubbles in foamed cement computed tomography (CT) scans. These scans include image compression, morphological image processing (MIP), and image segmentation. Based on the image-processing results, a computer program is developed for foamed cement qualification using a k-means clustering algorithm. The algorithm uses evaluation values calculated from the foamed cement qualification equation, which provides a critical point and separates the data into two clusters. When an image is inserted, the program calculates the evaluation value automatically and assesses its qualification.
Development of a Subsurface Reverse Circulation Tool System to Cement Weak and Depleted Zones in Deepwater Formations
Authors: Reagins Deandre , Herr David , Jee Bobby , Ownby John , Duthie Jason , Giroux Richard , Kendziora Larry 
Published: September 2016

Abstract
Reverse circulation cementing is a placement technique that reduces bottomhole equivalent circulating densities (ECDs) and reduces lost circulation risk in wells in which conventional circulation pressures would break down formations. Until now, reverse circulation cementing has been performed only on land or in shallow-water wells in which the annulus was accessible from the surface to pump down. This paper describes the design, development, and validation of technology that enables subsurface reverse circulation.
Gaps in technology have made it challenging to transfer reverse-cementing-placement techniques to primary cementing operations in deepwater. To reverse cement a liner, fluids must be pumped down the work string to prevent potential contact inside the riser and blowout preventer (BOP), and then fluids must be injected into the annulus downhole while full circulation continues. A tool system was developed to facilitate this unique flow path, provide alternative methods to set liner hangers, and provide flexibility for contingencies and other operational requirements.
The developed subsurface reverse circulation tool system uses radio frequency identification (RFID) technology so that the tools can be operated remotely and repeatedly either by RFID tags or through surface-pressure pulse sequences. Three RFID-activated tools were designed: a circulation tool, a crossover tool, and a downhole flapper. The prototype tool system was first evaluated through bench testing of individual components and then through large-scale rig testing. During the rig trials, the entire system was run into a test well, and a multiday sequence of flow testing validated the function and performance of each tool. After successful testing in rig trials, the subsurface reverse circulation tools (RCT) were deployed in the Appalachia basin field, located in the Northeastern United States.
This paper discusses the requirements of a subsurface reverse-circulation-cementing system. It describes the design, development, and validation of technology that enables subsurface reverse circulation. It also describes the prototype system that was built and the field testing results. This new capability enables the cement to be pumped down the work string and then to exit to the annulus at a point above the liner string.
Making a Cross-Flow water injector in the Alvheim Field
Authors: Langaas K. , Hjellbakk A. , Leonthin M. A. , Stuart K. L. 
Published: September 2016

Abstract
A dual lateral horizontal well was drilled on the Kneler structure of the Alvheim Field (offshore Norway) in 2015. The use of a newly processed 4D seismic dataset changed the original planned target for the main branch and led to justifying drilling the branch below an existing producer. The objective of the main branch was to target undrained oil below a stratigraphically compartmentalized segment. The Alvheim Field started production in 2008. The baseline seismic survey was acquired in 1996 and a 4D monitor survey was acquired in 2013. The 4D seismic data was used to estimate the movement of the oil water contact, and 4D difference geobodies were benchmarked against production data directly, giving high confidence in the estimates. The 4D difference geobodies were integrated in the history matching process. A lower zone infill target below an existing upper zone producer was identified as the result of the multidisciplinary data integration. The lower zone has excellent pressure support via the large Heimdal aquifer system while the upper zone producer has limited pressure support and has historically produced at low rates. Pre-drill reservoir simulation studies indicated a benefit in enabling cross-flow between the two zones. The drilling results showed oil as predicted by the 4D seismic data. However, the upper zone was thicker than expected. A thin oil column was found in the lower zone before drilling into water, again confirming the 4D seismic interpretation. As the lower zone target was smaller than expected, the main value of the branch was refocused towards enabling optimal cross-flow. The pre-drill reservoir models were updated pragmatically and studies were done to optimize the lower completion, e.g. deciding the optimal cross-flow rate, production and injection intervals and how to use inflow control devices to assist the clean-up of all zones. The clean-up went as planned in November 2015 and a 20 bar drawdown was achieved across the injection interval of the branch. The branch was produced for 40 days before shut-in to act as a cross-flow injector. Pressure interference data indicated a successful clean-up of the injection interval. The cross flow well has showed to work as intended giving an increased oil rate of around 4000 stb/d. A cross-flow injector can be a cost effective solution for partly segmented compartments close to strong aquifers. To the knowledge of the authors, no example of this type of cross-flow injection has been documented in the literature.
Deconvolution of Vibrational Data to Reduce the Ambiguity in Downhole Tool Failure
Authors: Lakhanpal Vikrant , Samuel Robello 
Published: September 2016

Abstract
As the drilling industry enters the era of big data, it has become necessary to find ways to organize and understand the vast amounts of real-time high frequency data recorded.
Shor et al. (2014) show that real-time accelerations recorded down hole actually differ from those predicted by various models, either in the high frequency range or at peak values. These differences in vibration levels can be attributed to noise from various sources, such as the motor or surface equipment, design of measurement devices, uneven shape of the borehole, and/or dynamic effects, such as dampening/cushioning of fluids, bit rock interactions, drillstring-borehole wall interactions, etc. These differences can cause real-time drill log analysts to miss instances of actual failure or predict false failures.
The industry currently focuses on the peak and average values of the accelerations recorded down hole, and there is no established method to examine the trend of these accelerations. The methodology proposed in this paper first focuses on obtaining the actual unmodulated acceleration values from the recorded downhole gauge data and then processes these values to understand the trend of acceleration as the drilling proceeds. This demodulation (or deconvolution) of the recorded data can reduce the likliehood of false predictions and, at the same time, increase the credibility of the mode of acceleration predicted (and hence more accurately predict failure), which currently relies only on the experience of the engineer. Thus, this technique can make real-time data monitoring more reliable and simple. Further, if combined with a gamma ray log to know the lithology of the formation being drilled, this data monitoring technique can reveal a significant amount of information.
In addition, this paper suggests calculating instantaneous jerk intensity and decomposing it to its monotonic intrinsic mode function. This reveals that these monotonic functions follow a certain trend, which might be useful in future endeavors to understand the underlying physics of drillstring failure.
Evaluating the Development of a Multi Stacked Gas-Condensate Field to Supply LNG Using A Multi-Tiered Optimization Tool
Authors: Lemke Alexander van , Bouts Marcel , Drohm Julius 
Published: September 2016

Abstract
For the screening of a significant new LNG development a multi-tiered optimization tool was built with the following objectives: To optimise the sequence of drilling and producing condensate and gas from a field consisting of multiple stacked reservoirs.To understand that gas requirements could be fulfilled to supply gas to the multiple planned LNG trainsTo evaluate if the tool delivered export results of various scenarios for economic screening and future auditing
An integrated model was built consisting of a Controlling Optimization Software (Resolve) to communicate and control the link between a Surface Network Development (GAP), the wells (Prosper), material balance model (MBAL) and a data export and plotting software (Excel). Visual workflow programming in Resolve allowed for simple adjustment of constraints and inputs through all the linked models which can optimise of multiple scenarios.
Parameters that were optimised included: Sequence of reservoirs to produceWell phasing over the different reservoirs showing varying condensate gas ratiosWell type, count and respective targeted reservoirSurface infrastructure including pipelinesCompressor timing
The fully integrated model provided the required flexibility for evaluating various scenarios while delivering credible consistent results. Running quick scenarios can help to make decisions for the planning of the surface network and production thus helping to reduce CAPEX. Using central controlling software simplified varying both subsurface and surface constraints for the LNG development. This included seasonality influenced safety margins, the addition of compression as soon as the gas rate potential drops below critical levels and drilling new wells into the optimal reservoir when required to fill the LNG trains.
Integrated History Matching on Interference Well Test Data in a Naturally Fractured Reservoir with Automated Adjoint Gradient Based Inversion Technique
Authors: Sarac S. , Morton K. L. , Theuveny B. 
Published: September 2016

Abstract
It is common practice to perform well test interpretations as stand-alone analyses with dedicated well test interpretation software, independent from the actual geologic and geophysical information used for reservoir simulation. This can lead to non-geologic interpretations, lacking in geological and geophysical prior information, which also means that the well test data cannot be readily incorporated into reservoir simulation models. This paper describes an automated history matching procedure for well test interpretation, constrained by simultaneous dynamic well test data from multiple wells, which improves production forecasting and reservoir development decisions. The procedure is applied to a synthetic naturally fractured reservoir to identify inter-well connectivity, fracture and formation properties within the reservoir volume investigated by the interference well test. The outcome of this integrated interpretation methodology with an interference test is compared to conventional interpretation results from four individual well tests in the same reservoir model.
The permeability field of the reservoir model was automatically updated using an adjoint gradient-based inversion technique to produce a pressure response that matches the well test data. The updated permeability field was then used to generate a fracture network in the model. The results indicate that the conventional interpretation of individual well tests in such complex reservoirs can lead to unrealistic reservoir descriptions. On the other hand, the integrated methodology explained in this paper, together with a proper well test strategy, leads to a more accurate reservoir characterization with an updated reservoir model. The resulting fracture network that is determined from the data very well represents the original "truth" model and is able to reproduce the individual well test responses accurately. The results also show that the connectivity of the wells positioned perpendicular to the mean fracture strike orientation can also be estimated and this connectivity can be determined with an interference test and an integrated interpretation methodology.