bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal Signature of Free-Phase CO2 in Porous Rocks: Detectability of CO2 by Temperature Logging
Authors: Hurter S. , Garnett A. , Bielinski A. , Kopp A. 
Published: December 2007

Abstract
This study examines the suitability of thermal methods, especially DTS (Distributed Temperature Sensing) cables (in the annulus or behind casing) to monitor the fate of injected CO2 for emissions reduction purposes. The static temperature signal of CO2 stored in pores of sandstone and claystone examples is calculated as a function of porosity, CO2 saturation, and CO2-filled reservoir thickness. The dynamic temperature signal associated with the movement of CO2 in the well and the porous rock is discussed and results of numerical simulations are presented. The detectability of these temperature signals is assessed and found to be useful in detecting leakage over short time intervals and saturation changes in the storage reservoir over the longer term.
Qualification of CO2-Capture Technology
Authors: Helle Kaare , Myhrvold Tore , Bratfos Hans 
Published: December 2007

Abstract
The present document describes a systematic procedure for the qualification of CO2 capture technology based on DNV-RP-A203 "Qualification Procedures for New Technology".
The procedure explains in detail how to identify, describe, and manage risks (failure modes or threats) with the implementation of new CO2 capture technology in a quantitative way by following a set of sequential steps known as the qualification process.
A Scarce Resource
Authors: Tyler Seth , Cornwell Kevin 
Published: December 2007

Abstract
The lack of availability of required skills and experience in most if not all parts of the oil and gas value chain is well documented so, rather than trying to make the case, we will summarise the challenge thus: the industry in all parts of the world can't find the capability it needs to safely get its work done in the timeframes it would like.
However or wherever the situation is measured, the consequence is that in days when the oil price might suggest that the industry has "never had it so good", many companies are falling seriously short of stakeholder expectations with projects of all types not being completed as planned or failing to deliver anticipated returns.
Close to home we see producers consistently missing quarterly production targets and a seemingly constant downgrading of forecasts and year-on-year plans. This leads to a constant stream of bad news and criticism in the media, greater stress through all levels of management and an inevitable "knee jerk" towards a more short term focus.
Unique Methodology for Well Re-entries Requiring Sand Control Improves Production Potential
Authors: Penno Andrew , Fitzpatrick Harvey , Garrison Greg 
Published: December 2007

Abstract
In re-entry or workover type situations, the primary performance objectives determined during the initial well completion remain the same, especially in deepwater, high-rate wells. These generally require running the largest-diameter casing string possible, since the dimensions of the completion equipment can determine critical well objectives. Especially in reservoirs requiring sand-control reliability, production rate becomes a primary concern in the workover situation. Issues regarding critical erosional velocities, reservoir sweep or recovery efficiency and feasibility of installing flow controls or intelligent-well equipment remain.
For mature wells requiring a side-track, the current well-construction practices necessitate reduced dimensions of the sand-control completion-equipment. This paper presents a well construction/completion methodology that supports increased completion-component dimensions in side-tracked or new wells, potentially improving overall well performance. The system is suitable for any openhole gravel-pack completion.
BP Norway: Zonal Isolation in Openhole Chalk Formation
Authors: Jorgensen T. , Anderssen S. , Skjerven T. , Vadset K. , Angell P. 
Published: December 2007

Abstract
The Valhall field has been producing oil for 25 years. The completion strategy of the field has continuously been developed over the years, with cased hole completions with multiple propped fractures as main completion strategy since the mid 1990s. This completion technique was also chosen for the Valhall Flank Project initiated in 2001. The later stages of the project several of the well targets were located on the borders of the field, where the reservoir formation is considerably thinner and has a lower porosity and higher reservoir pressure than in the centre of the field. Using multiple propped fracture completion technique for these targets was not regarded attractive, and to access the reserves in these targets in a cost effective manner it was decided that the optimal design for the "thin pay" targets was a concept with pre-perforated liner in open hole.
This paper describes the completion design evolution on Valhall and the considerations made for choice of completion method for the later stages of the Valhall Flank Project. An overview of the swell packer technology, in addition to the specific packer design for Valhall, is given and it is discussed how this technology provided opportunities to isolate several parts of the well if excessive water production occurred. Future applications for swell packer technology are also discussed.
Continuous Downhole Fluid Log Powered by an Integrated Approach Reveals Reservoir Fluid Complexities and Minimizes Uncertainties
Authors: Okuyig Moyosore , Berrim Ahmed , Xian ChengGang , Haddad Sammy 
Published: December 2007

Abstract
Fluid characterization quantifies the reservoir phase behavior, fluid compositional changes throughout the reservoir, and changes in fluid properties as a result of production and injection processes. High-quality fluid data are critical for reliable modeling, reservoir-engineering calculations, and performance predictions and for subsequent economic analysis. Compartmentalization and spatial variations of fluid composition are two primary factors that cause major and expensive differences between predicted and actual performance in the oil field. Furthermore, different depletion/development levels, and injection and production processes of different reservoir zones or compartments not only motivate more variations of fluid properties, also trigger contacts migration and unexpected injection fluids channeling or breakthrough. A large number of Downhole Fluid Analysis (DFA) stations coupled with several DFA directed sampling stations throughout all interested zones, toward a ‘Continuous Downhole Fluid Log’, is essential to reveal fluid complexities effectively and efficiently.
In this paper, we highlight a successful ‘continuous downhole fluid log’ case to address complexities of reservoir fluids in a complex carbonate reservoir. The ‘continuous downhole fluid Log’ provided significant clues and answers to a broad range of reservoir issues including compartmentalization, fluid compositional variation, unexpected identification of oil, oil reserve assessment, and gas compositional analysis to understand its origin and potential contact migration. We stress the need for an integrated and a multidisciplinary approach to fluid characterization to increase data acquisition efficiency and minimize measurement uncertainty. The approach has integrated drilling fluid optimization, new technology utilization, operation best practices, and real-time quality control and decision making. Such an approach ensured reliable rock and fluid data, thus minimizing technical risks and maximizing the economic value of the hydrocarbon assets.
The Application of NMR Logs for the Evaluation of Gas Reservoirs with Low Salinity Formation Waters
Authors: Claverie M. , Maggs D. , Van Steene M. , Westacott D. 
Published: December 2007

Abstract
The analysis of shaly sand gas reservoirs with low and variable formation water salinity presents specific challenges. These formations usually exhibit low resistivity contrast between water and hydrocarbon zones, and high apparent clay content. Calculated water saturations are high, and need to be accurately split between clay-bound, capillary-bound and free water. In addition to these reservoir characterization problems, we observe effects caused by the drilling process, such as gas dissolution in OBM filtrate, and time-lapse effects between LWD and Wireline logs.
NMR measurements of porosity, bound fluid volume, pore size distribution, and direct fluid identification can be applied to resolve the challenges mentioned above.
We demonstrate the use of NMR data to calculate total and effective porosity, and volume of irreducible water in productive reservoir sands and in shales, to validate the petrophysical model. We also present a method based on NMR analysis to estimate net producible pay and its uncertainty.
We apply fluid typing from NMR Relaxation and Diffusion maps to quantify small volumes of gas present in the water zone. This analysis enables us to calculate the fluids composition in the invaded zone and to improve the accuracy of density porosity, even when LWD and Wireline logs are combined. We also show how the NMR measurement of gas volume in the invaded zone can be correlated to sonic measurements for quantitative fluid substitution.
We identify gas in thin and shaly reservoirs from NMR stand-alone fluid typing, and present examples of successful sampling with wireline tester in these elusive reservoirs.
The various examples presented in this paper describe practical petrophysical methods used to improve the formation evaluation of shaly gas reservoirs in fresh formation water, and demonstrate how the NMR data can be integrated into an existing petrophysical analysis, improving the accuracy of results in this challenging environment.
A Standard Real-Time Information Architecture for Drilling and Completions
Authors: Pickering J. G. , Whiteley N. , Roye J. , Turnbull H. , Cavanagh D. 
Published: December 2007

Abstract
BP is looking to implement a standard data architecture for real-time drilling & completions information. This will enable us to make wider use of our collaboration centres through a common approach and will allow us to leverage the developing WITSML standard more effectively in our operations.
BP uses many different service organisations to deliver its global drilling & completions agenda. In the past, this has resulted in a lack of standardisation in real-time information flow. We have been unable to share data and expertise readily between different operating centres. Applying a common approach to information access on a global basis will enable us to streamline our operations and make wider use of emerging collaboration technologies.
WITSML is now finding greater uptake in our industry and we are seeing new compliant intelligent software tools emerging from different vendors. These will undoubtedly enable us to drill and complete smarter but we need a standard information infrastructure to deploy them widely and consistently. It is these smart tools that will ultimately deliver real value to oil companies.
The adoption of a standard D&C information architecture may seem an obvious step but there are very few oil companies that can claim to have delivered it. WITSML is the vehicle to allow this to happen and over the next few years it is likely that there will be much more emphasis on open connectivity between different vendors and services supporting the drilling & completions functions.
Fluid Loss Pills Control Losses through Sand Control Screens without Damage or Cleanup
Authors: Lamb Keith F. , Ali Syed A. , Harper Brian F. , Darring Michael T. , Marine Hope C. , Foxenberg William E. 
Published: December 2007

Abstract
This paper describes workover and completion operations offshore Trinidad & Tobago and the Gulf of Mexico in which the operator desired non-mechanical isolation of the reservoir section above the sand-control assembly. Each well required clear brine of kill-weight density and in the case of the five dry gas wells described, losses of significant volume of brine to the formation was unacceptable. Isolation of the reservoir was required for up to 18 days. The following objectives were specified: Reduce fluid losses to the formation from inside the sand control screen,Minimize the potential for formation or screen damage, andEliminate post-job, clean-up treatment of any kind.
This paper describes the development of specially formulated fluid-loss control pills and their subsequent use in the field to provide reservoir isolation by placing a temporary filter cake on the inside surface of the sand control screen. The paper describes laboratory tests designed to optimize the pill formulation to seal the inside surface of each specific screen, minimize spurt loss, maintain rheological properties for an extended period at reservoir condition and, importantly, displace off the screen with gas production. In each of the cases described, field spotting procedures were designed to eliminate killing the wells by bullheading, thus significantly reducing the volume of fluid lost to the reservoir. The authors provide details of the properties of the pill and the field procedures used to place the pills in the wells. All wells were returned to production without any remedial treatment whatsoever or impact on productivity. Additionally, the savings in time, costs and lessons learned associated with these projects and recommendations for similar future projects are discussed.
Solid Expandable Tubulars Deliver on Promise and Potential
Authors: Holland Mark , Jennings Iain , Kaschke Markus 
Published: December 2007

Abstract
With over 750 installations worldwide, solid expandable tubular systems have gone from an evolutionary idea to a technology that delivers on its promise. Long touted as a technology that can help operators mitigate downhole challenges, expandable tubulars are now being applied as enabling systems in wellbore construction, in field development, for casing repair and remediation and for field-wide revitalization.
The installation records for these systems are as wide as the application realm and exemplify the adaptable nature of the technology. This adaptability has led to the technology evolving from being used strictly as a drilling-problem solution to an integral wellbore component. Solid expandable systems have been used in a variety of environments, such as HTHP and ultra-deepwater projects, and for a myriad of conditions such as control of lost circulation zones, casing shoe extensions and isolation of unstable formations. In cased-hole situations, these systems have been used to isolate old perforated intervals or protect weak casing, replacing less reliable conventional squeeze cementing techniques. Solid expandable systems have helped operators reach and produce reserves that previously were unattainable due to drilling conditions and economic constraints, have provided flexibility for exploration-well uncertainties, and have reduced well costs with a slimmer well design.
Case histories will demonstrate how solid expandable tubulars have delivered on the promise and potential as an enabling technology. Case histories to be included will describe how solid expandable systems have been successfully incorporated in a field-development project in Malaysia, a casing-repair project in China and as a vital component in a total drilling-management project in the Arabian Sea. This paper will also validate the economic viability of these systems as a contributive and reliable technology.
Fast Shut-in Tools Improve Near Wellbore Characterisation from Build-up Test Interpretation
Authors: Guerrero Rodolfo Phillips , Lessi Jacques 
Published: December 2007

Abstract
The wellbore storage effect has been extensively studied during the last 40 years, highlighting its effects on the early time build-up data and on the resulting hurdles or mismatching tendency during the interpretation process. Although these phenomena, mainly due to the compressibility of the fluids1, can be reduced using a down-hole shut-in tool, they are not completely eliminated and most of the information related to the near wellbore area remains inaccessible. However, it appears that the interpretation inaccuracy is greatly influenced by how fast the production is shut down before the build-up test. An instantaneous down-hole shut-in action reduces the masking effect due to the wellbore storage. Therefore, during the build-up early time, it will provide more valuable data, useful for an accurate characterisation of the near wellbore region and its heterogeneities.
The following paper shows the effects of the shut-in time on the data acquisition at early time and its interpretation. Simulations have been performed in typical well configurations and reservoir types (near wellbore permeability reduction, fractured well, layered reservoir). The results illustrate clearly the benefits of an instantaneous production shut-in action to characterise near wellbore reservoir. Oilfield data have been acquired during an oil well test using a fast shut-in tool which allows shutting down the production within 2 seconds. A slight deflection in pressure build-up can be observed in the first minutes. This deflection has been interpreted as a reduction of the fluid mobility close to the well. Numerical simulations performed using the resulting model matched on this data set, demonstrate that the mobility reduction could not have been detected using a slow action shut-in tool.
Application of Pressure Derivative Function for Well Test Analysis of Triple Porosity Naturally Fractured Reservoirs
Authors: Mirshekari B. , Modarress H. , Hamzehnataj Z. , Momennasab E. 
Published: December 2007

Abstract
This paper concentrates on pressure transient tests in triple porosity naturally reservoirs (NFR) with pseudo steady state flow regime using direct synthesis technique.
The direct synthesis technique couples the characteristic points and lines from a log-log plot of pressure and pressure derivative data resulting in simple equations to solve for the desired reservoir parameters. Parametric analysis in dimensionless space illustrates the behavior desired reservoir parameters and provides the basis for newly empirical correlations relating these parameters to the field data. Applicability of the empirical correlations corresponding to the characteristic points developed as a result of this work is demonstrated by successfully analyzing simulated pressure transient tests. The direct synthesis method is proposed to overcome problems for the case where there is no guarantee on existence of an early-time unit slope line and/or the latetime infinite acting radial flow line has not been seen due to inner and outer boundaries, lack of points and severe noise problem. Both the effect of wellbore storage and skin are included in the analysis. As a result of this work, direct synthesis simplifies evaluation of pressure transient tests in triple porosity naturally fractured reservoirs (NFR) with pseudo steady state flow regime, eliminates the type curve matching or regression analysis. Before this paper, only one paper was published for well test analysis of triple porosity naturally fractured reservoirs with unsteady state behavior using direct synthesis technique. But in that paper, the effect of wellbore storage and skin in the analysis was not considered and also several interrelated constants were included in the equations used for estimating the reservoir parameters which makes the estimation complicated and erroneous.
A New Method to Evaluate Leak-Off Tests in Shallow Marine Sediments (SMS)
Authors: Paknejad Amir , Schubert Jerome , Amani Mahmood 
Published: December 2007

Abstract
Leak-off Tests (LOT) and Pressure Integrity Tests (PIT), are verification methods to evaluate cement jobs and estimate the formation fracture pressure at the casing shoe.
Although analysis of LOT in deep wells is considered a well known and practical procedure, the interpretation of LOT in Shallow Marine Sediments (SMS) is less clear. LOT in SMS gives a non-linear relationship between the pumped volume and the observed pump pressure and there is no obvious point of deflection or "leak off’ from the initial linear section of the plot. Because of non-linearity of LOT plots in SMS, LOT could be inconclusive and difficult to interpret. Incorrect interpretation of LOT would lead to costly problems that might jeopardize well progress such as; unnecessary squeeze jobs, premature setting of casing, and lost circulation problems.
This paper presents a new method to analyze casing shoe leak-off pressure in the SMS. A mathematical model is derived to assist in analyzing non-linear LOT behavior and the new method is supported by field data from LOT in SMS.
LOT interpretation is the basis for the critical drilling decisions such as; casing setting depths, cement job evaluation, drilling fluid selections, and well control methods. Correct interpretation of the LOT can help to avoid variety of problems and save considerable amount of time and money.
Study on the Pilot Test with Microbial Profile Modification after Polymer Flooding in Daqing Oil Field
Authors: Jun Sui , Fenglan Wang , Zhiyao Wang , Yanqing Bian , Zhenyu Yang , Menghua Guo , Wei Li , Zhaowei Hou 
Published: December 2007

Abstract
In order to further enhance oil recovery of the reservoirs, after polymer flooding, two strains of bacterium that could be used on microbial profile modification have been screened. The bacteria are separated from the fluid sample produced within the commercial polymer flooding blocks of Daqing oil-field, and named DT-1 and DT-2. The evaluation of performance shows that these two microorganisms could not only adapt to the special conditions of the reservoirs after polymer flooding, but also could grow well with the in-situ microorganisms. The results of physical simulation core flooding proved that injection profile modification bacteria play a good part in plugging after polymer flooding (the rate of plugging is more than 70%) and oil recovery could be improved about 3.9%(OOIP). In order to demonstrate the technique might as well be feasible, for the first time, after Daqing oilfield polymer is flooding, the test area carries through microbe injection pilot tracey in the world wide. The test data of two adjustment wells interpret that the permeability rate of north2 -fourth 5-p16 well falls to 45.18%, the second half year's adjustment of permeability rate is measured 393.7×10−3μm2, that is compared with the former adjustment still falling to 34.54%. At the same time, injection pressure of 2-fourth 5-p16 well by injection profile modification preceding 8.0mpa comes up to 9.4MPa, rising clearly 1.4MPa; the injection pressure of north 2-4 -p26 well rises 0.8MPa. The six environmental production wells are compared with the former adjustment, containing water decreases 3.9%, the daily production oil ekes 16t, the accumulative amount of oil totally increases 1300t. After microbial treatment, injection profile has been changed greatly, which some of the old taking-fluid zones disappear or others taking more of the fluid become taking less of that and several new zones are taking water. As a result, water cut has decreased and oil production has increased. This study has provided a good method for enhancing oil recovery after polymer flooding.