bluuebunny/crossref_metadata_2025_split huggingface dataset:
Slim-Hole Sidetrack Cuts Costs by 50%
Authors: Scott I.J. , Black F.J. 
Published: December 2007

Abstract
The Shell/Esso Brent Field contains many small pockets of oil; 0.5 to 1.5 million barrels that are uneconomic to develop using conventional sidetrack techniques. The sidetrack of Brent Bravo well BB-08 takes advantage of the latest slim- hole through tubing technology reducing the well costs by 50% over a conventional sidetrack. The operation was carried out with a conventional rig utilising a slim-hole drillstring to exploit an expected 1.5 million barrel target and also provide a technical comparison with a coiled tubing sidetrack. The entire operation was carried out through the existing xmas tree and completion string.
The original perforations were isolated then a through tubing whipstock was used to exit through the existing 7" liner and 9-5/8" casing strings. A 1500 ft 3-7/8" hole section was drilled with a steerable BHA, which gave an average dogleg of 9 deg/100 ft in the build section. The mud weight required for hole stability meant high over-balance pressures through the reservoir section. The hole was logged with a wireline conveyed resistivity tool. A 2-7/8" liner was run and cemented in place with a liner top production packer to provide well integrity. Wireline access into the 2-7/8" liner was not possible due to debris and therefore the well had to be cleaned out with coiled tubing before perforating.
This paper describes the planning process, the operations (from abandonment to perforations), lessons learned and the teamwork which made it all possible.
P. 111
Field Data vs. Theoretical Model to Quantify Drilling Efficiency and Disruption
Authors: Putot C.J.M. , Perreau P.J. , Constantinescu A. 
Published: December 2007

Abstract
Mechanical and kinematics data at the bit have been collected during drilling operations and organized to identify optimal drilling efficiency. Transitional conditions towards abnormal behavior have been distinguished. Normal drilling is usually characterized by regular linear relationships between global control variables at the bit, which approximately correspond to an up scaling of a local Mohr Coulomb type failure mechanism of the rock. Most of our experimental data confirm this classical disposition. However, considerable departure from these relationships is noted, especially when there is BHA resonance or when there is partial balling at the bit. The field tests presented here allows us to verify classical theory and to draw up new guidelines for behavior in non- optimal or dangerous, evolving operating conditions, such as those that occur under poor cleaning conditions. The main features of a mechanical structuring model involving transition towards low efficiency conditions are presented, and it is shown how this model confirms our interpretation of field data. The model couples the drillability of rock and the general dynamics of the bit in an original and synthetic way. It makes it possible to understand and test the sensitivity of bit response to variables such as "weight on hook", torque on the drillstring and flow rate of the fluid.
P. 119
Cost-Effectiveness and Flexibility Through the Brent Gas-Lift Insert String Completions
Authors: Brakel J.D. , Taggart I. , Yahia Z. Bin 
Published: December 2007

Abstract
The Brent field, developed as an oil producing field in the mid 70's, is now approaching the end of its economic life. However, the large quantity of remaining oil, although only 40% of initial reserves, and the high Gas-Oil ratio of the oil allow extended production from the field by reducing the reservoir pressure. The de-pressurisation will add some 10-15 year of economic life to the field.
The de-pressurisation project, unique in the world due to the size and complexity of the Brent field, brings many uncertainties. The well completion design is key in the management of these uncertainties. Cost-effective reservoir management (zonal solation) is a pre-requisite and the choosen completion design should accommodate sand, scale and even H2S management. Furthermore certain wells will require artificial (gas) lift, although the number and location of these wells will be largely unknown up front.
The adopted monobore completion design combines maximum flexibility and cost-effectiveness with simplicity and is readily adaptable to gas lift installation. The Brent monobore completion design has reduced cost by 30% and installation time by 65% as opposed to the Multi-Straddle Assembly completion run previously in Brent. Key features of the completion and retrofit gas lift installation are described in this paper.
P. 169
DeepLook: A Progress Report on Collaboration and Funded Research
Authors: McCaffery Frank G. 
Published: December 2007

Abstract
This paper provides a progress report on the DeepLook Fluid Imaging Collaboration during its second year of formal operation. Its mission is to create a significant and fundamental improvement in the oil industry's ability to measure reservoir fluid and rock properties, and monitor fluid movement, at distances of 10 to 200 meters from existing wells. This challenge is being approached through identification and sponsorship of promising breakthrough technologies primarily developed for applications outside of the oil industry, from what is termed "Far Market" high-technology providers.
Discussion is concentrated on the following subjects:
Objectives and start-up actions of the collaboration - A brief history of DeepLook's organization, current participants and funding, and the roles and activities of the three technical teams charged with developing R&D projects in the areas of Detection, Monitoring, and Prediction. Efforts leading to sponsorship of R&D efforts on a new downhole sensor for fluid characterization - This topic is chosen for more detailed review due to the author's involvement in leading the Monitoring team that identified and guides the project. The sensor was originally designed for chemical weapons treaty verification and nonproliferation work. Our project seeks to evaluate its use for detecting fluid type in a flowing well, as well as for monitoring fluid saturation changes in reservoir rock when placed in open or cased wellbores, including microboreholes. Brief review of other DeepLook R&D projects - Five other projects are underway besides the downhole sensor effort. These include studies being performed by researchers at several U.S. National Laboratories and a NASA facility. The current projects are structured as feasibility or scoping studies, with a built-in deliverable of defining follow-up work if initial demonstrations from the first phase are successful. Approval of proposed project extensions will be made in competition with new investment opportunities that have been identified, and according to available funds. 4.Challenges and lessons learned affecting the ultimate success of the collaboration - A collaboration as complex as this one is expected to encounter growing pains. Issues faced by DeepLook are discussed, and next steps are noted.
P. 219
Field Test Results and Processing Methods for Remote Acoustic Sensing of Stratigraphic Bed Boundaries
Authors: Leggett J.V. , Dubinsky V. , Bolshakov A. , Nakken E.I. 
Published: December 2007

Abstract
Determining the position, above and below a deviated wellbore, relative to key drilling markers and stratigraphic features such as fluid contacts, geological markers and reservoir target boundaries has been a major goal for "Tieing-in" to a reservoir model while drilling. Acquiring, processing raw data, and identifying these features in real time, at ranges to 20 meters, in a measurement while drilling (MWD) tool has not been possible with existing MWD Formation Evaluation and geo-steering systems.
An experimental pipe conveyed field prototype acoustic tool was run to echo range for identification of certain stratigraphic features and to make Sonic measurements (acoustic velocity/slowness). The Sonic measurements were used to insure accurate formation velocity since a combined measurement was essential in determining the correct distance to the feature. The experiment was run with a wireline and wet-connector inside the pipe for rapid two-way communication, thus enabling a quick view and analysis of the large amount of data recorded. A set of data analysis techniques was developed to emulate real-time downhole data processing. These techniques also are reviewed in the paper. Additionally, this paper presents the field test results relating to stratigraphic positioning, with comments for other key applications benefits such as reservoir navigation, formation dip estimation, coring point selection, seismic correlation, and high resolution near wellbore reservoir imaging.
P. 225
Economics of Downhole Oil-Water Separation: A Case History and Implications for the North Sea
Authors: Shaw Chris , Fox Mike 
Published: December 2007

Abstract
This paper describes a system used for the separation of oil and water in the far reaches of the wellbore where the separated produced water is re-injected into a zone accessible from the same wellbore. Successful application of this technology in low risk wells has been achieved and documented1. Risk is defined here as a function of workover cost and deferred oil production; high risk therefore being a prolific well with high workover costs. Application of this separation technology in high risk wells can only occur when the issues of the technology, cost and reliability have been defined. The more sophisticated completions that will be required for high risk wells will be more reliable, while the prolific nature of the wells gives a rapid return on the investment.
This paper outlines the factors that make up the economic decision whether to install such a system and, using a low risk case history, demonstrates the favorable economics of installing a separator system in a given application. Using the low risk example, it is shown how the ideas can be extrapolated to a typical North sea well where, although higher risk, the potential reward is also far higher.
Water Shut-Off: Simulation and Laboratory Evaluation
Authors: Surguchev Leonid M. 
Published: December 2007

Abstract
Many North Sea reservoirs are produced under waterflooding. With time the production wells start to experience water breakthrough problems due to incorformance of flood, gravity underride, presence of high permeable thief zones. The most common water shut off methods today are polymer gel treatment, cement squeeze and mechanical isolation. The polymer gel systems have several important advantages in comparison with other methods:
– The polymer system is injected as a solution and can penetrate deep in the reservoir and reduce permeability in the near wellbore area. – The injected solution can move up and down the outside well bore, sealing cracks and existing microannuli especially in poorly cemented high permeable sands. – Gel left in the well bore can be cleaned out by jetting via coiled tubing with either a mild acid or water. – Not expensive due to reduced crew and rig time.
During recent years polymer gel systems with Disproportional Permeability Reduction (DPR) effect were developed and successfully tested in the laboratories for North Sea reservoir conditions. Selective gels preferentially blocking water phase in the reservoir make well treatments more attractive, especially for advanced wells with complicated completion design (deviated, horizontal, multilateral). In spite of relatively small volume of chemicals involved in well treatments, evaluation of potential and possible benefits of near well treatments remain an important issue. Accurate near well model is required to simulate production of the well and effects of chemical treatment in the near well bore. Correct modelling of inflow is as important as representative modelling of gel generation process. Fine grid radial models allow to account more accurately for near well reservoir properties based on available log, core and production data. Template well models were established and used for screening of potential candidate wells for treatments. They proved to be useful in history matching and evaluating treatment effect in several field pilots in the North Sea.
The paper will discuss the mechanism of water shut off, recent laboratory studies and screening results, give simulation and field evaluation examples for North Sea wells.
P. 447
Water Shut-Off Using an Inflatable Composite Sleeve Polymerised In-Situ. A Case History on Forties Delta
Authors: Leighton J. , Saltel J.L. , Morrison J. , Welch R. , Pilla J. 
Published: December 2007

Abstract
An expandable composite patch, run on electric wireline, was used to shut-off water producing perforations for the first time on Forties Delta. This is a new technology, based on using insitu polymerisation to exploit both the deformability of a flexible composite and the mechanical characteristics of a polymerised composite. The results of this operation have shown an inflatable composite sleeve can be used as an efficient and cost effective solution for reducing unwanted water production.
P. 455
Microbial Clarification for Treating Reinjected Oilfield Brine
Authors: Philippovich N. , Winter J. 
Published: December 2007

Abstract
Ever rising water volumes and processing costs in the oil field have spurred OMV to look for alternatives to traditional water processing. Despite an elaborate central multistep water treating system, increasing injection pressures, water fouling in the pipelines and reservoir souring were noticed.
A comprehensive water analysis program was instrumental to understanding that available oxygen, nutrients and the recycling of water promoted the growth of bacteria in the large distribution system. Since, on the long run, no biocide proved effective, a soft strategy was adopted: by removing key components (sulfate, biodegradable carbon) essential for bacterial growth, the population could be starved and the injection water quality stabilized.
The feasibility of this concept was tested in a laboratory clarification apparatus that helped establish critical parameters, optimise additives and define performance limits. After due accommodation time, bacteria recovered from a refinery waste treatment plant could eliminate &gt;90% of BOD and the effluent water was biologically inert. At the same time, a field pilot plant was installed that now has been injecting biologically processed water since fall of 1996. On- site core experiments demonstrate superior injectivity compared to normal brine. Other parameters (COD, TOC, turbidity, membrane filterability) support these findings.
A revamp of the whole water conditioning system is now underway. So far, benefits of the new strategy have been considerable savings in biocide expenditures, reduced injection pressures, and a lower H2S production.
P. 477
Natural, Downhole Separation and its Impact on Production Performance
Authors: Asheim H. 
Published: December 2007

Abstract
Gravity and viscosity differences will cause gas-liquid separation already along the completed interval. For wells completed over longer intervals, the heavier liquid will accumulate and may build up sufficient static pressure to seep back to lower layers of the reservoir.
The model developed computes production performance with two-phase inflow, two-phase flow along the completed interval and possible back-seepage of accumulated liquid. From the results follow that both the apparent inflow performance and the gas-liquid ratio observed at surface are affected.
It is shown that downhole separation may be constrained by either back-seepage to the reservoir, or counter-current flooding along the wellbore. The liquid backflow rate limit due to flooding has been derived explicitly, providing a design parameter for downhole separation devices.
P. 497
Well Log Preprocessing and Modelling for Quantitative Seismic Interpretation
Authors: Olotu S.O. , Olukayode A.O. 
Published: December 2007

Abstract
Critical to quantitative seismic interpretation (QSI) is a good well to seismic calibration (WTSC). The technical challenge in the calibration of seismic and well datasets is accounting for various data-impacting effects prior to merging of these two sources of information. These effects are inherently introduced by method(s) employed for accessing and acquiring (drilling and well logging) data from the subsurface.
In the past, it was common practices to correct for effects such as drilling, fluid invasion, washout and other wellbore effects. Experience has shown that corrections now have to be made for inadequacies of tools in certain geologic settings (thinbed, soft or hard shales) that may lead to erroneous interpretation.
The petrophysical modelling necessary for the correction of the aforementioned effects require interpretative editing and subsequent generation of correct logs in zones that are giving spurious readings.
This paper demonstrates with two case studies for the essential data b and t.
In the case of b - Borehole geometry, fluid invasion and residual virgin formation porefill effects affect nuclear porosity tools such that relatively high porosities (and hence low b) are interpreted across shales compared to sands. These effects are also manifested across sands particularly when HC bearing.
In the case of t - Washouts, residual virgin formation porefill and possible formation alteration result in spurious slow travel time.
Combining the b and t data would normally result in erroneous WTSC and the interpretation of acoustically soft environment. This will be conflicting with the acoustically hard environment indications from the resistivity and where the hole conditions are good - b and t.
The correction and petrophysical modelling were achieved by concomitant interpretation of all available log data with the various responses referenced to known lithology, porefill and compaction trend(s). Consistency in stacking patterns is recognised from log data combining shallow and deep readings. as well as varying vertical resolutions. This approach has given better result in WTSC and rock property modelling which subsequently has improved QSI immeasurably.
P. 511
Steady-State Upscaling: From Lamina-Scale to Full-Field Model
Authors: Pickup Gillian E. 
Published: December 2007

Abstract
In recent years, the impact of small-scale permeability structure on hydrocarbon recovery has been demonstrated, and upscaling procedures, such as the Geopseudo Method, have been developed to scale-up from the lamina scale, using the hierarchy of geological length scales. However, upscaling is very time consuming, so many engineers still input rock curves into large-scale simulations,
In this study, we show how the process may be speeded up using steady-state methods for calculating the pseudo functions. A three-stage scale-up of a fluvio-aeolian reservoir was carried out. Capillary equilibrium was assumed for the first two stages, and viscous-dominated steady-state for the third stage. Two different wettability cases were examined - water-wet and intermediate-wet. The effect of using the small-scale pseudo relative permeabilities depends on both nature of the heterogeneities and on the wettability. In this study the recovery was reduced, especially in the water-wet case.
P. 527
Core-Log Integrated Approach to Seeding Reservoir Models with Physically Consistent Porosity, Permeability, and Saturation Data
Authors: Olukayode A.O. , Ahonsi B. 
Published: December 2007

Abstract
Essential to hydrocarbon reservoir modeling are input data of porosity, permeability, and saturation. These inputs are derivable from different sources that may not be linked, thereby giving room for inconsistency in interpretation of the reservoir.
A case study from the Niger Delta shows that when all three data sets are coupled into a cap-curve based saturation function, this problem is resolved. Using a generalized form of a cap-curve equation, interpreted porosity and permeability were used to estimate saturation profiles across hydrocarbon reservoirs.
The hydrocarbon saturation calculated by the capillary pressure curves demonstrated good agreement with the Waxman-Smits log derived saturation. In all reservoirs studied to date, good log-to-cap-curve derived saturation calibrations were observed to depend on the accuracy and precision inherent in the generalized synthetic cap-curve equation.
Improved predictions of hydrocarbon saturation from cap- curves were achieved through the use of flow zone indicator (FZIT) as fitting parameter, where FZIT combines both porosity and permeability in these relationships.
Base case deterministic STOIIP from models exceeded previous expectation values by 20%. Further, the value adding calibrated permeability and bulk hydrocarbon distributions ensure that ultimate recoveries, and hence field economics, can be better estimated.
NMR technology presents opportunity to extend the generalized synthetic cap-curve equation and data calibration methodology to other reservoirs / environments with minimal resource investment.
P. 537
Modern Reservoir Modelling for Rehabilitation of a Giant Oil Field
Authors: Bolotnik D.N. , Sarkisov G.G. , Sharifullin F.A. 
Published: December 2007

Abstract
More than 400 wells segment of Giant Russian oil field, having long term production history, was modelled using modem 3D geological and flow simulation software. Complex reservoir geology, large volume and low quality of geological/production historyr data were complicating field modelling with standard (2D) software tools. The geological models obtained with standard 2D geological software tools were not detailed enough, did not allowed fast detection of input data errors, so it was impossible to achieve history match of production data.
Solution of these problems was found by using modern mapping and 3D geological modelling software algorithms. Fine 3D geological model allowed to integrate all the geological data and was detailed enough to describe the real field geology. Modern upscaling tools were used to upscale the model from fine geological grid to the coarse simulation grid with minimum loss of heterogeneity details. 3D visualisation tools were useful in quality checking of input data and error detection.
Simulation model with a large number of grid blocks was handled by modem efficient simulation software and allowed to history match this large segment in a very short time by using limited hardware resources.
P. 45
A Global Perspective on Sand Control Treatments
Authors: Sherlock-Willis Terri M. , Morales R.H. , Price P. 
Published: December 2007

Abstract
Sand control treatments are typically in the form of gravel- packs (slurried-pack or water-pack), frac-packs or horizontal completions using screens only. When selecting a sand control method, it is necessary first to understand the formation sanding mechanism(s), including the response to pressure depletion and drawdown, and second, to select the most appropriate sand control completion. However, because of economical limitations, traditional practices and/or lack of sufficient data, the selected sand control completion is not always the best one. Alternately, the success of the completion maybe compromised.
The success of a sand control treatment can be described in terms of operations and well performance. In recent years, significant progress has been made to improve well performance, by focusing on proppant carrier fluids, placement methods, pumping/blending technique and downhole completion hardware. In addition, sand control software simulators have been evolving rapidly to meet the demands of improving the well's productivity. This paper summarizes regional sand control preferences, highlights advances in new teclmology and offers solutions to common problems in various completions techniques.
The industry will gain benefits from lessons learned from the various sectors of the world. We identify possible causes for failure; i.e., improperly designed treatments typically result in inefficiently packed annulus and perforation tunnels, sand bridges, and ultimately, premature screenouts. Additionally, general recommendations and guidelines are given based on the evaluation of the relevant treatments.
P. 201