bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advanced Horizontal Well Production Logging – An Australian Offshore Example
Authors: Carnegie A. 
Published: December 2007

Abstract
A production log (PL) was run in a horizontal well in a high permeability field offshore Australia. The well was completed with slotted liner and ECP's. The main answers sought by the log were: the location of any unproductive sections of the well bore, a measurement of the inflow profile, a check on the trajectory of the well (as derived from measurement whilst drilling), and an understanding on whether flow was occuring between the ECP's and the formation. This information helps answer the following important questions: a) What should the lengths and trajectories be of horizontal wells drilled in the future life of the field? b) Can such trajectories of such wells be drilled with sufficient depth accuracy, c) What are the optimum clean up strategies for these wells? d) Should these future wells contain ECP's? e) How should the productivity be optimised, of the existing wells in the field (including the one logged)? The well only flowed oil to surface. But previous experience showed that water sumps and gas traps would probably exist, and potentially cause multi-phase flow conditions to prevail down hole, thereby complicating the responses of sensors. For example, stagnant or circulating water could completely distort the spinner response. A further complication was that flow could be occurring between the liner and the formation. Therefore, a logging approach was chosen which had previously been proven to be able to deal with multiphase flow in horizontal wells completed with slotted liner. The approach chosen relies on combining traditional PL sensors (spinners, pressure and temperature) with recently developed sensors, which image down hole flow, determine the holdups of oil water and gas inside the wellbore, measure the velocity of water, and provide knowledge of holdup and flow in the liner to formation annulus. To save rig time all sensors were deployed on one tool string, which was conveyed by coiled tubing.
Large amounts of data were generated from each sensor. These were integrated to provide answers to all the questions mentioned above – these would almost certainly have been left unanswered or answered incorrectly if the individual sensors had been interpreted in isolation from one another. Additionally, some surprising results were found. Notably: 1) Apparently small downward shifts of approximately 1 metre in sections of the trajectory towards the toe could be causing significant productivity impairment from these sections, 2) It is possible to have almost no drawdown inside the liner, whilst having significant production from the liner to formation annulus – this last result is associated with sections of liner which have remained impermeable since the time of completion.
Application of Seismic Inversion and Special Processing Techniques to Fracture Distribution Prediction
Authors: Chen Jun , Song Xinmin , Yao Fengchang , Cao Hong 
Published: December 2007

Abstract
Although there are some advances in geophysical methods of identifying subsurface fractures (for example, imaging well logs, cross-hole tomography and seismic reflection analysis of shear wave), they are generally quite expensive and commonly are not economically justifiable in mature, relatively low-production reservoirs. This paper presents an integrated method of recognizing subsurface fractures mainly based on conventional geophysical information (conventional well-logging and compressional wave data). The research thinking is to first extract lithology and fracture information from conventional well-logging data according to the responses of well logs to all kinds of geological features, then reconstruct pseudo-acoustic curves by transforming lithology and fracture information into acoustic information, and complete seismic inversion under well quality control or well constrained inversion. Through research and practice of certain fractured reservoirs, a few methods are summed up as follows. (1) Lithology control on fractured distribution are well known, fractured zone can be indirectly predicted by means of seismic inversion detecting lithology distribution. The applications of the method in carbonate and conglomerate reservoirs have gained good effects. (2) It is certain that seismic data mainly contain lithology and fracture information in very low-permeability fractured reservoirs, fractured zone can be identified by comparison of seismic inversion results from lithology and fracture information.
Tapis - New Opportunities from a Maturing Field
Authors: Abdullah Muhammad Aw Yong , Olsen B. S. 
Published: December 2007

Abstract
This paper focuses on how the integration of technologies such as sequence stratigraphy, log analysis, 3D seismic, reservoir simulation and drilling have helped in overcoming the many challenges, and increased Tapis field's reserves by about 30 percent. The work program for realizing these reserves includes rig workovers, infill/step-out drilling from existing platforms, and installation of a new satellite platform. To date, the rig workovers and most of the infill drilling have been completed, and results have been mixed but overall, encouraging. The new satellite platform was installed in third quarter of 1998 and development drilling off this platform is now underway. The experience at Tapis demonstrates the value of looking for new opportunities in mature fields.
The Tapis field is located approximately 210 km (130 miles) off the east coast of Peninsular Malaysia in the South China Sea at water depth of about 64 m (200 feet). The field was discovered in 1969 by the Tapis −1 exploration well and further delineated with three appraisal wells before development drilling commenced in 1977. Five platforms were installed and a total of 90 development wells were drilled as at year-end 1998. Waterflood was implemented to maximize ultimate recovery from the field. Over 47.7 million st.kL (300 million STB) of oil has been produced to date with a peak oil rate of about 12.7 thousand st.kL (80 thousand STB) per day achieved after the initial two years of production buildup. From about the seventh year, the field's production went on a steady decline and reached a rate of about 3.3 thousand st.kL (21 thousand STB) per day after about 15 years of production. In 1993, a multi-disciplinary team consisting of geophysicists, geologists, petrophysicists and reservoir engineers was assembled to identify both near- and longer-term opportunities in the field to mitigate the production decline.
Evaluating the Effectiveness of 3D-Seismic in Northwest Paluh Tabuhan Field: A Case Study
Authors: Basuki Puspo P. , Santoso Djoko , Hendrajaya Lilik 
Published: December 2007

Abstract
The effectiveness of 3D-seismic is controlled by four factors: the physical properties of reservoirs, the seismic frequency content, the field parameter design, and the goals to be achieved, provided that the collected data be processed and interpreted appropriately. By understanding the first and second factors, one can design the third factor optimally, and also estimate the effectiveness of 3D-seismic. This paper proposes a concept of 3D-seismic effectiveness measurement based on the dominant seismic wavelength and the thickness of reservoirs. The concept enables one to estimate the effectiveness of a 3D-seismic project and even to prepare actions to improve the effectiveness. To check the validity, the concept is applied to a case study of Northwest Paluh Tabuhan Field in North Sumatra Basin. The purpose of the 3D-seismic survey in this field was to better understand the detailed geological interpretation which enables one to effectively drain the field and to delineate the extension of the field. Using the above mentioned proposal, it was estimated that the 3D-seismic survey would be 54% effective or 72% conditionally effective. The interpretation of seismic data provided satisfying structural maps, however, it was unable to map the lateral distribution of the objective reservoirs. It was evident that the 3D-seismic data was ineffective in achieving the goal. This ineffectiveness, more specifically the inability of seismic data to show the lateral distribution of objective reservoirs, occurred due to the limited thickness of the reservoirs and the frequency content of seismic data. The results of interpretation meets the estimation derived from the concept of effectiveness. The concept proposed for onshore 3D-seismic survey is applicable to offshore data as well.
Successful Application of Water-Conformance Technology: A Case Study from East Kalimantan, Indonesia
Authors: Hunter Steven , Soetedja Vincent , Rinadi M. , Mitchell Wayne , Gauntt Gary 
Published: December 2007

Abstract
Until recently, excessive water production in this East Kalimantan Field was not considered to present a major problem. The two main reasons for this were (1) adequate water disposal facilities for the water production and (2) the perception that water control treatments would not have a material impact in reducing water production or increasing oil recovery. This paper presents a case study from the Semberah field in East Kalimantan, which shows that with proper problem identification, the use of available technology and placement techniques can significantly reduce water production and simultaneously realize an increase in oil production.
Applications of Carbon/Oxygen Logging in Indonesian Reservoirs
Authors: Fox P. E. , Adnyiana G. , Setiadi I. 
Published: December 2007

Abstract
Clastic reservoirs with waterdrive mechanisms can lead to tricky interpretations in instances where resistivity measurements have little contrast between freshwater- and oil-bearing rocks. Indonesia’s clastic and carbonate environments can provide challenges in reservoir monitor evaluation, especially in the detection of fluid types behind pipe, quantification of reserve depletion, and control of high water production.
Carbon/oxygen (C/O) logging is primarily utilized to determine oil-water saturations and reservoir performance in areas with low or unknown formation-water salinities. The C/O measurement is based on carbon and oxygen reactions with high-energy "fast" neutrons producing characteristic gamma rays. From this measurement, one can distinguish between hydrocarbons (C + H) and water (H + O). This, of course, is a very simplistic model of real-world applications that are complicated by mineralogy, wellbore environmental conditions, and reservoir behavior. Successful applications of C/O logging in Indonesia have included
Identification of oil reserves otherwise difficult to detect Monitoring reservoir depletion Identification of horizontal well placement target Detection of oil-water contacts for conformance treatment applications Inter-reservoir crossflow identification by oxygen activation combined with production logs Oil-saturation analysis for initial well completions when openhole logs are not obtainable Confirmation of steamflood efficiency
This paper presents a few of over 100 C/O logging and interpretation experiences in Indonesia since 1993. Job planning and well preparation critical to successful use of the technology are discussed. Several log examples are shown to highlight a cross section of applications in hopes of encouraging increased future use of the technology in optimizing reservoir performance.
Creative Interdisciplinary Team's Effort Results in Economic Development of a Previously Sub-Economic Field, South Zelda Field, Offshore Southeast Sumatra
Authors: Oglesby Chris A. , Schneider Mark , Pringgadani Meilando , Johnston Warren , Maulana Chandra , Williford John , Galuccio Miguel M. , Ridjab Timothy , Sambas Marlina 
Published: December 2007

Abstract
YPF/Maxus’ South Zelda field, offshore southeast Sumatra, Indonesia, was successfully developed in late 1998 with the installation of a braced caisson, the drilling of six development wells, and the successful tie-back and completion of the original discovery and delineation wells in the Zelda sandstones (Oligocene). At the platform’s October 1998 startup (prior to the development drilling and excluding the two non-platform wells), the field began producing at a rate of 2,500 BOPD from two wells and subsequent to the development drilling and completion of the remaining six platform wells in March 1999, the field’s anticipated production rate is over 8,000 BOPD. What made this project unique was the creative combination of engineering and science that converted a ten-year old sub-commercial discovery into an economic development despite the lowest oil prices since the field's discovery and without government incentives.
The South Zelda project was developed for $18MM as implemented, compared to $35MM estimated for a conventional development in the 1997 Plan of Development (POD). Savings resulted from innovative solutions implemented by the structural, drilling, and production engineering teams and the reservoir geology/engineering group. Using a caisson structure versus the traditional 4-pile platform resulted in savings of $5.4MM for platform and facilities. Tubular costs were lowered by $1MM by opting for smaller casing (7") and tubing (2-7/8") previously not used by the company in this area. And finally, a reservoir description project determined that the bulk of the reserves in the POD were in the Upper Zelda sandstones while the Middle and Lower Zelda reservoirs were riskier and poorer performers. Subsequently, YPF/Maxus chose to fully develop the Upper Zelda sandstones and to forego development of the deeper reservoirs, resulting in a decrease (from 12 to 10) in the required number of wells for full development. The ten wells include two development wells that were drilled from an existing platform to the north (Zelda C-14 and C-15), allowing YPF/Maxus to capture 100% of the Upper Zelda reserves in the 1997 POD.
Linked Tectonics, A Powerful New Paradigm for Deciphering the Structural Evolution of the Menggala North Oil Field
Authors: Baroek Maria Patricia , Heidrick Tom L. , Kelsch Ken D. 
Published: December 2007

Abstract
A recent structural synthesis of the North Menggala field, Central Sumatra, reveals deformation patterns which are unequivocal and portray in detail the field's tectogenetic development over the past 30 million years (Ma). The EDGE-Voxelgeo-Gocad++ work process (Kelsch et al., 1998) was used to pick the high quality North Menggala 3D seismic volume. Ninety-five faults were identified, named, gridded and smoothed. The character of each fault and its deformation style, mode, orientation and age were noted. Well logs and biostratigraphic control from the Mangga #1 was used to identify seven Mio-Pliocene sequence boundaries. Along with the timing of fault displacement, particular attention was paid to the character and orientation of associated syndepositional extensional rollover and compressional folds, pop-ups, unconformities and pull-apart depocenters. Tectonostratigraphic data suggest Menggala North is an anticlinal trap produced by inversion of the South Balam half-graben along the N-S-trending South Balam Border Fault (SBBF). The trap is compound having evolved under three contrasting episodes of transtensional (F1, Eo-Oligocene), transpressional (F1L/2E, ± 28 – 21 Ma) and compressional (F3L, 3.8Ma – Recent) deformation. The derived Eocene-Recent near field maximum principal horizontal stress axis rotated relatively through time bearing 340°,±10° 060°,±10°, 050°,±10° and 040°,±5° respectively during F1 (45-±28Ma), F1L/2E(± 28-21 Ma), F2L (21-12.5 Ma) and F3 (12.5-0 Ma).
Mapped faults and folds are organized into six unique structural families that share common geometrical, kinematic and dynamic characteristics. The spatial and temporal distribution of fault-fold styles and modes of deformation unequivocally demonstrate that the six structural families are not the result of isolated structural events; instead, syntectonic faults and folds at different locations within the 3D volume are in kinematic communication. Strain associated with displacement on the 30°-35°, east-dipping listric SBBF was repeatedly partitioned vertically through the hanging-wall along favorably oriented elements of the fault framework. The flat-lying, through-going SBBF is clearly the unifying master structure that efficiently links the five structural families through time and space. The outstanding Menggala North example of low-angle linked tectonics has widespread application within our industry.
A New Method for Effective Reservoir Recognition Using Principal Component Analysis of Conventional Well-logging Interpretation in Fractured Complex Lithologic Reservoir
Authors: Zhu Yixiang , Yuan Shiyi , Liu Mingxin , Mu Longxin , Song Xinming , Yang Qiuling 
Published: December 2007

Abstract
In view of the fact that many factors, such as lithology, physical property, pore structure and fracture, control the classification of effective reservoir in fractured complex lithologic stratigraphy, and considering any pair of bi-variables(such as porosity to resistivity or capillary pressure to porosity, etc.)can not distinguish different kinds of zones, a new method to recognize effective reservoir by conventional well-logging principal component analysis is present in this paper. In this method, first, eight feature parameters to reflect reservoir lithology, physical property, fracture and pore structure are drawn on the basis of sensor response analysis and interpretation of conventional well logs. Then principal component analysis is applied to draw two main factors(F1 and F2) which include 85 percent information of the eight feature parameters. Secondly, points which come from pay zones and nonproductive zones are classified successfully by the crossplot of principal component F1 and F2, and finally, effective reservoir can be identified by pattern recognition. This method has been proven correct in more than 100 well's applications.
Evaluation of Pseudo Functions
Authors: Cao H. , Aziz K. 
Published: December 2007

AbstractTo determine the range of validity of pseudo functions for upscaling of multiphase flow with gravity and capillary pressure, the performance of different kinds of pseudo functions is evaluated under different gravity numbers, capillary numbers and upscaling levels. The performance of pseudo functions can be measured as the percentage error between the results of fine grid simulation and the results of coarse grid simulation using pseudo functions. Furthermore, the performance can be shown as the bar graphs of percentage error for varying gravity number, capillary number and upscaling levels. A two-dimensional homogeneous water flooding case and a three-dimensional heterogeneous case have been studied using pseudo functions (Jacks et al.2, Kyte and Berry3, Pore Volume Weighted7, Flux Weighted Potential10, Modified Stone*4, Streamline5), and pseudo function performance has been evaluated under different conditions. Some guidelines for the use of pseudo functions are provided. The results show that (1) all of the pseudo functions have similar performance for the homogeneous case considered; (2) only the Jacks et al. pseudo function can be used in all cases; (3) using pseudo functions (except Jacks et al.) is unreliable, especially for the highly heterogeneous cases.
Fiber Optic Temperature Monitoring Technology
Authors: Carnahan B. D. , Clanton R. W. , Koehler K. D. , Harkins G. O. , Williams G. R. 
Published: December 2007

Abstract
Fiber optic distributed temperature monitoring of downhole conditions is an emerging technology that can be used to obtain important reservoir temperature information where conventional methods have failed. Due to the development of fiber coatings and improved deployment techniques, fibers are now used reliably up to 480 °F in Aera Energy's California field. Case lis an installation on tubing in rod pump wells has been useful in detecting early steam breakthrough and is expected to reduce the need for temperature observation (TO) wells in the future. Case 2 is a permanent installation on the outside of casing in TO wells which is used to determine accurate reservoir temperature profiles. In one example, the fiber has shown fluid migration behind pipe which was remediated successfully before the steam reached the surface. Case 3 is a failed attempt to use fiber to continuously monitor multilateral horizontal well temperatures to determine relative fluid contributions of the wellbores without shutting in the well.
Dip Interpretation from Resistivity at Bit Images (RAB) Provides a New and Efficient Method for Evaluating Structurally Complex Areas in the Cook Inlet, Alaska
Authors: Ford Gary , Hartner John , Grether Bill , Waters Doug , Cryer Jesse 
Published: December 2007

Abstract
Many of the producing fields in the Cook Inlet area of Alaska are found in tightly folded, asymmetric, fault bounded, anticlinal structures that are not easily imaged with modern seismic. Historically, exploration wells have been drilled initially on the crest of these features, only to find at total depth that the bore holes had deviated off the crest and were several thousand feet down dip from the initial structural objective. In Cook Inlet, where difficult hole conditions prevail, a new approach to real time structural analysis was needed to evaluate complexly folded features as they were being drilled.
Acquisition of structural dips while drilling a potentially complex structure was critical in evaluating the position of the well on the structure and steering it if necessary. Measurement while drilling (MWD), coupled with logging while drilling (LWD) provided the data necessary to enable a successful drilling operation and well completion.
The Resistivity-at-the-Bit (RAB)* tool was used during drilling to acquire resistivity measurements close to the bit. These resistivity measurements were then used to produce images and calculate dips similar to a Fullbore Formation MicroImager (FMI)*. Modifications to the structural model were continually made based on interpretations from the RAB images, allowing the bore hole to be steered towards a preferred structural position.
FMI and RAB images and interpreted dips were compared in a shallow interval to evaluate the quality of RAB data. Excellent agreement in measurements between the tools resulted in the continued use of RAB for the duration of the well.
Prediction of Steamflood Performance Using Carbon Isotope Signatures of CO2
Authors: Juprasert Max S. , Haught Mark B. , Schoell Martin 
Published: December 2007

Abstract
The economics of a steamflood project are largely dependent upon the rates at which steam is injected and oil is recovered. One of the dominant features of the steam drive process is the tendency of steam to override the reservoir and break through in the producing wells. To accommodate this situation, engineers are challenged to achieve the balance between production of heated oil and by-passed steam. A significant effort is being made to overcome this difficulty with the aid of a by-product gas tracer, carbon dioxide. The isotopic signatures of this non-condensable gas can be used to predict the changes in reservoir dynamics resulting from the reaction of reservoir rock and fluids with injected steam.
Steam-enhanced oil recovery often produces large quantities of CO2. Two primary sources are oil derived CO2 and CO2 associated with injected steam. These two distinct sources can be differentiated by the carbon isotopic composition of the CO2. The CO2 generated from oil tends to be depleted in the heavy isotope of carbon, 13C, while water-derived CO2 is enriched in 13C. Results of isotope analyses of CO2 from the Cymric field steamflood show that CO2 in good flood response wells is primarily derived from oil and CO2 in steam breakthrough wells is mainly water/mineral derived. These results suggest that carbon isotopes of CO2 are useful natural tracers for its origin and may be used as a diagnostic and possibly predictive reservoir management tool for monitoring steamflood performance.