bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Downhole Displacement and Inferred Production for Verification of Measured Test Data
Authors: Ray Louis I. 
Published: December 2007

Abstract
This paper describes a technique used to verify measured well test data in shallow rod pumped fields. Typically, the availability of measured well test data is constrained by test facility accuracy and the availability of the test facility for acceptable testing frequency. This technique involves the use of RPC (Rod Pumped Controller) calculated total fluid production as one source of production data for each well. A second source of production data comes from a wave equation driven diagnostic software program. This program uses load and position data gathered from each RPC to generate a downhole card from which pump displacement (production) can be calculated for all wells.
The measured well test data for each well can then be compared to the "inferred production" and the "downhole displacement" data for any observed discrepancy. "Inferred production" and "downhole displacement" make it possible for operating personnel to track daily individual well production with a high degree of accuracy without the use of actual well gauging facilities that might not be available on demand or that give questionable results.
This paper will also address methods necessary to setup RPC inferred production for reasonably accurate results, as well as necessary techniques for good displacement calculations from RPC dynagraph cards. These techniques involve the use of central site software for RPC setup and data telemetry.
Relative Permeability in Dual-Porosity Porous Media
Authors: Deghmoum A. H. , Tiab D. , Mazouzi A. 
Published: December 2007

Abstract
Reliable relative permeability data is an essential input parameter in reservoir engineering, most significantly in the area of reservoir simulation of dual-porosity systems. However, measurements of relative permeability do not work well because of laboratory limitation. Also, reservoir core samples are generally extracted from zones, where induced or natural fractures are absent. Obviously, data obtained from these cores may not reflect the real behavior of naturally fractured reservoirs. Because of this laboratory limitation, many commercial reservoir simulators neglect the effect of dual porosity on relative permeability, and implicitly assume that relative permeability is a straight line. This assumption in naturally fractured systems may lead to erroneous results.
The purpose of this study is to rectify these shortcomings by laboratory experimental contribution. Thus, the main objectives are: (a) to perform special core analyses on Berea outcrop core samples as a model of rock. (b) to simulate fracture opening, by cutting these samples in such away to get different fracture apertures. (c) to investigate the effect of dual porosity on the shape of capillary pressure curves, and (d) to evaluate the effect of fracture opening on both absolute and relative permeability.
A good correlation between absolute permeability and fracture aperture is obtained. The effect of dual porosity is clearly observed on capillary pressure curves. Unsteady-state tests could not be used to measure relative permeability on these specially prepared core samples. This is due to the fact that fractures become the easiest pathway for water flow, which results in high residual oil saturation in the matrix. However, the centrifuge technique test is run with success because both matrix and fracture are subjected to the centrifuge field.
These findings are extended to actual naturally fractured reservoir (NFR) in Algeria. Tin Fouye Tabankort (TFT) reservoir is selected as a prototype of Algerian NFR. Availability of naturally fractured cores and published data are the principal reasons for this selection. A discussion of TFT natural fracture indicators is presented, including: core observations, well test analysis and borehole imager tools. Displacement test is conducted on a full diameter core in order to solve the laboratory limitations and to obtain representative data of relative permeability. These laboratory tests indicate the existence of a good correlation between permeability and fracture opening. The correlation is used to estimate the aperture of natural fractures in TFT reservoir. This study may also lead to the development of a laboratory technique for systematically determining the fracture intensity index.
The Benefits of In Situ Upgrading Reactions to the Integrated Operations of the Orinoco Heavy-Oil Fields and Downstream Facilities
Authors: Kuhlman Myron 
Published: December 2007

Abstract
The value of heavy-oil production is reduced because extra refining is required to market the oil and a diluent may be needed to transport the oil. In some reservoirs, insitu pyrolysis reactions can remove this limitation.
The oil in most reservoirs produced by steam-drive is not hot long enough for pyrolysis to drastically change properties of the oil. However, deep, high permeability, thick formations like the Orinoco tar belt offer a new opportunity. When steam is injected at a pressure above 8.93 M Pascal (1300 psi), and the production is constrained, large volumes of 10 API oil can be upgraded underground to 25 API oil. Moreover, production from the reservoir more than doubles, and the coke and sulfur are left underground. Since the viscosity of the produced crude is reduced several orders of magnitude, no diluent would be needed to transport the crude. Finally, much lighter oil arrives at the refinery, so extra investment in distillation and cracking equipment is unnecessary.
Thus, in situ upgrading could reduce the investment needed to market heavy oil, generate higher profits and make smaller reservoirs more attractive for development.
McKittrick Reservoir Modeling Study: Operation and Redevelopment Strategy
Authors: Chiou C. S. , Lentz W. D. , Nisenbaum Y. , Langen R. A. 
Published: December 2007

Abstract
This paper describes a reservoir modeling study that integrates 3D geological modeling with thermal simulation. The objective of the study was to optimize the steam injection schedule and establish a redevelopment strategy for the Tulare reservoir in the McKittrick field. 3D geological interpretation and visualization technology helps capture detailed heterogeneity to properly represent relevant flow units and barriers. The reservoir model was validated by history matching 10 years of field performance. Modeling past performance has identified weaknesses in reservoir description and suggested modifications that were needed to improve the model.
Forecasts of future performance were made under different operating conditions and redevelopment scenarios. Simulation results show that the steamflood efficiency and project profitability can be improved by reducing current steam injection. Evaluation of various development scenarios indicates that twinning the injection wells, to separately provide steam injection support to the upper and more mature, lower sands, makes a significant improvement on production performance and project economics.
Precise Tiltmeter Subsidence Monitoring Enhances Reservoir Management
Authors: Davis E. , Wright C. , Demetrius S. , Choi J. , Craley G. 
Published: December 2007

Abstract
Subsidence monitoring is most commonly conducted using either level surveys or GPS surveys of elevation monuments to determine changes in elevation across a field as a result of injection and production activities. Several operators near Bakersfield, CA are using tiltmeter-based subsidence monitoring to obtain highly detailed maps of subsidence with continuous data acquisition. The tiltmeter measured subsidence is then correlated to production and injection on a day-by-day basis so the impact of individual injection and production events can be quantified. The data is presented in a video format that allows visual assessment of the field motion. In some fields, the monitoring array is also equipped with monuments for periodic level survey and GPS measurements of the ground motion.
This paper discusses the design and installation of tiltmeter subsidence monitoring arrays and the format of the results. In addition, the subsidence data is correlated to field activities to show how the monitoring can be used to correlate ground movement with reservoir events.
A New Approach for Most Realistic Wellpath Computation
Authors: Gfrerrer A. , Glaser G. P. 
Published: December 2007

Abstract
The trajectory of a wellpath is a tortuous space curve with permanent changes in directions and curvatures. A usage of steerable directional drilling tools in nowadays drilling practices even more forces the bit apart from its natural tendencies of running a smooth course - enforcing a highly curved shape of the well. Although this is well known all to the author's knowledge existing wellpath computation methods are based on piecewise approximating the wellpath with constant curvature linear, circular and helical curves and arcs.
A new proposed trajectory computation method gives up these old paradigms and introduces a new approach to accurately calculate the spatial course of a wellpath while maintaining its realistic shape from standard wellbore survey measured depth, inclination and azimuth data. In detail the discussed algorithm is founded on fundamental differential geometry practices in synergy with piecewise spline-curve approximation techniques. This limits the common problems of spline-curve approximations. The result is a highly accurate wellpath description with proven curvature continuity in any position along its course.
The proposed new method is a further step in more accurate wellbore trajectory and dogleg severity computation- especially for complex shaped and extended reach wells. The proposed model's accuracy and reliability is proven and verified with a complex shaped, 11.3 km synthetic wellbore example (with known results) followed by extended-reach and complex shaped field case studies.
Deriving Greater Business Value Through Improved Drilling Information Management
Authors: Bidi Mohammad Z. , Razak Rozalina Abd. , Jusoh Kamri 
Published: December 2007

Abstract
Well expenditure represents a significant part of Petronas Carigali Sdn Bhd's (PCSB) CAPEX where most of the cost comes from drilling. This has prompted the Drilling Department to continuously look for ways to reduce its drilling costs and be as efficient as possible. Back in 1996, PCSB embarked on a drilling initiative project so called DICE (Drilling Information and Communication Environment). The aims were to capture, store and analyze information relating to all PCSB drilling activities and operations. In support of this, a system was introduced whereby operations data were captured at offshore well sites and transmitted electronically to a central office database for drilling analysis and future reference.
More recently, the primary focus of the project was to make better use of the valuable well data and information that had been collected, with particular emphasis on the derivation of drilling performance and cost metrics. Key to this was the development of a set of standard queries to interrogate the drilling database, and to derive performance information such as Drilling Days per Thousand Foot, Well Cost per Foot, NPT and other trends. This also provided the opportunity to perform a thorough data quality check on previous wells and to standardize the operations time breakdown and cost coding systems to ensure reporting consistency.
Besides gathering drilling activities and operations information, steps have been taken to also capture knowledge (i.e. lessons learnt) using the same database. Various customized reports were introduced to ensure effortless daily monitoring of drilling operations and standardization of the PCSB reporting system. The major customization work involved the introduction of an improved, automated, Final Well Report (FWR). This has tremendously reduced the time taken by drilling engineers for the preparation of Final Well Report at the end of each well.
Overall, by enhancing its drilling data management system, PCSB has been able to better monitor its drilling activities and to more readily identify opportunities to reduce its operational costs.
Technique for Close Cluster Well Head Concentrated High Quality and High Speed Drilling Cementing Surface Interval in Sz36-1d of Liaodong Bay
Authors: Wei Jiang 
Published: December 2007

Abstract
This paper summarizes the application of high quality and high speed concentrated surface drilling technique for the first time in drilling and cementing surface interval of 14 wells in 56 hours with average time of 3.99hr/well in phase II development of this field. The project was characterized by improvement mainly in 4 aspects: conductors were 15m shorter than normal; wellhead spacing reduced from 2m×2m to 1.5×1.8m; surface casing changed from seamless casing to erw casing; with additives; the strength of quick hardening cement reached 4.2MPa in 4 hours, 61% stronger, so the whole operation process was safe and smooth compared with that of Block J, which was the fastest then, the efficiency was improved by 55.7%, 3 hours saved each well. The success of this technique had 3 significant meanings: broke the wellhead spacing of 2m×2m and realized the close wellhead spacing of 1.5m×1.8m successfully, so the wellhead platform dimension and project cost were; realized the quick hardening cementing of low temperature surface interval, resolved the leakage on concentrated drilling and cementing surface interval, explored the method of surface open-hole volume calculation, which laid basis for the concept of close wellheads and big platform and provided reference experience for the phase II overall development of SZ36-1 oil field.
Large-Scale Comparative Study of Prepacked Screen Cleanup using Acid and Enzyme Breaker
Authors: Asadi Mahmoud , Penny Glenn S. 
Published: December 2007

Abstract
Some of the completion failures are due to screen plugging. A number of remedies have been adopted by the industry to cleanup plugged screens. However, these cleanup methods are not investigated under downhole conditions. This study utilized a large-scale radial flow-loop to study prepacked screen cleanup under downhole conditions. First, the original permeability of each screen was measured with 10 ppg NaCl brine solution. A sized carbonate drill-in-fluid was then formulated and pumped for 3 hours and at a constant differential pressure of 60 psi across the screen, simulating a screen run in a wellbore. Inlet and outlet samples were collected for size distribution analysis and removal efficiency calculations of each screen. Each plugged screen was then subjected to a cleanup method such as acidizing, use of enzyme breaker, backflow, or a combination of these methods. Following cleanup, the permeability of each treated screen was measured with 10-ppg NaCl brine solution and compared to the screen's original permeability. The degree of plugging and percent area open to flow was evaluated based on the retained permeability of each screen.
Drilling Fluid Optimisation Study for K-Shale in the Malay Basin
Authors: Tan C. P. , Willoughby D. R. , Yaakub Mohd Azriyuddin , Chen X. , Hamid Pauziyah Abdul , Ibrahim Zamanuri , Ibrahim Zahari 
Published: December 2007

Abstract
Drilling experience in K-shale in the Malay Basin (South China Sea, Malaysia) highlighted the issue of wellbore stability in the formation. A wide range of drilling problems has been experienced, ranging from tight hole to stuck pipe. Subsequently, a collaborative project between CSIRO Petroleum and Petronas Research & Scientific Services Sdn Bhd was conducted to address the problems. The aim is to develop a technical framework of drilling fluid design and consolidated into a methodology for overcoming wellbore instability-related problems in the shale.
This paper describes the outline of the project and the approach adopted in the development of the methodology. The approach is based on drilling fluid-shale interaction and proven rock mechanics principles. Based on the gathered drilling experience and laboratory tests conducted on downhole core material, dominant failure mechanisms of the shale were identified. Examples of critical mud weight contour plots and design charts of pressure change (due to drilling fluid-shale interaction mechanisms) which form part of the consolidated methodology for designing optimal drilling fluid are presented. The methodology provides a pragmatic approach for managing shale instability problems in drilling extended reach wells in the Malay Basin as well as other regions worldwide. The approach would result in an increase in drilling efficiency and a reduction in drilling cost.
Time-Dependent Wellbore (In) Stability Predictions: Theory and Case Study
Authors: Abousleiman Y. , Ekbote S. , Tare U. 
Published: December 2007

Abstract
Time-dependent wellbore (in)stability during oil and gas drilling account for a significant amount of lost rig time and substantially increased drilling costs ($700 million annually according to conservative estimates). Coupled time-dependent processes have been previously described in the realm of the poroelasticity theory. This wellbore (in)stability modeling approach allows the drilling engineer to systematically include the stress variation around the wellbore and the associated rock deformation and pore pressure changes. In this paper, in addition to the analyses conducted on the previously derived solutions for thermal and pore fluid diffusion, the time-dependent solution for stresses and pore pressures considering the mud and formation shale activities are presented. These solutions are the basis of the software, PBORE-3D, which utilizes contemporary programming techniques and can perform analyses of stress/pore pressure, formation failure, mud weight, and mud-salinity design for drilling shale formations. The model is especially useful in the prediction and visualization of time-dependent break-outs created due to inadequate mud weights; as well as time-dependent alteration of the near wellbore stress concentration caused by excessive mud weights leading to lost circulation problems. A case study is presented in this work which demonstrates the straightforward application of the model to challenging drilling conditions.
Successful Isolation of a Loss Circulation Zone of a Short Radius Horizontal in a Highly Fractured Environment
Authors: Ubaidan A. Al , Esmail W. J. , Aborshaid H. , Umair M. Al 
Published: December 2007

Abstract
This paper addresses the successful isolation of a loss circulation zone of a short radius horizontal completion utilizing the cement retainer technique in a highly fractured environment. The process was applied to a well in a highly fractured carbonate reservoir undergoing pressure maintenance by water injection. Fracture orientation in the area is running mainly NE/SW. While drilling the horizontal section, complete lost circulation was encountered in the middle of the planned lateral section, most probably through a fracture. Circulation could not be regained by pumping LCM pills or placing cement plugs. The horizontal section had to be plugged and a new horizontal lateral was drilled in a different direction. A drillable squeeze packer was used to hold a good kick-off cement column above the loss circulation zone. Prior to the workover, the well was producing 3.3 MBOD at 47% water cut. The initial post workover test showed 3.0 MBOD restricted (choked) water-free production.
Petrophysical Measurements on Shales Using NMR
Authors: Martínez Gabriela A. , Davis Lorne A. 
Published: December 2007

Abstract
Shales are important constituents of petroleum systems, and it is necessary to study their petrophysical properties as both reservoir components and as seals. Nuclear magnetic resonance has proven to be a good technique for measuring the reservoir engineering properties of rocks. This paper presents measurements of NMR relaxation in shales. It establishes that shale petrophysical information is accessible using standard NMR lab techniques employed in the oil industry. Even for good seals, shale porosity and pseudocapillary pressure curves can be derived from NMR relaxation data. This opens the question as to whether NMR logging can be used to ascertain seal quality for oil and gas storage reservoirs and for CO2 disposal reservoirs.
NMR measurements were performed in a low field spectrometer primarily on shales characterizing seals. Multiexponential T2 and T1 relaxation rates were determined from CPMG and inversion recovery experiments, respectively. Mean log T2 values of the undersaturated samples were about 0.4 ms. The T2 relaxation times increased after the shales were saturated but remained below 2 ms. Porosity for each sample was derived from the T2 magnetization and calibrated against a standard. Since NMR detects total porosity, the porosity was generally larger than that determined from laboratory gas flow-saturation techniques. The T2 relaxation rate distributions were normalized using the total magnetization calibration and integrated from the larger times to yield pseudo-capillary pressure curves.
Drilling Engineering Challenges in Commercial SAGD Well Design in Alberta
Authors: Knoll R. , Yeung K. C. 
Published: December 2007

Abstract
Recently, the field pilots in Canada using SAGD (Steam Assisted Gravity Drainage) technology have generated sufficient positive response to encourage commercial scale development in the Alberta Oil Sands Deposits. This will be a very interesting time for drilling engineers, since SAGD well pairs present some unique design and operational challenges. This paper will attempt to review some of the drilling engineering challenges of generic SAGD well design in the Alberta setting, specifically, the need to cool the drilling mud to maintain hole stability, and the selection of slant or vertical intermediate hole section geometry.
An Innovative Approach for the Analysis of Production History in Mature Fields: A Key stage for Field Re-engineering
Authors: Coste J. -F. , Valois J. -P. 
Published: December 2007

Abstract
Mature fields are defined as fields with a relatively long production history (up to 70 years) and many wells drilled (up to 1000 wells). Generally, little data is available on these wells, therefore the analysis of the long production history for the understanding of field behavior is a key stage in the reservoir process prior to field re-engineering. This paper proposes a new approach for optimizing the analysis of production history: after the graphical analysis of the global data set, we applied non-linear regression methods to the oil rates, and smoothing methods to the water cut curves. We extract original indicators of production. Multivariate statistical analysis methods can then be applied with a new (robust) approach of clustering. This methodology consists in classifying wells by dividing the field into areas. Mapping of statistical results helps identify the production mechanisms and locate the poorly-drained zones which potentially contain remaining reserves. The method is illustrated by two field cases: the first one is a carbonate reservoir bearing light oil, and the other one is a shaly sandstone reservoir containing heavy oil.
Field Application of Production Analysis
Authors: Chu Wei-Chun , Cox S. A. , Gilbert J. V. , McCarthy C. J. 
Published: December 2007

Abstract
This work presents the application of the combined type-curve and decline-curve analysis methods to five distinct examples of continuously declining rate and pressure data. Examples of both volumetric and geopressured gas reservoirs are examined.
Production analysis is a powerful tool when used with traditional well testing techniques to obtain consistent results. Used in isolation the limitations of production analysis can lead to erroneous conclusions. The limitations of production analysis are proportional to (1) the quality of the production data (frequency, accuracy and extent) and (2) the uncertainty in the average reservoir pressure.
These deficiencies can be alleviated by judicious use of periodic buildups to quantify average reservoir pressure and to capture the transient behavior of the reservoir.