bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Performance Coil Tubing Drilling in Shallow North Slope Heavy Oil
Authors: Rixse Mel , Johnson Mark O. 
Published: December 2007

Abstract
Coil tubing drilling (CTD) completed a very successful 4 well pilot project that drilled lengthy horizontal multi-laterals into shallow heavy oil reserves at the Milne Point field on Alaska's North Slope. The CTD sidetracks were drilled with the proper combination of tools that delivered good incremental oil production rate at low cost.
This was a new field for the CTD team with challenging directional and completion issues. A coiled tubing electric line drilling BHA and innovative completion techniques were required to achieve objectives. Three dual-lateral wells and one single-lateral well were drilled into thin shallow sands and completed using slotted liner and flow-through whipstocks.
Sensors in the modular electric-line CTD bottom-hole-assembly communicated to the surface with an electric line umbilical that provided extremely high-speed directional information, real time downhole weight on bit (DWOB), resistivity data, gamma-ray data, internal pressure and annular pressure data. The electric line also provided power to accurately drive a downhole electric orienter. These features combined with high performance PDM motors achieved very high penetration rates with 3.75 inch PDC bits. Several North Slope CTD drilling records were set during the project.
Liner running from high departure parent wellbores proved to be quite challenging but ultimately successful. Learning and performance improvements were made as the project progressed. This paper will review the performance of the CTD BHAs and the completion innovations applied in this project.
The Effect of Drilling Fluid Rheological Properties on Hole Cleaning
Authors: Saasen A. , Løklingholm G. 
Published: December 2007

Abstract
Hole cleaning is still among the most important problems to handle in drilling operations. The difficulty in removing cuttings bed during drilling arises because of the drilling fluid interacts with the cuttings in cuttings bed to form a cuttings bed gel. The drilling fluid composition can be designed to minimize the gel formation in the cuttings bed. At the same time the drilling fluid properties are optimized to ensure a sufficient shear stress on the cuttings particles to be able to remove the cuttings. This technique has been used in several of Statoil's drilling operations.
The paper explains the effect of the cuttings bed properties on hole cleaning in detail. Furthermore, the paper demonstrates how the drilling operations were improved compared to earlier drilling operations using conventional drilling fluids. From drilling operations in North Sea fields it is shown how the total drilling progress is improved. The torque curves of comparable wells are shown. These curves demonstrate that a significantly improved hole cleaning have been experienced in the wells drilled with the drilling fluid made to minimize cuttings bed gel formation.
Web-Based Occupational Health, Safety and Environmental (OHSE) Management Tools: Can They Help Companies Manage OHSE Performance in a Cost-Effective Manner?
Authors: Shaw R. D. , Livingston R. D. 
Published: December 2007

Abstract
Management of information is a major challenge facing corporations operating in today's regulated environment. Information relevant to corporate OHSE performance arises from various sources, e.g., OHSE laws and regulations, corporate monitoring programs, and corporate management systems to name a few. Further, the requirement for managing this information is continually growing, e.g., changes in OHSE laws and regulations, collection and analysis of new monitoring data, changes in corporate OHSE programs, increasing concerns related to litigation, and increasing scrutiny of OHSE performance by the public. Many companies, particularly those operating internationally, are seeking ways to effectively deal with this information.
There are various tools available for a corporation to manage this information. Many companies have over the years developed their own in-house databases, which are maintained internally and provide a reasonable approach for managing certain types of data. Unfortunately, many of these databases rely on the expertise of one or a few key individuals, and when those individuals depart the database is generally not maintained or modified to account for the changing needs of the company. Few companies have any formal approach for ensuring that they are compliant with all relevant legislation and regulations.
The Internet has led to the development of a wide range of OHSE management tools. The various products that are available all suggest that they are a panacea for solving corporate OHSE problems. In reality, many are simply web-based extensions of existing management tools and are not taking full advantage of the opportunities that the web can provide. For instance, the web allows the customization of management tools that are easy to use yet incorporate sophisticated intelligence or analysis that links back to databases in various locations. We will describe examples of such web-based tools and how they can aid in effective OHSE management.
Latest Technology Equidistant Power Section Increases Overall Performance of a Workover Motor
Authors: Hazenberg Frans , Regener Thorsten 
Published: December 2007

Abstract
A new workover motor, incorporating equidistant power section technology, has demonstrated that it can produce more torque for milling/workover operations and can operate at higher temperatures than previous positive displacement motor (PDM) designs. This paper discusses the operating principles of PDM tools to show how the equidistant technology increases efficiency and improves performance. In addition, the paper presents laboratory and operational test examples that verify the performance improvements. Three case histories demonstrate how this technology has reduced the cost of well intervention through higher Rates of Penetration, reduced milling times, fewer trips to surface and increased equipment reliability.
The new technology incorporates a unique and innovative "equidistant" power section design. The power section is made with a proprietary, contoured stator manufacturing process that reduces the motor’s rubber content considerably for higher efficiency, lower friction and less distortion. The case histories presented here discuss applications that previously would have been considered too risky or impractical for standard PDM motors. The case histories also substantiate that this power section technology is more tolerant when exposed to higher temperatures, pressures and fluid solids.
Use of a Crosslinked Polymer Fluid-Loss Control Agent to Aid Well Cleanouts
Authors: Rosato M. J. , Supriyono A. 
Published: December 2007

Abstract
Low-permeability gas sands are often cased, perforated, and hydraulically fractured in stages. Commingled production is common, and coiled tubing (CT) has become the medium of choice for opening multiple productive intervals between fracture stages and for use as a remedial workover method.
High differential pressures in the wellbore complicate CT intervention considerably. Bridging agents are sometimes used to combat severe lost circulation and associated well control problems. Calcium carbonate may be the most common bridging agent because it is inexpensive and easy to mix; however, removing the damage caused by calcium carbonate slurries to the formation and proppant packs is difficult and costly. Salt pills are widely used because they cause less formation damage, but they are ineffective at controlling severe fluid loss. Furthermore, to prevent dissolution of the pill, saturated brine must be used as a workover fluid, increasing costs and contributing to scaling problems.
A unique fluid-loss control agent has been gaining popularity for temporarily isolating low-pressure, fractured sands. This double-derivatized, crosslinkable, hydroxyethyl cellulose (DDHEC) polymer leaves less than 0.5% gel residue by weight, minimizing impact on production. It has demonstrated a regained permeability of 91 to 93% under laboratory conditions and can be completely removed by acid. The polymer has been used in conjunction with 1.25- and 1.75-in. CT with a high degree of success. It does not require expensive brines, is resistant to solvents, and can be used with foam.1,2
Eight field applications of the polymer have been performed, none of which have negatively affected production. This paper provides case histories for several of these field applications and defines techniques and selection criteria for applying the polymer under specific well conditions.
Single Well Chemical Tracer Test to Determine ASP Injection Efficiency at Lagomar VLA-6/9/21 Area, C4 Member, Lake Maracaibo, Venezuela
Authors: Hernández Clara , Chacón Larry , Anselmi Lorenzo , Angulo Reinaldo , Manrique Eduardo , Romero Eucario , de Audemard Nancy , Carlisle Charles 
Published: December 2007

Abstract
Single well chemical tracer tests (SWCT) were carried out at the VLA-1325 well located in Lagomar, C4 reservoir, Lake Maracaibo, Venezuela, to measure residual oil saturation in zone C4-U3 before and after an ASP injection, in order to determine the swept efficiency of a custom made blend. The tests included: Phase I, measurement of residual oil saturation to water (SorW) of the pay zone, previous to an ASP application and after waterflooding procedure; Phase II, application of an ASP blend, specially designed for the aforementioned zone; and Phase III, second measurement of residual oil saturation to ASP (SorASP) after ASP application.
The results show that prior to the ASP injection, the residual oil saturation at the VLA-1325 was (31 ± 3)%. This saturation measurement represents pore space in a 6.7 m (22 ft) thickness portion (1,842.4 - 1,849.1 m; 6,048 - 6,070 ft) of the C4-U3 zone from the well bore to a radial position of about 3.04 m (10 ft). A few days after this initial residual saturation, measurement was completed. A 0.35 porous volume, Vp, (1,750 bbl) ASP injection was carried out in the same 6.7 m (22 ft) completion of the C4-U3 zone. This ASP mixture was followed by 0.15 Vp (750 bbl) polymer drive solution, and a 1.2 Vp (6,000 bbl) of fresh water to push the ASP mixture and any mobilized oil about 15.8 m (52 ft) away from the test well-bore. After ASP treatment, the residual oil saturation measurement was repeated in the same pore space as the initial SWCT test investigated. This post-ASP flood SWCT test showed that the residual oil saturation in this pore space had been reduced to (16±3)%. This reduction in the SorW represents (48±1)% mobilized oil by the chemical treatment. The reported Sor measurements represent the average Sor s for the sub-zones penetrated by the tracer fluids during the test. The field data recorded during the test are presented, and compared with best-fitting simulation model results.
Reservoir Mechanism for Hunton Formation Production
Authors: Marwah Vineet , Kelkar Mohan , Keefer Brian 
Published: December 2007

Abstract
Hunton Formation is one of the most promising formations producing oil and gas in Oklahoma. The formation has an anomalous producing behavior. At the inception, the wells produce at relatively high water –oil and gas-oil ratios. Eventually, both the WOR and GOR decrease. This results in an increase in oil cut and hence reduction in lifting costs over time. Because of relatively high WOR's, many operators are discouraged from completing the wells, and hence abandoning the effort to produce oil from these formations.
This particular behavior has been addressed with different names: de-watering, reverse coning, to name a few. We call this behavior ROC (retrograde oil cut) mechanism. Our goal is to explain various anomalous behaviors in the field production, which can be reproduced by geologically defensible reservoir model. We tested several models by comparing the field data with the simulated behavior. Finally, we converged on to a three-layer model – which is geologically and core data consistent – and can produce various anomalous characteristics. These include decrease in WOR over time, increase in GOR after the well has been shut-in, long transient state behavior of oil production, and the decline in pressure (instead of pressure build-up) after some of the wells have been shut-in for 24 hour periods. We have integrated available core and log data, relative permeability data, geological understanding as well as PVT data to build this model. We tested this model by mimicking production from several wells in West Carney Field in Oklahoma.
The implications of understanding the mechanism are enormous. Although we only concentrated on Hunton Formation in one county, Hunton formation extends over 2 million acres in Oklahoma alone. Similar formations also exist in other states, which were deemed unproductive in the past. By correctly understanding the production mechanism, the viability of producing from other similar formations can be better investigated.
A Study of Steam-Assisted Gravity Drainage Performance in the Presence of Noncondensable Gases
Authors: Canbolat Serhat , Serhat Akin , Kovscek Anthony R. 
Published: December 2007

Abstract
Traditionally, the addition of a non-condensable gas to steam is known to have a beneficial effect on heavy-oil production when conventional vertical wells are used. Little information and experimental evidence exists regarding the effect of the addition of such gases in the steam assisted gravity drainage (SAGD) process. The limited literature suggests that the addition of small amounts of such gases (e.g., carbon dioxide) may improve oil recovery. The gas accumulates at the top of the reservoir and provides a thermal and pressure insulation effect that in turn limits the rate of front spreading at the corners of the steam chamber.
In order to investigate these phenomena, SAGD experiments with and without carbon dioxide injection were conducted in a physical model. It is packed with crushed limestone premixed with a 12.4° API heavy-oil. Temperature, pressure and production data as well as the asphaltene content of the produced oil were monitored continuously during the experiments. It was observed that for small well separations as the amount of carbon dioxide increased, the steam condensation temperature and the steam-oil ratio decreased. The heavy oil became less mobile in the steam chamber due to lower temperatures. Thus, the heating period was prolonged and the cumulative oil recovery as well as the recovery rate decreased. In this instance, the produced oil contained a relatively high concentration of asphaltenes. This supports the observation of poorer oil recovery as the fraction of carbon dioxide injected increased. A large asphaltene fraction in mobile oil serves to maintain high viscosity. On the other hand little or no change in oil recovery and oil recovery rate was observed for larger well separations regardless of the fraction of carbon dioxide in the injection gas. Similar behavior was observed when n-butane was injected along with steam instead of carbon dioxide. The impact of initial gas saturation (carbon dioxide or n-butane) was also investigated. It was observed that cumulative oil recovery, rate of oil recovery, and steam-oil ratio decreased independent of well separation compared to a reservoir with no initial non-condensable gas.
Fluid Flow Control Using Magnetorheological Fluids
Authors: Zitha P. L. J. , Wessel F. 
Published: December 2007

Abstract
Magnetorheological fluids (MRFs), i.e. suspensions of ferri- or ferromagnetic particles in a water or an oil-based carrier fluid, stabilized by a surfactant or polymer, are deemed suitable for fluid flow control in oil and gas recovery operations. This paper reports a laboratory study on the rheology of oil-based MRF and its influence on oil and water flow in cores. Two types of experiments will be discussed: (a) flow of an MRF in a tube and (b) flow of oil or brine in sand-packs previously saturated with a MRF. In both types of experiments, the flow rate and the strength of the magnetic field were varied.
Tube flow experiments show that MRFs can be characterized by yield point and, above the yield point, by a shear-thinning behavior. In the presence of a magnetic field the rheological parameters change drastically leading to a gel type of behavior. On one hand, the yield point and the plastic viscosity increase strongly and, on the other hand, the power law exponent decreases and then levels off to a plateau. We propose a simple rheological model conveying these features.
On the core side, residual resistance factors (FRR) in the order of a few thousand were obtained under moderate magnetic fields. For a fixed magnetic field, the FRR for oil is lower that that for water by at least an order of magnitude. The data suggest that magnetorheological fluids are efficient flow control systems that could be used to maintain pressure in the well at a certain level (e.g., to prevent a "blowout"or leakoff during drilling), to reduce circulation loss or to reduce water production in hydrocarbon wells.
Hydraulic Fracturing Improves Recovery in a Layered Reservoir Under Waterflood in Kazakhstan
Authors: Shaoul Josef , Folmar Edgar , van Gijtenbeek Klaas 
Published: December 2007

Abstract
This paper presents a case study of a successful hydraulic fracturing campaign in the Arman field in western Kazakhstan: the first large scale campaign ever performed by a western service company in Kazakhstan. The Arman field is a mature field, originally delineated in Soviet times, and currently producing from four of the original vertical wells, and from newly drilled deviated (30 to 60 degree) wells. The field is currently under waterflood in three of the producing zones, but formation water is also being produced from wet zones. There is significant gas production, since the wells are all producing below the bubble point, either with ESP's or rod pumps.
We believed that hydraulic fracturing had good potential for stimulation in this field since most of the wells were producing with a positive skin. In addition to the positive skin, the reservoir was normally pressured, and also depleted in some zones, limiting the amount of drawdown to about 1000 psi. The wells were also producing water and gas in addition to oil, which further reduced the oil production (by a variety of mechanisms).
In this paper, we first describe the hydraulic fracturing operations, and the specific actions taken to deal with difficult features of this reservoir. We then examine the production mechanisms in the reservoir and compare the pre and post-fracture production data. Finally, we evaluate the effectiveness of hydraulic fracture stimulation as a method for improving oil recovery in this type of moderate permeability reservoir under waterflood.
Some Aspects of 4-D Seismics for Reservoir Monitoring
Authors: Marschall Roland , Sherlock Donald 
Published: December 2007

Abstract
This contribution demonstrates how the seismic technique can be a valuable tool to improve the accuracy of simulation predictions and optimize the efficiency of hydrocarbon production. We illustrate how time-lapse 3D (or 4D) seismic can be used to monitor the movement of oil-water contacts and map changes in saturation throughout a reservoir over discrete intervals in time.
Quantitative data can be extracted from the monitoring quantity, i.e. either seismic amplitude data or acoustic impedance data, depending on whether the flow regime being considered is segregated or diffusive. For segregated flow conditions, 4D seismic can be used to monitor the movement of the oil-water contact (OWC) in time and space. It can also clearly identify undrained compartments of a producing reservoir and be a valuable guide for planning new wells. Potential problems such as coning can be ‘seen’ prior to water breakthrough and be prevented by controlling production and injection rates. For diffusive flow, where there is no explicit OWC, acoustic impedances can be used to map changes in saturation and evaluate areal sweep efficiency.
Two examples are discussed to illustrate 4D seismic monitoring of segregated and diffusive flow respectively. The first example is from a sandstone reservoir at 1600m depth in the North Sea, with porosity of 27% and permeability of 4 Darcy. The second example is of an inverted 5-spot water flood pilot project, where 4D seismic was used over a time span of 6 months for a 90m thick carbonate reservoir at 2000m depth, with porosity of 21% and permeability of 31mD. We will also show results of two physical fluid-flow models where air and kerosene were injected and monitored with 4D acoustics under controlled conditions. These results serve as an impressive demonstration of the ultimate resolving power of the seismic technique in measuring actual flow in a reservoir.
Field Evaluation of Different Recovery Processes in Zone 4 of the Prudhoe Bay Field
Authors: McGuire P. L. , Foakes A. , Spence A. P. 
Published: December 2007

Abstract
This paper summarizes the core analysis data and the reservoir simulation history match of two Zone 4 cores in areas of Prudhoe Bay that were produced by different recovery mechanisms. It also describes the process comparison studies and the updip waterflood and miscible gas flood field-tests which resulted from those studies. One Zone 4 core was taken in the gravity drainage area and one Zone 4 core was taken in the waterflood/WAG area. Both cores were history matched with a reservoir simulator to reproduce the measured oil saturations and to determine the ultimate recovery potential of the process currently being employed. The success of the simulations in matching the actual core data increased our confidence in the accuracy of the ultimate recovery forecasts. Additional simulations were run to evaluate converting part of the updip portion of Zone 4 from gravity drainage to some form of water and/or miscible gas injection. These simulations indicated that the gravity drainage process was leaving high oil saturations behind the gas front that could not be produced economically because of excessive gas-oil ratios (GORs). Both water injection and miscible gas injection mobilized large volumes of oil and dramatically reduced GOR. This behavior has been observed in early field-test results.