bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shallow Azimuthal Measurements A Step Towards 3D Petrophysical Evaluation in Thin Reservoirs
Authors: Daghar Khadija Ahmed , Sayed Raza Hassan , Abdelaal Atef Farouk 
Published: February 2011

Abstract
Petrophysical evaluation in horizontal wells using standard logging while drilling (LWD) data is challenging, especially in thin reservoirs (~ 4 ft) bounded by dense resistive formation. These challenges are predominately associated with the propagation deeper depth of investigation (DOI) resistivity measurements and limitation in recording azimuthal data around the borehole.
In thin reservoirs the currently used electromagnetic (EM) resistivity tools with deeper DOI are usually affected by proximal beds which results in inaccurate saturation estimation for the target zone. Add to that, the traditional way of computing saturation using average porosity and resistivity measurements neglecting the variation around the borehole; this may result over/underestimating the water saturation which is an important factor in the STOOIP calculation.
This paper will discuss a "3D Petrophysical" approach utilizing a new technology that provides shallow azimuthal resistivity measurements around the borehole. The approach is used in integration with the available methodology of utilizing azimuthal density data to capture the variation in water saturation (Sw) around the borehole in thin heterogeneous carbonate reservoirs.
The Effects of Low-Permeability Mudcake on Time-Dependent Wellbore Failure Analyses
Authors: Tran Minh H. , Abousleiman Younane N. , Nguyen Vinh X. 
Published: February 2011

Abstract
The effects of filter cake buildup and filter cake properties variation with time on the wellbore stresses and wellbore stability have been plaguing the industry for long. The increasing use of lost circulation materials (LCM) in recent years for wellbore strengthening in weak and/or depleted formations nessesitates real-time models that can predict these effects. However, the complexities of effective stresses and pore pressure real-time evolution, i.e. while drilling, coupled with the time-dependent properties of mud filtration have delayed such modeling attempts. In this paper, the analytical solutions for the time-dependent coupled effects of mudcake buildup on the wellbore stresses and formation pore pressures controlling wellbore collapse and fracturing are derived. The transient effects of mudcake buildup, mudcake permeabilities, and mudcake buildup coupled with its permeability reduction during filtration on the safe drilling mud window were illustrated through numerical examples. The results showed that the safe mud weight windows are greatly affected by the buildup of filter cake and its permeability variation. In particular, the analysis for the mudcake with permeability of 10-2 mD showed a widening of safe mud weight window by 0.9 g/cc after 2.5 hrs post excavation compared to that of a wellbore without mudcake. On the other hand, analysis with a 10-3 mD mudcake showed a widenining of mud weight window by as much as 1 g/cc. In addition, analyses revealed that even for mudcake permeability as low as 10-3 mD neglecting the permeable nature of the mudcake results in overestimation of the safe drilling mud weight window.
Gyro-While-Drilling Technology–Solution for Directional Tophole Drilling
Authors: Kasumov Ruslan , Houvet Joris , Kasumov Timur 
Published: February 2011

Abstract
A new borehole surveying technology, gyro while drilling (GWD), provided benefits for Sakhalin Energy Investment Company Ltd. (Sakhalin Energy) when used on two multiwell offshore platforms with only 2.5 to 3 m spacing between well slots. Such narrow slot spacing makes it impossible to get good MWD surveys while drilling top hole because nearby casing magnetic interference results in extremely high collision risk. Conventionally, this risk is mitigated by using wireline single-shot gyro and drop gyro, but both of these methods have drawbacks, such as extra personnel involved in wireline operations, additional rig time, and higher risk of stuck pipe. GWD was used to survey 30-in. conductors, already driven in place at the start of the campaign, and to survey 17.5- to 24-in. tophole sections. To date, 15 top holes have been successfully drilled and surveyed with this technology, with significant savings in rig time and reduced personnel on board (POB) due to the lower number of personnel needed in comparison with conventional wireline gyro surveys.
This paper intends to raise the awareness of the oil and gas industry about the new GWD borehole surveying technology, which has been proven to be reliable and which requires much less rig time and fewer POB for the job.
The overall results after 15 top holes drilled are: 12.6 rig days saved due to reduction of surveying time, reduced HSE exposure by eliminating wireline operations, improved platform POB while drilling top holes, and increased precision of the BHA steering by bringing the direction and inclination (D&I) package closer to the bit.
In this project, GWD technology has proven its ability to reduce rig time while providing close-to-the-bit and accurate D&I measurements, which is essential for drilling directional top holes in offshore environments. A full field data analysis details the significant rig time reduction and reduced POB when using GWD technology versus conventional wireline single shot and drop gyros.
GWD technology can be applied as a solution to any offshore project where using gyro surveys is inevitable because of a crowded well setting that makes the use of conventional MWD tools impossible.
Undersaturated Tagai Oil Reservoir Evaluation And Development, West Siberia, Russia
Authors: Parnachev Sergei , Molodykh Pavel , Mezentsev Dmitriy , Anop Alexander 
Published: February 2011

Abstract
Example of integrated study including adapted laboratory research program and reservoir engineering is provided. Results received are to be of interest of reservoir engineers and geologists especially in view of numerous low permeable oil fields’ production in low-amplitude closures. Combination of independent analysis techniques allowed detecting undersaturated type of Tagai reservoir. Oil displacement efficieny test was realized under specified oil saturation similar to log interpretation results. Resulted displacement efficieny values allowed previous oil recovery factor reduction as well as recoverable reserves by 30 percent, the latest were approved by State Authorities in 2009. Description of saturation estimation technique with undersaturated reservoir laboratory model formation is provided in the paper as well as laboratory research program. Advanced field development experience and iterative laboratory research program resulted in atypical level of interaction between laboratory and engineering departments based on complex geology understanding and modern reservoir engineering methods. Especial importance of implemented laboratory research consists in conception of undersaturated reservoir estimation, modeling and field development planning because of their quantity and distribution underevaluation at least at West Siberia.
Artificial Lift Practice for Heavy Oil Production with Sand Control
Authors: Petrov Alexander , Mikhaylov Alexander , Litvinenko Konstantin , Ramazanov Rustem 
Published: February 2011

Abstract
The goal of present study was to develop and test a new algorithm to selection proper artificial lift method for heavy oil production with sand control. We developed a Matrix of technologies for such oilfields using operating experience worldwide. For selected methods we defined production characteristics using Technology Application Template - a special tool which determines the most profitable artificial lift system based on net present value criteria. Solutions were implemented in North Komsomolskoe field located in Western Siberian basin.
Before performing calculations we defined the following: ■Oilfield characteristics■Well parameters■Limitations of artificial lift methods■Operational expenses for each artificial lift method
Recommended methods were tested on vertical wells of North-Komsomolskoe oilfield pilot area and on remote horizontal well in the north part of the field. The highest rate was reached using progressing cavity pump on horizontal well. On vertical wells of pilot low productivity area gaslift and hydraulic jet pump (which are economicaly efficient) have been successfully tested.
This paper describes combined analytical and operational approach for complicate field development.
Real-Time Bit Wear Optimization Using the Intelligent Drilling Advisory System
Authors: Rashidi B. , Hareland G. , Tahmeen M. , Anisimov M. , Abdorazakov S. 
Published: February 2011

Abstract
Real-time tools and techniques have recently been used in drilling operations to minimize time and cost, thus improving drilling performance. The real-time drilling data transmission and analysis, from a remote server to an office location, plays an important role in the drilling optimization process. The drilling engineers can provide their expert opinions to the rig personnel, thus increasing drilling efficiency as well as reducing the associated risks. It has been shown that associated drill bit problems can greatly affect total drilling efficiency. Among them, bit wear while the bit is still in the hole can highly influence the operation if it is not properly analyzed. This paper describes the real-time application of a developed model for bit wear analysis. The model was developed based on the differences between rock energy models, Mechanical Specific Energy (MSE), and rock drillability from rate of penetration models. It has been modified and implemented as an engineering module in the newly developed software, Intelligent Drilling Advisory system (IDA's), and is used to estimate real-time bit wear for both rollercone and PDC bits. The drilling data is retrieved by the software from a remote server for the analysis. The data is subsequently quality controlled before calculating instantaneous bit wear while the bit is in the hole. In this study, bit runs for two offset wells in Alberta, Canada, will be analyzed in detail using the software module. Similarities between the recorded bit wear outs reported in the field and the simulation results indicate that the procedure can be used for bit wear estimation with good accuracy. This engineering software module could be used to identify unnecessary tripping which will result in time and cost reductions as well as an additional tool to aid in estimating bit wear status while drilling.
Soft Multiphase Flow Metering for Accurate Production Allocation
Authors: Lorentzen Rolf J. , Nævdal Geir 
Published: February 2011

Abstract
Distributed temperature sensing (DTS) based on fiber-optics has successfully been applied for injection monitoring, see e.g. [1, 2], as well as production monitoring, see e.g. [3]. In the current paper we combine a transient well flow model and the ensemble Kalman filter into a tool for interpretation of high frequency downhole temperature measurements. Our case study clearly demonstrates the feasibility of automatic identification of reservoir influx distribution from temperature measurements.
Using Hydrajet Perforating Technique as an Effective Alternative to Explosive Perforating for Algerian Oil and Gas Fields
Authors: Kritsanaphak Kritsana , Tirichine Salah , Lamine Abed Mohamed 
Published: February 2011

Abstract
Hydrajet perforating (HJP) has been used in the oil industry for several decades to perforate or slot through casing by high-pressure abrasive jetting, which generally is not cost effective compared to conventional explosive (shaped-charge) perforating. However, within the Algerian oil fields, perforating using explosives has become time consuming and costly because of the strict security requirements associated with explosives. Operators commonly encounter delays in getting the explosives, varying from one week to one month, causing loss of production time and added standby costs for the rig and associated service equipment. Therefore, a nonexplosive solution like HJP has great value as an alternative to explosive perforating.
HJP, which forces highly pressured abrasives through jets to impinge/penetrate casing, cement, and formation, can be deployed on coiled tubing (CT) or jointed pipe. Typical penetration depths of 5 to 8 in. can be achieved, depending on the formation characteristics, tool configurations, pressure differential through the jet, and stand-off of the tool inside the casing. Perforation diameters from 0.75 to 3 in. have been achieved, as indicated by field tests and image logs run after perforating. This process has been developed and optimized for various applications, such as perforating for production, remedial cementing, or for hydraulic fracturing. It also has often shown advantages over explosive perforating, not only on a technical level but also from an economic perspective.
Therefore, hydrajet perforating is a valuable alternative to explosive-perforating techniques and does not require special authorizations for transportation and handling. This technique has benefited several operators in Algeria, saving cost and time, and also providing other advantages. This paper presents various applications of this technique and how it became an effective alternative to explosive perforating in several case histories from Algeria.
Casing While Drilling (CwD); A New Approach Drilling FIQA Formation in the Sultanate of Oman. A Success Story
Authors: Sánchez F. , Turki M. , Nabhani Y. , Cruz M. , Houqani S. 
Published: February 2011

Abstract
The highly reactive FIQA shale used to compel well engineers in The Sultanate of Oman to plan the drilling phase of surface and intermediate sections based on time exposure to aqueous drilling fluid system (WBM). The new approach of drilling the time-dependent FIQA shale formation using Casing-while-Drilling (CwD) allows well engineers to plan prospect top/intermediate wellbore sections differently by enhancing the drilling performance and reducing the risk of setting casing strings shallower, external corrosion due to aquifers, and getting stuck or reaming continuosly while drilling conventionally. The technical feasibility study, planning, risk assessment, execution, as well as the lessons learned during the process of drilling top sections are described in this document. The CwD team compares the drilling performance of several offset wells and suggest actions to improve the CwD technology in Oman.
Two surface sections were drilled successfully with large OD casing strings. Both surface sections 17½" and 22" reached 750m and 894m measured depth, respectively, reducing drilling phase by 40–45% in comparison with the average in the field. The exposure time of FIQA to aqueous environment was reduced considerably eliminating conditioning trips and non-productive-time (NPT) associated with wellbore instability. The volume of returns as cementing increased from 20% - with conventional drillstring - to 92–98% of pumped excess volume. CwD will allow drilling teams to slim down top holes by drilling/casing much deeper sections within less time preventing FIQA from collapsing and avoiding potential applications of Oil Based Mud (OBM). This new technology may also allow the optimization of existing rigs reducing cost and size of rig prints, as well as minimize HSE risk while handling large-OD casing and extremely heavy DC’s.
Simulation of the drilling phase using torque/drag and BHA-analysis software were run. The drillable PDC bit performance is compared to bit-records from offset wells recently drilled with conventional BHA’s. The effect of CwD on resulting uniform cement sheath (related to the "smear effect") and the reduced size of cuttings at surface which positively aid on preventing flow-line plugging as an unplanned event will be described.
It is important to highlight that Nonretrievable 17½"×13⅜ and 22"×18⅝ CwD with drillable bit and the casing drive mechanism, did not require any rig modification. The optimization of the process as well as the familiarization of drilling teams with the main components of the CwD system, will lead to a long, demanding scope for its implementation in several fields in Oman.
Optimizing Methods of Profitability Assessment and Well Cluster Drilling Rating with Account of Capital Expenditures
Authors: Atnagulov A. R. , Ismagilov R. R. , Nekipelov Y. V. , Kireev G. A. 
Published: February 2011

Abstract
When assessing economic feasibility using the NPV indicator, of some importance is the order of commissioning well clusters – the earlier a prospective well cluster is commissioned, the higher the NPV. This being said, creation of an optimal well commissioning schedule is directly conducive to maximizing the project's total efficiency. Traditionally, Rosneft uses a ‘geological’ drilling rating system when making up well cluster drilling schedules; this approach is based on initial production rates. This system ignores capital expenditures, the bulk of which goes to well drilling and the associated surface construction; but quite often well clusters with high initial production rates prove less profitable owing to outweighing capital costs.
With the purpose of increase NPV of the project, it is proposed to exercise drilling of well clusters according to their economic efficiency. The initial step in field development is constructing the basic common objects. For a quick payback, it is necessary to first commission well clusters having the greatest economic efficiency. The calculation of the technical/economic rating is performed iteratively in several steps, each of which picks up a well cluster with the maximum NPV. The amount of surface facilities for each well cluster remains variable across the iterations. This approach is implemented in the company's proprietary software package.
Viscosity Influences of High Pressure on Borate Crosslinked Gels
Authors: England K.W.. W. , Parris M.D.. D. 
Published: February 2011

Abstract
Fracturing fluid formulations, testing methodology and equipment has evolved, as have industry-accepted standards for testing. These standards have undergone a number of revisions over the years, and were published first as a recommended practice under the American Petroleum Institute (API-RP39) and subsequently under the International Standards Organization as ISO-13503-1. These standards define the geometry, shear rate, temperature control and other test parameters to measure the fluid performance under in-situ reservoir conditions. Little focus was given to the pressure applied to the fluid, other to ensure that it would not be allowed to boil under the test conditions. This lack of emphasis on pressure is completely understandable, as condensed matter (solids and liquids) typically have a limited response to the pressures experienced in the wellbore or during fracturing operations. And a typical expectation for compressible fluids, oils for example, is to experience an increase in viscosity with increased pressure.
It has been found that pressures (hydrostatic and pressure applied during pumping operations) encountered during hydraulic fracturing can materially reduce the viscosity of a borate crosslinked fluid. The loss in viscosity, depending on fluid formulation, temperature and pressure, can range from negligible to catastrophic. This phenomenon has been studied using high pressure rheometry and high pressure nuclear magnetic resonance (NMR), and has only recently been published in the scientific literature.
This paper will present results from testing a variety of fracturing fluids, including polymeric and viscoelastic surfactant-based, under in-situ conditions. It will detail the results of these tests for borate crosslinked fracturing fluids, and analogues not employed in the industry.
Based on these data, it will be clear that fracture geometry and proppant placement will be influenced. This is particularly true for deepwater treatments where the in-situ pressures are very high.
Multi-Layer Steady-State Injection Test With Higher Bottomhole Pressure Than the Formation Fracturing Pressure
Authors: Davletbaev Alfred , Baikov Vitaly , Ozkan Erdal , Garipov Timur , Usmanov Timur , Asmandiyarov Ruslan , Slabetskiy Andrey , Nazargalin Eduard 
Published: February 2011

Abstract
Field A considered in this paper is an oil field characterized by low permeability and large vertical variability of formation properties. Injection and production take place in commingled multi-layer zones of Field A. Wells are hydraulically fractured across the entire stack of the producing layers. In the injection wells, the bottomhole pressure is higher than the formation fracturing pressures causing continuing growth of fracture length.
This paper discusses 60 multi-rate injection tests to determine the injection profiles in Field A. The tests consisted of continuous measurements of the bottomhole pressures for several constant injection rates. Measurements were made for three different injection periods with pressures below and above the formation fracturing pressure. Each injection period lasted until steady-state conditions were established. Layer injection rates were determined from stabilized injection profiles obtained by spinner surveys before the tests. Layer properties were determined by matching the constant injecting rates and layer pressures for multiple injection periods.
Test results demonstrated that well performances in Field A could not be described by known solutions for a constant fracture length. The non-linear relationship between the steady-state pressure and injection rate indicated that continuous change in fracture geometry had to be taken into account. These tests were useful to determine individual layer injectivities, current formation pressures and fracture opening pressures of each layer.
Based on the results, it is concluded that multi-layer, multi-rate injection tests are useful to monitor layer pressure distributions and effectively produce multi-layer fields. The Simultaneous Separate Injection (SSI) technology used in these tests provides the ability to control layer injection rates and maintain uniform production from multiple layers. The SSI technology also allows injecting controlled volumes simultaneously into several layers through one injection well. Comparison of the tests using the SSI technology and adjusted valves demonstrates redistribution of injection rates from a higher- permeability layer to a lower-permeability layer.