bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of Production Logging Technologies and Capabilities: In Quest to Know the Unknown, A Brownfield Case Study, Mumbai High, ONGC Western Offshore
Authors: Chandra Yogesh , Ogra Konark , Verma Vibhor , Pandey Arun , Sinha Ravi , Kumar Ajit 
Published: March 2012

Abstract
Production logging traditionally has been used to describe the flow characteristic of a well. Over the years with the advancement of the technology, for the techno economic success, deviated and horizontal wells have been drilled. Application of highly deviated and horizontal wells for field development primary recovery is now a worldwide practice.
Diagnosing production problems in a near horizontal environment is a herculean task; complex flow regimes in highly deviated well aggravate complications. At the same time, with advancement in completion system design, it has become imperative to evaluate the effectiveness of the new completion design. Unfortunately traditional production logging techniques have not been successful in these conditions.
One of the key issues in diagnosing production problems is detecting and distinguishing hydrocarbons in high water cut wells with water phase flowing as continuous medium at the low side and dispersed hydrocarbon phase at the high side of wellbore. Technologies like the digital entry fluid imaging tool and gas holdup optical sensor tool have proven to provide accurate results. For horizontal and highly deviated wells where recirculation, crossflow, and phase segregation further complicate the flow behavior, complete imaging of the wellbore is needed to characterize the wells.
In brownfield scenario, the complications aggravate and may require real-time decision making and intensive data analysis. Some of the typical brownfield issues are scale buildup due to immense water injection for pressure support, which is required for efficient oil displacement, complex fluid flow regime, recirculation due to insufficient lift, and casing damage resulting in unwanted formation water entry.
The study provides the most prolific summary and guide for case studies, success stories and lessons learned from the Mumbai High field in the last decade; evolution of the production logging tool from the most standard unit to multipoint digital entry fluid imaging, gas holdup optical sensor tools to identify and distinguish between the three fluid phases. The paradigm shifts towards the key technologies like flow scan imager to evaluate the complex borehole fluid behavior, flow regimes identification is also presented in this paper. The results derived are indispensable for future well placement campaign
Innovative Subsea Intervention Plan to Avoid Production Loss-Case Study
Authors: Reddy Shiva , Rama Sumit 
Published: March 2012

Abstract
The D1D3 gas field in Krishna Godavari basin has deep water Subsea structures namely well, manifold, Subsea Distribution Assembly (SDA), Deep Water Pipeline end manifold (DWPLEM). These structures will be monitored and controlled by a Subsea Control Module (SCM) installed on each particular structure and the top side Subsea control system "iconSCU" supplied by Aker Kvaerner Subsea, Aberdeen. All SCMs have redundant Subsea Electronic modules (SEMs) with Fiber Optic communications (FO) & back up combined power signal (CPS) links connected to the top side monitoring system. SCM is a critical part of each subsea structure and if required may need to be replaced as and when failures are evident. For changing the Manifold SCM the associated flowing well to the specific manifold requires to be shut-in because the power supply to the associated well SCM is through manifold SCM via Electrical Distribution Box and hence causing production loss. To avoid this production loss, an innovative approach has been developed. The highlight of this approach is SCM change-out without taking any shutdown of the flowing wells or interrupting the production by using redundancy of communication and power to the manifold and well SCM in real time. While design was such that shut in of all wells for each associated manifold would be required to replace a manifold SCM, the approach described in this paper will illustrate how use of redundant power paths are used to keep all production online, while changing the manifold SCM. This necessitates designing and subsea installation of electrical distribution box/EFLs on a Deep Water Manifold while maintaining production.
Multi-dimensional NMR Technique for Wireline Formation Tester Sampling Optimization and Perforation Strategy Determination in a Brown Field, India
Authors: Ghosh Arnab , Klimentos Theodore , Singh R. K. , Nangia Viraj , Malik Sonia , Ghosh Krishnendu , Bhattacharya Shyamal , Chadha H. K. 
Published: March 2012

Abstract
The Neelam field is situated in south-east of the giant Mumbai High oilfield in western offshore basin of India. This field was discovered in 1987 and has been put under production since 1990. The field is presently under active water injection and the average oil production from the study area is approximately around 100 BOPD with 95 percent water-cut.
Perforation strategy determination in a brownfield carbonate reservoir under extensive water injection is very challenging. Fluid identification is critical in these reservoirs. Wireline formation tester sampling at defined depths can be very useful for downhole fluid identification. However, the sampling is a stationary measurement and depends on successful communication with the formation fluids. Multi-dimensional nuclear magnetic resonance (NMR) data can efficiently optimize the wireline formation tester operations in such critical wells by using continuous porosity and permeability at various depths of investigations. Additionally, resistivity independent fluid typing and saturation results from NMR analysis at different depths of investigation can be used to optimize the perforation strategy.
Our study established a workflow for designing an efficient completion plan and perforation strategy by integration of multi-dimensional NMR and formation tester wireline logging technologies in a single acquisition run in the Neelam field. However, the workflow is applicable to similar reservoirs elsewhere in the world. The objective was to enhance oil recovery and reduce water-cut and rig-time. NMR data were used to optimize the formation tester operations by identifying possible tight zones. Moreover, the NMR saturation profiling results provided continuous fluid typing and fluid saturations at different depths of investigations. Formation tester fluid sampling was carried out at discrete station depths in the same run after NMR acquisition; the formation tester station measurements of reservoir mobility and in-situ fluid analysis were then used to validate the continuous NMR log derived fluid characterization and permeability. Based on all this integrated workflow and timely analysis the best possible completion strategy was decided and perforation intervals were optimized. The well is presently producing around 270 BOPD with a 30 percent water-cut.
Advances in Invert Emulsion Performance through Novel Emulsifier Chemistry
Authors: Young Steve , De Stefano Guido , Lee John 
Published: March 2012

Abstract
As wellbores continue to be drilled deeper and farther than ever before, the need for improved drilling fluid systems that optimize fluid performance in harsh and challenging environments is at its highest demand.
Invert emulsion fluids are frequently chosen due to their high performance and low risk in various applications. Invert fluids are a particularly good choice when dealing with extreme environments, such as those with surface temperatures as low as - 26C (-15F) or those wells having bottom hole temperatures in excess of 250C (485F). Invert fluids are typically the preferred choice over water-based alternatives in deepwater and extended reach wells because of their inherently better lubricity and improved wellbore stability. The most important component of the invert fluid is the surfactant package, which maintains the solids in an oil-wet state, assists in filtration control, and stabilizes the internal phase of the fluid.
The latest developments in surfactant chemistries designed for invert emulsion fluids has resulted in a significant improvement in the performance of these fluid systems. Newly developed systems allow for simplified engineering due to formulation flexibility across temperature and density, high internal phase ratios with low viscosity, emulsion stability at temperature extremes, and a greener chemical profile. Each of these has a positive effect on drilling economics, environmental compliance, logistics, and health and safety.
This paper will review the new surfactant technologies, describing both their advantages and drawbacks from the standpoints of drilling performance and applicability, showing example data leading to these conclusions. The authors will also review the recent field usage of the surfactants described.
Flow Assurance Challenges - FPSO Based Development of MA Deep Water Field
Authors: Singh Sunil Kumar 
Published: March 2012

Abstract
MA (D-26) field in KG DWN 98/3 (KG D6) block is located on East Coast of India, about 60 km away from the Onshore Terminal (OT). This is India’s first deep water oil and gas field developed and being operated by Reliance Industries Limited (RIL). The water depth in this field varies from 1100m to 1400m. This field was put on production through FPSO in September 2008 and production was gradually ramped up to 35,000 BOPD and 8.5 MMSCMD gas.
MA field had major flow assurance challenges of hydrate formation, wax and scale deposition and slug flow. This paper describes the strategy adopted to address the flow assurance challenges and the lessons learnt from practical field experiences related to three distinct areas of MA field operations:Field start up and production from wells through the subsea manifold and risers.Changeover of gas injector well into a producer.Gas export from FPSO to Onshore terminal.
The initial startup of the field highlights the importance of having a suitable fluid in the production tubing to minimize the J-T effect across the subsea choke to prevent hydrate formation. Startup of a well also posed slug handling challenge which was mitigated by using topside chokes and adequate slug handling capacity of separators. The hydrate management strategy developed for successfully managing the shutdown and start ups within the available cool down period of 4-5 hours for MA field is discussed.
Changeover of gas injector into gas producer had its challenge of understanding the well bore temperature dynamics. Continuous injection of methanol at the well head of the changeover well was resulting in carryover of methanol in the crude oil/gas at the FPSO which called for a relook at the hydrate management strategy.
Comparison of the options of flowing the dehydrated gas in trunk pipe line containing pre commissioning fluid (MEG-Water) vis a vis vacuum drying of the trunk pipeline for gas export from FPSO to Onshore Terminal is discussed and the field experience is presented.
Use of Amplitude Inversion in Facies Characterization and Appraisal of a Deep-water Gas Discovery: A case study
Authors: Arsalan Syed. I. , Sharma Sandeep 
Published: March 2012

Abstract
Deep water reservoirs, in general, exhibit wide variation in facies characteristics because of their complex depositional processes and sedimentation pattern. Characterization of these reservoir facies with respect to their spatial extension and property distribution, during the appraisal phase particularly when the well control is sparse, is quite challenging and difficult.
This paper, through a case study, discusses about an approach where amplitude inversion and the inverted data volumes are used in the characterization and appraisal of a gas discovery in the lower slope deep-water Miocene channel-lobe complex in the east-coast of India that has only four drilled wells in 150 sq.km area. A combined inversion of three seismic angle stacks into P-impedance, S-impedance and Vp/Vs is performed and a Gas Indicator Index (GII) volume is generated which proves to be a reliable attribute for identification and mapping of reservoir facies. Using the GII and S-Impedance volumes in combination, the reservoir facies geometry and quality are mapped, that are observed to be consistent with the geological interpretation.
CBM Prediction: A Case Study of Field Scale Development in Bokaro Basin, India
Authors: Roy Kalyan Kumar , Parulkar S N 
Published: March 2012

Abstract
CBM is likely to address in a limited way the world's growing energy needs. In India the epicenter of such a process is geographically active in the east, predominantly known for conventional coal mining. Devoid of any known natural gas resource, the area though conducive for CBM production, commercial prediction needs utmost care and caution, as supply commitment is never equipped with fall back option. The geological model thus for Barakar Formation of Bokaro Field is defined with reasonable confidence for three potential CBM seams assessed through 3 vertical wells with a deliverability 10,000 m3/d for the first tested well. Proven CBM potential volumes estimated thus needs to be translated into a way forward programme of monetization firmed up through simulation based profile.
A comprehensive full field dual porosity/permeability simulation model, incorporating Langmuir isotherm and GC data generated across the geographical spread is built to understand the process intricacy. Effort to history match the initial Qw with time in all CBM simulation as a depressurization event is a difficult proposition as interruption in Qw, coupled with Wp bookkeeping are often very subjective. However, permeability/volume modifiers within acceptable limits led to replicating near history of Qg and Gp. The prediction was QC'd on single well forecasting basis through other commercial software, and the profiles though identical was in substantial variation in gas breakthrough timing, the possible reasons identified as a learning for the future.
Field scale development with an optimized variant of 38 vertical wells at 60 acres well spacing envisages peak Qg of 1.3 LCMD and RF being 32% after 15 years. The criticality is however well scheduling designed to cater to the industry needs of a reasonable plateau period.
This paper assimilates the lessons learnt from the applications of simulation to be used for devising field scale CBM development strategy and is suggestive of the Do's and Don'ts of initial data generation and lists caution in the prediction specially the depressurization process, well spacing criteria, drilling schedule for plateau generation.
Advanced Application of Borehole Images and Acoustic Logs in Building Robust Geomechanical Model for Tapti-Daman Field, Western Offshore India
Authors: Kumar Rajeev , Rao Dhiresh Govind , Parashar Sarvagya , Swain Saraswat , Sikdar Koushik , Majithia P P , Suresh G. V 
Published: March 2012

Abstract
Tapti-Daman is one of the established prolific gas producing clastic sub-basin in offshore Mumbai, India. Paleo-Miocene shallow sands are the dominant reservoir in this area. Drilling surprises have been observed frequently in this area due to geomechanics-related wellbore instability. We present a case study showcasing detailed analysis and integration of multi-well advanced acoustic and borehole image data set. Considering the uncertainty with the variation in stress regime on well basis as compared to regional geological setting, it becomes critical to identify stress regime in order to optimize mud weight programme to drill high inclined wells where safe mud weight window becomes narrow. The borehole image analysis leads to identification of breakouts and drilling induced fractures which reveal horizontal stress directions whilst sonic anisotropy analysis provides more robust insight on maximum horizontal stress direction based on fast shear azimuth. In addition, radial profiles of fast shear and slow shear were used to invert and determine absolute values of maximum and minimum horizontal stress magnitudes. Integration of the high resolution data set reveals the present day stress regime of the study area is strike slip (σH&gt;σV&gt;σh) regime. Using the quantitative values of horizontal stresses determined at different depth intervals, a post-drill Mechanical Earth Model (MEM) was developed to perform history matching of predicted failure with observed drilling events. This model was then validated with another well in the field which clearly demonstrated the value addition of the sonic answer products and image analysis. Similar workflow can be adopted to address sanding propensity to optimize completion design to mitigate or manage sand production.
A New Generation of Flat Rheology Invert Drilling Fluids
Authors: Young Steve , Friedheim Jim , Lee John , Prebensen Ole Iacob 
Published: March 2012

Abstract
Flat Rheology Invert Drilling Fluid (FRIDF) has been successfully used for deepwater drilling due to its outstanding performance in providing excellent hole cleaning, temperature-independent rheology profile, good barite sag control and good ECD control. The high performance is achieved by using correct combinations of emulsifier, wetting agent, rheology modifiers and supplementary viscosifiers. Because of the multiple products used, the FRIDF can be complex to engineer and manage. An improved and simplified flat rheology system has been developed to aid in the field engineering and ease of system maintenance without sacrificing fluid performance.
The newly developed flat rheology system utilizes a single emulsifier component to provide dual functions of emulsification and surface wetting. This helps to improve emulsion stability and enhance thermal stability and fluid lubricity. The system can be formulated for deepwater applications with mud weights up to 18.0 lb/gal and temperatures up to 350°F. In addition, the system uses a new rheology modifier that provides a temperature-independent rheology profile for hole cleaning, barite suspension, ECD management and lost circulation control.
Recent field trials indicated that the new system is easy to maintain and provides good fluid performance in terms of drilling rate, ECD management, lost circulation control and hole cleaning. Even when the system was contaminated with a severe saltwater flow, there were no fluid-related problems before the synthetic/water ratio was restored. The new fluid system exhibited flat rheology profiles and non-progressive gel structures. Hydraulic modeling showed excellent hole cleaning with low ECDs and breaking-circulation pressure. This resulted in a noticeable reduction of lost circulation potential in lost circulation prone areas. The performance of the new flat rheology system (NFRS) also will be compared to the current system to demonstrate some advantages of the new system.
The Evolution of Completion Designs Using Alternate Path (Shunt-Tubes) Technology
Authors: Saebi Shahryar 
Published: March 2012

Abstract
Alternate Path* (shunt-tubes) technology has been available to the petroleum industry for well more than a decade. Its applications have expanded over time around the world ranging from single-zone cased-hole gravel packs to multizone gravel packs or frac packs and openhole gravel packs. The recent advances have expanded applicability from specialty gravel packing to a general, all-purpose technology with huge benefits. Its flexibility permits use in extremely challenging environments, allowing completions previously considered difficult or impossible.
Development of multizone packers (cup type or swellable) has helped to push the envelope for Alternate Path technology both for cased-hole and openhole applications. This technology has enabled operators to not only perform multizone gravel-pack and frac-pack completions, but also provide solutions for gravel packing in exceptional conditions such as gravel packing a new zone in presence of open perforations in the zone above, isolating unwanted zones while completing new intervals, or gravel packing in exceptional well geometry.
This paper provides a review of the recent unique completions using a shunt-tube system to overcome complicated well completion challenges and expand the limits of using this technology further.
Quick Drilling Decision Based on LWD and Downhole Fluid Profiling in a Horizontal Well - A Case Study in a Mature Carbonate Field
Authors: Kumar Ajay , Shanker Vivek , Tellapaneni Prasanna 
Published: March 2012

Abstract
Realtime formation evaluation is critical not only for various geomechanical applications but also for quick drilling decision making in both exploration and development scenarios. The study focuses on a horizontal development well in a carbonate field which has a thin oil column overlain by a large gas cap. Large exposure multi-lateral development wells are used to improve drainage of the oil column by reducing the tendency for gas coning.
The real time formation evaluation proved formation fluid in the landing section as gas, and as a result a quick decision was made to change the well trajectory. The well was drilled 20m down in TVD as a pilot well to perform down hole fluid profiling using the Modular Formation Dynamics Tester (MDT), however, MDT could not be carried out due to heavy mud losses and the well was plugged. Finally, it was decided to sidetrack the well.
MDT with Live Fluid Analyzer (LFA) and Compositional Fluid Analyzer (CFA) was deployed to perform downhole fluid profiling in the side tracked well to identify the hydrocarbon type and composition at 3 stations. With the help of inclinometry information well trajectory and probe orientation were monitored so that sampling points were selected with probe on the high side of hole and outside of sumps if present. Fluid scanning stations using CFA/LFA clearly indicated the fluid type as gas. Fluorescence was monitored in real time to ensure that gas samples were collected above dew point. Samples collected at 3 depths were examined at surface and to confirm the CFA result. The CFA provided the C1, C2-C5, C6+ weight fractions, GOR and apparent hydrocarbon density in real-time. The fluid analysis recorded by the CFA matched well with the known gas composition and fluid density after corrections for mud filtrate were applied.
This paper shows the importance of LWD in terms of quick real-time decision making over wire line logs which are recorded after the well is drilled up to target depth. The downhole fluid profiling in sidetracked well helped in taking quick decision as not to drill further.