bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a Fuzzy System Model for Candidate-well Selection for Hydraulic Fracturing in a Carbonate Reservoir
Authors: Zoveidavianpoor Mansoor , Samsuri Ariffin , Shadizadeh Seyed Reza 
Published: March 2012

Abstract
With current technology, it is only possible to extract 20% to 25% of the original oil in place from Iranian carbonate reservoirs, 10% less than the world average. In addition, formation damage is a serious problem in those reservoirs, which mainly caused by asphaltene precipitation, sand production, and ineffective stimulation method. The majority of mature carbonate reservoirs in Iran have low permeability and high skin values. Therefore, such reservoirs are capable of producing at commercial rates only if they are hydraulically fractured. Acid fracturing is usually reported as a standard method for fracturing in carbonate reservoirs. Hydraulic Fracturing (HF) technology, which was originally applied to overcome near wellbore damage, is a proper replacement stimulation method. It is evident that to adopt this technology, considerable efforts have to be strenuous in candidate-well selection. As asserted in the literature, even though a common practice, candidate-well selection is not a straightforward process and up to now, there has not been a well-defined approach to address this process. The techniques applied in HF candidate-well selection could be divided into two methods; conventional and advanced approaches. Conventional methods are not easy to use for nonlinear processes, such as candidate-well selection that goes through a group of parameters having different attributes and features such as geological aspect, reservoir and fluid characteristics, production details, etc. and that’s because it is difficult to describe properly all their nonlinearities. However, it is believed that advanced methods such as Fuzzy Logic (FL) could be better decrease the uncertainty existed in candidate-well selection. This paper presents a Mamdani fuzzy model where rules for HF candidate-well selection were derived from multiple knowledge sources such as existing literature, intuition of expert opinion to verify the gathered information. The needs for adapting HF as replacement stimulation in Iranina carbonate reservoirs are discussed and advanced methods for HF candidate selection will be reviewed in this paper. Also, the main reasons which show why propped HF is the choice in carbonate reservoirs will be discussed. Finally, the proposed Fuzzy system model is applied along with a case study in a carbonate reservoir.
An Approach for Spreadsheet-Independent Reserves Management Tracking, Archiving, and Reporting
Authors: Al-Sumaiti Hamad , Sethi Muhammad Usman 
Published: March 2012

Abstract
The tracking and management of both resources and reserves estimations are of primary importance for any oil and gas company. When managing reserves data using spreadsheets, organizations face numerous daily challenges in reserves tracking and reporting. This technical paper discusses the implementation and methodology adopted at one of the Middle East’s leading oil and gas companies for a reserves management system free from spreadsheet-based tracking and reporting. The resulting system provides much enhanced security and efficiency in managing reserves, and improves the flexibility of reserves reporting.
Hydrate Inhibition _ Optimization In Deep Water Field
Authors: Gupta Gaurav , Singh Sunil Kumar 
Published: March 2012

Abstract
Reliance Industries Limited operates D1D3 deep water gas field in Krishna-Godavari basin in India. Water depth at well heads varies from 550 meter to 1150 meter. Horizontal Christmas trees (XMT) are installed on each well head. Hydrate inhibitor is continuously injected at Christmas tree to prevent hydrate formation occurring in the system during all operating conditions. For a properly designed system, hydrate formation should not be possible in normal operation. The only risk of hydrate formation is related to abnormal operating conditions. Hydrate management philosophy should be developed to address the risk of hydrate formation in all condition with minimum hydrate inhibitor injection.
There are always some uncertainties in measurements therefore some level of hydrate inhibitor overdosing is required. In this field Mono Ethylene Glycol (MEG) is injected to prevent hydrate formation. To optimize MEG injection, reliable water and MEG measurements are the important keys. Salinity of slug, pipeline network and different well head water depths are major driving factors to optimize MEG injection.
Hydrate curve is developed either with professional software like PVTsim or rocking cell apparatus in laboratory. In this field minimum required MEG percentage is calculated from PVTsim software. MEG optimization is continuous process and since inception of field, the level of overdosing is reduced from 80% to 15%. Wet Gas Flow Meter (WGFM) is installed on each XMT to measure water production. To verify WGFM water measurement from individual well, other methods of measurement were also developed. MEG injection valves are installed on each XMT which can measure the injection quantity. Correlation is established between different measurement techniques to consider most reliable and accurate value of water and MEG measurement which aided to optimize the MEG injection rates.
Analysis is done through software for some of wells, to find out the feasibility to stop continuous MEG injection in deep water pipeline network system. After this study, continuous MEG injection was stopped in one well. The paper will describe various steps of MEG optimization and level of confidence on hydrate management philosophy.
Asset Integrity Management in Onshore & Offshore-enhancing Reliability at KGD6
Authors: Rao A. Rama , Rao S. S. , Sharma Tata , Krishna Karra Rama 
Published: March 2012

Abstract
In the life cycle of any asset during earlier days the majority of the focus was on frequently occurring incidents whose impact may be less, but the thought process has changed keeping in mind the recent incidents in the industry. The focus has now shifted to less frequently happening incidents whose impact will be substantial some times devastating.
The aim of this Asset Integrity at KG D6 is to develop the Hazards and Effects Management Process (HEMP), which identifies and assesses HSE hazards and potential risk, implements control and recovery measures, and maintains a documented demonstration that HSE risks have been reduced to a level that is As Low As Reasonably Practicable (ALARP).
In order to achieve ALARP level we identified to carry out many activities, with the help of number of systems, for which we are taking support of number of softwares, all of which are explained in coming pages.
Implementing the elements of Asset Integrity Management (AIM) has considerably increased the reliability decreasing the recordable incident rates. This has lead to "Thousad plus days" of uninterrupted gas supply without an incident.
Integrated Control System & Human Machine Interface – Challenges for Uninterrupted Onshore & Subsea Operations
Authors: Subbarao Mandava Venkata , Srinagesh Yerramalla 
Published: March 2012

Abstract
The health and effectiveness of any Integrated Control System depends on many factors. Among these factors is the proper design, selection of Control System, seamless integration, System Architecture, System Configuration, System Integration Testing, Control System Installation, Commissioning, Site Acceptance Test, Preventive Maintenance, Predictive Maintenance, Functional Testing etc.
The integrated solution for the Onshore, Offshore & Subsea Control System includes a dedicated Subsea Control System, DCS System, ESD System, Process Simulator System, F& G System, Large Screen Abnormal Situation Management Video Wall, Measurement Systems etc.
The power to the Offshore and communication to Offshore & Subsea is through Umbilical’s. The backup communication from Onshore to Offshore is through dedicated Microwave Network. The communication from Onshore Terminal (OT) Control Room to Subsea wells is about 50 Km to 60 Km. The remote Subsea wells are Controlled and can be Shut down from OT.
The best-in-class technologies in Control & Safety was effectively implemented by deploying various protocols like Foundation Fieldbus, HART, Control Net, OPC, MODBUS TCP I/P, Serial Interface etc. The digital Control System reliably monitors and controls the over 1, 10,000 tags. All the DCS hardware is integrated with the non DCS hardware while having a common control system information. The System has the facility to provide information across the organization giving the best possible foundation for collaboration between people, processes and systems.
In such a large network of integration of technologies & integrated operations of Subsea & Onshore, identifying and minimizing control system errors are a big challenge. It is a big challenge to ensure continued operations of these facilities without any Trips.
This article focuses on Control & Instrumentation Systems contributing factors for uninterrupted Operations of Onshore/Offshore/Subsea facilities during the first 1033 days of operations & the challenges to ensure continued operations without any facility Trips.
A Study of Differences in Array Induction and Multi-Laterolog Responses in a Well Drilled with High-Salinity Water-Based Mud
Authors: Corley Bill , Khokhar Rashid , Maurer Hans Martin , Li JianZhou , Xiao Dong , Yang ShaoKun 
Published: March 2012

Abstract
High data quality and improved environmental corrections of array induction logging tools have expanded their operating range into wells drilled with high-salinity water-based mud. Multi-laterolog tools are preferred for these borehole conditions when formation resistivity is high, but if the ratio of formation-to-mud resistivity is moderate, array induction tools can be used successfully.
A fairly large region of formation resistivity and formation-to-mud resistivity contrasts exists where you would expect either array induction or multi-laterolog devices to perform well. However, each responds differently to borehole effects, near-borehole effects, and invasion.
Data from both array induction and multi-laterolog devices was acquired in an offshore well from China with low-to-moderate formation resistivity drilled with high-salinity water-based mud. In some sections of the well the drilling assembly produced a "spiral" effect with small, periodic changes in borehole size. The majority of the well had no invasion but there was shallow conductive invasion in some permeable intervals.
The differences in sensitivity to shallow conductive invasion and the significant effect of a very conductive "spiral" borehole on the array induction responses is illustrated and explained by modeling. A filtering technique to eliminate the spiral effect and improve the responses is described and illustrated. The multi-laterolog tool has no sensitivity to the spiral borehole shape.
The determination as to whether an array induction or a multi-laterolog is the preferred resistivity device should be based on more than the value of formation resistivity or the contrast between mud and formation resistivity. In some conditions one has preference, while in other conditions it would be advisable to acquire both.
Gravel Pack Evaluation Techniques to Ensure Sand Control in Deep Water Unconsolidated Gas Reservoir
Authors: Dhar Samir Kumar , Bora Ajoy Krishna , Reddy Peesu Rathnakar , Mund Bineet K , Mishra Anoop Kumar 
Published: March 2012

Abstract
Effective sand control is extremely important for production of hydrocarbons from shallow unconsolidated sand reservoir. In absence of any sand control measure installed in the well, there is high risk of Sand production along with the hydrocarbons. Sand production may result in damage of X-Mass tree and/or Sub-sea infrastructure components. In extreme cases, when the sand production goes beyond the critical limit, it may lead to a situation when the field production has to be stopped. In view of this, in Deep water environment, sand production is considered as a potential hazard. It may lead to tremendous impact on reservoir economics and sustained production from the field.
The commonly used sand control technique is to install suitable sand screens and a packing of gravel at the sand face to restrict the movement of sand particles from the reservoir to the borehole. Gravel packing can be achieved through open hole gravel pack, cased hole frac pack or simply by lowering a pre-pack perforated liner/screen. Once the gravel packing is done, it is required to know the competency of the pack to confirm its effectiveness. Gravel pack evaluation is basically done from the data acquired by a logging tool conveyed either through wireline or wash pipe below the Gravel pack assembly run on the work string.
The techniques described in the paper were applied in deepwater gas reservoir consisting of thick unconsolidated sand and thin bedded sand- shale sequences. Wireline logging was done to evaluate the pack efficiency. In the absence of a single tailor made tool or technology, four different tools were used for this purpose with various advantages and limitations. Pipe conveyed memory logging device was also used for gravel pack evaluation in few cases. The results of all the methods were analyzed and an attempt was made to find a suitable cost effective technology for the evaluation of gravel pack. No Gravel pack evaluation job was included in the initial development plan by the operator, however as the operations progressed it was found to be essential especially in Deep water environment.
This paper describes the experience of the operator with different gravel pack evaluation methods and highlights associated merits and demerits. It also describes some specific cases where gravel pack evaluation became crucial for decision making and saved the production well.
Pre-fracture Treatment of Coal Seams for Fracture Conductivity Enhancement in Hydro Fracturing of CBM Wells and Coal Fines Mitigation in Multilateral CBM Wells through Wettability Alteration of Coal Fines - A Laboratory Study
Authors: Kumar Ajay , Roy D. C. , Yadav N. , Rao Y. R. , Singhal C. P. , Kumar Ajit 
Published: March 2012

Abstract
India has sixth largest coal reserves in the world and estimated to be at 206 billion tons and it ranks 10th in CBM resources having 4.6 TCM methane gas covers 20,000 km2 of area. The CBM reservoirs is multilayered, heterogamous, naturally fractured (cleats) and having fine micro pores. Bulk porosity of the coal is very small (&lt;5%), the initial gas saturation is very low (&lt;10%) and most of the gas in coal (&gt;90%) is adsorbed in the micro pores of coal matrix and under saturated condition. Rapid dewatering is needed for reduction the reservoir pressures below critical pressure for desorption of gas from coal bed. Therefore, conventional / horizontal well with fracturing, multilateral well to cover many zones in CBM is being opted for economic exploitation. More than 60 no of conventional and horizontal/multilateral wells are drilled so far and many of them are completed with hydro-fracturing.
As coal is a weak substance and small pressure can cause the coal to fail and generate fines, hence enormous coal fines are normally produced during production (in case of high draw-down) and during hydro fracturing of coal seams. In some fracturing job, fines generation & migration reduces the fracture length and conductivity lead to reduced dewatering. Similarly, in multilateral well of CBM, coal fines are accumulated at the heel of the well in case of high draw drawdown and creating the restriction in dewatering and gas production.
In view of the above, innovative pre-fracture treatment technique with innovative formulation (Mixture Nonylphenoxy polythyleneoxide and Nonylphenoxy polythyleneoxide in the ratio of 1:2 with 0.5 % biopolymer) is developed & successfully tested in laboratory to change the wettability of the coal fine by making it hydrophobic to hydrophilic. Coal fines can easily come out with water based fluid during pre-treatment, hydro-fracturing and multilateral wellbore cleaning.
Tailpipe Disconnects Ideal for Setting Cement Plugs in Complex Wellbores; Procedures and Case Histories Provided
Authors: Rogers Hank , Poole David 
Published: March 2012

Abstract
The primary goal of operators and drilling contractors is to safely, economically, and efficiently drill more holes in less time to enable completion and production operations to begin. However, unplanned events that introduce unexpected and costly delays often occur during the drilling phase. These unplanned events must be dealt with in a timely and effective manner to enable drilling operations to continue.
One event type common to drilling operations is the need to set openhole cement plugs for plug back, kickoff, or curing loss-circulation intervals. The time and cost associated with spotting cement plugs directly impacts well operations and is often classified as nonproductive time (NPT) by operators, especially if initial plugs fail to achieve the purpose for which they were set. Placing cement plugs in today’s complex wellbores and the increased costs associated with these operations necessitates the use of plug designs and procedures that have been designed to reduce risk and utilize new technologies and documented processes to achieve the desired results. Reviewing current practices for deploying new technology helps to optimize overall plug cementing operations in both vertical and extended-reach wellbores.
However, there are a number of challenges associated with setting cement plugs in an openhole well. Most importantly, drillpipe can become differentially stuck across a lost-circulation zone, and the plug can become contaminated with the intermixing of the mud, resulting in inadequate isolation or insufficient strength.
An innovative tool (Rogers et al. 2004) has been designed to meet the challenges associated with setting cement plugs. The tool connects sacrificial/drillable tubing to the drillpipe and allows an operator to trip into the well and spot the cement plug across the problematic zone. Once cement is placed, the tool is disengaged and the operator trips the drillpipe out of the hole, leaving the cement plug and tubing undisturbed. The sacrificial tubing can be drillable; therefore, the operator can drill through the plug or commence other operations, as required.
This paper discusses the challenges operators face when setting cement plugs and how risks and NPT are reduced with this innovative plug-setting process and tool. Well examples are documented from case histories to illustrate the success and lessons learned.
Application of Microbial Treatment for Mitigating the Paraffin Deposition in Down Hole Tubulars and Surface Flow Lines of Wells- A Success Story
Authors: Biswas Susanta Kumar , Kukreti Vipin , Rana Dolly Pal , Sarbhai Munish Prasad , Bateja Surendra , Misra Tilak Ram 
Published: March 2012

Abstract
Severe wax deposition problem is encountered in down hole tubulars and at the face of producing zone in the well bore region and surface flow lines of most of the oil fields producing waxy crude. Paraffin in the crude begins to precipitate and deposit around well bore and tubulars as the pressures and temperatures decrease, frequently resulting into partial/complete blockage of crude passage and pose severe production problems. Traditional methods such as thermal, magnetic, mechanical scraping, and chemical treatment etc. are not only cumbersome, costly and hazardous but also provide temporary respite.
Use of microbes, a novel approach was conceived to find alternate effective solution. Institute of Reservoir Studies (IRS), ONGC, has developed two separate microbial systems for mitigating the vexed problem of paraffin deposition in oil wells and surface flow lines.
The microbial system for down hole tubulars comprises of paraffin degrading bacterial (PDB) consortium, nutrient supplements and growth enhancer. The bacterial consortium, is naturally occurring, micro-aerophilic, thermophilic, capable of degrading paraffin up to 90°C. Paraffin degrading ability was maximum at 55°C which is the temperature around which most paraffins get deposited.
The candidate wells having severe wax deposition problem, were selected from different fields of Mehsana Asset of ONGC. Application of the technology has been done successfully on commercial scale in 45 wells (48 jobs) of Mehsana Asset. The microbial treatment not only checked the paraffin deposition in all the treated wells but also improved oil production by 20-80% in many wells. Most of the treated wells flowed without any wax deposition for 6-8 months after the treatment. Some of the wells even flowed for over a year giving average success ratio of around 70%. Net incremental oil gain from 48 jobs was around 4000 m3.
Bacterial consortium, named as FIB-19, showing 67% wax degradation at 37°C prevents wax deposition in surface flow lines. The bacterial consortium is micro aerophilic, mesophillic and remains active upto 43°C. Application in surface flow lines of ten wells of Mehsana Asset was quite successful resulting in elimination of requirement of line flushing for considerable time along with reduction of pressure in the flow line.
Production Enhancement by Customised Hydraulic Fracturing Operations: Success Stories of Gamij Field
Authors: Medavarapu Kishore Kumar , Mahato P K , Das Santanu , Singh S K , Patel K C , Nandan Alok 
Published: March 2012

Abstract
Customized hydraulic fracturing operations in low temperature and shallow reservoirs of Gamij field of western onshore India yielded impressive post frac production gains. This paper describes in detail, the various challenges for hydraulic fracturing in Gamij field, development of fracturing fluid, execution methodology and fracturing’s vital role in production enhancement.
Successful hydraulic fracturing operations turned Gamij as one of the promising producing field. Poor reservoir characteristics, thin pay zones, presence of coal layers, shallow depths and low reservoir temperatures were the main challenges for hydraulic fracturing. Numerous lab studies carried out and fracturing fluids were customized for good rheological capabilities and postfrac gel cleanups. Frac job sizes were optimized based on sensitivity analysis carried out using frac simulators. Large size jobs were carried out in suitable candidate wells. Pre and Post frac temperature logs were taken to ascertain the fluid intake and frac confinements. Activation methodologies developed so as to bring the wells on production in minimum time.
Hydraulic fracturing jobs in Gamij field were quite successful. Fracturing jobs were carried out in 35 wells in the last two years mostly with drilling rig in position. Most of the wells came on self. Oil production up to 30m3/d in a single well was observed. Job sizes were designed based on reservoir characteristics which ranged from 60000 lb to 242500 lb. 20/40 low strength proppant pumped in these frac jobs with maximum concentration of 15 ppg. Job scheduling varied based on thickness of payzones, behavior of nearby coal layers. Temperature logs showed a good placement of proppant in target zones which helped in getting impressive post frac productions. The results of frac jobs turned this small field into one of the most promising fields in the area.
Customized hydraulic fracturing helped in the enhancing the production from ageing & mature western onshore oil fields of India. Success of fracturing campaign in Gamij field led to augmented drilling activity in similar pay zones to extract hydrocarbons and support the increasing energy demand. This strategic hydraulic fracturing methodology customized for other fields in the region which were also proved quite successful.