bluuebunny/crossref_metadata_2025 huggingface dataset:
Body Image Disturbance, Weight Perception and Body Mass Index of Female College Students in Delhi having Normal and Disordered Eating Behaviours
Authors: Gupta Shipra , Kapur Deeksha
Published: April 2019

Body image and self-perception about weight, irrespective of their actual body mass index, may predispose young females to disordered eating behaviour. A study was conducted to determine body image disturbance, weight perception and body mass index among female college students in Delhi having normal and disordered eating behaviours. The study sample comprised 734 female under-graduate students between 18-21 years from women’s colleges of Delhi University. An interview-cum-questionnaire schedule was used to assess the general profile of subjects and perceptions about their body weight. Adapted Eating Attitudes Test (EAT)-26 and Body Shape Questionnaire (BSQ)-8c was used to determine disordered eating behaviour and body image disturbance among the subjects respectively. Body Mass Index of the subjects was also computed. Findings revealed a significant difference in self-perception about body weight among subjects showing normal and disordered eating behaviours. Higher percentage of subjects from disordered eating group perceived themselves to be either overweight or obese as compared to subjects from normal eating behaviour group.Significantly higher BSQ-8c scores and Body Mass Index were also observed among subjects having disordered eating behaviour. The study indicated that poor body image, self-perception about body weight being high as well as high body mass index played a significant role in occurrence of disordered eating behaviour among female college students in Delhi.The study depicted the urgent need to have appropriate health and nutrition education programmes for female college students to improve their perceptions about body shape and weight to further prevent the occurrence of disordered eating behaviour among them and make them less vulnerable to consequent nutritional problems.
Potato Flour Products - Protein and Starch Digestibilities and Mineral Availability
Authors: Lakra Poonam , Sehgal Salil
Published: April 2019

The technique for the development of potato flour from the potato variety ‘Kufri Badshah’ was standardized in the laboratory. Five products viz sevian, doughnuts, vadi, cutlet and kofta were developed by incorporating potato flour, defatted soy flour and corn flour in various proportions. Frying and fermentation were the major processing techniques employed for the development of these products. Protein, ash and fat contents of potato flour were almost similar to those of raw potatoes. Significant differences in protein, ash and fat contents of all the products were observed. Protein and starch digestibility and mineral availability of potato flour was significantly higher than that of raw potatoes. Protein digestibility increased 13-16 % on frying and 25 % on fermentation of products. Starch digestibility was increased by 17-19 % on frying and 33 % on fermentation. Processing significantly increased mineral availability. Frying increased calcium availability by 19.45 to 20.51% and iron availability by 19 to 21.52 %. Fermentation increased calcium and iron availability by 34%. Processed products had significantly higher protein digestibility, starch digestibility and mineral availability compared to their raw products. Thus, it can be concluded that frying and fermentation are effective methods of improving starch and protein digestibilities and mineral availability of products.
Evaluation of Physico-chemical and Rheological Properties of Blend of Soy with Standardized Milk
Authors: Pratap Devendra , Singh Rakhi , Ojha Ankur
Published: April 2019

The present investigation was carried out to evaluate the feasibility of fortification of soymilk with standardized milk for the production of fortified nutritive milk formulation. The functional properties of cattle milk can be enhanced by blending of soy milk. The soymilk was obtained by using standard procedure by grinding soaked seeds of soybean with hot water (bean to water ratio, 1: 4 w/v). In the present study three formulations of soy and standardized milk were prepared as follows T1 (100% soymilk), T2 (50% soymilk: 50% standardized milk), T3 (60% soymilk: 40% standardized milk), and T4 (70% soymilk: 30% standardized milk) and Control as T0 (standardized milk). The changes in physico-chemical, sensory and rheological properties were recorded. The results revealed that overall organoleptic acceptability scores of formulated milks formulations were 6.9, 8.06, 7.65, 7.04 and 8.49 for the formulation T1, T2, T3, T4 and T0, respectively. Fat, total solids, titratable acidity, pH, ash and solid non fat content were decreased with increasing soymilk proportion, while moisture and protein content were increased. The blending of different ratio of soymilk with standardized milk had significant affect on colour attributes (L*, a* and b*). Yellowness and greenness increased while lightness decreased as the proportion of soymilk increased.
Tratamiento transdiagnóstico de los trastornos emocionales en la infancia: Una revisión sistemática
Authors: Diego Castaño Sara
Published: April 2019

En la población clínica infanto-juvenil, es común que los niños con ansiedad presenten de forma comórbida otros síntomas internalizantes. Esta comorbilidad, asociada a una menor respuesta al tratamiento, ha hecho que en los últimos años se ponga énfasis en los programas transdiagnósticos. El objetivo de este trabajo es analizar la eficacia del tratamiento transdiagnóstico en los trastornos de ansiedad y depresión en la infancia. Para ello se llevó a cabo una revisión de la literatura disponible hasta la fecha en las bases de datos MEDLINE-Ovid, Web Of Science, ProQuest Central, Scopus y Science Direct. En los 9 artículos incluidos en la revisión se observa que la mayoría de los programas han sido diseñados para el tratamiento de varios trastornos de ansiedad, más que para el abordaje simultáneo de la ansiedad y la depresión. Estos programas pueden considerarse eficaces para el tratamiento de los trastornos de ansiedad, y aunque la mayoría señala beneficios sobre la sintomatología depresiva, el escaso tamaño muestral, la falta de métodos de control y otras limitaciones impiden establecer conclusiones firmes.
First Implementation of an Underbalanced Drilling Project for an Operator in India: Case Study
Authors: Kulhare Ekta , Khati Milind , Sarode Mahesh , Mclare David
Published: April 2019

Underbalanced drilling (UBD) is a method where equivalent circulating density (ECD) is kept less than the effective pore pressure of the zone being drilled by 100 psi or more. Drilling in an underbalanced state provides a unique opportunity to gather real-time virgin reservoir data that would never be observed again after typical damaging effects from conventional overbalanced drilling. This condition allows formation fluid to flow into the wellbore during the drilling process, helping prevent drilling mud and associated contaminants from penetrating the producing formation, which protects the producing zone and minimizes the potential for formation damage. Proper instrumentation and drilling procedures allow acquisition of data that is then interpreted and analyzed to extract information about the reservoir. UBD benefits include: Increased rates of penetration by up to 50%Increased value by producing hydrocarbons while drillingIncreased production rates mean quicker payoutsReduced formation damageReduced lost circulation costsReduced potential risks of differentially stuck pipe

An operator in India was truly the first to implement UBD technology within depleted reservoir sections of identified wells in an offshore asset. Three wells were planned as a part of the project. Project objectives, feasibility studies to determine applicability of the UBD technology to the selected field, an operational summary, and results of UBD operations on the first well are discussed.

Objectives for implementing UBD technology within the identified field included helping prevent reservoir damage, thereby enhancing oil production and recoverable reserves from the wells, and helping improve drilling performance within the reservoir section by eliminating mud losses, hence increasing lateral length and reservoir contact.
Estimation of Bottom Hole Pressure BHP in Coal Bed Methane CBM Wells
Authors: Vora Jinen , Patel Pratik , Bhamidipati Santosh
Published: April 2019

The objective of this paper is to estimate the Bottom hole Pressure (BHP) from water level and other available parameters in CBM wells by (a) calibrating the dynamic water level (b) surveying the available literature (c) testing and comparing different models for wells in CBM Sohagpur field which have bottom hole gauges (d) selecting an appropriate model and finalizing the algorithm to estimate the BHP with reasonable accuracy and (e) automating the process to calculate the estimated BHP.

We have proposed a method for calibrating the water level taken by echo meter by calculating the acoustic velocity for actual conditions prevalent in a CBM well. We have then estimated the BHP for 3 wells of CBM Sohagpur field, operated by Reliance Industries limited in India, with the help of calibrated water level and other parameters using 4 different models (Podio, Godbey & Dimon, Gilbert models and Rashid Hasan, C. Shah Kabir and Rehana Rahman model) and compared the results of those models with the actual BHP provided by the bottom hole gauges

The algorithm when used with Rashid Hasan, C. Shah Kabir and Rehana Rahman model gave more accurate results irrespective of the production parameter in CBM wells. A maximum error of 3% and minimum error of 0.5% was observed in Rashid Hasan, C. Shah Kabir and Rehana Rahman model while the other models gave up to 25% error. Thus, we have finalized the algorithm to be used for estimation of BHP with minimal error in our case and we have automated the process which has helped the operator in calculating the estimated BHP from other parameters very easily.

We have proposed a method for calibration of water level for actual conditions, which is necessary to arrive at correct BHP, tested different models available for calculation of BHP for CBM wells and compared the results. We have proposed an algorithm for calculation of BHP from water level and other parameters in CBM wells and automated the process which has helped the operator immensely in optimizing the dewatering operation and improving the production forecasts.
Case Study: Metallurgy Selection and Choke Design Incorporating Trim Interchangeability to Cater to the Entire Production Lifecycle of Raageshwari Deep Gas Field
Authors: Bhardwaj Charu , Ranjan Vishal , Jetley Shailendra Kumar , Tiwari Shobhit , Ghosh Anirban , Sharma Swapnil , Bohra Avinash , Kumar Abhishek , Beohar Abhudai , Sharma Sidharth
Published: April 2019

The Raageshwari Deep Gas (RDG) field, situated within Barmer Basin in the State of Rajasthan, India, was discovered in 2003. The field is a tight gas condensate reservoir, with excellent gas quality of approximately 80% methane, low CO2 and no H2S. Since the permeability (0.01 - 1 md) is low in this reservoir, hydraulic fracturing is required to get substantial recovery from the wells. The field has been under production since 2010. The development of this field has been carried out in three phases and more than 150 fracturing treatments have been pumped in this reservoir till date to achieve sustained economical production. This paper deals with the lessons learnt and changes implemented in choke design through various development phases of the field.

In the initial phase of field development, chokes with a low Flow Coefficient (Cv) were installed to meet the requirement of controlling the wells at low flow rates and high differential pressure. Later as the surface handling capacity increased, the chokes had to be de-bottlenecked, requiring additional Capex for new chokes. To avoid a similar scenario in the future, a comprehensive approach has been followed to envisage Cv requirement, considering well wise production profiles and surface handling capacities throughout the life of field. Since a single trim can't operate over the complete life-cycle of a well, trim interchangeability has been included in the choke design such that low and high Cv trims are interchangeable.

Pre-mature failures of trims were observed in initial phase and a root cause analysis was done to ascertain the reason. Based on the analysis, trim metallurgy has been changed from Tungsten Carbide to ASTM A276 Specific Stainless Steel Grade 440C. Trims with newly selected mettalurgy have been installed in the existing chokes.

The introduction of trim interchangeability has saved MMUSD 0.3 in the future Opex as the requirement of procuring altogether new chokes for late life period of wells is avoided. Initially failures in the trim bodies were observed as early as two months of commissioning but with the change in metallurgy zero failures have been observed with operational life of chokes being higher than four years. This has avoided significant downtime on wells and expenditure on regular trim changeovers.

Although Tungsten Carbide is one of the most common materials used for constructing trims world over, there could be specific cases where-in other metallurgy may add better value. The workflow followed in this paper will help select a suitable metallurgy and can impart a significant value to the industry.
Gravity Assisted Immiscible Gas Injection in a Depleted Reservoir: A Case Study of Successful Pilot Implementation
Authors: Mandal Dipak , Baruah Nabajit , Jena Smita Swarup , Nayak Bichitra
Published: April 2019

Hydrocarbon gas injection into the reservoir is one of the most effective EOR processes. In case of a dipping and light oil reservoir, immiscible gas injection can give further impetus to the oil recovery. Since, average current gas saturation in the subject reservoir has become high due to depletion rendering water injection at this late stage is found to be ineffective, scope of gravity assisted immiscible gas injection as an alternative has been evaluated to assess its impact on reservoir pressure and ultimate recovery.

The present study pertains to a high permeable clastic light oil reservoir with reasonable dip, belonging to an old field of South Assam Shelf of India under production since 1990 with current recovery of 22% of STOIIP. The reservoir being undersaturated with no aquifer support, shows significant decline in reservoir pressure (260 ksc of initial pressure to current level of 50 ksc). Simulation study has been carried out on a fine scale geo-cellular model. Multiple realizations have been created considering combinations of oil producers and gas injection wells assigning varied rates to study the different development scenarios and impact on recovery improvement. The study indicates an incremental oil recovery of about 14% of STOIIP by immiscible gas injection.

Based on the study, immiscible gas injection has been initiated in the reservoir on pilot scale basis through two gas injectors with continuous monitoring. After gas injection during last one year, reservoir pressure increased about 25 ksc and consequently per well productivity also increased. Non-flowing well starts producing and currently sand is producing nearly 25% higher than earlier production before gas injection. Based on the encouraging result from pilot gas injection, decided to expand the process at field level and subsequently drilling of new oil producers after jacking up of reservoir.

The study has brought out that the gas injection into shallower portion of the reservoir yields better sweep efficiency to displace the oil to the deeper portion of the reservoir due to the gravity effects and hence, appropriate locales of the reservoir are targeted for additional input generation to augment the oil recovery.
Source-Less Evaluation Modeling of Complex Tight and Depleted Gas Formation for Better Hydraulic Fracture Strategy of Vertical and Highly Deviated Wells
Authors: AL Isaee Omar , Lukmanov Rinat , Frese Daniela
Published: April 2019

The paper discusses a petrophysical evaluation method for complex tight gas formations in a mature and partially depleted gas condensate field in Oman, allowing a full petrophyscial evaluation as well as geomechanical modeling from a source-less petrophysical dataset, thus reducing operational data acquisition risk in partially depleted reservoirs without compromising on hydraulic fracturing design. The developed methodology includes the volume of shale estimation from correlation with Poisson's ratio for the feldspathic rich tight formation.

This methodology was used in deep tight fields in Oman for more than 3 years in both vertical and highly deviated wells greatly reducing the risk, logging cost and complexity of operations.
Novel Permeability Evaluation Methods for Under-Saturated Coalbed Methane Reservoirs with Application to Realistic Field Cases: Effect of Heterogeneous Feature
Authors: Sun Zheng , Shi Juntai , Wu Keliu , Gong Dahong , Peng Hui , Hou Yuhua , Ma Hongyan , Wang Daning , Ramachandran Hariharan , Liu Yisheng , Liu Wenyuan , Wang Suran , Li Xiangfang
Published: April 2019

With respect to the sharp increase in population all around the world, more and more energy and fuels are expected to achieve the counterbalance between supply and demand. Deeply attracted by its considerable and prospect recovery reserve, the exploitation, development and related research contents regarding coalbed methane (CBM), i.e., one of the unconventional gas reservoirs, are currently heat and essential topics. Without any doubt, precise determination of coal permeability will dramatically contribute to the development efficiency of CBM reservoirs. It should be noted that the permeability in CBM reservoirs possesses unique heterogeneous characteristics, especially for the different permeability at directions of face cleats and butt cleats, which will inevitably result in greatly shape-change for fluid flow field and eventually the production performance. To my best knowledge, nearly all the previous methods proposed for evaluating coal permeability assume the homogeneous permeability feature in CBM reservoirs, which show fairly great discrepancy compared with that of the realistic situation. In this work, in order to address this urgent issue, a novel permeability evaluation method is developed for the first time, which is able to generate precisely heterogeneous characteristics of coal permeability based on the water production rate versus production time curve at the early production stage. First of all, considering both orthotropic heterogeneous permeability and pressure propagation behavior in CBM reservoirs, single water phase productivity equation is seriously derived. Secondly, for simply usage purpose in field application, the obtained equation is transformed through linearization treat. Finally, combining the water production performance with the linearized equation, efficient iteration calculation procedures are given to determine the heterogeneous permeability feature. Also, the skin factor of corresponding CBM well can be determined. The applicability and accuracy of the proposed method have been successfully verified through field application. In sum, the proposed method can serve as a simple as well as an accurate tool to determine the crucial heterogeneous permeability feature in CBM reservoirs. More importantly, during the determination process, the method just requires the water production performance at the early production stage, which means that the obtained permeability characteristics can be utilized to guide production strategy adjustment in the following gas production stage. As a result, the proposed method can be regarded as a necessary preparatory work before gas production takes place in CBM reservoirs, which will play a positive and active role in optimization of ultimate gas recovery and well configuration.
Feasibility of Gas Injection in Gas Cap for Decline Management of a Mature Offshore Field
Authors: Thapliyal Anil , Kundu Sudeb , Chowdhury Suparna , Singh Deepika , Singh Harjinder
Published: April 2019

Pressure maintenance by gas injection in gas cap is one of the well-established methods for improving the ultimate recovery. Gas injection in the crestal part of reservoir into the primary or secondary gas cap for pressure maintenance is generally used in reservoirs with thick oil columns and good vertical permeability and this process is called gravity drainage. This paper comprises methodology and results of study to evaluate the feasibility of gas injection in gas cap for maintenance of reservoir pressure and to envisage incremental oil gain of a mature offshore carbonate field located in western offshore of India.

Field has already produced more than 30% oil of its initial inplace volume. Water injection was started after 4 years of production and currently field is producing oil with 90% water cut. After one year of initial production phase the field producing GOR rose to two to three fold of its initial value mainly due to contribution of gas from gas cap. Depletion of gas cap gas made significant adverse impact on reservoir pressure and also fast pressure depletion from crestal part had allowed water breakthrough of injection and aquifer water to oil producers. At this stage to reduce the decline rate of wells for maximizing the future recovery without drilling of new wells and also without extension of existing infrastructure, the injection of gas in depleted small gas cap have been studied.

In order to evaluate the feasibility of gas injection in depleted gas cap and its overall impact on oil recovery, three aspects were seen. First the optimized quantity of gas injection and its sensitivity along with the number of gas injectors were decided through reservoir simulation. Therefore, suboptimal oil producers falling within gas cap area are chosen for conversion to Gas injectors. Secondly injection gas requirement for the process will be fulfilled partly through the recycling of produced gas and rest from free gas production from another pay of the same field. Finally it is examined that current existing facility of gas compression will sufficiently cater the additional requirement of gas compression. The process will have additional 10 to 11% contribution in future oil production.

The process of charging gas cap will provide additional support over ongoing water injection leading to a significant additional oil recovery by reducing the oil decline rate.
Increasing Sweep Efficiency by Shutting Off Water Flow Through Thief Zones in a Heterogeneous Reservoir
Authors: Matveev Sergei , Gazizov Aidar , Gazizov Almaz , Garipov Renat , Galaktionova Lydia
Published: April 2019

With high reservoir heterogeneity in terms of permeability and fluid properties, substantial amounts of oil are produced along with water. At water cuts higher than 96–98%, wells become uneconomic and are shut in or undergo water shut-off treatments. For this reason, shutting off water flow through thief zones in flooded reservoirs to prevent it from entering wells is one of the biggest technical challenges in enhancing oil recovery from mature multi-reservoir oil fields.

As the water cut increases, water flow through thief zones must be reduced, along with the amount of water entering the well, to enhance sweep efficiency in lower-permeability portions of the reservoir. A new technology employing polymer dispersed systems (PDS) shuts off formation and injected water flows by increasing flow resistance in thief zones. This process redistributes the energy of the injected water in the reservoir and helps produce oil from unswept zones, thus increasing flooding efficiency and oil recovery. PDSs do not require drastic changes in existing development systems and are employed together with conventional water-flooding methods.

This paper presents studies of basic and modified PDS versions for oil recovery enhancement adapted for conditions existing in the Vyatka area of the Arlan oil field containing poorly continuous reservoirs with lithofacies heterogeneity. This depleted area had a stable, high water cut.

The new method for enhancing water flooding efficiency using polymer dispersed systems presented in the paper selectively increases flow resistance in the thief zones of productive formations with a resulting increase in sweep efficiency.
Usage of Data Science to Predict String Integrity Failures
Authors: Singh Rahul , Baidya Dipayan
Published: April 2019

This paper discusses about the various approaches that has been taken to reduce downtime in Coal bed methane (CBM) wells by predicting the string integrity failure in advance. Various approaches such as the Principal component analysis (PCA) based T-statistics approach and the Bag of Features approach have been taken to find a solution. These approaches fall under the classical classification approach of supervised learning. The power and usefulness of these approaches are fuelled and limited by the number and richness of annotations and sensors at the Well site. These approaches used on the CBM wells gave very encouraging results, thereby proving the helpfulness of this approach in enhancing the well efficiency and decreasing the well downtime by planning based on the failure prediction of the model.
Estimation of Pore Pressure and Fracture Gradient in Volve Field, Norwegian North Sea
Authors: Sen Souvik , Ganguli Shib Sankar
Published: April 2019

Maintaining a stable borehole and optimizing drilling are still considered to be vital practice for the success of any hydrocarbon field development and planning. The present study deliberates a case study on the estimation of pore pressure and fracture gradient for the recently decommissioned Volve oil field at the North Sea. High resolution geophysical logs drilled through the reservoir formation of the studied field have been used to estimate the overburden, pore pressure, and fracture pressure. The well-known Eaton’s method and Matthews-Kelly’s tools were used for the estimation of pore pressure and fracture gradient, respectively. Estimated outputs were calibrated and validated with the available direct downhole measurements (formation pressure measurements, LOT/FIT). Further, shear failure gradient has been calculated using Mohr-Coulomb rock failure criterion to understand the wellbore stability issues in the studied field. Largely, the pore pressure in the reservoir formation is hydrostatic in nature, except the lower Cretaceous to upper Jurassic shales, which were found to be associated with mild overpressure regimes. This study is an attempt to assess the in-situ stress system of the Volve field if CO2 is injected for geological storage in near future.
Water-Flood Management in a Mature Field Through Pilot Approach
Authors: Thapliyal Anil , Kundu Sudeb , Chowdhury Suparna , Singh Harjinder
Published: April 2019

A successful water injection management is a key to increase or stabilize oil production and to maximize oil recovery from a mature field. This paper describes an approach to draw maximum benefit through existing set up of a water injection in a mature offshore carbonate field of India. Water injection initiated after the six years of oil production and field is under water flood since last 28 years. The field witnessed favorable water flood condition and almost negligible aquifer support. During its long production period most of the producers had been sideracked from one to three times to target better saturation areas which has led to uneven subsurface water distribution. The field has also suffered less voidage compensation for quite some time.

To understand and mitigate the problem, a small pilot area within a field has been selected for implementing a good surveillance and monitoring program with pattern injection and possible intervention strategy. It was decided that based on the success of this pilot, the concept would be developed for implementation in step by step manner for entire field. The importance of multidisciplinary team has been recognized and detailed SWOT analysis was done for effective implementation of plan. Initially pilot area comprised of 15 oil producers and 4 water injectors. Conversion of one producer to water injector and restoration of water injection in 3 injectors were done as per plan and optimized injection rate (in this case maximum 3000 bbl per day) per injector were implemented. Peripheral pattern for pilot area with 5 injectors and 5 spot inverted patterns from rest 3 injectors were decided.

After one year of the implementation a thorough performance analysis of the pilot has been carried out which indicates the overall improvement of liquid and oil production rates along with reduction in GOR and decreasing trend of oil decline rates of producers.

The pilot approach has certainly helped to understand the Reservoir conformance in short duration of time. Encouraging results of this methodology guides to extent and implement this approach in other parts of field to cover the entire field in phased manner.
Exploring the Capability of Temperature-Only Analysis for Zonal Flow Quantification
Authors: Dutta Shaktim , Kumar Apoorva , Mishra Siddharth
Published: April 2019

Temperature logs have been used to monitor producing wells since the early 1930s. Normally, analysis of the temperature log is viewed as secondary to that of the spinner flowmeter, which gives flow velocity directly, and temperature is conventionally used only as an indicator of fluid entry/exit with the production logging tool (PLT). The main disadvantage of the PLT is that if spinner flowmeter data are not good due to tool problems, then flow quantification is jeopardized. Additionally, in recent years, the cost of production logging has increased considerably because many wells are now drilled horizontally through the reservoir, and the PLTs must be conveyed on coiled tubing or well tractors, and, in some cases (subsea wells), even this may not be possible. Consequently, alternative technologies become viable if they can be used for flow quantification using just temperature data. This paper presents a new flow quantification model using temperature data acquired using production logging or a distributed temperature sensor (DTS) system.

The model presented in this paper can handle multiple production zones with their zonal fluid properties as input to give corresponding zonal flow rates as output. The said model is applicable for single-phase oil and gas producer wells as well as water injection wells in both onshore and offshore environments. There are two modes of flow calculation for each answer product-steady state or transient. The model is integrated into easy-to-use software, and it has options for forward simulation as well as optimization. The forward simulation calculates temperature distribution along the wellbore for any given production profile, which is critical for model calibration for any reservoir. After the model has been validated for a reservoir, it can be used for zonal flow quantification using any temperature survey. The objective of the optimization option is to allow the user to fit the model output temperature curve to a selected temperature curve by means of a genetic fitting algorithm that will adjust one or two user-selected reservoir parameters, such as permeability, pressure, skin, gas-oil ratio (GOR), temperature, or water-cut, until a fit is achieved.

The model has been extensively tested against synthetic, literature and field examples and good agreements have been obtained, confirming the robustness of this novel approach.
Application of Pulsed Neutron Logging in Open Hole Environment
Authors: Shiwang Rahul , Banerjee Anirban , Ramaswamy Vijay , Malik Sonia , Deshpande Chandrashekhar , Kumar Sanjeev , Chadha A. K
Published: April 2019

The identification of fluid saturations in depleted reservoir sands is critical to understand the reservoir potential and field life. However, in case of water flooding, the formation water salinity of the reservoirs sands might be altered and fluid saturations from conventional petrophysical analysis can be misleading. This will have direct impact on the field economics. A salinity independent saturation computation from Carbon/Oxygen (C/O) log becomes a necessity in such development wells– a first of such application in a field under secondary recovery for this basin.

C/O well logging has been extensively used in cased hole environments to determine saturation behind casing. They are used essentially to determine oil saturation in cased hole conditions for depleted reservoirs. While their cased hole applications have been well established; for the study well, a pulsed neutron tool was used in an open hole environment to determine the fluid saturations to compare against the saturations computed from conventional resistivity logs. This study helped in the determination of fluid saturations in mixed salinity reservoir sands, which were to be explored from subsequent wells in the field.

The hydrocarbon-bearing sands in the field were water injected in nearby wells to enhance recovery. Development wells drilled in the field relied on petrophysical evaluation from conventional open hole data and pressure testing and fluid sampling depths were determined accordingly. A pulsed neutron tool was deployed in an open hole well after operational constraints were encountered with the formation testing tool. As an alternative, the pulsed neutron data were acquired in the well to compute salinity independent water saturation based on C/O log response as against the fluid saturation computation from resistivity logs. The determination of fluid saturations from C/O helped in determination of altered salinity for the sand intervals in the field. For the study well, C/O-derived water saturation was found to be higher than that from resistivity log computation. This was significant in identification of water breakthrough in the bottom interval of the reservoir sands.

This paper details the method and findings of C/O logging in open hole environment from Western Onland Basin in India. The critical solutions provided for the reservoir sands in the field and enabled the operator to save significant well cost and rig time by making informed decision of not lowering the casing in this well section.
A Case Study on Identification & Mitigation of Surges in a Cluster of Composite Well Flow Line Network
Authors: Gupta M K , Sukanandan J N , Singh V K , Bansal R , Pawar A S , Deuri Budhin
Published: April 2019

This paper discusses a case study of one of the onshore field of ONGC where while processing well fluid, frequent surge has been observed leading to shutdown of the SDVs creating severe operational problems and loss of production. It was imperative to find out the problematic wells/lines located in clusters which contribute for surge formation and mitigation approach with minimum modifications.

A transient complex network of sixty five wells flowing with a different lift mode such as intermittent gas lift, continuous gas lift etc were developed in a dynamic multiphase flow simulator OLGA. Time cycle of each well were introduced for intermittent lift wells. Simulation study reveals pulsating transient trends of liquid flow, pressure which was matched with the real time data of the plant and hence confirms the accuracy of the model. After verifying the results, different scenarios were created to determine the causes of surge formation. After finding the cause, a low cost approach was considered for surge mitigations.

An integrated rigorous simulation was carried out in OLGA, by feeding more than 12,000 data points to obtain model match. Several scenarios were also created such as optimization of lift gas quantity, optimization of elevation and size. Trend obtained after each scenario was pulsating behaviour and it matched with the real time data appearing in the SCADA system of the field. After rigorous simulation with each scenario, it was established that the cause of surge forming wells/pipelines. Once the root cause of surge has been confirmed then quantum of liquid generated due to surge was determined. Adequacy checks of the existing separators were carried out to estimate the handling capacity of the existing separators at prevalent operating condition. After adequacy check it was found that existing separators cannot handle the surge generated in that time interval leading to cross the high-high safety level, resulting closure of shut down valve (SDV). After establishment of root cause of the surge, a low cost solution with small modification in pipelines and control system/valves was adopted to arrest the surges. It was first of its kind simulation carried out for a huge network of wells/ pipelines by feeding more than 12,000 data to analyze the surge formation cause and capture its dynamism owing to wide array of suspected causes. This will help to address the challenges of efficiently reviewing the entire pipeline network while designing new well pad/GGS and will also help to arrest surge by adopting a low cost solution wherever such situation arises.
Overturning the Rapid Production Decline of a New Infill Well Using a Permanent Downhole Gauge
Authors: Abdulhadi Muhammad , Tran Toan Van , Chin Hon Voon , Jacobs Steve , Wahid Muhammad Izad , Usop Mohammad Zulfiqar , Zamzuri Dzulfahmi , Dolah Khairul Arifin , Abdussalam Khomeini , Munandai Hasim , Yusop Zainuddin
Published: April 2019

Infill Well B-23, which was recently drilled in the CIII-2 reservoir located in the Balingian Province, experienced a rapid pressure and production decline. The production decreased from 2,200 to 600 BLPD within 1 year. Analysis of the permanent downhole gauge (PDG) data revealed that Well B-23 production was actually influenced by two other wells, B-20 and B-18, each located 2,000 ft away. This paper discusses the ensuing analysis and optimization efforts that helped reverse the Well B-23 pressure decline and restored its production to 2,200 BLPD.

Based on the typical causes of rapid production and pressure decline, operators initially believed Well B-23 was located in a small, separate compartment compared to Wells B-18 and B-20. Additionally, the Well B-23 behavior differed significantly from Wells B-18 and B-20. PDG data analysis provided clear evidence of well interference despite the significant distance between the well locations. Changes in the other wells immediately affected the Well B-23 pressure, thus leading to the conclusion that production from Wells B-20 and B-18 impeded the pressure support for Well B-23. To optimize Well B-23 production, Well B-20 was shut in while Well B-18 was produced at a reduced rate because of a mechanical issue.

The optimization initially resulted in more than 500 BOPD incremental oil from Well B-23. The well pressure decline was reversed, with PDG data showing a continuous increase of bottomhole pressure (BHP) despite an increase in the production rate. Subsequently, production was fully restored from 600 to 2,200 BLPD, and reservoir pressure returned to its predrill pressure. Going forward, the optimum withdrawal rate from the CIII-2 reservoir will be determined to ensure maximum oil recovery from both Wells B-18 and B-23. The case study proved the significant benefit of PDG data, which helped identify well interference as the actual cause of the rapid decline in Well B-23, instead of a reservoir or geological issue. Through in-depth analysis and thorough understanding of the reservoir, the operator restored what initially appeared to be a poor well to full production.

This case study shows the clear and strong effect of well interference and highlights how the subsequent results of the optimization effort were rapidly obtained. A comprehensive understanding of the reservoir behavior could not have been achieved at minimum cost without the pair of PDGs installed. The analysis and lessons learned from the Well B-23 PDG data provide valuable insight regarding the impact of well completions to the field of reservoir engineering.
Three-Dimensional 3D Lithofacies Identification and Modeling Using 3D Seismic Attribute and Well Data Calibration
Authors: Roy Samiran , Saikia Kalyan
Published: April 2019

Seismic attributes play an important role during reservoir characterization and three-dimensional (3D) lithofacies modeling by providing indirect insight of the subsurface. Using seismic attributes for such studies has always been challenging because it is difficult to determine a realistic relationship between hard data points (i.e., well information) and a 3D volume of seismic attributes. However, a probability-based approach for 3D seismic attribute calibration with well data provides better results of lithofacies modeling and spatial distribution of reservoir properties. This paper presents a probability-based seismic attribute calibration technique that has been described for 3D lithofacies modeling and distribution. This approach helps in subsurface reservoir characterization and provides a realistic lithofacies distribution model. This approach also helps reduce uncertainty of lithofacies prediction compared to conventional methods of simply using geostatistical algorithms.
Revisiting Old Sands with a Different Perspective – A Pragmatic Approach for Maximizing Recovery from Gas Reservoirs
Authors: Devshali Sagun , Manchalwar Vinod , Deuri Budhin , Malhotra Sanjay Kumar , Prasad Bulusu V.R.V. , Yadav Mahendra , Kumar Avinav , Uniyal Rishabh
Published: April 2019

The paper describes the feasibility of revisiting old sands, for improving the recovery factors and enhancing production, which otherwise were already abandoned. The paper also outlines the systematic methods for predicting the onset of liquid loading in gas wells, evaluation of completions for optimization and comparison of various deliquification techniques. ONGC is operating in two gas fields in eastern and western regions in India. Earlier in both the fields, many sands had to be closed/isolated after the wells ceased to flow due to liquid loading in the absence of continuous deliquification. In order to predict liquid loading tendencies and identify opportunities for production enhancement, performance of 150 gas wells has been analyzed. To select most suitable deliquification technique for the present condition, all technically feasible methods have been evaluated and compared in order to get the maximum ultimate gas recovery possible.

After an extensive study, 3 wells were identified in the preliminary stage and SRP was selected as the most suitable Deliquification technique. Initially, two non-flowing wells, which had ceased due to liquid loading and were about to be abandoned, were selected. After SRP installation and sustained unloading of water for about 30 days, these wells started producing 12000 SCMD gas. In the third well, one of the top sands had earlier been isolated due to liquid loading and production history indicated that the isolated sand had a very good potential. Also, production from the well was declining in the current bottom operating sand as well due to liquid loading. Encouraged by the results that deliquification had yielded in the initial two gas wells, the isolated sand interval in the third well was opened again with the aim to revive production. The well was re-completed with SRP with both the reservoirs open. Before deliquification, the well was producing about 15000 SCMD gas from the bottom sand. After SRP installation and continuous deliquification, the well started producing gas at a stabilized rate of 45000 SCMD, thereby resulting in an additional gas recovery of 30000 SCMD for nearly one year as on date. The approach of putting in place continuous deliquification techniques has not only helped in enhancing production from the existing reservoirs, but has also opened up new avenues to revisit the earlier isolated / abandoned reservoirs for possible enhanced recoveries.
Empirical Correlations for Quick and Accurate Hydrate Formation Prediction - Which One to Apply?
Authors: Khanna Anchit , Burla Ravishankar , Patwardhan Samarth
Published: April 2019

Natural gas hydrate formation is a costly and challenging problem for the oil and gas industry. Prediction of hydrates have been carried out through rigorous and laborious solving of mathematical equations called equations of state (EOS) which give accurate results but require appropriate setup and time. Few examples of such equations of state currently used by industry benchmarked software tools include Peng-Robinson (PR), Cubic-Plus-Association (CPA), Soave-Redlich-Kwong (SRK) etc. which more or less provide us with an accurate hydrate stability curve i.e. a pressure-temperature profile for a given composition, which allows us to keep the pressures and temperatures (operating conditions) out of the hydrate stability zone.

Hydrate stability curves are a function of the composition of the fluid (gas) being produced. Compositional changes in the percentage of C1 to C7+ components of gas, would not only affect the specific gravity, but would also change the hydrate stability curve of the gas significantly.

Previous studies have been aimed at finding a quick and precise prediction method for hydrate formation, so as to make swift arrangements to counter any chance of flow assurance issue. Different empirical correlations have been developed on the basis of the composition of the gas being produced that take into consideration the pressure and predict the temperature of hydrate formation. Multiple data points, i.e. fluid compositions from different areas/fields are considered and correlations have been developed to fit the hydrate stability zones of these data points which were found through a more accurate equation of state. As the initial data sets for each correlation are different, the possibility of any two correlations giving the correct and same prediction is very low.

This paper gives an insight into how different empirical correlations like Hammershmidt, Motiee, Makogon, Towler and Mokhtab etc., that have already been derived can be used with better accuracy for a set of different fluid compositions and specific gravities. A sensitivity analysis is done on the performance of each correlation against the accurate hydrate curves found out through the software tool, using different available equations of state. The data points picked here are random and were not included in any data sets adopted for derivation of the correlation.

Furthermore, the mimicked hydrate curve from this new method is cast against the software simulated hydrate curve for a flow assurance steady state simulation study with two deepwater gas wells with different gas compositions. The results of the study suggest that the use of the imitated hydrate curve through analytical approach works well in predicting the hydrate stability zone. It would also not require any software proficiency, would give quick results and would cost a fraction compared to the state of the art simulators.