bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recovering Well Productivity in Banyu Urip Field
Authors: Putra Ardian P. , Barrow Jonathan M. , Susanto Edward , Hutauruk Leonardo E. , Daud Munir M. 
Published: October 2013

Abstract
Banyu Urip Field is a newly developed oil reservoir located in between Central and East Java provinces, Indonesia. The field is currently producing in an early development phase. There are 4 producer wells, 1 gas injector and 1 water injector. The six wells are located on one well pad and production flows to temporary facilities operated by another party.
Two years after starting production, inflow capacity began to rapidly deteriorate in one of the producers; resulting in a decline in overall field deliverability. The declining well is a deviated well which had experienced massive lost circulation while being drilled. The well initially produced at the highest rate among the 4 producers. However after the rapid production decline it produced at the lowest rate of the four producers.
This paper describes steps taken in evaluating the root causes of the decline in well productivity. Research and screening mitigation options are also discussed in this paper. Lost circulation materials, plugging, and scale/wax build-up are suspected as potential root causes of the decline in productivity. Acid stimulation, coiled-tubing cleanup, and re-perforating were identified as possible mitigations. The workover was divided into 2 phases; phase-1 was conducted for data acquisition and phase-2 for execution. Furthermore, this paper continues with describing the well work execution and challenges.
Zonal Isolation Remedial Solutions in Mature Fields Using Sealant Polymer and Straddle Assembly
Authors: Nziembo Cyr Rodrigue , Martocchia Francesco , Okassa Fabrice , Quero Philippe , Santin Yoann 
Published: October 2013

Abstract
Water and gas management in mature fields is a daily challenge. It is even more critical when re-development is required using existing assets to be side tracked. The severe depletion of the oil zones creates significant pressure contrast with water and gas layers that need to be properly isolated.
Failure to correctly cement the casings or liners generally ends up by generating cross flows, not only affecting the current well but also other wells producing from same levels.
The paper is based on a successful case history, performed in Congo for a major, where the restoration of the zonal isolation on highly deviated wells was required.
The objective of the paper is to describe the methodology process to determine the source of water in a well, the merge of oil field competencies to engineer a chemical and mechanic solution, the fluid design and the full operational deployment on location to cure the problem.
The combination of several specialties provided an innovative solution that gave the following benefits: -Minimize the number of runs, with only two trips required to perforate the liner to access the cross flow area and to set a straddle assembly-Minimize well restrictions and still give access to the lower completion-Minimize risks of getting stuck using sealant polymer instead of cement-Provide complete annular isolation and restore casing integrity in a same run-Evaluation and control of the cross flow before sealing operation-Protect the lower oil producing zone during the entire remedial operation
At the end, the objective of the paper is to give best practices to perform remedial cement operations in similar well architectures.
Low Salinity Cyclic Water Floods for Enhanced Oil Recovery on Alaska North Slope
Authors: Kulathu S. , Dandekar A. Y. , Patil S. , Khataniar S. 
Published: October 2013

Abstract
With low salinity waterflooding already implemented, cyclic waterflooding is under extensive research for increased oil recovery than conventional waterflooding. Low salinity cyclic water injection (CWI) is an interesting combination that offers the effects of both, with notably high oil recovery and less usage of water. Careful evaluation might promote the application of cyclic injection in the fields, especially on Alaska North Slope (ANS).
Two phase flow experiments were conducted on representative sandstone cores. After establishing initial water saturation, Amott-Harvey Wettability tests were performed with spontaneous and forced displacement of the fluids by one another. Cyclic water floods were conducted to calculate oil recovery from the volume of produced fluids. Pulsed cyclic floods were programmed in the injection pump. The experiments were repeated with cores of different permeability and lab reconstituted brines of 22000, 11000 and 5500 ppm salinity. Results were compared with available data from continuous injection performed on the same cores. Cyclic floods were also tested for two symmetric on-off time intervals.
With the dead oil experiments, it is observed that residual oil saturation (Sor) is achieved as early as 3-4 pore volumes (PV) of injected water in cyclic injection as compared to 6-7 PV’s in continuous injection. Additional oil recovery is observed in cyclic injection’s idle time, when the already flooded water spreads smoothly within the pores to displace oil out of the core. Better recovery was obtained with lower salinity brines. Within cyclic injection, shorter pulse intervals yielded better results. To conclude, low salinity CWI with shorter pulse intervals yield better oil recovery and early Sor. This is an attractive option for ANS operators.
An Overview of Polymer Broken Down for Increasing Injectability in Polymer Flooding
Authors: Liu He , Yang Gao , Fangchao Liu 
Published: October 2013

Abstract
There are many reasons for the low fluid volume of oil wells and decreasing injectability of the polymer injection wells, such as the unreasonable process, the variations of the formation conditions, imperfect injection-production pattern, and improper production management, etc., and moreover, another important factor is the injected polymer and cross-linked polymer jamming in the near wellbore area and deep oil reservoir. According to the Statistical analysis of the 289 wells in Daqing Oilfield, there are two situations existing in polymer jamming which caused decreasing injectability, one is the shallow blocking, blockage radius within 3 meters, mainly caused by the polymer micelles, polymer floc, mechanical impurities, salt scale and iron sulfide, etc.; the second is the deep formation block, blockage radius around 10 meters, there are two factors resulting in this situation, which are, high viscosity caused near wellbore area jamming and polymer retention and adsorption in far wellbore zone. Aiming at these two situations, we have developed the polymer blockage remover and its supporting technology, which can efficiently remove blockage from polymer / cross-linked polymer, through this technology, the injection stop or under-injection can be solved to some extent, and the development effects of the polymer injection area have been improved.
Reducing Target Uncertainties and Guiding Drilling Using Seismic While Drilling Technology, a Novel Approach in Andaman Sea Deepwater
Authors: Chandrasekhar S. , Dotiwala F. , Lim T. K , Khaitan M. L. , Kumar R. 
Published: October 2013

Abstract
Seismic while drilling (SWD) technology was first time being used by Oil and Natural Gas Corporation, ONGC recently, on their Andaman Seas deepwater drilling campaign. Numerous publications have been made by the industry experts over the past 10 year on SWD technology In this case study we demonstrate the practical applications of SWD technology that help to guide the real-time drilling process with effective cost and time in acquiring checkshot data.
ONGC has started exploration campaign in Andaman deep water area recently in 2011. The drilling was commenced with very limited information available from surface seismic, because of no well control in the area. By virtue of surface seismic technique, uncertainties are always associated with it. Uncertainties in seismic impacts the well plan and safety, which effectively impacts the well cost. Any technology which can reduce the seismic uncertainties and risks can be useful to reduce the cost and enhance safety.
In this paper a case example is presented, where real time checkshot was acquired without disturbing the normal drilling operation. The real-time checkshot was recorded at every drill string stand and recorded waveform was transmitted uphole through mud telemetry system. The computed time-depth function was used to refine pre-drill velocity model and this was subsequently used to update the drilling target prognosis depths and geomechanics model. Real-time checkshot also confirmed the drill bit position on the surface seismic section. Updated seismic lookahead give confidence to ONGC to continue drill ahead with single 12.25" hole to reach their final TD at 3700m. All targets were reached within a few meters errors of the prediction. This case study demonstrated that SWD technique added considerable values in helping eliminating drilling 17.5" enlarge hole and 13 3/8" casing run.
Predicting Drilling Target Ahead of Bit Using VSP Lookahead Technique that Help Mitigate Drilling Risk in Over Pressure Zone, a Case Example from South China Sea
Authors: Yang H , Cai J. , Guo S. , Gao Y. , Yanhua Y. Li , Lim T K 
Published: October 2013

Abstract
Yinggehai basin is located in South China Sea; it is characterized with high geothermal gradient and high overpressure. Numerous pore pressure predictions with VSP look-ahead have been conducted in this area. As pore pressure prediction with this approach is very sensitive to the inverted VSP velocity, based on our post drill analysis of pore pressure prediction results with VSP look-ahead data, it has been demonstrated that undercompaction is not the only overpressure mechanism in this study area, unloading may also have contributed to the overpressure. Both Bowers and Eaton models can be applied to predict pore pressure ahead-of-bit for the overpressure mechanisms in the area. An error of 5% in VSP-inverted velocity could generate the error in predicted pore pressure approximately 0.16SG based on Bowers model. Therefore, with experiences gained from VSP velocity inversion part, determining the top depth of the high pressure target with the inverted VSP velocity curve is proposed in this study block to allow for an optimal setting depth of the casing shoe. A case study with this approach is presented in this paper.
Cased Hole Formation Connectivity Investigation Aids in Completion and Production Optimization: Offshore Malaysia Field
Authors: Hanalim L. , Kyi K. , Haddad S. S. , Hooi Yee K. , Wa W. , Lim L. 
Published: October 2013

Abstract
Reservoir pressure is one of the key properties needed in formation characterization. In addition to reservoir fluid identification through pressure gradient, reservoir pressure measurement plays a vital role in evaluating reservoir connectivity. This understanding of reservoir connectivity will subsequently aid in reservoir management planning, including completion design optimization. Formation connectivity investigation is especially challenging in a cased-hole environment where unfavorable wellbore conditions prevented open-hole evaluations.
This paper presents a case study in a Malaysia offshore field where formation pressure measurements behind casing were carried out to allow the investigation of formation connectivity which is required for completion design, production planning, and potential cross-flow for zone commingling strategies. Cased-hole formation tester was used to evaluate formation pressure in the target zones where two wells were drilled in the same field. The formation pressure acquired was subsequently utilized in completion design and perforation planning based on reservoir connectivity.
The pertinent questions about this field have been answered and helped in making the best possible connection between the wellbore and production optimization. This application of formation pressure measurement behind casing has been proven to add value to the completion design optimization process. Lessons learned supported by field data will be presented along with recommended cased-hole reservoir connectivity investigation techniques and strategy.
Redesign of ICCP System for Ladinda FSO for Effective Corrosion Protection
Authors: Gangsar Agus , Purwanto Sugeng , Antono Ari 
Published: October 2013

Abstract
The Impressed Current Cathodic Protection (ICCP) System is a corrosion control method where there is a flow of electrons to a metal structure, thus protecting it. As a ship owner, the EMP Malacca Strait SA used a coating method combined with the ICCP system to control corrosion on the Ladinda FSO. However, nowadays, the Ladinda FSO is known to carry a decreased volume of oil cargo due to declining oil production. This results in a change in the wetted area on the tanker’s hull in the design conditions of the ICCP system from early 1983 to the current conditions (2010) that affect the current magnitude of the protection given. This leads to an over- protection that destroys the coating layer.
To avoid over-protection on the hull of the Ladinda FSO, an analysis and redesign of the ICCP system has been conducted. In the redesign of the cathodic protection system on the Ladinda FSO, the NACE Standard RP 0176- 2003 "Corrosion Control of Steel Fixed Offshore Structures Associated with Petroleum Production" was used as a basic reference in the design. The first step was to make the initial ICCP system design and then rebuild the initial ICCP system design for cathodic protection according to recent conditions. Next, the new design was analyzed and the results are the recommendations. The monitoring system was also redesigned to maintain proper control at a range of–1100 mV to–800 mV vs. Ag/AgCl/seawater.
The new design will needs two transformer rectifier units as the power supply, which will give sufficient voltage to drive six titanium anodes coated with mixed metal oxide (MMO). The capacity of each transformer rectifier is 236.25 kV.A with a DC current of 21 A and DC voltage of 9 V. Four potential test boxes featuring Ag/AgCl reference electrodes and the "Protection Current Control Program" as the control system and monitoring system are added in this new ICCP system design.
A Numerical Study on Long-Term Water Injection Procedure and the Corresponding Formation Property Variation
Authors: Liu He , Wang Han , Wu Heng'An , Wang Xiu'Xi 
Published: October 2013

Abstract
The technique of water injection is a commonly used technology for enhancing oil recovery. We establish finite element models (2D axial symmetric model and 3D model) to simulate the procedure of long-term water injection. In the models, fluid- solid coupling is considered. The primary equations include stress equilibrium, Darcy’s law, the effective stress principle, formation damage and so on.
The basic mechanism of water injection is discussed with the 2D axial symmetric model. The results show that water injection may lead to increase of the pore pressure evidently and enlargement of the influenced area gradually in the duration of injection, and thus the main purpose of water injection is achieved. However, the stress field redistributes. The stress distribution near wellbore is more complicated and results in stress concentration. Consequently the formation is damaged and the permeability changes obviously. The effect of original formation heterogeneity on water injection is also studied. The original formation property obeys Weibull distribution. The results indicate that the more inhomogeneous the formation is, the larger the damaged area will be.
The influence of different helical perforation densities on water injection procedure is discussed with the 3D model. The results show that high perforation density may lead the formation damaged more seriously. Since perforation is a kind of artificial defect in the formation, more perforations make the stress concentration near wellbore more serious. As a result, the damaged formation area is larger.
Our work can provide an understanding of formation property variation due to water injection, and the petroleum engineering practice will benefit.
Flng Lean – A Natural Development
Authors: van Dongen Marc , van der Velde Harry 
Published: October 2013

Abstract
Construction of the Shell Prelude FLNG facility is currently well underway. When completed, the facility is expected to export LNG, LPG and condensate from a rich gas stream. Developments with rich gas streams, using similar facilities, may also benefit from the considerable amount of revenue possible from condensate and LPG sales. However, some fields contain gas that is significantly leaner, and will not have the benefit of condensateand LPG revenue streams. Recognising that the world has lots of low liquid content gas, so called ‘lean gas’, Shell saw a strategic opportunity and is developing FLNG Lean.
FLNG Lean is an FLNG concept with a nominal LNG production capacity of 6 million tonnes per annum and reduced functionality for other liquids. FLNG Lean is a natural development within the Shell standardised FLNG design approach and it is designed to expand our LNG capabilities. We anticipate it to be cost-competitive for larger, lean gas fields. FLNG Lean has many similarities when compared to the standard FLNG design. We continue to focus on standardisation, with modifications only as required. The substructure design with its utilities, the accommodation, the operating and the safety philosophies, the flare and blow-down system, the LNG containment systems, and the LNG off loading system are all the same thereby enabling repeatability gains. Lessons learnt and the latest technology developments have also been implemented. Some utilities are relocated to the substructure to create sufficient deck space for the liquefaction trains and process equipment. High capacity modern aero-derivative gas turbines will drive the liquefaction compressors and power generators. Process heating requirements will be largely met by waste heat recovery units.
This paper will describe the FLNG Lean design and its potential application area. We will highlight the approach followed, explain the main features of FLNG Lean, and compare it with the generic Prelude FLNG design.
Planning, Organization And Success Of A Wide, Detailed Geophysical Survey Offshore Makassar Strait
Authors: Coral Juan Carlos , Paone Francesco , Marceglia Andrea 
Published: October 2013

Abstract
The Oil & Gas industry has seen recently a strong push towards high end goals required by the tight bond between economics, the time for the development of an investment, planning and finally construction and service of plants. This is the specific case of the Jangkrik field development. As part of the POD (Plan of Development) approval by the Government of Indonesia, eni Indonesia committed to a "fast track" strategy in which the field would come into production in 2016 and consequently directed all efforts towards early development of the engineering design for the production facilities. Thanks to the execution of the geophysical site investigations during the early project design stages, several elements were discovered, which quality allowed a much clearer picture of several morphologic elements affecting the field design. Among the most important decisions that were taken during this design phase, we can consider the one to relocate the FPU in a shallower water depth (100mt WD on the continental shelf) with respect to the preliminary design (about 320mt WD along the escarpment). Such decision, if not taken on time, would have created major reworks during the execution phase, together with a potential big delay in the project and potentially jeopardizing the possibility of the Jangkrik North East integration. Another important decision was the one relevant to the use of rigid versus flexible flow lines. This is also critical for the procurement activities to be progressed on time and also for the flow assurance studies. This type of decisions, taken during this phase of the project, in the long term will lead to better design, minimize re-works, reduce costs and time and ensure project integrity.
Drilling Statically Underbalanced Gas Well with Managed-Pressure Drilling to Target Depth Safely and Efficiently
Authors: Krisboa Agustinus , Iskandar Yoshua P. , Irawan Fikri , Karnugroho Ardia , Toralde Julmar Shaun 
Published: October 2013

Abstract
Drilling a statically underbalanced well means that the hydrostatic head exerted by the fluid used for drilling is lower than the formation pressure. However, by utilizing Managed Pressure Drilling (MPD) equipment, such as a Rotating Control Device (RCD), an automated MPD choke manifold, and a downhole isolation valve (DIV), and employing MPD techniques, such as Constant Bottomhole Pressure (CBHP) and Pressurized Mud Cap Drilling PMCD), surface backpressure can be exerted during drilling and a dynamically overbalanced condition can be established during the operation, thereby preventing the constant flow of reservoir fluids to surface.
The CBHP variant of MPD was initially deployed with statically underbalanced drilling fluid to minimize damage to the reservoir until severe circulation losses were encountered, once the high permeability areas being targeted for the big-bore gas wells were penetrated. Thereafter, the same drilling fluid was to be utilized to make the transition to another MPD variant, PMCD, faster and easier. PMCD was utilized in order to continue drilling the well to target depth without needing to restore circulation and pump lost circulation material (LCM) and cement, which will also impair the productivity of the gas reservoir.
This paper focuses on how these combinations of MPD techniques were successfully utilized in order to drill high-rate gas wells in South Sumatra safely and efficiently. Details of how the system was safely and efficiently installed and subsequently deployed, as well as the set-up and procedures utilized will be elaborated. Further improvements to the system and to the operation are also discussed for future applications. Finally, the evolution of MPD methods used in drilling the gas reservoir is also described in relation to the changes that have occurred to the reservoir after it has already been put in production for a number of years.