bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coiled Tubing Deployed Electrical Submersible Pump (CT-ESP) Application at Offshore Operation
Authors: Bakar Hasmizah Binti , Chee Xianlung Ivan , M Rozali M Irsyaduddin , M Nadzri M Zulhairi , Ayad Kamal Mohamad , Jaafar Juhaidi 
Published: February 2015

T offshore field is located in north-west of Kota Kinabalu, Sabah, Malaysia and has been in operation for almost 40 years. The major challenges faced by this field are depleted reservoir pressure, gas lift compressor frequent interruptions and shortage of gas lift supply hence various new artificial lift technologies have been evaluated. ESP is identified to be the most operationally decent technology to increase production, prolong field life and increase the ultimate recovery. Historically, T field had attempted downhole hydraulic jet pumps to lift quarter of the platform's oil wells but failed. ESP deployment via coiled tubing was deemed the most effective and economical due to performing rigless intervention and significantly shorter trip times into the well as compared to the time taken to make-up conventional jointed tubing. Within 2 years, this technology successfully contributed over RM50million cost saving from 3 rigless workover and zero Lost Time Injury (LTI).
This paper will share the journey and lesson learnt of this project starting from technology assessment, planning to execution phase. The experience gained during this project will be a valuable input in replicating this ESP deployment method for other wells in this platform and for other offshore prospects in term of safety, performance, reliability and cost saving.
3D Structural restoration and Geomechanical Forward Modeling in a visco-plastic medium to natural fracture prediction in a Malay producing field, offshore Malaysia
Authors: Lefranc M. , Hussein A. Mohamad , Tan C.P. , Legrand X. , Lee B.C. , Maerten L. , Press D. , Anis L. 
Published: February 2015

In order to ensure a successful drilling campaign, it was required to obtain knowledge of the possible location of natural fractures generated by different tectonic events affecting the Malay Basin through geological time to a high level of certainty. Acquiring this information would assist in the optimization of well trajectories to avoid these naturally fractured regions which would likely result in severe wellbore instability problems.
As described by Petronas (1999&2007) the Malay Basin underwent an extensional phase during the Oligocene period with deposition of lacustrine source rocks. The Miocene was a time of fluvio-deltaic source and reservoir deposition and a compressional phase starting Early Miocene resulted in structural inversion. A major unconformity underlined the peak of the tectonic inversion in relation with the closure of Proto-South China Sea and the opening of South China Sea further to the North. In the Malay Basin, the geological history led to a complex structure trapping which requires further works and then an innovative approach based on the geomechanics was proposed to predict the locations containing natural fractures. The objective of the study was to model the heterogeneous paleo stress and strain states by the construction of a geomechanical model in this field and to relate the predicted strain and stresses to fracture characteristics.
The first part of the study was to quality control the interpretation of the 3D structure of the area, which had been constructed from 3D seismic interpreted surfaces and faults. 1D Mechanical Earth Models computed from well data provided the required elastic parameters for the 3D structural restoration. The technique used to perform the restoration was based on the Finite Element Method, particularly suited for modeling complex geological structures.
The second part of the study consisted in the computation of the paleo stress state via geomechanical forward modeling and relating the resulting plastic strain attributes with fracture density. In this step, the strains calculated from the displacements derived from the structural restoration were applied at the boundaries at each geological time-step in order to calculate the internal stress condition and plastic strain distribution accumulated through geological time.
Feasibility of the Steam-Assisted-Gravity-Drainage Process in Offshore Heavy Oil Reservoirs with Bottom Water
Authors: Dong Xiaohu , Liu Huiqing , Zhang Zhaoxiang , Lu Chuan , Fang Xin , Zhang Gaige 
Published: February 2015

Due to the water-coning problem, cycle steam stimulation (CSS) in the heavy oil reservoirs with bottom water is often less effective, and the oil recovery is even below 10%. Steam assisted gravity drainage (SAGD) is the oil-producing process with a constant pressure-drop (about 0.30 MPa), and it is a potential technique for this reservoirs. Through the implementation of SAGD, bottom water could be effectively controlled.
Aiming at the heavy oil block of LD5-2N in Bohai offshore oilfield, the SAGD performance in heterogeneous heavy oil reservoir with bottom water was numerically studied in this paper. In these simulation models, the water was broken into three components (connate water, injected water and bottom water) to study the water producing in SAGD process. Thus, the influences of startup approach, oillayer thickness, water thickness and the distance between well-pair and bottom-water on the water rising were all simulated. Thereafter, a set of numerical simulations were performed to assess the shale issues in SAGD process, e.g. the vertical and horizontal position of shale-barriers, the shale distribution range, the barrier permeable condition and the macroscopic vertical permeability.
Results indicated that bottom water reduced the ultimate recovery of SAGD process by about 10%~20% of the OOIP. The startup by steam-circulation was much suitable for the bottom water heavy oil reservoir instead of CSS approach. The bottom water tremendously reduced the startup pressure-decline rate, and thus the startup-time was prolonged. The distance between well pair and water zone had a great influence on the SAGD performance, and a small distance would delay the beginning time of the steam-chamber rising. For reservoir heterogeneity, the vertical and horizontal heterogeneity have great influence on the drainage process, especially the shale cases. It tremendously decreased the recovery rate by about one time.
This investigation could be used as a tool for the successful design of SAGD process in heavy oil reservoirs with bottom water.
Study on Erosive and Magnetic Effects of Weighting Agent in a High Density Water-Based Drilling Fluid
Authors: Yan L.L. , Wang J.H. , Xu X.G. , Feng J. , Liang H.J. , Xing X.N. 
Published: February 2015

Erosive and abrasive wear effect of water-based drilling fluid (WBM) on down-hole tools may reduce the service life of down-hole tools, and its magnetic contamination on Measurement-While-Drilling (MWD) directional tools may cause azimuth errors and reduce the wellbore position accuracy. The erosive and magnetic effects would be worse when a high density WBM densified with a high content weighting agent was employed. One of the main reasons of the erosive and magnetic effect is related to the weighting agent used. To reduce the erosive effect and magnetic interference of weighting agent, a micronized barite as a new weighting material was prepared in this paper, and then characterized by scanning electron microscope (SEM) and laser particle size analyzer.
The prepared micronized barite, as a new weighting agent of high density WBM, has great promise to reduce the drag, erosion and magnetic interference along the horizontal section of large extended-reach wells and horizontal wells. It can also be used in HTHP wells and coiled tubing drilling technology.
In our experiments, two conventionally weighting agents, barite and hematite were chosen to as the comparing samples. The erosive effects, magnetic contaminate tests, lubricity and rheological properties of high density WBM weighting with micronized barite, barite and hematite were evaluated on erosion instrument, a fluxgate magnetometer, an EP lubricity tester and a rotational viscosimeter, respectively. It was found that the high density WBM weighted with micronized barite showed less erosion, lower magnetic susceptibility, similar or better rheological properties, and smaller lubricating coefficient than that weighted with hematite or barite.
Comparing with hematite or barite, the micronized barite could effectively reduce erosive wear on down-hole tools, reduce magnetic contamination on MWD directional tools, and control the rheological property of high density WBM, which would significantly contribute to the service life of down-hole tools, the wellbore position accuracy and the safety of drilling operations.
Chemical EOR Produced Water Management at Malay Basin Field
Authors: Najamudin Khairul Ezani , Halim Nor Hadhirah , Salleh Intan Khalida , Chai Ching Hsia Ivy , Yusof M Yusri , Sedaralit M Faizal 
Published: February 2015

This paper examines the requirements, mechanisms and mitigation options for management of produced water from chemical EOR field. As the application of Chemical EOR at Angsi field, the produced water is expected to contain some levels of injected chemicals such as surfactant and polymer.
A key concern is the potential impacts on marine environment in which current field facilities design is not cater for the produced chemicals management. A detail laboratory studies were conducted such as toxicity assessment on local marine fish, grouper indicated the polymer is practically nontoxic with LC50&gt;500 mg/L, and the surfactant is relatively toxic with LC50=1.23 mg/L. The polymer also poses significant environmental concern as it has low biodegradation property with less than 20% are biodegradable in 28 days.
Complicating this situation, alterations of produced fluids physical and chemical properties are also demonstrated. Laboratory analyses of ASP produced fluids predicted higher fluids viscosities, with stable and higher emulsion formed (increment up to 40%) which contributed to higher basic sediments and water (BS&W) percentage. Even minimal scale issues is predicted, mentioned conditions had already contributed significant impact on existing facilities and chemical dosage efficiency and requirements.
The complexities in the conditions render managing ASP breakthrough required defined EOR produced fluid management. In view of current facilities limitations, the study was focused in identifying suitable chemicals and mechanicals mitigation options to treat and manage surfactant and polymer residues toward Angsi Chemical EOR implementation. Recommended solutions were based on laboratory studies, current facilities configuration, technical and regulatory acceptance and economic viability as the actual impacts varied depending on fluids composition and characteristic of the receiving environment.
Fatigue Analysis of OCTG Premium Connections: Theory, Laboratory Testing and Application
Authors: Jordan G. Rodriguez , Merliahmad M. , Grittini S. , Mazzaferro G. 
Published: February 2015

The paper describes the additional design considerations on top of standard design criteria for casing or tubing strings when subjected to cyclic loads. In addition, this paper chronicles comprehensive laboratory testing programs that have been carried out to analyze and quantify the fatigue limit of various semi-premium and premium connections.
OCTG connections are being increasingly used in drilling environments as an alternative to conventional drill pipe. Furthermore, OCTGs are commonly rotated into place in horizontal and ERD wells. During the drilling and running of OCTG in deviated sections, the combination of the resultant bending of the string and its rotation generate alternating stresses in the pipe body and connections, creating the conditions for potential fatigue damage.
OCTG connections are not as fatigue resistant as tool joints due to its inherent design. Fatigue is a complex process that affects mechanical components that are subjected to cyclic loads. Fatigue failure is a sudden crack, but it comes from a process that involves different development phases until the failure of the component becomes evident; this failure is produced at stress levels far below the static elastic limit of the material. Several factors present in OCTG connections applications including mean stress, stress range, make-up torque, and material grades have been introduced in the full scale testing programs. As a result, robust fatigue life limit curves, used for real cases fatigue analyses, have been developed and are presented in this paper.
Since fatigue damage could lead to the failure of the string based on its weakest link, which in general terms would predominantly be the connections, its resistance to cyclic loading must be thoroughly considered to understand the performance limitations this may impose on the entire drilling assembly.
Use of Sequential Downtime Analysis in Planning Offshore Operations
Authors: Ballard E. , Evans M. 
Published: February 2015

A sequential downtime analysis method is presented, which is applied to the prediction of the expected duration of a typical offshore installation campaign made up of a series of tasks. Accounting for typical limiting sea states for each step of the installation sequence, it is shown how a sequential downtime analysis using a hindcast metocean time series can be used to estimate the likely duration to complete the series of tasks.
The analysis is based on typical stages in the installation of an FPSO mooring and riser system, including set-up before and re-positioning between tasks, combined with multi-year hindcast metocean data. Each task has a set of limiting sea states associated with it, as well as an expected duration and the likely variation in the duration due to delays. The effect of delays in each task on the duration of the complete sequence of operations is accounted for by a Monte Carlo type method.
The results of the analysis show that a sequential downtime analysis can be used in a number of ways to optimise an offshore installation campaign. Firstly, it can identify the best times of the year at a particular site for wave conditions which will minimise weather related delays. Secondly, by correctly accounting for realistic variations in the duration of each task due to delays, the potential total duration of the offshore operation can be more accurately estimated, along with likely costs. Finally, examples will be presented of how this analysis technique can be used to test the economics of employing more expensive equipment and/or vessels with improved capabilities to increase the limiting wave conditions for particular operations, thereby reducing total cost.
The methods presented in the paper are considered to represent a significant improvement over typical methods for planning and costing offshore operations. By allowing the likelihood and magnitude of potential delays to be better quantified, informed decisions on the potential benefits of using more capable vessels and/or equipment can be made and costs connected to the duration of the operation better predicted.
Finite Element Approach to Predict the Effect of Annular Pressure Buildup on Wellbore Materials
Authors: Jandhyala Siva Rama Krishna , Chiney Abhinandan 
Published: February 2015

Annular pressure build up (APB) is caused by thermal expansion of wellbore fluid enclosed in an annulus experiencing cyclic thermal loads due to production and injection. This may lead to significant damage to the cement sheath causing zonal isolation issues and may also cause casing collapse/burst. This work focuses on using an engineered approach based on finite element modeling to analyze the cement sheath response to APB loads for the life of the well. Actual field data of pressure build up and bleeding rates are used in our analysis.
The present study provides a methodology to analyze cement systems for their ability to survive APB conditions. A proper knowledge of response of wellbore materials (cement and casing) to APB can be helpful in design of better cement systems and in selection of appropriate casing materials which can withstand the APB conditions.
It has been observed from our comparative study of two cement systems that the stresses in the elastic cement are less than those in conventional cement. A parametric study has also been performed to analyze the effect of different cement properties. The results are quantified in terms of stresses experienced by cement sheath and casing.
This study is based on fundamental principles of structural mechanics, thus providing more reliable predictions. It helps in deciding the appropriate cement system for a predetermined production/injection rate or can give a recommendation of production/injection rates for a given cement system such that damage to the cement sheath can be avoided.
Foundation Integrity: Shallow Gas Mitigation Using the XPP Monitoring Tool - An Offshore Malaysia Case History
Authors: M.J. Rohani , A.R. Azam , T. Lunne , J.M. Strout 
Published: February 2015

Gas migration along wells from reservoir formations to shallow sub-seabed strata was identified to occur at a field, offshore Malaysia. Since 1993 numerous shallow gas kick events had occurred in the vicinity of the platform designated in this paper as Platform DB, at gas charged layers of 60m and 90m below mudline. The occurrence of shallow gas kicks is a concern as it relates to the development of excess pore water pressure in soil which in turn can potentially impose detrimental effect to foundation integrity.
Due to the dynamic nature of shallow gas migration at various depths around the subject platform, the foundation integrity of the platform complexes needs to be monitored to ensure that possible progressive increase in excess pore pressure can be identified and reduced to maintain foundation integrity.
This paper describes the efforts undertaken by Petronas Carigali Sdn Bhd (PCSB) to install the XPP@TM monitoring tool to measure the magnitude of the excess pore pressures. This paper also discusses the studies undertaken to understand the extend of the shallow gas migration and the mitigation plans that are put in place to monitor the foundation integrity at the designated Platform DB. Equipment design and operational procedures are also presented to record the efforts undertaken by PCSB engineers to ensure that XPP@TM Monitoring Tool is robust and fit for purpose.
An Experimental Study on Vertical Oil Storage System
Authors: Cai Zhonghua , Wang Jin , Li Zhe , Wang Deyu 
Published: February 2015

A new vertical oil storage system based on oil-water exchange method for a deepwater floating production system was investigated experimentally. The system mainly consists of a storage tank, water tank, upper tank, lower tank, oil pumps and pipes. Two kinds of oils (light oil and heavy oil) were investigated in the experiment. 12 oil/water exchange tests and 18 dynamic tests were carried out. The Oil/water exchange test simulates oil-water exchange progress. A special oil/water separation device was designed to separate stored oil from the water by the use of density difference between oil and water. The oil content in the discharged water at different locations was measured in terms of PPM. The cycle time of oil/water exchanges was also investigated. The aim of the dynamic test is to find out if there is significant disturbance or sloshing at the oil/water interface due the motion of the floater. The storage tank was placed on the 3-DOF sloshing equipment. Sloshing tests were done for 50% and 75% filling level. During the experiment, the oil/water separation device was set on the oil/water interface to reduce the disturbance.
Main finding from the experiment are:The oil content of in the discharged water is less than 50ppm, which meet the oily wastewater discharge standards of offshore petroleum development industry (GB 4914-85).Compared with light oil, the oil content in the water seems larger for the heavy oil in the oil/water exchange tests.The device of upper and lower tanks can reduce the oil content in the water.In the dynamic tests, no matter there is oil/water separation box or not, there is no significant disturbance at the oil/water interface.
Ultimate Gas Recovery by Use of Full Field Simulations in Concept Selection Phase
Authors: Irmann-Jacobsen Tine Bauck , Headridge Barry 
Published: February 2015

This paper presents a simulator that has been developed for the full production system from reservoir to receiving facilities including a subsea boosting station. Thus, the simulator provides a powerful tool to screen design alternatives to identify the optimal field solution in a cost efficient way at an early stage. The objective of the screening is to expose the system to all possible operational scenarios over the life of field so as to answer technical feasibility, maximum recovery and select the optimal business case.
Deeper water, longer flowlines and the demand for increased recovery have lead to the development of more complex subsea systems. A " right design first time" strategy has great impact on the subsequent phases in terms of implementation and cost. Early phase selection is particularly challenging when a Subsea Boosting Process is introduced in a large network of wells and flow-lines. The physical parameters that affect the solution increase in numbers which means increased uncertainty and risk. When evaluating the use of subsea processing on an existing or a new field, it is of crucial importance to investigate how the process will perform in the total production system from reservoir to topside.
The simulator gives the opportunity to efficiently investigate huge amounts of data and parameters. For any possible combinations of input parameters and production targets, bottlenecks in the system are revealed and challenged. Thus, all design elements that affect the conditions upstream and downstream the gas compression station are considered. The simulator uses mechanistic field proven models for all flow components (wells, pipelines and process equipment) giving realistic system responses. If a system is designed to work in balance with the natural system responses from the beginning, complicated process control can be minimized.
In this paper, optimal Subsea Gas Compression design simulation results for specific fields are presented. In addition is shown how Flow Assurance strategies for hydrate and liquid management are integrated as a part of the total system design. It is shown that using a full field simulator in the concept selection phase ensures robust and optimized field design.