bluuebunny/crossref_metadata_2025_split huggingface dataset:
Innovative Downhole Flow Control Solution and Challenges in a Carbonate Field Offshore Indonesia
Authors: Rahmanto Wahyu Agung , Setiawan Andreas Lukman , Triyono Triyono , Zulfikar Zulfikar , Handono Indan , Suryadana Siswara , Thopyen William , Fah Gordon Goh Kim , Wismawan Satriya Galih 
Published: April 2019

Abstract
Pangkah field located at offshore East Java Indonesia is an oil and gas producer within fractured carbonate reservoir lithology. Fractured corridors introduce challenges during drilling and production phase. To optimize production, several wells had been completed with novel Inflow Control Device (ICD) design. This paper highlights the potentials of such customized ICD's innovation with integral sliding sleeve.
This novel ICD design preserves intended ICD position, and in addition could be shifted in the downhole later either to be in open or closed position if required. Either coil tubing or electric-line could be deployed to shift the downhole 3-positions of this integral ICD with sliding sleeve. The integral design allows a fully open position for well stimulation or circulation in formation damage treatment. Meanwhile another position enables ICD configuration for inflow control. The last position which is fully-shut or closed can be activated during completions string Run in Hole (RIH) to allow floating toward Total Depth (TD), minimizing torque and drag, and maintaining wash-down capability without wash pipe. The whole closed or floating system while RIH makes it possible to set assemblies of open hole hydraulic set packers or any pressure activated devices. During late-life, selective compartment could be shut-off against excessive water production decisively whenever required.
Good sealing of the open hole packers against borehole is essential for the effectiveness of open hole compartmentalization and ICD production. The open hole hydraulic packers must be placed and set properly within its expanding range. Combination of petrophysical analysis, caliper log, image log, seismic coherency, and drilling loss data are used to define the compartments and packer placement.
This novel ICD's innovation with water shut-off capability in addition to the main ICD's inflow control is designed comprehensively with 3D single wellbore dynamic modeling. ICD's single well dynamic modeling were executed along three phases i.e. pre-drilled, real-time and post-job. Each phase respond to operation readiness and reservoir management. Intensive engagement with asset team and realistic modeling design range lead to positive production results.
Successful Use of Directional Casing While Drilling
Authors: Penot Steve , Segui Emmanuel , Pickup Duncan 
Published: April 2019

Abstract
This paper provides technical feedback of a successful use of Directional Casing While Drilling (D-CwD), a technique allowing to simultaneously drill and case the hole while following the directional plan. It highlights how substantial gains were realized on Badamyar project in Myanmar, having benefited from the D-CwD technique to optimize the architecture.
The Badamyar development campaign involved the drilling of four horizontal gas wells in conventional offshore environment in Myanmar. Other regional wells had already experienced wellbore issues to get the 13 3/8″ casing vertically to 450m. On Badamyar, drilling directly with the casing allowed to minimize operational exposure to losses and wellbore instability, and to achieve the challenge to get the 13 3/8″ to 800m and 45deg inclination, avoiding the requirement for an additional surface casing.
All four 13 3/8" sections were successfully directionally casing-drilled and cemented in fourteen days within budget duration, which, despite the additional complexity, is comparable to the best performance in the block in the last twenty years. The average Rate of Penetration was 30 m/hr, same as fastest conventional case in the field, without mentioning the huge advantage that when reaching the required depth, the casing is already in the hole. Indeed, once the casing has reached the required depth, drill pipe is run inside the casing to unlatch and recover the directional BHA, and pull it back to surface, leaving the casing in place ready for the cement job. While conventionally, casing still needs to be run with associated time and risks (losses, wellbore stability, stuck casing, accidental side-track, etc…).
This Directional-CwD was a new concept to most of the teams involved: Operator, Rig contractor and Tubular Running Services. It required changing the "hundred and thirty years of conventional drill-pipe drilling" mindset. This paper describes the decision making process to switch from conventional to casing-drilling, the preparation phase where risks were identified and mitigated, as well as the excellent operational results.
This paper, by presenting a successful first implementation within a major O&G company, brings to the drilling industry an additional case that the system works, is technically fit-for purpose, cost effective, and has the tremendous potential to replace conventional drilling in several applications. It also highlights some potential limits and opportunities for optimization which should be considered for further development (trajectory constraints, fatigue life and well control).
A Strategic and Flexible Approach to Through Tubing Electrical Submersible Pump Cable Deployed TTESP-CD Replication for Technology Robustness
Authors: Radzuan Nurul Asyikin M. , Salleh Nurfarah Izwana , Chandrakant Ashvin Avalani , Rusman Liyana , Zamanuri Kautsar , Bakar Azfar Israa Abu , Yip Pui Mun , Jamaluddin M. Helmi , Ghonim Elsayed Ouda , Nambiar Vijay , Alexander Euan 
Published: April 2019

Abstract
Following the first pilot success of the truly rigless 3-1/2" tubing cable deployed ESP (TTESP-CD in offshore field of Sarawak Basin, PETRONAS has taken steps to further advance in the technology development and application through more replications within Sarawak and Malay Basin. PETRONAS had been looking into a strong business case for the TTESP-CD technology for a wider application throughout Malaysia region by looking at fields with strong/moderate water drive and low bubble point pressure besides having other limitations on the platform including the facilities reliability issues.
TTESP-CD are to be applied widely in Malaysia with more flexibilities in design and improvement towards the subsurface equipment, installation equipment and procedures. With the challenges in the existing completion and production requirement for replications, based on the lesson learnt from the pilot implementation, multiple improvements to the system have been done including; 1) A High Rate Slim Pump with Flexible Application 2) Alignment Tool for Cable Hanger Orientation. With this in place, more opportunities identified for the candidate selection which improve the installation philosophy specifically in dual string applications and enhance the efficiency in installation procedures.
Case studies of TTESP-CD replications in Malay & Sarawak Basin for Field T, Field B and Field P presenting the best case for TTESP-CD application with improvement to design, equipment and application. These will bring additional value to PETRONAS with estimated production gain of ∼1.5 KBD and up to 1.2 MMSTB reserves to be monetized with additional value saving of up to RM 6 Mill.
Besides the subsurface challenges, aging offshore assets brings a lot of challenges, especially on the space availability, structural integrity, power availability and distribution, instrumentation and data transmission. This requires an integrated approach from multiple disciplines in delivering the studies as per required within the targeted timeframe.
Improved Gas Recovery for Bottom-Water-Drive Gas Reservoir Using Downhole Water Drain Technique: A Success Story from Arthit Field, Thailand
Authors: Phummanee Sutthipat , Rittirong Ake , Pongsripian Winit , Phongchawalit Natthaphat 
Published: April 2019

Abstract
The objective of this paper is to demonstrate the implementation of downhole water drain (DHWD) technique to improve gas recovery factor for bottom-water-drive gas reservoir in the multi-thin reservoirs system in Arthit field. This technique was selected as an alternative method to defer water loading in the wellbore by preventing early water breakthrough meanwhile enhancing gas expansion. Project planning, operation, and performance evaluation are the gist of the discussion here.
Candidate selection was the critical first step to the success of DHWD technique. The suitable wells require a gas-water contact reservoir at the upper part of the well and totally depleted reservoirs below it. After identifying candidates, bottomhole pressure survey was performed to investigate the reservoir condition for reservoir simulation. Both gas and water layers above and below the gas-water contact were perforated as designed. A plug was set between the perforated gas and water layers to isolate the flow. This allows gas to be produced to surface while water flows downwards to the depleted reservoirs.
The key parameters used in evaluating the effectiveness of DHWD technique are incremental gas recovery and water breakthrough time. According to the production history of existing gas-water contact reservoirs in Arthit field, massive water production generally starts to intrude after 1.35 months of production at which water-gas ratio increases above 50 STB/MMscf. As a consequence, the gas production sharply declines and eventually ceases to flow. The water breakthrough time of the two trial wells in which DHWD technique was applied is significantly slower than the field average. One was observed water breakthrough after 2.05 months and the other was after 5.40 months of the production. Gas EUR gain is the difference between the EUR when applying DHWD technique by declined curve analysis and the expected EUR of conventional production by statistical method. The results from the two trial wells indicate that DHWD technique can significantly improve the EUR by 110% and 871%.
Downhole water drain is a groundbreaking technique that can be practically implemented to enhance gas recovery of bottom-water-drive gas reservoirs. This technique is recommended for gas field as an alternative strategy since it yields substantial additional reserves gain while required only a small additional cost from the additional perforation of water sand and permanent bridge plug.
4-D Geomechanics Modelling for Potential CO2 Storage Site in Malaysia – Fault Reactivation and Maximum Pressure Injection Limit
Authors: Nik Kamaruddin Nik M Fadhlan , Teng Kevin Ging Ern , Musa Ikhwanul Hafizi , Tan Chee Phuat 
Published: April 2019

This paper presents a study on the risk associated with CO2 injection in geological storage and fault reactivation through a comprehensive workflow for determining the feasibility of CO2 storage campaign in carbonate reservoir in Malaysia. The study includes constructing a 4-D coupled reservoir geomechanical model and developing a workflow that can be used to evaluate geomechanics risks associated with carbon capture and storage (CCS) by outlining results and findings that drive key decisions in the planning of CCS strategy.
The workflows aims to better delineate and enumerate the risks with CCS as it constructing and calibrating single well models by corroborating numerous inputs including stringent laboratory testing data and drilling analysis, and combining with structural model and reservoir model to create a field wide 4-D geomechanical model using advanced time lapsed geomechanics simulation. Coupled simulations with the dynamic reservoir model provided predictions of the fault stability by considering fault deformation. The paper further highlights the geomechanics evaluation consideration (economics and engineering trade-off) in designing maximum safe injection pressure for CO2 sequestration program.
The results of the study show fault condition subjected to different time-steps of the coupled simulation during depletion and injection. At each time-step, the development of plastic shear strain and absolute displacement are plotted and risks associated with the change in reservoir pressure are assessed and quantified. Different injection plans are modelled to determine the impact on final storage capacity, long term fluid containment and upper safe injection limit to avoid breaching the caprock.
The study offers the utilization of the latest techniques in 4-D coupled geomechanical modelling which reduced the study time and cost significantly, making it affordable for in-time solution for decision making. The paper also aims to encourage the consideration of the applied novel workflow involved in CCS strategye valuation focusing on risk assessment which ultimately will affect reservoir maximum safe injection limit, capacity, long term storage safety, and monitoring program to mitigate potential geohazard leakage.
Heterogeneity and Relative Permeability Role in Primary Drainage: from Lateral to Vertical Perching
Authors: Hulea Iulian N , Kim Igor 
Published: April 2019

Abstract
Building realistic and reliable subsurface models requires detailed knowledge of both the rock and fluids involved. While the hydrocarbon volume estimation has a profound impact on the viability of a development, next to the saturation height models and free fluid levels the hydraulic communication and permeability have a significant role as well. Compartmentalization could change the field development plan: e.g. increase the well count, necessitate significant change to the well profiles (e.g. extended range drilling), require complex and expensive completion strategy.
When in different parts of the same field different free fluid levels are identified, leading to different fluid contacts for the same rock quality, the lateral hydraulic communication at the field level can be challenged. This aspect is of importance since the hydrocarbon volume distribution has drastic impact on total hydrocarbon recovery. At the same time building and initializing a model based on different free water level positions across the field, zero capillary pressure, is challenging.
Perched water contacts are the result of water entrapment during the hydrocarbon migration that could lead to variability in free fluid levels across a field. The fundamental controls that lead to the perched contacts formation are studied and shown to be the rock quality and relative permeability. Counter-intuitively, the perching effect is not going to feature in poor quality rocks with sub-milli Darcy permeability – the effects would be visible only for a considerable barrier height, with Free Water Level to barrier height of tensto hundred meters.
In addition, realistic heterogeneous models are studied to investigate the heterogeneity effect on perching and on formation pressures. Whilst low permeability is correlated to a wide range of depths where two phases are mobile, the perching controls in high permeability contrast formations are studied.
Using a dynamic modelling route, potential water entrapment occurrence as a result of high permeability contrast is shown, without structural control, i.e. an underlying impermeably zone defining a trap. The main control in such a case is water permeability just as in structurally controlled perching. This work challenges the industry view that model initialization should be performed with buoyancy as an equilibrium driving mechanism. Such a saturation modelling route would lead to discrepancies when compared to using the capillary pressure as a direct input instead of buoyancy.
Seismic Attribute Feasibility Study for Fault and Fracture Analysis and Integration with Spectral Decomposition: Application in Sarawak Basin
Authors: Hamidi Rosita , Ghosh Deva 
Published: April 2019

Abstract
Fault and fracture study has a great importance in hydrocarbon prospect exploration and development. Consequently, there have been lots of efforts to analyze the existence and extent of faults in subsurface layers using different methods and tools available to geoscientists; among which the seismic attributes have been proven to be efficient in detecting areas affected by faults and fractures. Seismic attributes help interpreters to highlight details focusing on the geological features of interest in seismic data. However, there are some limitations in the performance of these tools, as the algorithms are dependent on the seismic survey parameters, quality of the data and its existing patterns, and geology of the study area. Consequently, new strategies and algorithms are needed to improve the information obtained from the calculated attributes.
In this study, fault and fracture damage zone analysis is done on three – dimensional seismic data from Sarawak basin in Malaysia. Commonly used seismic attributes to detect such features including variance, dip – magnitude, curvature, and gradient – magnitude are applied. Next, spectral analysis, as a tool to identify events with different frequency content is used which can detect the patterns related to faulting and fracturing of the subsurface layers. The proposed method in this work is to examine the attributes’ performance on spectrally decomposed seismic cubes to unmask the details present at different frequencies. Accordingly, the seismic attributes are applied on the selected cubes, and the color blended cubes of the outputs are evaluated. As the results show, the new strategy reveals more detailed information that already exist in seismic data but cannot be distinguished because they are concealed in the full band seismic cube. Comparing each pair of conventional vs. spectral assisted attributes shows enhancement of the results (more details and better resolution) in all evaluated seismic attributes with the proposed method.
Rate of Penetration Prediction in Shale Formation Using Fuzzy Logic
Authors: Ahmed S Abdulmalek , Elkatatny Salaheldin , Ali Abdulwahab Z , Mahmoud Mohamed , Abdulraheem Abdulazeez 
Published: April 2019

Abstract
Rate of Penetration (ROP) means how fast the drilling bit is drilling through the formations. It is known that in the oil and gas industry, most of the well cost is taken by the drilling operations. So, it is very crucial to drill carefully and improve the drilling processes. Nevertheless, it is hard to know the influence of every single parameter because most of the drilling parameters depend on each other, and altering an individual parameter will have an impact on the other. Due to the difficulty of the drilling operations, up to the present time, there is no dependable model that can estimate the ROP correctly. Consequently, using the artificial intelligence (AI) in the drilling is becoming more and more applicable because it can consider all the unknown parameters in building the model.
In this work, a real filed data that contain the real time surface drilling parameters and the drilling fluid properties were utilized by fuzzy logic (FL) to estimate the rate of penetration. The achieved results proved that fuzzy logic technique can be applied effectively to estimate the rate of penetration accurately with R = 0.97 and AAPE = 7.3%, which outperformed the other ROP models. The developed AI models also have the advantage of using less input parameters than the previous ROP models.
DESCRIPTION OF MATHEMATICS REASONING ABILITY IN SOLVING STORY QUESTIONS BASED ON COGNITIVE STYLES AND INITIAL ABILITY OF STUDENTS
Authors: Mutmainnah Mutmainnah , Mulbar Usman , Djadir Djadir 
Published: April 2019

This study is descriptive research which employs qualitative approach, aims at describingMathematics reasoning ability in solving story questions based on cognitive style and initial ability of students. The cognitive styles examined are Field Independent (FI) and Field Dependent(FD). Where as, initial ability of students arecategorized as high and low. The research site was at MtsN 1 Makassar City with 8 students of grade VIII as the research subjects. The research subjects represented four categories, namely (1) FI with high initial ability, (2) FI with low initial ability, (3) FD with high initial ability and (4) FD with low initial ability. Data collection techniques were conducted through interview based on mathematics reasoning ability test. The research instruments were Group Embedded Figure Test (GEFT), initial ability test, mathematics reasoning ability test, and interview guidance which were valid and reliable. The results of the study reveal that: (1) FI subjects with high initial ability has a good reasoning level in understanding the structure in solving mathematics problems, (2) FD subjects with high initial ability has minor problems in understanding the structure when solving rectangular story questions but still able to arise his reasoning ability, (3 ) FI subjects with low initial ability has reasoning ability but inaccurate in conducting solution plan, and (4) FD subjects with low initial ability has less reasoning ability so that they need guidance in solving rectangular story questions
Writer Identification Based on Arabic Handwriting Recognition by using Speed Up Robust Feature and K- Nearest Neighbor Classification
Authors: Abdul Hassan Alia Karim , Mahdi Bashar Saadoon , Mohammed Asmaa Abdullah 
Published: April 2019

In a writer recognition system, the system performs a “one-to-many” search in a large database with handwriting samples of known authors and returns a possible candidate list. This paper proposes method for writer identification handwritten Arabic word without segmentation to sub letters based on feature extraction speed up robust feature transform (SURF) and K nearest neighbor classification (KNN) to enhance the writer's identification accuracy. After feature extraction, it can be cluster by K-means algorithm to standardize the number of features. The feature extraction and feature clustering called to gather Bag of Word (BOW); it converts arbitrary number of image feature to uniform length feature vector. The proposed method experimented using (IFN/ENIT) database. The recognition rate of experiment result is (96.666).