bluuebunny/crossref_metadata_2025_split huggingface dataset:
Risk Management in Deepwater Exploration Well: Reduced Depth Uncertainty Through Acquiring Seismic While Drilling
Authors: Purnomo Agung , Octaviani Tenny , Paterson Graeme , Pasaribu Ihsan Taufik , Mori Ryota , Ahmed Aqil , Akama Kenichi , Aini Muhamad Faizol Badrul 
Published: April 2019

Abstract
One of the key for successful drilling through carbonates build up structure is accurate time depth information to avoid kick-loss scenario during drilling if the carbonate is accidentally penetrated in the unexpected shallower hole size. Setting the casing point accurately to isolate the high overpressure regime on the overlying shale above the carbonate is required. During Kangean operation, Geostopping using Seismic While Drilling (SWD) technology was applied for setting the 9 5/8" casing before penetrating the Prupuh carbonate formation and updating the pore pressure model. This paper will demonstrate an application of SWD in Indonesia’s deepwater operation of predicting critical carbonate depth enabling well construction on time and on budget.
Acquisition of SWD was done during an acoustically ‘quiet’ period, during stand connections while pumps are off. Real-time waveforms are transmitted to surface through the mud telemetry system and sent to processing center via secure connection systematically after each seismic level acquired. Processing was done in real-time providing updated time-depth information, placing bit position on the seismic section in depth domain for refining depth prediction and ultimately Vertical Seismic Profile (VSP) corridor stack containing seismic reflectors along the wellbore and ahead of the bit for look-ahead information. The real-time updated interval velocity was used to update pore pressure model for monitoring the overpressured zone and to adjust mud weight accordingly while drilling to prevent a kick situation.
A total of 27 real-time SWD levels were acquired during drilling over interval ~1,800 ftMD. The data was found to be of a high quality that allowed for an accurate well tie of the Prupuh Carbonate top with a final depth prediction. Real time velocity showed that velocity of Cepu shale above the Prupuh carbonate was slower than pre-job velocity model, meaning that the Prupuh carbonate depth is shallower than initial prediction. Real time decision was made to set the casing before Prupuh Carbonate top. The actual Prupuh top was 23 ft deeper than the latest real time Prupuh prediction. This SWD technology allows us to reduce top carbonate uncertainty from +697 ft/-375 ft to become +/− 23 ft and ultimately saved the well from potential catastrophic event.
This study demonstrates that SWD technology give us confidence to manage risk in real-time.
Calibrated Natural State Model in Sorik Marapi Geothermal Field, Indonesia
Authors: Mulyani Sri , Sarmiento Zammy , Chandra Vicky , Hendry Ridha , Nasution Syukri , Hidayat Ryan , Jhonny Jhonny , Sari Pebrina , Juandi Dedi 
Published: April 2019

Abstract
Understanding the reservoir conditions through 3D subsurface modeling is the key to optimize the exploration stage in geothermal field. A calibrated reservoir model based on updated data can be very important for this process. The main challenge of reservoir characterization in a geothermal field is the lack of subsurface data, therefore surface data are useful for reservoir modeling. This study utilized Sorik Marapi geothermal field data as a reference for reservoir modeling. This field is one of the geothermal fields in Indonesia that has been recently drilled, with results indicating the existence of a high temperature-neutral acidity resource. Initial reservoir model has been built from the previous study to create conceptual 3D subsurface model which includes structural, lithology, resistivity, and temperature distribution from surface exploration data, including surface mapping, remote sensing image interpretation, the magnetotelluric method, and subsurface data from six wells data.
The objective of this paper is to calibrate the initial reservoir model with information from an additional ten new wells data to improve delineation for updated reservoir area in the field. Software that allowed multidisciplinary data integration from surface to subsurface information was used for the calibration of the initial 3D model. The workflow to calibrate the model started with data loading and quality control, preparing the old 3D model and comparing it to new well data, analyzing the comparison, and updating the 3D model. Finally, the new delineation of reservoir zone can be determined.
The result of this study is an updated 3D subsurface static model defining the vertical and lateral reservoir boundaries, as well as the prime resource areas, which would be the basis for designing future well targets, and parameters for a dynamic reservoir model. The same model can be expanded to construct the numerical model to match the natural state condition of the field and make forecasts of the future reservoir behavior at different operating conditions. The main properties of the updated 3D model are lithology and temperature, which are important in geothermal reservoir delineation.
Surge Peak Pressure Magnitude Impact due to Vapour Formation and Collapse: Simulation Study, Mitigation and Testing
Authors: Alwi Aqeela Hani , Philip Nicholas 
Published: April 2019

Abstract
A surge study was conducted for the addition of a new LNG storage tank in PETRONAS Malaysia LNG in Bintulu, Sarawak. With the new LNG storage tank being the largest, furthest, highest elevation and with the biggest LNG loading pump capacity, a thorough surge study is essential to ensure safe operations of the existing loading lines network.
During emergency situations, Emergency Shutdown (ESD) system may be activated where the ESD valves will be closed within 15 seconds to return the loading lines network into safe conditions. However, with the rapid closure of ESD valves, there is a sudden velocity change to the LNG liquid in the loading lines. This results in a vapour formation and collapse phenomenon which causes a surge pressure peak and resultant transient force onto the piping.
The surge study started with a simulation study, where it was found that the initial surge pressure may surpass the loading lines piping design pressure. Then, the simulation carries on evaluating the possible mitigation measures that could be applied to the loading lines network to reduce the surge pressure to safe operating limits below the piping design pressure. Once satisfied, an actual ESD test was conducted where the ESD situation is replicated and the actual surge pressure was recorded. This test serves to reaffirm the simulation study and possibly quantify the magnitude of surge pressure experienced in real ESD situations.
The mitigation measures of a 20 second pump delay timer and kick back valves to open during ESD activation was applied prior to the ESD test. During the test, the surge pressure peaks at approx. 20 barg, which was 4 times the normal loading pressure. This is as expected from the surge simulation considering mitigation measures are applied. If the mitigation measures were not applied, the surge pressure peak may go up to 10x the normal loading pressure, enormously exceeding the loading lines design pressure and may be catastrophic. Additional findings and discussion on the test results are presented in this manuscript.
In conclusion, the surge pressure magnitude experienced due to sudden velocity change may peak numerous times above the normal pressure even though only for a short time. This situation is applicable to LNG loading lines but is also possibly applicable to other liquid lines with sudden fluid velocity change within the piping. It is important to ensure that the necessary mitigation actions are taken prior to putting the lines into service.
Investigation of Multi-Scale Approach for Damage Control in Ultra-Deep Tight Sandstone Gas Reservoirs Based on the Multi-Scale Formation Damage Mechanisms
Authors: Zhang Dujie , Kang Yili , You Lijun , Li Xiangchen , Li Jiaxue , Chen Yashu 
Published: April 2019

Abstract
Cretaceous Bashijiqike ultra-deep tight sandstone, the main pay zone of Keshen gas field in Tarim Basin, has characteristics such as huge buried depth (6500 m ~ 8000 m), ultra-low matrix permeability and well-developed natural fractures. Due to lacking of a thorough research on the formation damage mechanism, there is no corresponding formation damage control method. And that's why this reservoir is suffering from severe formation damage. In this paper, the multi-scale characteristic of the reservoir space and seepage channel was described firstly. Then, a series of experiments were carried out to determine the multi-scale damage mechanisms, including the fluid sensitivity damage of matrix and fracture, the phase trapping damage of matrix and fracture, the loading capacity and the dynamic damage of fracture induced by drilling fluids. Then, the multi-scale formation damage mechanisms were summarized. Results showed the gas reservoir are characterized by typical multi-scale structures, i.e. micro-nano pore-throat and multiscale natural fractures. Severe salt sensitivity damage, alkali sensitivity damage and water phase trapping damage were the main damage mechanism of micro-nano pore-throat. For micro-fracture (aperture ≤ 100 μm), the dynamic damage degree induced by drilling fluids can reach up to 60.01 %. For Mesoscale fracture (aperture &gt; 100 μm), lost circulation induced by inadequate loading capacity of drilling fluids was the main damage mechanism. Then, a complete multi-scale approach for damage control was proposed: ① Using oil-based drilling fluids to inhibit the fluids sensitivity damage and phase trapping damage of micro-nano pore-throat and natural microfracture; ②Optimizing the solid particle size distribution of drill-in fluid to reduce the dynamic damage degree of micro-fracture induced by drilling fluids; ③Adding acid soluble temporary plugging materials while drilling to prevent lost circulation. According to the proposed approach, the total production of the test well was 94 × 104 m3, which is much higher than that of non-test wells. This research provides a detailed case of forming the multi-scale approach for damage control based on the multi-scale formation damage mechanisms. This method is practical and useful, and it has important guiding significance to develop the ultra-deep fractured tight gas reservoirs efficiently.
Experimental Study of Sand Erosion in Multistage Electrical Submersible Pump ESP: Performance Degradation, Wear and Vibration
Authors: Zhu Haiwen , Zhu Jianjun , Zhou Zulin , Rutter Risa , Forsberg Michael , Gunter Shawn , Zhang Hong-Quan 
Published: April 2019

Abstract
As one of the most widely used artificial lift methods, electrical submersible pumps (ESPs) have been improved gradually since the 1910s. However, its performance and run life are affected by many problems such as gas lock, high viscosity fluid, corrosion, and erosion. With the development of horizontal well drilling and multistage hydraulic fracturing, sand production from unconsolidated sandstone and proppant backflow often cause severe damage to ESPs resulting in reduced operating lifespan. Measuring wear in an ESP pump and monitoring performance degradation is not only very difficult in field cases, but also in experimental studies. The results are precious for understanding the wear mechanism inside an ESP as well as guiding the ESP design and simulation. At the same time, vibration and performance data can provide significant guidance to ESP failure diagnosis, which can potentially reduce the time and cost of well service and extend ESP run life.
Wear processes inside an ESP can be classified by different modes of mechanisms. Erosive wear can be observed in the primary flow channel of the impeller (rotor) and diffuser (stator). Particle strike shroud surfaces and the scratched material is flushed away by fluids. Various semi-mechanistic erosion equations are available to be coupled with Computational Fluid Dynamics (CFD) to predict the erosion in ESPs. In the secondary flow region, balance chamber and sealing rings, particles are presented between the stator and the rotating rotor. Therefore, abrasive wear is believed to dominate the wearing process. Unlike erosion, abrasion is more complicated and abrasion equations are highly depended on geometries, physical mechanism and load between particle and target surface. In this study, a sand wear test flow-loop is designed and constructed to investigate wear in ESPs. Performance degradation, Erosion pattern, abrasion rate, and stage vibration of an ESP were recorded in a 64-hour sandy flow test.
Yanbei-Unlocking the Tight Gas Green Field Development Potential Through Integrated Technology Application
Authors: Zaini Muhamad Zaki , Du Kuifu , Zhu Ming , Feng Li Jun , Yang Hai Hua , Wei Lin , Liu Yi 
Published: April 2019

Abstract
Yanbei Project is a tight unconventional gas development that covers a vast area of 2,341 km2 in the Ordos basin – the largest gas producing basin in China. The paper outlines the innovative technologies applied, major achievements and the integrated approach used to successfully develop this large-scale gas greenfield of highly heterogeneous fluvial thin sands with very complicated surface terrains and resources overlaying issues (coal mines and water reservoirs). The project scope calls for drilling and fracturing 784 wells in the full field development in two phases. Phase 1 includes construction of 7 hubs, central processing facilities (CPF), and 360 km of pipelines on a complex hilly topography and aims to deliver production of 1.4 bcm/year. Phase 2 will ramp up to a higher rate. The horizontal well with multi-stage fracture development concept was introduced for the first time in the project and has significantly improved both single well productivity and project economics. More than 20 different technologies, ranging from subsurface, drilling, logging, completion, stimulation, production and facilities, have been applied each of which has been carefully assessed to ensure its value to the project. The advanced 2D seismic technologies have enabled the project to successfully reprocess and interpret a complicated 2D seismic dataset that is heavily distorted by the hilly terrains. The integration of the 2D seismic interpretation with a variety of subsurface and drilling datasets have enhanced the understanding of reservoir characterization and sandbody architectures hence significantly reduce geological risks in drilling horizontal wells in such a complex fluvial system. The drilling and surface engineering work have dealt with a variety of different challenges such as well pad acquisitions, conflicting with coal mines & surface water reservoir areas along with local community issues. One of the key success factors for the project is the integration of the industry's worldwide expertise of technologies, procedures and HSE standards coupled with the local experience, which has ensured an innovative and fit-for-purpose technology-driven solution in planning and execution of the project. The paper describes the main geological and engineering challenges and outlines an integrated approach in applying extensive but selected technologies to resolve those challenges.
Optimization of Drilling Performance Based on an Intelligent Drilling Advisory System
Authors: Abughaban Mahmoud , Alshaarawi Amjad , Meng Cui , Ji Guodong , Guo Weihong 
Published: April 2019

Optimization of drilling parameters during drilling operations is a key component to obtain maximum rate of penetration (ROP) as well as minimizing the drilling cost. Advancement in computer technologies and communication are among the most important factors that can contribute to drilling optimization. In the current work, a novel rig advisory system is developed to continually improve ROP and the drilling performance. Conventionally, drillers apply drilling parameters (weight-on-bit, rotary speed and pump rate) according to past experience or to parameters specified in the drilling program. These parameters are usually kept constant over a long interval regardless of the formations being drilled. However, it is well-known that keeping constant drilling parameters to drive the bit will lead to redundant depth of cut (DOC), inducing stick-slip vibration that leads to low ROP, higher drilling specific energy (DSE), and potential damage to the bottom-hole assembly (BHA).
An intelligent drilling advisory system (IDAS), based on a soft-closed-loop solution with multiple regression analysis called optimum parameters global retrieval, has been established. Integrated with machine-learning methodology (Principal component analysis), the response of the drilling parameters with lithology changes was analyzed in real time. Additionally, the optimum control parameters direction were obtained from the gradient search and decision tree algorithms. This system monitored the relationship between the ROP and input energy delivered to the bit in real time, and calculated the optimized drilling parameters. The work presented how the IDAS procedures were applied in China, how the data was interpreted, and how optimum working parameters were obtained to guide drillers to improve drilling performance and reduce non-productive time (NPT).
IDAS has been introduced to hard formation drilling, which proved to be a success in real-time advisory aiding drillers applying proper working parameters for maximum ROP. Field applications of IDAS guidance showed significant ROP improvement compared to that of conventional drilling.
As an effective tool for further achieving the optimum DOC, a novel control system achieved satisfactory outcomes that overcome the drilling challenges in Saudi Arabia and China, which will serve as a step forward towards automated drilling operations.
A Rotating Continuous Circulation Tool RCCT for Increasing Drilling Efficiency and Optimizing Borehole Cleaning
Authors: Badran Mohammed , Gooneratne Chinthaka , Ahsalan Meshari , Shaarawi Amjad 
Published: April 2019

Abstract
This paper presents the design, deployment and field trial test of a uniquely designed Rotating Continuous Circulation Tool (RCCT). The RCCT provides nearly continuous rotation of the pipe string and continuous circulation of fluid while making up or breaking out a new stand. Nearly continuous rotation decreases the period of static contact between the formations surrounding the pipe string and the pipe string, thus reducing the risk of the pipe becoming stuck inside the wellbore and also the wellbore collapsing. Continuous circulation results in efficient borehole cleaning. Therefore, the RCCT increases drilling efficiency and optimizes borehole cleaning. Proof-of-concept testing of the RCCT was successfully performed inside casing during a cement clean out operation, which also aided to clearly define drilling parameters required for successful operation of the tool while drilling.
Complex Geological Modeling Using Unstructured Grids: Quality Assurance Approaches and Improved Prediction
Authors: Harris Simon , Santoshini Samita , Smith Stewart , Levannier Arnaud , Khan Osama 
Published: April 2019

Abstract
The vast majority of grids for reservoir modeling and simulation workflows are based on pillar gridding or stairstep grid technologies. The grids are part of a feature-rich and well-established modeling workflow provided by many commercial software packages. Undesirable and significant simplifications to the gridding often arise when employing such approaches in structurally complex areas, and this will clearly lead to poor predictions from the downstream modeling.
In the classical gridding and modeling workflow, the grid is built in geological space from input horizon and fault interpretations, and the property modeling occurs in an approximated ‘depositional’ space generated from the geological space grid cells. The unstructured grids that we consider here are based on a very different workflow: a volume-based structural model is first constructed from the fault/horizon input data; a flattening (‘depositional’) mapping deforms the mesh of the structural model under mechanical and geometric constraints; the property modeling occurs in this depositional space on a regular cuboidal grid; after ‘cutting’ this grid by the geological discontinuities, the inverse depositional mapping recovers the final unstructured grid in geological space. A critical part of the depositional transformation is the improved preservation of geodetic distances and the layer-orthogonality of the grid cells.
The final grid is an accurate representation of the input structural model, and therefore the quality checking of the modeling workflow must be focused on the input data and structural model creation. We describe a variety of basic quality checking and structurally-focused tools that should be applied at this stage; these tools aim to ensure the accuracy of the depositional transformation, and consequently ensure both the quality of the generated grid and the consistent representation of the property models. A variety of quality assurance metrics applied to the depositional/geological grid geometries provide spatial measures of the ‘quality’ of the gridding and modeling workflow, and the ultimate validation of the structural quality of the input data.
Two case studies will be used to demonstrate this novel workflow for creating high-quality unstructured grids in structurally complex areas. The improved quality is validated by monitoring downstream impacts on property prediction and reservoir simulation; these improved prediction scenarios are a more accurate basis for history matching approaches.
Saving a Challenging Sidetrack Through Optimizing the Trajectory by Accurately Predicting the Fracture Gradient
Authors: Fang Zhi , Zamikhan Norshah , Huver Pieter , Ali Waznah , Ahmadiah Hanisah 
Published: April 2019

Abstract
Whilst drilling an exploration well through shallow depleted reservoirs, the heavily deviated intermediate hole section encountered uncontrollable losses, hole pack off, and ultimately was abandoned. A replacement sidetrack was proposed and the asset team requested an assessment of the drilling risks for the proposed trajectory. An integrated geomechanics approach was developed to analyze the fracture initiation pressures (FIP) of wellbores, which are dependent on well trajectories except on the field stresses and formation pressures. An FG model was elaborated with the integrated geomechanics approach analyzing the field data and the drilling history of the lost hole section. It predicted the FIPs of the initially proposed sidetrack trajectory with a value lower than the minimum required by the drilling team. The sidetrack trajectory was revised as instructed by the FG model analyses, which resulted in an increased FIP value slightly above the minimum required. The revised sidetrack trajectory observed minor losses with the ECD slightly exceeded the predicted FIP value during drilling, but the remaining section was successfully drilled by controlling the ECD under the predicted FIP value. If the primarily proposed sidetrack trajectory had been drilled, there could have been another lost-hole event due to the unmanageable drilling operation window. The integrated geomechanics approach eventually saved the challenging sidetrack through optimizing the trajectory by accurately predicting the FIPs.