bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unlocking Marginal Deep Water Fields Development through Reservoir to Surface Integrated Asset Modelling
Authors: Marmier Remy , Ajiboye Ajibola , Berson François , Darde Mathieu , Houdbert Vincent 
Published: April 2019

Abstract
Development of marginal deep water fields requires an integrated and cost-effective approach for costs minimization and production enhancement by synergies with existing surrounding infrastructures. This paper details the successful use of Integrated Reservoir and Production Modelling to unlock the development of three marginal deep water oil discoveries in synergy with an existing surrounding subsea development. A marginal field is usually defined as a field that may not produce enough net income to make it worth developing. Deep water satellites are among those, requiring important development optimizations to unlock their potential. Integrated Reservoir and Production Modelling is largely used within the Oil and Gas industry for evaluating production forecasts associated to development assumptions by modeling the fluid flow from pore to process while honoring all required subsurface to surface constraints. This paper describes how the use of such modeling approach has been used to unlock the development of these marginal oil discoveries by evaluating the value of different development concepts from stand-alone to tie-back together with standardized and under-qualification subsea technologies. The Integrated Reservoir and Production Models were made of the three reservoir dynamic models of the three marginal fields connected to the well and network production models capturing the various concepts evaluated. Three main development concepts have been tested: stand-alone, short tie-back to field X and long tie-back to field Y. For all these concepts, many sensitivities have been performed: well implementation patterns, well completion and activation, production and injection networks design including subsea boosting and surface capacities debottlenecking. Tie-back to field X has then been further evaluated to determine detailed bases of design maximizing the value of the project. Integrated Reservoir and Production Modelling has been key to enable cross-functional team work and determine the best incremental value of these marginal fields in synergy with the production of the surrounding existing field.
Real-Time Interpretation of Supercharged Formations during Pore Pressure Monitoring
Authors: Paul Scott , Garcia Mayans Aldrick , Patel Nikhil , Blyth Matthew , Rodrigues Anthony 
Published: April 2019

Abstract
The basic objective of real-time pore pressure (RTPP) services is to maintain the equivalent static density (ESD) and equivalent circulating density (ECD) within a desired mud weight (MW) window. This paper will present a new workflow to differentiate between supercharging in low-permeability, limited lateral extent sands, and genuine elevated pore pressure; ultimately preventing unwarranted MW increases that might either result in premature termination of the section or induce losses.
In a typical workflow, log-derived models are used to compute the pore pressure (PP) in shales. These models are calibrated with drilling events and prompt formation pressure-while-drilling (FPWD) pretests in sands. However, in the Gulf of Mexico (GoM), sub seismic sand lenses are susceptible to supercharging; sometimes manifesting as an event gas peak. Moreover, using these gas events to determine supercharging have proven unreliable as they do not systematically occur. A novel workflow using time-lapse FPWD measurements, incorporating the acquisition environment, and the ability to circulate drilling mud at different flowrates to iteratively demonstrate the presence of supercharging has been developed.
A common scenario is presented from a deep water well in the GoM in which both RTPP and FPWD services were run. As drilling progressed, the shale PP computed from the sonic logging-while-drilling tool was repeatedly validated with FPWD measurements. However, then a pretest conducted across an underlying sand showed PP value slightly higher than the computed shale PP. Based on conventional methodology, this condition would trigger a MW increase. Following regulatory requirements, ESD should be in a specified range above the confirmed PP. If the MW was increased further, the resulting ECD would be near the last casing shoe leak off test value, compromising wellbore integrity. If the flow rate was reduced to control the ECD, then wellbore cleaning would be compromised. A departure from the previously observed sand-shale PP equilibrium was unexpected and supercharging was suspected in this underlying sand. Clear evidence of supercharging was demonstrated by employing an iterative sequence of four repeated pretests with parameter adjustments. Experimental data were obtained and showed that no MW increase was required. Based on these results, the RTPP model was adjusted accordingly, and drilling continued without any problems to the planned section total depth.
The presence of potentially supercharged sub seismic sand lenses complicates PP calibration. This new workflow is proposed to identify supercharging in these sands; thus, minimizing unwarranted MW increases, which could either result in premature termination of the section or induce losses. Either of these results could lead to operation cost overruns and extra casing and liner runs. The efficiency of the new workflow is demonstrated by the safe and successful drilling of a Deepwater prospect.
Disclose Hidden Hydrocarbon HC Reserves from Additional Zone of Interest AZIs Using dT LogR Method in Lunar Field, Gulf of Thailand
Authors: Kamkong Paphitchaya , Karnjanamuntana Thamaporn , Prungkwanmuang Weera , Yingyuen Jakkrich , Oatwaree Dejasarn , Amornpiyapong Nichakorn , Khositchaisri Patcharin , Tivayanonda Vartit , Wongsuvapich Dutkamon , Tongsuk Soraya 
Published: April 2019

Abstract
Lunar field is a marginal gas field located in the Gulf of Thailand. A significant portion of reservoir sands is currently categorized as Additional Zones of Interest (AZI) which is not accounted in reserves. As for this kind of sand, the conventional petrophysical evaluation alone cannot certainly distinguish between hydrocarbon and water in the porous medium. The alternative method (dT LogR) for formation re-evaluation is therefore considered in attempt to reduce uncertainty in fluid classification and reveal hidden hydrocarbon potential from these AZIs.
There are 2 phases in verifying the validity of dT LogR method. Phase I: dT logR method (Ref. Q.R. Passey et al., AAPG 1990) was tested against the unperforated AZI sands of 10 selected platforms in order to fine-tune scaling parameters in dT logR. The total of 12 gas-potential AZI candidates were selected for perforation test. Data acquisition was also planned to obtain the reservoir deliverability information in order to further calibrate the interpretation model. The production test results of these sands showed that the accuracy of the interpretation was 41% (5 sands of 12 candidates produced gas) but 33% (4 sands of 12 candidates) showed water flow.
Phase II: The production test data from perforated AZIs in phase I and the well correlation were then incorporated in dT LogR assisted log reinterpretation. Additional 13 gas-potential AZI candidates were identified for 2nd perforation test to prove the correctness of the recalibrated petrophysical model. The results showed success in model improvement of which its accuracy increased to 61% and no high water production was observed in any of them.
After using dT LogR method to assist petrophysical evaluation, a total of 469 metres of unperforated AZIs were reconsidered to be productive gas bearing formation. In other words, 22 BCF of gas reserves and 873 MSTB of condensate reserves from these upgraded AZIs were added. In addition, it is foreseen that the remaining AZIs of other platforms are to be further reevaluated and therefore improves the confidence in reserves booking and field development planning of Lunar Field.
In conclusion, the dT LogR method is a very useful tool for Lunar Field to significantly reduce uncertainty of fluid classification which in turn provides lots of benefits in gas field management adding immeasurable value to Lunar Field.
Study on the Brittleness Evaluation in the Naturally Fractured Carbonate Formation and Its Application in the Ordos Basin
Authors: Ma Xinxing , Kao Jiawei , Zhou Zhou 
Published: April 2019

Abstract
Rock brittleness is a key factor to influence the fracture behavior in the formation. Therefore, it is important to evaluate the brittleness when doing the hydraulic fracturing. Previous studies provided various methods for rock brittleness evaluation. Few evaluations, however, could be applied for the naturally fractured carbonate formation because those methods did not integrate the influence from lithology, natural fractures and vugs. Hence, this paper indicated an integration evaluation method to investigate the brittleness in the naturally fractured carbonate formation.
The rock in this study was from the formation in the Ordos Basin. The brittleness evaluation method asked the experiment studies that included triaxial compression test, continuous strength test, Kaiser test and X-Ray Diffraction analyze. Based on the results, the influence of substrate properties and fractures-vugs in fractured carbonate rock are analyzed. Then a method to evaluate the brittleness of fractured carbonate rock is raised in which the stress-strain curves of rock mechanics tests, geologic microcharacter and the characteristics of fractures are considered. The method can give a better application in Ordos Basin.
The results show that the failure mode of fractured carbonate rock under the effect of confining pressure is mainly the shear failure. The facture will have an obvious effect on the strength of rock. The brittleness of fractured carbonate rock appears as the ability for resisting inelastic deformation before rupture and losing rate of bearing capacity after rupture, besides the minerals of rock and the development of fracture will influence the brittleness. With the increasing of confining pressure, the fractures tend to be closed which leads to the increasing of brittleness. However, the carbonate in high confining pressure is characterized by plasticity, the brittleness would reduce. The brittleness was used to design hydraulic fracturing work in the naturally fractured carbonate formation of Ordos Basin.
Hydraulic fracturing is necessary to guarantee a successful development in the naturally fractured carbonate formation. Therefore, the brittleness evaluation method is worth to study when designing the hydraulic fracturing.
The Study and Application of Intelligent Thixotropic Cement Slurry Based on Nanotechnology
Authors: Lu Haichuan , Zheng Huikai , Li Zongyao , Feng Wangsheng , Tang Shaobing , Zou Jianlong , Li Lirong , Tan Wenli 
Published: April 2019

Abstract
Lost circulation and fluid channeling in cementing process are common technical problems in domestic and overseas oil-gas field, and making huge damage to oil-gas field development. The cement sheath is easy to be broken because it has only little deformation under force which will affect the cement long-term packing property that could ensure the oil and gas production go smoothly. Aiming at the above problems, to conquer the shortage of traditional materials, a new multi-functional material is developed by combining nanotechnology and polymer synthesis technology according to microstructure design principle. And then an intelligent thixotropic cement slurry system is built. The novel intelligent thixotropic cement slurry is able to rapidly respond to the external stimulus of shear force due to the dynamic net structure between the nanometer material and the polymer. It is thin under shear and become thick rapidly when it is still and become thin again after shear. The process is reversible. The new system which conquers the problems existing in the conventional thixotropic cement slurry could not only make full use of its functions but also reduce the construction risk. The experiments show that the cement slurry has strong thixotropy unaffected by temperature and short transition time and can prevent lost circulation and fluid channeling in cementing process. And the cement stone with the multi-functional material has well tenacity and excellent ability of resisting damage which could keep long-term packing property. Besides, the thixotropic mechanism of nanometer material and its function on mechanical property improvement are studied in the point of microstructure, which will lay a certain foundation for the application of nanotechnology in well cementing. The intelligent thixotropic cement slurry have been used successfully in many oil fields, which prove its function on solving the problems of fluid channeling and lost circulation.
Advanced Study of Pore Structure and Mechanical Property Change of Tight Sand Due to Thermochemical Treatment
Authors: Al-Nakhli Ayman , Mahmoud Mohamed , Al-Badairy Hameed , Alqam Mohammed 
Published: April 2019

Abstract
The demand for unconventional gas is rapidly increasing to provide enough energy to maintain sustainable growth for industrial countries. Even oil producers can develop UG to be directed to internal industrial and power consumptions. As Unconventional gas reservoirs are located in deep high-stress formations, one of the critical challenges gas producers are facing is to develop a cost effective stimulation method that can reduce production cost to lower than Break-even.
In this paper a novel stimulation method, based on thermochemicals, is introduced. Thermochemicals when injected in tight reservoirs generate localized pressure-pulses, which result in creating microfractures, improve permeability and increase stimulated reservoir volume (SRV). Tight core samples were treated with thermochemicals and the impact on mechanical properties were studied. Generated localized pressure was clearly detected during Coreflood treatment. Microstructural and mineralogical properties were also investigated using microscopy and spectroscopy. CT-scan, micro CT-Scan, Young's modulus, Poisson's ratio and ultrasonic velocities were measured pre and post treatment. Results showed creation of fractures and microfractures, which resulted in improved rock conductivity.
Results show that, micro-factures are created inside the used sample due to the in-situ generation of heat and pressure. The density of those micro-factures is strong function of the chemical concentration and the injected volume. Creation of micro-factures leads to improve the formation conductivity and reduce the capillary forces, therefore, enhances the hydrocarbon recovery. The outcome of this study is to understand the impact of thermochemical treatment on rock integrity. The ultimate objective is to establish a relationship between the injected chemicals and the alterations of formation properties such as permeability and porosity. This work will serve as a baseline for designing and conducting thermochemical operations for hydrocarbon reservoirs.
In this study a novel stimulation technique to increase stimulated reservoir volume (SRV) is presented. In basins with excessive tectonic stresses, the current novel treatment can become an enabler to deeply stimulate well stages which otherwise left untreated. A new methodology is developed to lower fracturing cost and increase unconventional gas production. A better connectivity reduces the required number of hydraulic fracturing-stages.
Shaped Memory Polymer: An Innovative Approach to Sand Control Open Hole Completion in Thin, Multilayered, Depleted Low Permeability Gas Reservoirs
Authors: Fuxa Jason , Di Giampaolo Paolo , Ferrara Giovanni , Di Pietro Mario , Sportelli Marco , Ripa Giuseppe , Di Campli Antonio 
Published: April 2019

Abstract
This paper details a field application of Shaped Memory Polymer (SMP) material for sand management delivering an innovative approach for sand control completions. The use of the technology has enabled profitable exploitation of residual reserves in a mature gas field offshore Adriatic Sea. The paper reviews details of the field deployment, with both economic and well performance results described.
The offshore field was discovered in 1971 and 102 wells have been drilled to date. The trap is a very gentle, slightly asymmetrical anticline made by Pleistocene sandy turbidites, sedimented on the underlying carbonate substrate. Methane gas bearing layers have been sealed by several argillaceous intercalations that worked also as the source rocks of this multilayer reservoir. The sandy layers in this Pleistocene sequence, have thickness ranging from few centimeters up to some meters, and porosity from 22 up to 33%. Isolation of multiple gas-water contacts and fines production have been two crucial issues while producing the field.
Since 2000, all seven platforms in this field have required workovers by means of performing sidetracks. Due to the reservoir characteristics, the well interventions have been completed with multi-layer, stacked cased-hole sand control completions. Despite a continuous improvement of procedures and technique, the traditional sand control methods have been efficient but were no longer profitable, due to challenging market conditions.
An open-hole completion using SMP combined with zonal isolation and selective production has proved to be an effective alternative to cased-hole sand control. This novel completion approach resulted in a significant reduction in both cost and rig time. It is estimated that nearly two weeks of rig time was saved and an overall workover cost reduction of approximately 35%, with further efficiencies to be realized on upcoming deployments. To date, the completion has proved to be an effective sand control method, with no produced solids, no plugging effect, and gas production that has met expectations.
A Comparison of Gas Hydrate Petroleum Systems in Marine and Permafrost Regions
Authors: Lau Hon Chung , Zhang Ming , Wang Jinjie , Huai Yinchao 
Published: April 2019

Abstract
In this paper, we present for the first time, a classification system for naturally-occurring gas hydrate deposits existing in the permafrost and marine environment. This classification is relatively simple but highlights the salient features of a gas hydrate deposit which are important for their exploration and production such as location, porosity system, gas origin and migration path. We then show how this classification can be used to describe eight well-studied gas hydrate deposits in permafrost and marine environment. Potential implications of this classification are also discussed.
The Application of CBM Case Library Based on Data Mining
Authors: Qiu Maoxin , Zhang Huazhen , Zhang Huanzhi , Liu Jia , He Yanqing , Wang Lu , Zhang Jiaming 
Published: April 2019

Abstract
The development of China's coalbed methane (CBM) industry is restricted by the complex geological conditions, unmatched technology and lack of development experience. To solve this problem, a case library covering typical CBM fields at home and abroad is established. Through data analysis and mining, the differences between domestic and foreign CBM fields are compared and the influence factors of CBM single well production were analyzed.
This study includes the data preparation of CBM fields, the establishment of the case library system, the establishment of data analysis model and the result analysis. The data of case library covers the geological conditions, development history, main technology and economy of CBM field. The case library is based on the MVC development idea and adopts the object-oriented method. The analysis of data includes correlation analysis of single well production and quantitative gap analysis.
The case library contains a number of typical case data, such as San Juan, Black warrior, Bowen, Surat, Qinshui, Hancheng, etc. The relevant parameters of different CBM fields can be quickly compared by using the case library. By mining the data such as coal rank, permeability, thickness, depth, gas content and proved reserves, the influence factors of single well production of CBM well are analyzed quantitatively. It is found that the thickness and permeability of coal seam have the greatest influence on single well production. Quantitative gap analysis shows that there is a large gap between the coal seam thickness, permeability, the gas drainage technology and well production improvement technology of domestic CBM fields compared with the foreign fields with the best development effect.
Through the application of CBM case library, data is analyzed and utilized effectively and data values are fully exploited. This study provides an effective way to analyze the gap of CBM in China and draw lessons from abroad.
Modeling Study of Wellbore Vortex Flow and Helical Angle Design of Downhole Vortex Tool
Authors: Zhou Chao , Zhang Tongyi , Wu Xiaodong , Zhao Fei , Xiong Xiaofei 
Published: April 2019

Abstract
Vortex drainage gas recovery is a new drainage gas recovery technology. However, its operating mechanism has not been figured out. Theoretical analysis of force condition of the liquid film in the wellbore vortex flow field is still lacking, and dynamic analysis method of the liquid film is not established. The objective of the proposed paper is to establish the liquid film dynamic analysis model and calculate the optimal helical angle of the vortex tool. Dynamic analysis of the liquid film in the wellbore vortex flow field is carried out on the basis of the flow pattern and force condition of the liquid film. Expression of each acting force is determined and the force equilibrium equation is obtained. Referring to the annular flow theory, friction coefficient and average thickness of the liquid film are calculated. Through derivation of the vertical resultant force equation of the liquid film, the optimal helical angle of the vortex tool is obtained. Then, vortex tools were designed and deployed in the wellbore of a gas well in field. Field study shows that the relative difference of the optimal helical angle obtained by liquid film dynamic analysis relative to that obtained by numerical simulation is less than 4%. The optimal helical angle calculated by the liquid film dynamic analysis model is reliable and provides guidance for the structure optimization of vortex tools. Optimal helical angle would increase with well depth decreases because of enhancement of fluid-carrying capability of the gas. The liquid film dynamic analysis model can reasonably explain the motion and force condition of the liquid phase in the wellbore vortex flow. Compared with the conventional annular flow field, vortex flow filed includes additional centrifugal force on the liquid film, which may benefit the upward motion of the liquid film. The liquid film dynamic analysis model in the wellbore vortex flow field and the formula for calculating the optimal helical angle of the vortex tool are established for the first time, whose results fill the gap in existing studies and have a guiding significance for optimization design and field application of vortex tools.