bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diagnostic Plots of Pressure Transient, Rate-Transient, and Diagnostic Fracture-Injection/Falloff Tests
Authors: Craig David , Blasingame Thomas 
Published: September 2021

Abstract
All transient test interpretation methods rely on or utilize diagnostic plots for the identification of wellbore or fracture storage distortion, flow regimes, and other parameters (e.g., minimum horizontal stress). Although all "test" interpretations of interest are transient test data (i.e., those involving an "event"), the associated diagnostic plots are not interchangeable between such tests. The objective of this work is to clearly define the appropriate diagnostic plot(s) for each type of transient test.
The work applies the appropriate transient test theory to demonstrate the applicability of each diagnostic plot along with clearly defining the characteristic features that make a given plot "diagnostic." For pressure transient testing, the material is largely a review, but for rate transient tests and diagnostic fracture-injection/falloff tests, new ideas are introduced and documented to justify appropriate diagnostic plots. Data examples are provided for illustration and application.
In general, pressure transient test diagnostic plots are not misused, but the same cannot be said for diagnostic fracture-injection/falloff tests (or DFITs) where it is common to ascribe flow regimes and/or draw other erroneous conclusions based on observations from an inappropriately constructed or interpretated diagnostic plot. The examples provided illustrate both the correct diagnostic plot and interpretations, but also illustrate how data can be easily misinterpreted in common practice.
Core Competencies Identification and Development: Evidence from Oil and Gas Exploration Company
Authors: Vlasov Mikhail 
Published: September 2021

Abstract

Background
Key trends say that to stay as a primary energy source for the upcoming years Oil & Gas companies shall concentrate their efforts on efficiency and technologies, including digital. The situation in the Exploration sector is challenging, as there are almost no "easy" resources left to explore. One of the ways to build a further development strategy for the Oil & Gas Exploration Companies is to define and build development plans for their core internal capabilities. To boost their efficiency, companies shall concentrate their attention and efforts around their core competencies.

Purpose
The principal aim of this paper is to suggest the method of identifying the internal sources of competitive advantage (the core competencies of an organization) and building the plans of their development on the example of the selected Oil & Gas Exploration Company.

Methodology
A case study was carried out utilizing the methods synthesized by the author basing on the critical analysis of the previous conceptual and research studies, including strategic architecture, value chain analysis, POCCI model and both quantitative and qualitative methods. The identification of core competencies was based on a discussion nature of focus group activities organized in the form of strategic sessions among the top management level of the selected Company.

Findings
Five core competencies were identified for any Oil & Gas Exploration Company: managing personnel motivation and development, managing uncertainties, regional / basin analysis, building an integrated business-case, and geological modelling. These results were validated and proved by a crosscheck analysis, final discussions with the focus group and a round table discussion among industry experts, consultants and top managers of major oil companies.

Discussions and recommendations for further development
The validity of methods suggested by the author is proved, however, some points of further methodology were identified during the research. The clear understanding of internal capabilities, the core competencies development level and what is the company is capable of today and tends to be capable of in the future will become one of the most valuable parts in every strategic decision-support package. The clear picture of identified and estimated competences together with an on-going benchmarking becomes a valuable guide in systematization and managing the company's development.
Automating Wireline Perforation and Frac Plug Set Depths into Wellsite Reporting System Using a Time-Synchronous Digital Platform and IIOT
Authors: Van Buskirk Chad , Duncan Bob 
Published: September 2021

Abstract
During plug-and-perf zipper fracturing operations, the capture of incorrect perforation and frac plug depths plagues the future use of this data. Production models currently run on the assumptions of where stage boundaries and perforations should be - not using inputs of where they are. The entry points to the reservoir and stimulation schedule may have left considerable bypassed pay. These models may not require calibration, they simply required accurate data inputs from the onset - or better yet, on-the-fly corrections to access the entire pay zone.
A collaborative project started with an operator need to auto-import wireline perforation and frac plug setting depths into an industry recognized wellsite reporting software. The project then revealed itself to be much more – an exercise in ensuring quality depth data from site. This is a game-changing tool for service companies and operators alike. Unique automation capabilities were developed that unified several processes and IIOT data on a completions site.
Axial Fracture Initiation During Diagnostic Fracture Injection Tests and Its Consequences on Interpretations
Authors: Cai Yuzhe , Dahi Taleghani Arash , Wang Rui 
Published: September 2021

Abstract
Diagnostic fracture injection tests (DFIT) are used widely in the unconventional reservoirs to obtain formation properties. These properties can be crucial in optimizing primary and infill completions. The interpretation methods are assuming that pumping fluid would create a single planar fracture, however, perforation frictions and near wellbore stress concentration may accommodate initiation of fractures along the casing first (axial fractures). The possibility of the formation of an axial fracture increases in high injection rates and low differential stresses. In this study, we investigate the effect of the formation of an additional axial fracture on a DFIT test and its interpretation, using a fully coupled geomechanics and fluid flow model. We provide a model for the initiation and closure of axial and transverse fractures during the process. We also demonstrate that the estimate of the closure stress can be misleading when presence of an additional axial fracture is ignored. Finally, we discuss a potential method to determine the maximum horizontal stress under such circumstances. In fact, the variations in cement quality, cement type and its placement play roles in linking of adjacent perforations and form axial fractures, therefore it might be difficult to establish a safe perforation design to avoid initiation of axial fractures, but we can adjust our analysis to incorporate axial fractures effect.
Successfully Abandoning Wells with Extreme Corrosive Environment Using Mechanical Aids – A Case Study from South Iraq
Authors: Campana Barbosa Lucio Felipe , Iqbal Javaid , Bhaisora Devesh 
Published: September 2021

Abstract
Well abandonment under a corrosive environment is often unpredictable and challenging, especially if the zone exhibits irregular wellbore geometry due to severe corrosion. These situations not only increase associated risks, but also greatly increase the abandonment cost for workover operation. This paper presents a successful application of a mechanical aid to replace a firm base using bridge plug or viscous pill base to abandon a well in the province of Basra in Southern Iraq.
Numerous wells in Southern Iraq have compromised casing integrity due to sulphureous water flow from Umm Er-Radhuma / Tayarat formations, making their abandonment imperative. Due to unpredictable corrosion inside the casing, setting any type of mechanical bridge plug was a laborious operation, because the operator must run multiple logs to confirm the casing integrity and might not get the required casing integrity at the desired abandonment depth. Setting up a viscous pill was a challenge in the well environment, and in absence of a firm base it was highly probable that the cement plug would slump. Looking at multiple options to ensure the successful plug setting operation on the first attempt, it was decided to use a suitable mechanical aid, as a firm base to prevent the slumping motion of the fluids that were pumped to isolate sensitive zones. The unique foldable and adjustable parasol construction of the tool enabled it to be pumped through small diameter tubing avoiding any sticking, and it was a critical parameter for tool selection process.
This paper summarizes the first-successful well abandonment using such a tool in the province of Basra in 7-in. casing and 9 5/8-in. casing. The logging tool was not able to detect one section of 9 5/8-in casing, which was presumably completely corroded. The first attempt to isolate it using a polymer system was not successful, since the fluid flowed to different leaks in the outer casing. The parted 7-in. casing made it impossible to identify the depth of lower leaks. Then a plan to utilize the mechanical aid was presented and subsequently approved. Tool was dropped and set above the top of 7-in. casing and gave support to the first cement plug to abandon the well, significantly reducing the time and cost of abandonment of the well by reducing repeated plug jobs.
The use of the mechanical aid as a primary option to set plugs for abandonment purposes in corrosive environments has resulted in a great success by reducing non-productive time and enhancing zonal isolation results. Similar usages around the world will help in reducing workover operation economics where integrity of the casings is questionable.
A Novel Well Test Data Analyzer and Process Optimizer Using Artificial Intelligence and Machine Learning Techniques
Authors: Reddicharla Nagaraju , Rachapudi Subba Ramarao , Utama Indra , Khan Furqan Ahmed , Vanam Prabhker Reddy , Al Nuimi Saber Mubarak , Sultan Ali Mayada Ali 
Published: September 2021

Abstract
Well testing is one of the vital process as part of reservoir performance monitoring. As field matures with increase in number of well stock, testing becomes tedious job in terms of resources (MPFM and test separators) and this affect the production quota delivery. In addition, the test data validation and approval follow a business process that needs up to 10 days before to accept or reject the well tests. The volume of well tests conducted were almost 10,000 and out of them around 10 To 15 % of tests were rejected statistically per year. The objective of the paper is to develop a methodology to reduce well test rejections and timely raising the flag for operator intervention to recommence the well test.
This case study was applied in a mature field, which is producing for 40 years that has good volume of historical well test data is available. This paper discusses the development of a data driven Well test data analyzer and Optimizer supported by artificial intelligence (AI) for wells being tested using MPFM in two staged approach. The motivating idea is to ingest historical, real-time data, well model performance curve and prescribe the quality of the well test data to provide flag to operator on real time. The ML prediction results helps testing operations and can reduce the test acceptance turnaround timing drastically from 10 days to hours. In Second layer, an unsupervised model with historical data is helping to identify the parameters that affecting for rejection of the well test example duration of testing, choke size, GOR etc. The outcome from the modeling will be incorporated in updating the well test procedure and testing Philosophy. This approach is being under evaluation stage in one of the asset in ADNOC Onshore.
The results are expected to be reducing the well test rejection by at least 5 % that further optimize the resources required and improve the back allocation process. Furthermore, real time flagging of the test Quality will help in reduction of validation cycle from 10 days hours to improve the well testing cycle process. This methodology improves integrated reservoir management compliance of well testing requirements in asset where resources are limited. This methodology is envisioned to be integrated with full field digital oil field Implementation.
This is a novel approach to apply machine learning and artificial intelligence application to well testing. It maximizes the utilization of real-time data for creating advisory system that improve test data quality monitoring and timely decision-making to reduce the well test rejection.
Measurement of Cement in Situ Stresses and Mechanical Properties Without Cooling or Depressurization
Authors: Meng Meng , Frash Luke , Carey James , Li Wenfeng , Welch Nathan , Zhang Hongtao 
Published: September 2021

Abstract
Accurate characterization of oilwell cement mechanical properties is a prerequisite for maintaining long-term wellbore integrity. The drawback of the most widely used technique is unable to measure the mechanical property under in situ curing environment. We developed a high pressure and high temperature vessel that can hydrate cement under downhole conditions and directly measure its elastic modulus and Poisson's ratio at any interested time point without cooling or depressurization. The equipment has been validated by using water and a reasonable bulk modulus of 2.37 GPa was captured. Neat Class G cement was hydrated in this equipment for seven days under axial stress of 40 MPa, and an in situ measurement in the elastic range shows elastic modulus of 37.3 GPa and Poisson's ratio of 0.15. After that, the specimen was taken out from the vessel, and setted up in the triaxial compression platform. Under a similar confining pressure condition, elastic modulus was 23.6 GPa and Possion's ratio was 0.26. We also measured the properties of cement with the same batch of the slurry but cured under ambient conditions. The elastic modulus was 1.63 GPa, and Poisson's ratio was 0.085. Therefore, we found that the curing condition is significant to cement mechanical property, and the traditional cooling or depressurization method could provide mechanical properties that were quite different (50% difference) from the in situ measurement.
Phase Behaviour and Physical Properties of Dimethyl Ether DME/CO2/Water/Heavy Oil Systems under Reservoir Conditions
Authors: Huang Desheng , Li Yunlong , Yang Daoyong 
Published: September 2021

Abstract
In this paper, techniques have been developed to quantify phase behaviour and physical properties including phase boundaries, swelling factors, and phase volumes for reservoir fluids containing polar components from both experimental and theoretical aspects. Experimentally, a total of five pressure-volume-temperature (PVT) experiments including three sets of DME/CO2/heavy oil systems and two sets of DME/CO2/water/heavy oil systems have been carried out to measure saturation pressures, phase volumes, and swelling factors by using a versatile PVT setup. Theoretically, the modified Peng-Robinson equation of state (PR EOS) incorporated with the Huron-Vidal mixing rule and the Péneloux volume-translation strategy is employed as the thermodynamic model to perform phase equilibrium calculations. It is observed that the experimentally measured saturation pressures of DME/CO2/water/heavy oil mixtures are higher than those of DME/CO2/heavy oil mixtures at the same temperature and same molar ratio of solvents and heavy oil, owing to the fact that more water molecules can be evaporated into vapour phase. The binary interaction parameters (BIPs) between DME/heavy oil and CO2/DME pair, which are obtained by matching the measured saturation pressures of DME/CO2/heavy oil mixtures, work well for DME/CO2/heavy oil mixtures in the presence and absence of water. In addition, a swelling effect of heavy oil can be enhanced by adding the DME and CO2 mixtures compared to only DME or CO2. The new model developed in this work is capable of accurately reproducing the experimentally measured multiphase boundaries, swelling factors, phase volumes with a root-mean-squared relative error (RMSRE) of 4.68%, 0.71%, and 9.35%, respectively, indicating that it can provide fundamental data for simulating, designing, and optimizing the hybrid solvent-thermal recovery processes for heavy oil reservoirs.
Application of Machine Learning Methods to Well Completion Optimization: Problems with Groups of Interactive Inputs
Authors: Zhou Peng , Lu Ligang , Sang Huiyan , Dindoruk Birol 
Published: September 2021

Abstract
In unconventional reservoirs, optimal completion controls are essential to improving well productivity and reducing costs. In this article, we propose a statistical model to investigate associations between shale oil production and completion parameters (e.g., completion lateral length, total proppant, number of hydraulic fracturing stages), while accounting for the influence of spatially heterogeneous geological conditions on hydrocarbon production. We develop a non-parametric regression method that combines a generalized additive model with a fused LASSO regularization for geological homogeneity pursuit. We present an alternating augmented Lagrangian method for model parameter estimations. The novelty and advantages of our method over the published ones are a) it can control or remove the heterogeneous non-completion effects; 2) it can account for and analyze the interactions among the completion parameters. We apply our method to the analysis of a real case from a Permian Basin US onshore field and show how our model can account for the interaction between the completion parameters. Our results provide key findings on how completion parameters affect oil production in that can lead to optimal well completion designs.
Piloting the 1st Well-Test-Logging in the Middle East, Paving the Way to Low-Cost Dynamic Reservoir Characterization and Well Value Optimization
Authors: Nguyen Raymond , Jacques Antoine , Jaffrezic Vincent , Bigno Yann , Serry Amr Mohamed , Zakaria Hasan , Khan Owais Ameer , Jadallah Omar , Brouard Benoit 
Published: September 2021

Abstract
The development of carbonate reservoirs of a giant field, Offshore Abu Dhabi, requires long horizontal wells to maximize productivity, but at the risk of unwanted gas and water channeling through its inherent heterogeneities. Conformance can be enhanced with dedicated segmented completions (blank sections, Inflow Control Device, Autonomous Inflow Control Device, etc.) or selective acid stimulation (diverter, Limited Entry Liner), which are increasingly implemented to extend well life, and eventually well value.
If these technologies have matured, success depends heavily on the quality of the formation knowledge prior to completion. As of today, conventional logs provide the basic ground, but they lack dynamic information, whereas production logging results are obtained too late, when the well is already completed.
Initially introduced for the optimization of unconventional well completions (see Jacques et al, URTEC 2019), the Well Testing Logging (WTLog) offers the advantage to record a log of mobility, at the end of drilling the openhole, enabling a favorable timing to influence adapted completion and stimulation design. Contrasted viscosity brines are sequentially circulated through the drill pipes at a constant rate and back-produced from the casing at constant pressure. The fluids interface travels in the drain from the TD to the casing shoe, and the measurement of the differential formation seepage is interpreted into an injectivity profile. Combined with rate fall-off phase analysis, permeability and skin logs are derived. Lasting a few hours and realized with conventional rig equipment (such as cement pumps, coriolis flowmeters, Managed Pressure Drilling system), it is a nonintrusive, safe, and ultimately low-cost operation. Forward, it can replace costly logging, when aimed at characterizing heterogeneities.
Within a year, the two first WTLog pilots of the Middle East were successfully designed and carried out. They targeted two appraisal wells in distinct undeveloped reservoirs (Cretaceous and Upper Jurassic formations) which benefited from rich acquisition programs (Image log, Production log) to benchmark and qualify this technology.
After an explanation of the technology principles, this paper describes the design, operations, and results of these pilots. It then focuses on the petrophysical consolidation of the matrix/fracture characterization. It concludes by sharing the learnings and offers insight to what extent it is a promising technology to be applied in Middle East carbonate reservoir developments.
Digital Intelligent Artificial Lift DIAL Gas Lift Production Optimization Deployments Across Assets
Authors: Alshmakhy Ahmed , Bigno Yann , Saqib Talha , Soomro Moazim , Faustinelli Juan , Faux Stephen , BenAmara Abdel 
Published: September 2021

Abstract
Abu Dhabi National Oil Company (ADNOC) is expanding the use of DIAL (Digital Intelligent Artificial Lift) technology, across its assets, through a range of different oil production applications. These include gas lifted single and dual completions, Extended Reach Drilling (ERD) wells and In-Situ gas lift.
DIAL is a first-of-kind technology that enhances the efficiency of gas lift through downhole data, surface control and digital operations. This data driven approach enables production automation and minimizes well intervention requirements. This paper will present four different applications for the technology. These applications were selected by ADNOC assets, as they were deemed to bring the most value for DIAL implementation. The paper will describe technical details for each application, including gas lift designs, completion specificities, installation procedures and benefits observed or anticipated.
A summary of the value add for each of the four applications are listed below.
Gas lifted single completion is the most common application for the DIAL system. The benefits of the application have been described in previous papers and range from intervention savings to production optimization. This paper will highlight the additional benefit of automation, making full use of the system digital features. Gas lifted dual string completion, where the technology enables efficient lift of both strings, improving well production in the range of 40 to 100%. API (American Petroleum Institute) does not recommend pressure operated gas lift in dual wells. DIAL offers stability, simultaneous lifting of both strings through surface control and downhole data. ERD gas lifted well required flexibility for its gas lift operations. DIAL enables real time changes of injection depths based on reservoir response, and units can be installed deeper into the deviated section of the well without any deviation limits. In-Situ gas lift is a specific application where a gas zone is used to lift production from the oil zone in the same well. DIAL enables measurement of the gas injection rate at the point of injection, and adjustment of the flow area to optimize production. This is a world's first use of the technology for this type of application.
A range of applications are described in this paper with many technical details, recommendations and lessons learnt to enable replication within the industry. Some of these applications are world first.