bluuebunny/crossref_metadata_2025 huggingface dataset:
NMR T2 Response in Rough Pore Systems: Modeling and Analysis
Authors: Li Yiteng , Alsinan Marwa , He Xupeng , Ugolkov Evgeny , Kwak Hyung , Hoteit Hussein
Published: September 2022

Estimating pore size distribution from NMR T2 responses typically assumes a smooth solid-pore interface. However, surface roughness accelerates NMR T2 relaxation and thus leads to an underestimation of the pore size distribution. Until now, only a few studies investigated the surface roughness effect. This work systematically studies the influence of surface roughness on NMR T2 responses and introduces a correction factor to bring incorrect T2 values back to the correct values.

This study includes three main sections: creating 3D pore structures with roughness, simulating NMR T2 relaxation using the random walk method, and quantifying the roughness effect. Constrained Latin hypercube sampling is used to create representative examples in a space-filling manner, constrained by the fast diffusion limit. Then random walk simulations are implemented, and NMR T2 responses in smooth and rough pores are calculated. To accurately estimate pore radius, a "value-to-value" model is developed to map the nonlinear relationship between a 3D roughness parameter and the proposed correction factor. The accuracy of the proposed model is validated by comparing the corrected NMR T2 responses to the reference results obtained from smooth pore systems. Numerical results show that the proposed model can correctly evaluate pore sizes from decreased NMR T2 responses caused by the surface roughness effect. Previous works incorporated this effect into surface relaxivity as they attempted to retain the pore radius and meanwhile reproduce the faster relaxation rate. However, this may break down the assumption of fast diffusion limit. Instead, this study mitigates this limitation by separating the roughness effect from surface relaxivity. The proposed correction factor offers an alternative approach to calculating the correct pore radius by accounting for the influence of surface roughness at the pore scale.
Social Media and the Oil & Gas Sector: Challenges and Opportunities
Authors: Capello Maria Angela , Cox Denise , Battalora Linda Battalora
Published: September 2022

There are currently 4.62 billion users of social media worldwide1. This means that more than half of the population of the world uses social media (58.4%)2. The Oil and Gas sector cannot escape this reality, which is so valuable for communications and positioning strategies. One of the top-valued goals of modern organizations in all sectors is to have a positive presence on social media. For the oil and gas sector, this is particularly needed, as energy transition concepts are not necessarily well understood nor ingrained in society at large, making it difficult to revert any negative public opinion matrix about the sector.

The COVID-19 pandemic forced many traditional organizations in the oil and gas sector to embrace social media, increasing their active presence on the main professional online platforms, gaining more engagement with their own employees and society like never before. This paper compares the social media presence of prominent organizations related to oil and gas in 2022, analyzing trends and highlighting opportunities and challenges.

A comparison of key elements considered diagnostic in improving the recognition and reputation of oil and gas organizations are addressed in more detail, in particular sustainability and DE&I (gender representation, generally addressed as Diversty, Equity and Inclusion).

Conclusions are related to cultural frameworks, selected language for postings, geo-political affinities, and the profile of the companies analyzed. Framing the current trends analyzed resulted in the identification of organizations that are more successful in the utilization of these key channels that are important to general audiences and especially to younger generations.

Some unexpected findings shaped our conclusions that strategies needed for step-changes in political or cultural settings benefit greatly from the use of social media and have proven to be effective in furthering women's empowerment and for the uptake of sustainability at the corporate level.
Scalable High-Fidelity Hydraulic Fracturing and Geo-Mechanics Simulator for Unconventionals
Authors: Valiveti Dakshina Murthy , Dyadechko Vadim , Song Ting , Gupta Varun , Sharma Akriti , Venkatesan Jagannath , Gireesh Greeshma
Published: September 2022

Development optimization is the key to ensuring economic extraction of hydrocarbons in unconventionals. Every dollar saved per fracture grows by 3-4 orders of magnitude per pad. Typical questions of business interest include optimal number of perforations per fracture, fluid and proppant rates, cluster spacing, well spacing, influence of pre-existing fractures and depletion on infill wells/fractures etc. Evidently, these questions span broad length scales, wide variety of governing equations, and nonlinearities. This is compounded by the challenge of tight balance between maintaining the accuracy of numerical simulations and completing simulations fast enough for sensitivity analyses.

In this work, we describe how we addressed all these challenges in building our proprietary hydraulic fracturing and geomechanics simulator. We solve the single phase porous flow equations along with Terzaghi’s effective stress based force balance equations representing the reservoir. The model includes fluid and proppant flow from well head to the specific stage through 1D compressible pipe flow. The well flow is coupled with reservoir through perforation orifice flow. Flow in fractures is considered to be the typical plane Poiseuille flow with Darcy leak-off into reservoir. We adopted scalable data structures and parallel algorithms that enable solving ~50 million degrees of freedom with relative ease. The pore-pressure is solved on a Finite Volume grid, and the deformation on Finite Element grid. All these governing equations are solved simultaneously in a fully coupled approach using an iterative solver. The fracture is assumed to be planar, defined by element interfaces and prepared a priori with deactivated duplicate nodes to avoid modifying distributed data structures during runtime. Multiple different models are implemented for well and perforation and can be chosen based on suitability. The perforations belonging to various clusters, stages and wells are activated along the timeline of completion clock, mimicking a frac-job.

The article will focus primarily on the techniques that allowed us to build such a scalable fracturing simulator, followed by simulation results. Using this simulator we are able to perform stress update calculations due to depletion, multi-well and multi-stage hydraulic fracturing scenarios. The fracture interference across stages and wells is directly captured through the governing equations. We will also present strong scaling test results to show the scalability of the simulator to millions of degrees of freedom.
Experimental Study of Proppant Transport Using 3d-Printed Rough Fracture Surfaces
Authors: Tatman G. , Bahri A. , Zhu D. , Hill A. D. , Miskimins J. L.
Published: September 2022

3D printing is a type of additive manufacturing technology that allows for digital 3D models to be made into physical objects out of a wide range of thermoplastics, resins, and occasionally metals. In previous years, 3D printing models at high-resolution suitable for oil and gas research was either time consuming, cost-prohibitive, or limited to a small model build volume. However, the rapid advancement in resin 3D printing technology recently has allowed for a significant increase in production speeds and model size at little cost. In this study, we utilized 3D printed rough-wall fracture panels in a large-scaled proppant transport apparatus to evaluate the feasibility of repeatable and realistic experimental investigation by the 3D printing technology.

Understanding proppant transport in hydraulically created fractures helps to answer the questions about proppant distribution, resultant fracture conductivity, effectiveness of fracture fluid and additives, and all leads to fracture treatment efficiency. In the past, lab experiments showed that fracture topography plays an important role on fracture conductivity, and the characteristics of fracture surfaces have been grouped as random distribution, channel, wavy and ledge (step-change). These surface features can be described by geostatistical parameters. For large-scale proppant transport, the realistic surfaces are difficult to create, and thus most studies have used smooth-surfaced parallel acrylic panels for the fracture walls.

Stereolithography (SLA) resin 3D printers produce a physical model by using an ultraviolet light source to selectively illuminate and cure a photopolymer onto a travelling build platform. The physical models are based on a computer-generated surface with controlled statistical definition. We have successfully printed panels to build a 4ft X 2ft main fracture with a smaller fracture intersecting orthogonally. The panels are carefully printed with transparent resin to allow for video recording. Initial tests showed the mechanical integrity of printed fractures and proppant transport results.

This paper describes the detailed procedure of generating fractures by 3D printing, experimental setup and the test results of proppant transport.
Life-Cycle Production Optimization of the CO2-Water-Alternating-Gas Injection Process Using Least-Squares Support-Vector Regression (LS-SVR) Proxy
Authors: Almasov Azad , Onur Mustafa
Published: September 2022

In this study, we present a framework for efficient estimation of the optimal CO2-WAG parameters for robust production-optimization problems by replacing a high-fidelity model with a least-squares support vector regression (LS-SVR) model. We provide insight and information on proper training of the LS-SVR proxy model for the CO2-WAG life-cycle production optimization problem. Given a set of training points generated from high-fidelity model-based simulation results, an LS-SVR-based proxy model is built to approximate a reservoir-simulation model. The estimated optimal design parameters are then found by maximizing NPV using the LS-SVR proxy as the forward model within an iterative-sampling-refinement optimization algorithm that is designed specifically to promote the accuracy of the proxy model for robust production optimization. As an optimization tool, the sequential quadratic programming (SQP) method is used. CO2-WAG design variables are CO2 injection and water injection rates for each injection well at each cycle, production BHP for each production well at each WAG half-cycle, and inflow control valve (ICV) for each well at each WAG half-cycle and at each valve. We study different scenarios where we fix some of the design variables to investigate the importance of design variables on life-cycle production optimization of the CO2-WAG problem. We compare the performance of the proposed method using the LS-SVR runs with the popular stochastic simplex approximate gradient (StoSAG) and reservoir-simulations runs for a synthetic example considering a three-layer, channelized reservoir with 4 injectors and 9 producers. Results show that the proposed LS-SVR-based optimization framework is at least 3 to 6 times computationally more efficient, depending on the cases considered, than the StoSAG using a high-fidelity numerical simulator. However, we observe that the size and sampling of the training data, as well as the selection of well controls and their bound constraints for the well controls, seem to be influential on the performance of the LS-SVR-based optimization method. This is the first LS-SVR application to the CO2-WAG optimal well-control problem. The proposed LS-SVR-based optimization framework has great potential to be used as an efficient tool for the CO2-WAG optimization problem.
Cost-Effective and Environmentally Sustainable Permanent Magnet Motor for Artificial Lift
Authors: Li Yong , McManus Joseph , Thompson Howard
Published: September 2022

The challenge of climate change and the imperative of moving to a low carbon economy has intensified and added to traditional objectives of affordable, safe, and clean energy in oil and gas production. Recycling parts from artificial lift equipment has been an industry-standard practice for decades. Equipment component reclaim has been a way to deliver high-quality, cost-effective products to our customers, especially in tough market times. It will be a critical best practice to reduce carbon emissions and enhance environmental sustainability.

With customer cooperation, service companies develop procedures to re-use the most significant components of an Electrical Submersible Pump (ESP) system. These include the pump, cable, seal chamber section, and motor. The motor stator, bearings, and rotors are a high percentage of reclaimable parts in an ESP system. Reclaiming the induction motor (IM) rotors has been standard practice for decades. However, with the advent of permanent magnet motors (PMM) and the change in rotor construction, the current process does not apply. The driving force for PMM application is to improve energy efficiency and lower cradle to grave carbon emissions. We could not fully realize the vision of environmental sustainability and reduced carbon footprint if PMM rotors were not part of the reclaim process. Therefore, recycling the PMM rotors strengthens the justification for replacing IMs with PMMs, especially given that the value of magnetic material is highly variable and has doubled in the past year.

The PMM rotors from a recovered motor may suffer from de-magnetization or be contaminated with production fluids or metal debris. Like IM rotors, the most effective method to remove contaminants from the PM rotor is to bake at high temperatures for a period. However, baking the PMM rotor magnets at elevated temperatures will be at least partially de-magnetized during the process and result in the PMM rotors no longer meeting performance specifications. This paper will present innovative technology and apparatus to re-magnetize the de-magnetized rotors for reclaiming.

The research has developed a process where, without disassembling the rotor, the magnets in the rotor are re-magnetized in-situ by a specific apparatus. Testing has proven that PMMs assembled with reclaimed rotors have the same performance-rated power and torque as those built with new rotors. On the other hand, since magnets in PMMs account for more than 50% of total carbon emission of all reclaimable parts in PMMs, factoring in mining, manufacturing, logistics, and processing of magnets that generates toxic by-products to the environment, PMM rotor recycling contributes to corporate responsibility and our overall ESG (Environmental, Social, and Governance) rating. Furthermore, reclaiming PMM rotors can enable us to build PMM more cost-effectively, gain competitiveness in the market, and keep our PMM supply chain more stabilized.
Proppant Fluid Compatibility: Maximize Fracturing Efficiency
Authors: Malekahmadi Fatee , Moringo Nicole Carrejo , Adams Lance , Venugopal Rupa , Price Brian , Li Yifan
Published: September 2022

Many additives are used in unconventional resources fracturing to enhance performance of the fracture. Chemical additives are carefully chosen after stringent compatibility testing in the lab. Proppant is selected based on API/ISO procedures for quality control methodologies or simply by availability. However, the current procedures view proppant as a material and fail to address its compatibility with friction reducers (FRs) and other chemical additives in fracturing applications.

After chemical compatibility was confirmed via flow loop and viscosity testing, an FR was selected for field trial. Operators successfully placed Proppant 1 (Northern White) utilizing FR-A. However, when operators attempted to replace Proppant 1 with three other proppants, high surface pressure was seen, and operators could not maintain suitable pumping pressure. Operators initially concluded that FR-A was incompatible with the formation. Further review and discussion led to chemical compatibility testing of FR-A with each proppant. FR-A combined with field water and proppants shows the compatibility of FR-A with Proppant 1 and incompatibility of the other three proppants due to swelling or flocculation.

We demonstrate traditional compatibility testing of water and FR via flow loop and viscosity and quantifying proppant performance through API/ISO procedures are inadequate. Proppant selection should include mechanical and chemical testing to ensure well production is maximized while costs are minimized, ultimately achieving the desired outcome.
Incorporating Geothermal Curricula into Petroleum Classes: A Ten-Year Experience
Authors: Teodoriu Catalin
Published: September 2022

Over the years, petroleum curricula have been enjoying a continuous update to keep up with technology and industry progress, whereas geothermal is still working on establishing itself as an independent engineering study program. Recently, SPE has created the SPE Geothermal Technical Section, a strong signal towards expanding existing interest areas and strengthening the position of geothermal as a renewable energy resource. Geothermal is undoubtably the closest to oil and gas operations, as it needs, among others, drilling, well construction and completion, reservoir modeling and understanding, geology assessment and geophysics. Consequently, many authors have repeatedly asked for an acceleration of the technology transfer from oil and gas to geothermal. However, this technology transfer is still very slow and irregular. With this in mind, the main question is whether there is a need of fully dedicated courses to teach geothermal or we should rather slowly incorporate geothermal into established courses.

This paper is proposing an intensive discussion about how a petroleum-based program can promote and support the needs of future geothermal engineers through curriculum adaptations. As an example, ten years of teaching experience on two continents under different program concepts, layouts, requirements, and expectations will be summarized and presented here.

One of the main findings of this study is that unlike a class fully dedicated to geothermal, adding geothermal aspects into drilling and completion classes is more likely to facilitate the absorption of geothermal knowledge and enhance the desired technology transfer from oil and gas to geothermal.
Creating an Auto-Encoder Based Predictive Maintenance Tool for Offshore Annulus Wells
Authors: Jain A. , Morgenthal A. , Aman M. , Horton M. , Khan S.
Published: September 2022

Objectives/Scope

A key component of well integrity is annular integrity. Much of the focus on this has been on establishing maximum and minimum pressure limits and designing envelopes under various well conditions encountered during well construction and subsequent production and injection operations. Many operators have established systems for operating wells within this design envelope to monitor for pressure excursions. However, abnormal annulus pressure behavior within the design envelope could be overlooked using a system that relies on limit monitoring and excursions.

Methods, Procedures, Process

We propose a modeling workflow that combines novel deep learning techniques with statistical analysis to create online models which predict potential asset failures and alert on abnormal behavior such as abrupt pressure build up in producer and water injection wells’ A-Annulus. The model uses autoencoder architecture to learn the behavior of the wells during normal operating periods and generates alerts when it encounters new or abnormal behavior.

The autoencoder architecture outputs a risk score aggregated over the residuals from all input features. Sequential Probability Ratio Test (SPRT) is performed on the risk score to determine abnormal regime during operation to raise alerts. These alerts can be used for root cause analysis based on the top contributors to the risk score. In our approach, we use feature thresholds as filters to determine normal operating periods for training the model. To simulate live conditions during model training, the historical time series data is divided into training and prediction windows. The model is trained on each training window and risk scores are created for the prediction window using a sliding window technique. To find the optimum model, a grid search is performed over a wide distribution of autoencoder and SPRT hyper-parameters. The models are scored based on recall, precision and lead time provided before a failure.

Results, Observations, Conclusions

We demonstrate this workflow using annulus pressure, downhole pressure, upstream choke pressure and upstream choke temperature as input to the model. The model does not require the physical properties of a well but uses historic well data lending itself to be applicable to already existing well stock. Next, we demonstrate using engineered features and synthesized data to efficiently train and score the models. During our experiments, we have explored several engineered features across multiple platforms and found that the correct set of engineered features can deliver a model that accurately alerts on asset abnormalities and potential failures.

Novel/Additive Information

Our approach combines the strengths of deep learning techniques, statistical analytics and subject matter expertise to provide a framework that has demonstrated efficient scaling across multiple assets and sites and has potential application on a variety of oil and gas equipment.
First-Hand Perspectives of the Pro-Female Notion in the Oil and Gas Industry in the Gulf
Authors: Retnanto Albertus , Mohsin Anto , Shaikh Afsha , Shaikh Insha , Pinontoan Darrell
Published: September 2022

The oil and gas industry in the Gulf has been vital in contributing to Qatar's economy. With the industry's rapid growth, there was a need for an exponentially larger workforce. Gender imbalance still remains one of the industry's challenges in a largely male-dominated field. However, the good news is that the female workforce has gradually increased. The rise in female engineers and scientists in the industry has resulted in, among other things, better opportunities to access higher education and training in the oil and gas field. However, there remain some obstacles that aspiring female engineers face. Based on interviews conducted with several engineers who work in multinational oil and gas companies in the Gulf states, we discuss existing challenges and issues many women engineers still encounter today. The interviewees also noted some improvements and provided helpful advice for the females aspiring to be engineers.

We interviewed several female and male engineers, some of whom occupy managerial positions while others work in the fields. The interviews were conducted on Zoom over several weeks, and we then transcribed the interviews. We then analyzed the interview transcripts using a corpora analysis software, LancsBox, with each transcript separated as its own corpus. KWIC (keyword in context) tool was used to isolate a single keyword (for example, "female" or "girl") to find out how often those keywords were used and in what context in a sentence for each corpus, which helped identify the various themes that were discussed during the interview, such as gender and the workplace, challenges in the workplace, barriers to work and life balance, to list a few.

The interviewees recounted their experiences, and from that data, we describe their challenges, successes, and recommendations to make the oil and gas industry in the Gulf accommodating for both genders. The challenges they describe include a lack of appropriate facilities for women on the field; sexist or difficult treatment from male counterparts, managers, and family members; a gender pay gap; and a lack of policies or incentives that support women to achieve executive positions in their companies. Some of the successes they shared include strides being made to encourage women to enter STEM programs in schools and STEM careers, a changing environment for the prevalence and inclusion of women in the oil and gas industry, and a change of culture in the world surrounding the image of women in the STEM industry. Several female interviewees mentioned familial support in their educational pursuit, suggested the creation of mentorship programs and recommended having more female role models in the industry.
A Visual-Learning Project to Enhance the Understanding of Petrophysical Properties Using Pore-Scale Simulation
Authors: Alyafei Nayef , Zia Muhammad Farooq , Rabbani Harris
Published: September 2022

This paper aims to showcase a visual-learning project to enhance the understanding of petrophysical concepts through the use of pore-scale flow simulation. Open-source Field Operation and Manipulation (OpenFOAM) is used to simulate fluid flow through six unique pore structures and postprocessing of numerical results was conducted using Paraview. The images and data of each flow sequence (drainage and imbibition) is captured and available for analysis. In this paper, we discuss how each parameter is used and calculated. The data to calculate are porosity, fluid saturation, throat size distribution, capillary pressure, and relative permeability. The data of this project is open access and can be adopted by any institution. The project utilizes six cases where it enables visual demonstrations of both drainage and imbibition and highlights the effects of pore geometry over each of these processes. The students use open-access image analysis software to analyze the image output from the simulation data and calculate the properties above. Providing students with strong visual cues to otherwise abstract multiphase fluid processes occurring within hydrocarbon reservoirs strongly enhances their learning process. The project provides a unique learning experience to enhance the understanding of petrophysical concepts. The visual elements of this project make the understanding of the microscopic processes much simpler and more engaging. All the data associated with this project will be open access.
Monitoring Hole-Cleaning during Drilling Operations: Case Studies with a Real-Time Transient Model
Authors: Arévalo Pedro J. , Forshaw Matthew , Starostin Alexander , Aragall Roger , Grymalyuk Sergiy
Published: September 2022

Steady-state hole-cleaning models used to monitor cuttings during well construction rely on static parameters that portrait specific drilling scenarios disconnected from each other. This paper presents the integration of transient hole-cleaning models validated in the field into a digital twin of the wellbore deployed while drilling. Thus, enabling the monitoring of the evolution of cuttings, which reduces uncertainty around the state of hole-cleaning procedures and minimizes the associated risk.

A digital twin of the wellbore equipped with physics-based transient models is prepared in the planning phase, and later deployed to a real-time environment. While drilling, smart triggering algorithms constantly monitor drilling parameters at surface and downhole to automatically update the digital twin and refine simulation results. The physics-based transient model continuously estimates cuttings suspended in the drilling mud and cuttings deposited as stationary beds, which enables evaluation of cuttings distributions along the wellbore in real time. Automation systems consume the predicted results via an aggregation layer to refine fit-for-purpose hole-cleaning monitoring applications deployed at the rig.

The transient hole-cleaning model has been integrated into digital twins used during pre-job planning as well as in real-time environments. The system deployed in real-time successfully tracks the state of cuttings concentration in the wellbore during all operations (drilling, tripping, off-bottom circulation, connections) considering the effects of high-temperature and high-pressure on the drilling fluid. Moreover, since the model uses previous results as starting point for the next estimation cycle, it creates a dynamic prediction of how the cuttings evolve while drilling. Fit-for-purpose automation and monitoring services predict drilling issues related to hole-cleaning, downhole pressure, among others. Drillers and drilling optimization personnel receive actionable information to mitigate hole-cleaning issues and avoid detrimental effects for operations. The user interface (UI) presents how the cuttings distribution change with evolution of input parameters (rate of penetration, string rotation, and flow rate).

A set of case studies confirm the effectiveness of the approach and illustrate its benefits. One case study from the North Sea illustrates the reaction of the model to changing operational parameters, while another combines along-string-measurements of density with the cuttings predictions to confirm the trend established by the predicted cuttings concentration.
Insights From Benchmarking Methane Emissions of Oil & Natural Gas Production in the United States
Authors: Curry Tom , Russell Pye , Hellgren Luke
Published: September 2022

The U.S. Environmental Protection Agency (USEPA) collects emissions data each year from oil and natural gas operators in the U.S. through the Greenhouse Gas Reporting Program (GHGRP). While studies have indicated that these emissions are underestimated, the data are reported using a consistent methodology across operators, providing an opportunity to better understand operational differences and trends. The largest methane emissions source category for onshore oil and gas production is pneumatic devices, which make up 56% of methane emissions. From 2018 to 2020, reported emissions from pneumatic devices declined 16%. The drivers of this change include fewer high-bleed pneumatic devices in operation and fewer operating hours reported per intermittent bleed pneumatic device.
Drilling the Deepest High-Pressure High-Temperature (HPHT) Onshoreexploration Well Using a Combination of Mud Cooling and Managedpressure Drilling (MPD) Techniques: A Field Case Study from the Nile Deltaof Egypt Targeting Mesozoic Carbonate Platform
Authors: El-Husseiny Mahmoud , Elfakharany Taher
Published: September 2022

This paper reviews the successful application of a Mud Cooling and Managed Pressure Drilling (MPD) system in a HPHT well to explore the potential of the Mesozoic Carbonate Platform with pressure ramp and Narrow Mud Weight Window (NMWW) in the Nile Delta of Egypt. The Constant Bottom Hole Pressure (CBHP) variation of MPD in combination with mud cooling was used to drill from the middle of the pressure ramp to the target depth, maintaining the mud inlet temperature at around 50°C.

Drilling this well is challenging due to the uncertainty of pressure and temperature regimes and the lack of data in this area. This paper will discuss the application of the MPD and Mud Cooling combination. Also, the challenges encountered while drilling and how they were tackled will be explained, besides the best practices and recommendations for similar applications.

10 in. × 12 in. section completed the pressure ramp, then entered and drilled through the NMWW. The hole was drilled and enlarged simultaneously to 12 in. to section target depth (TD) at 5118 m. Losses at a rate of 3.5 to 5m3/h were encountered (lost 26m3) when circulating to increase mud weight from 2.16 to 2.20 sg to follow the pressure ramp. Then the mud weight was cut back to 2.16 sg, and drilling continued with active use of the MPD system to maintain a CBHP at 2.22 sg. Equivalent Mud Weight (EMW) both equivalent circulation density (ECD) while drilling and with surface back pressure (SBP) during connections. A dynamic formation integrity test (FIT) and a static Pore pressure Test were performed with the MPD to re-assess the drilling window and adjust mud weight accordingly. The mud cooler was running at 100% capacity keeping mud-in temperature 50°C while mud-out temperature ranging from 60 to 70°C and annular temperature from MWD was recorded while drilling at a maximum temperature of 139°C at TD. The 8 in. hole was drilled through the primary objective from 5118 to 5585 m. The MPD detected two well control events early at 5585 m which alleviated their consequences. Difficulties were experienced to regain control of the well, facing a kick and losses scenario due to NMWW. The open hole was plugged back with cement to secure the well after a fragile control was regained. The mud-in temperature was maintained at around 40°C.

T-1 well was the first well to reach that deeply buried Mesozoic carbonate structure. The Mesozoic carbonate platform has never been reached in this area. This paper provides an in-depth study for an innovative combination of utilizing MPD along with mud cooling technique to drill a HPHT exploratory well with a NMWW providing guidance for similar applications.
Applying Survival Analysis to Sand Failure Control Risk
Authors: Yang Huihui , Tallin Andrew , Lu Ligang , Xiao Xiaohui , Valteau Lisa , Wei Jia , Chen Jay
Published: September 2022

Sand production affects safety, reliability, equipment integrity and economics. To help production engineers understand and quantify sand control risks, we built sand control survival application. This application displays how survival is impacted by operating and well parameters as a function of cumulative production, which can help to save oil and gas industry hundreds of millions of dollars per year. Our application uses a dataset that tracks survival status and corresponding cumulative productions for more than 300 completions in GOM. Field data covering water cut, flowing pressure decline, and sand control survival was compiled and analyzed to determine the impact these both single and multiple cofactors on survival, which save time and cost while improving the overall quality of information.
Development and Deployment of Digital Twin for Production and Well Integrity
Authors: Vieira dos Santos Maycon , Menezes Duarte Rosa Rafael , Alves de Oliveira Livia , Newmar Carlos , Rodrigues GonÃ§alves da Silva Fabio , Fasolin Karina , Girardi Vinicius , Iri Nicola Cristofari Rosenbach Leonardo , Nogueira de AraÃºjo JoÃ£o Paulo , Esteves Aranha Pedro , Leibsihn Martins Andre
Published: September 2022

This work presents the development and deployment of a digital twin dedicated to monitor wellbore integrity in real time. Currently, the system is implemented and monitoring in real-time more than 230 production and injection wells. Due to reliable outcomes, the tool is also able to provide virtual well instrumentation to operations that do not have permanent downhole sensors. It consists of the coupling of different numerical simulation software, allowing the calculation of Annulus Pressure Buildup (APB) for confined well annulus and also safety factors for structural integrity analysis. This approach aims to ensure operational efficiency and safety during well interventions and to diagnose unplanned events, by automatically identifying potential operational problems, such as washouts (tubing, packer), reaching of operating limits (pressure and flow rate) per tubing equipment and failures (DHSV and Pack off). Simulations are helpful to predict pressures and temperatures that the well will be exposed to before the execution of specific operations in monitored wells. Different wells were selected and validated in order to corroborate the efficiency of the production digital twin, considering different production scenarios – steady-state and well shut-in (look-ahead), providing a qualitative comparison between calculated data and gauge readings.
Experimental Measurements and Molecular Simulation of Carbon Dioxide Adsorption on Carbon Surface
Authors: Gomaa Ibrahim , Guerrero Javier , Heidari Zoya , Espinoza D. Nicolas
Published: September 2022

Geological storage of carbon dioxide (CO2) in depleted gas reservoirs represents a cost-effective solution to mitigate global carbon emissions. The surface chemistry of the reservoir rock, pressure, temperature, and moisture content are critical factors that determine the CO2 adsorption capacity and storage mechanisms. Shale-gas reservoirs are good candidates for this application. However, the interactions of CO2 and organic content still need further investigation. The objectives of this paper are to (i) experimentally investigate the effect of pressure and temperature on the CO2 adsorption capacity of activated carbon, (ii) quantify the nanoscale interfacial interactions between CO2 and the activated carbon surface using Monte Carlo molecular modeling, and (iii) quantify the correlation between the adsorption isotherms of activated carbon-CO2 system and the actual carbon dioxide adsorption on shale-gas rock at different temperatures and geochemical conditions. Activated carbon is used as a proxy for kerogen. The objectives aim at obtaining a better understanding of the behavior of CO2 injection and storage into shale-gas formations.

We performed experimental measurements and Grand Canonical Monte Carlo (GCMC) simulations of CO2 adsorption onto activated carbon. The experimental work involved measurements of the high-pressure adsorption capacity of activated carbon using pure CO2 gas. Subsequently, we performed a series of GCMC simulations to calculate CO2 adsorption capacity on activated carbon to validate the experimental results. The simulated activated carbon structure consists of graphite sheets with a distance between the sheets equal to the average actual pore size of the activated carbon sample. Adsorption isotherms were calculated and modeled for each temperature value at various pressures.

The adsorption of CO2 on activated carbon is favorable from the energy and kinetic point of view. This is due to the presence of a wide micro to meso pore sizes that can accommodate a large amount of CO2 particles. The results of the experimental work show that excess adsorption results for gas mixtures lie in between the results for pure components. The simulation results agree with the experimental measurements. The strength of CO2 adsorption depends on both surface chemistry and pore size of activated carbon. Once strong adsorption sites within nanoscale network are established, gas adsorption even at very low pressure is governed by pore width rather than chemical composition. The outcomes of this paper provides new insights about the parameters affecting CO2 adsorption and storage in shale-gas reservoirs, which is critical for developing standalone representative models for CO2 adsorption on pure organic carbon.
Novel Method to Detect Fracture Closure Event Using Continuous Wavelet Transform
Authors: Adel Gabry Mohamed , Eltaleb Ibrahim , Soliman M. Y. , Farouq Ali S. M.
Published: September 2022

The Diagnostic Fracture Injection Test (DFIT) is widely used to get the fracture closure pressure, reservoir permeability, and reservoir pressure. Conventional methods for analyzing DFIT are based on the assumption of a vertical well but fail for horizontal wells drilled in ultra-low permeability reservoirs with potential multiple closures. There is still a significant debate about the rigorousness and validity of these techniques due to the complexity of the hydraulic fracture opening and closure process and assumptions of conventional fracture detection methods.

In this study, a new signal processing approach was proposed by M.Y. Soliman, U. Ebru, F. Siddiqi, A.Rezaei, and I. Eltaleb (2019) and (2020) was extended to use the continuous wavelet transform to identify the closure time and pressure. The new method was applied to synthetic and actual field data. The synthetic data were produced using commercial fracture simulators based on fracture propagation and closure simulation principles with predefined fracture closure. To determine this closure instant, we decompose the pressure fall-off signal as the output of the fracture system into multiple levels with different frequencies using the continuous wavelet transform. This "short wavy" function is stretched or compressed and placed at many positions along the signal to be analyzed. The wavelet is then multiplied term-by-term by the signal, and each product yields a wavelet coefficient value. The signal energy is observed during the fracture closure process (pressure fall-off) and the fracture closure event is identified when the signal energy stabilizes to a minimum level.

Because of the uncertainty of the real field fracture closure, a predefined simple synthetic fracture simulation with known fracture closure was used to validate the new methodology. The new continuous wavelet transform technique showed clear success without any prior assumptions or the need for additional reservoir data. The new methodology is also extended to actual field cases and showed the same success as conventional classical methods.
Typical Curve and Diagnosis Method for Identifying Fracture Closure Points of Fractured Wells in Flowback and Early-Time Production Period for Tight Oil Reservoir – A Field Example from Ordos Basin in China
Authors: Sun Zhaole , Cheng Linsong , Du Xulin , Jia Pin , Cao Renyi , Xue Yongchao
Published: September 2022

Fracturing fluids will carry an amount of proppant flowing back to the wellbore due to the inappropriate flowback schedule, which causes some parts of fractures to be closed without support. The appearance of closed fracture sections without support (pinch point) has a serious negative effect on well performance and is also a potential signal of refracturing. A four-region model considering fracture closure is developed to detect pinch points by analyzing production data in material equilibrium time.

Therefore, a novel four-region flow model is proposed to study the influence of pinch points on well dynamics performance in the initial stage of production and to diagnose the pinch point. In this model, the fluid flow to the wellbore is regarded as three parts: matrix, fracture, and pinch points. The position of the pinch point on the fracture (near wellbore) is considered. The existence of pinch points makes the fracture conductivity segmented, and the partial closure of fracture can be simulated by setting different fracture lengths, widths, and permeability. The flow in each region is treated as the linear flow and is coupled through boundary conditions and flux supply. Thereby, the mathematical model of flow containing pinch points is established.

This paper analyzes the production data of oil well, draws the logarithmic curve of RNP and its derivative RNP’ versus the material balance time (MBT), and conducts rate transient analysis to determine the occurrence of pinch points. In the case of the near-wellbore pinch point, the slope of the first half of RNP curves is relatively small, while the slope of the back section is about 1/2. Compared with RNP curves, the early slope of RNP’ curves is relatively large and gradually changes into the linear flow stage with a slope of 1/2. Different properties of pinch points mainly affect the slope of the left and right ends of RNP and RNP’ curves. The new analysis method can be used to analyze the influence of fracture closure position and degree of fracture closure on well productivity. Finally, the novel four-region flow analysis model was applied to the analysis of oil production data from a typical well in Ordos Basin. The length, width, and permeability of the near-wellbore fracture closure section can be obtained by fitting the proposed chart.

The novel four-region flow model method and its curve characteristics provided in this article can be used as an important reference for judging whether there is a pinch point in fracture. It has a certain guiding significance for the formulation of fracturing schemes for new wells and whether old wells need refracturing in actual production.
Effective Use of Surveillance to Optimize the Development Plan for a Deep-Water Reservoir
Authors: Satik Cengiz , Burgess Matthew , Carter Matthew , Evans Frank
Published: September 2022

A three-phase strategy was adopted for a deep-water reservoir development due to large uncertainties associated with fault compartmentalization and aquifer support. First phase started with primary production from several wells while water injection was implemented a few years later as second phase. Finally, the third phase involved infills. Data collected during drilling was utilized to improve reservoir characterization. This paper describes how a Surveillance, Analysis and Optimization (SA&O) plan was utilized to resolve key subsurface uncertainties and optimize the development plan, along with lessons learned and best practices.

The development plan included adding five infill wells during the infill campaign. Two of those infills, Well1 and Well2, delineated the reservoir south of a major fault. Early reservoir characterization placed two sealing faults between the Well1 and Well2 wells, creating a separate fault compartment with a future infill well in the development plan. Steeply dipping beds below a thick salt canopy make seismic imaging a challenge and fault delineation uncertain. Although a future infill well was planned to recover the reserves from this compartment, the length and transmissibility of the faults, as well as reservoir heterogeneity between the Well1 and Well2 wells were highly uncertain. Prior to start-up of Well2, a pulse test and multiple pressure build-up tests were conducted as part of the SA&O plan to resolve fault uncertainties. The pulse test involved creating pressure pulses by shutting-in and starting-up the Well1 and monitoring at Well2 for pulse arrival. Test design was developed using Intersect and Saphir numerical simulations sensitizing on the fault extent and transmissibility uncertainties.

The test was planned and executed successfully as a result of multi-functional collaboration between the asset development, reservoir management support, and operations teams. Analysis of all transient pressure data indicated very strong pressure communication without any detectable barrier between the Well1 and Well2 wells. Increased confidence in recent seismic imaging enhancements have since corroborated these results. Reservoir simulations without these compartmental faults, indicated that Well1 & Well2 can effectively drain most of the recoverable oil, with limited improvement from an additional well. Consequently, the development plan was optimized by removing the future infill well, translating to a significant capital cost saving.
Oil and Gas: Innovation, Patents, and the Future of an Industry
Authors: Brewer Peter L.
Published: September 2022

Overview

This article is written in support of the Society of Petroleum Engineers’ Annual Technical Conference and Exhibition. As of the time of this writing, the event is scheduled to take place in Houston, Texas, during the week of October 3, 2022. The ATCE is the SPE's flagship international event. The host facility will provide over 90,000 square feet of exhibition space along with numerous presentation rooms. It is an honor to be a part of this program.

The author has been tasked with preparing an article that discusses the role that patents have played in the development of the oil and gas industry. As someone who has written hundreds of patent applications in various energy generation fields over the last 22 years, and as a degreed petroleum engineer himself, the author believes that he is uniquely suited for the task.

A number of years ago, the author wrote an article for the Society of Petroleum Engineers entitled Intellectual Property for the Oilfield The article was written in connection with a presentation at an International Association of Drilling Contractors (IADC) Drilling Conference held in Dallas, Texas. A reciprocal article was published by a patent attorney in Canada the same year. See R.B. Caldwell, Patent Monopoly-Protecting Your Ideas (in Canada). The two articles focused much more on the patent process itself than the development of oil and gas technology and the role that the patent process has played.

The author is unaware of any attempts that have been made, scholarly or otherwise since 2002 to discuss the role that patents play in the oil and gas industry. This paper is a humble attempt to fill that void.