bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combining Machine Learning and Physics for Robust Optimization of Completion Design and Well Location of Unconventional Wells
Authors: Rafiee Javad , Sarma Pallav , Zhao Yong , Plotno Sebastian , Calad Carlos , Betancourt Dayanara 
Published: February 2022

Abstract
Various types of predictive models have been applied over the years to make quantitative decisions for unconventional development plans. These models are either very simple (e.g., type-curves) which ignore the reservoir physics or are too complex (e.g., simulation models) to be able to run for an entire field efficiently. In this paper, we propose a model for design, prediction and optimization of unconventional wells efficiently using a combination of reservoir physics with machine learning methodologies. The proposed model is the amalgamation of the state-of-the-art in machine learning and reservoir physics into a seamless full field model. The physical model ensures that model predictions are always realistic and reliable while the machine learning algorithm allows us to utilize different types of data to make a prediction which cannot be directly integrated into the physical model. The model uses a probabilistic approach to estimate P10-P50-P90 production curves to account for uncertainty in predictions.
The data from more than 1800 unconventional wells in a real field is used to train and test our proposed model. The input features are completion design parameters like lateral length, proppant concentration, well spacing, etc., and the output in a full time series of expected oil production from the well. The results show that our modelʼs prediction leads to correlations of more than 0.75 for the test set which is indicative of its good predictive accuracy. The sensitivity analysis of the parameters of the model on the cumulative production shows that volume of injection fluid, length of the lateral and the proppant concentration are among the most important parameters.
A Parameter Optimization Workflow of Fractured Horizontal Well in Unconventional Reservoir: Case Study
Authors: Chen Zhiming , Chen Duo , Li Wanyang , He Yanxiang , Li Dexuan , Wang Jianan 
Published: February 2022

Abstract
The application of fractured horizontal wells has become an effective mean to improve the ultimate recovery of tight gas reservoirs. However, there still lacks of a complete and systematic approach to optimize the fracturing-treatment parameters of multi-stage fractured horizontal wells (MFHW), like fracturing-fluid volume, stage spacing, and proppant volume. In this paper, a transient flow model of horizontal wells in tight gas reservoirs is developed with considering complex fracture network generated by large-scale fracturing. Based on this model, an optimization workflow of fracturing-treatment parameter is presented by coupling rate transient analysis, performance forecast, and multivariate nonlinear fitting method. First, the reservoir/fracture parameters are evaluated using the rate transient analysis. Then, performance forecasts are performed by using the transient flow model. With multivariate nonlinear fitting, a relationship model between production volume and fracturing-treatment parameters is found, including average fracturing-fluid volume per stage (AFV), average stage spacing (ASS), and average proppant volume (APV). To demonstrate the reliability and practicality of the parameter optimization workflow, a field case is studied. The results show that in the field case the optimal AFV and ASS are respectively ranging from 900-1100 m3 and 60-120 m, while the optimal APV is ranging from 200-500 t. In this situation, the average cumulative gas production can reach 2.73×108 m3, increasing by an average percent of 28.26%. This study provides a new and feasible way for parameter optimization of fractured horizontal wells in tight reservoirs.
Foams to Control Slugging Issues in Pipeline - From Lab to Simulation
Authors: Chai Ching Hsia Ivy , Falope Bishop , Halim Nor Hadhirah , Rodzali M Azmeer 
Published: February 2022

Abstract
Hydrodynamic slugging or two-phase liquid-gas flow instability in pipeline has caused loss in flow capacity and intense vibration at the separator leading to integrity issues. This issue can be resolve using foams generated from surfactants which are introduced into the pipeline to entrap and slow down gas flow, thus enhance its mixing with liquids. To understand how the behaviour or foams in a pipeline impact or alleviate slugging performances, the foams behaviour in the pipeline was simulated using OLGA. First, two main parameters i.e. foams viscosity and interfacial tension in the presence of crude oil were obtained from precision lab experiments. Using a foam rheometer, foam viscosity with crude oil was measured under actual pipeline conditions. Surfactant and crude oil were injected into the rheometer until 500 psi was reached. Then, gas was injected into the loop at a given foam quality (fg). Foam quality, or the gas-liquid ratio was sensitized to 40- and 50% (e.g. fg=40 is 40% gas volume of the total fluids). Shear rates of 100 to 1000 s-1 were applied, and foam viscosities were recorded. For interfacial tension test, the pendant drop method was used. A drop of aged emulsion was drop into a continuous phase of nitrogen gas. The interfacial tension values were assumed as gas-water (without and with surfactant) and gas-oil, at 90:10 water:crude oil cut as per field condition. In the model, first the baseline of the hydrodynamic slugging behaviour was established and simulated using actual pipeline dimension, gas and liquid flow rates, and actual fluids properties, which showed obvious liquid fluctuations. The simulation established at which viscosity and interfacial tension values would have an impact in alleviating slugging by interpreting the output QLT - total liquid volume flow (bbl/d). Foam viscosity for both fg=40 and 50 showed shear thinning behaviour i.e. as shear rate increases, viscosity falls as accordance to the power law. In the model, viscosity as low as 2.5 cP (at 1000 s-1, fg=40) showed reduction in liquid fluctuations as read from the QLT arriving at the inlet of the pipeline, compared to baseline without foam viscosity input. Liquid fluctuations were reduced by 97% just from viscosity change due to presence of foam. Interfacial tension input at 0.024 and 0.021 mN/m for gas-brine and gas-oil, respectively in the presence of surfactant was able to reduce the number of QLT spikes by 24%. By combining the inputs of both parameters, a reduction of QLT or liquid fluctuations by a total of 97% was recorded. This study showed that foams were able to slow down gas velocity and reduced liquid fluctuations thus reducing slugging in one of the problematic pipelines in Malaysia. Accurate foam viscosity measurements generated from the lab remains a vital input to the model - so as to understand behaviour of foam and quantify its impact before actual field applications.
Characterizing Cohesive Zone Parameters to Model Crack Growth in Composite Materials
Authors: Al-Dakheel Hussain , Albinmousa Jafar , Temitope Idris 
Published: February 2022

Abstract
CFRP is gaining interest in several industries such as aerospace, sports, and oil field. When this material is assembled, the adhesive is considered a preference over screws and fasteners as screws holes can lead to matrix delamination. Prior applying an adhesive, surface pre-treatment is done to enhance bonding. Due to the complexity of the composite material namely in complex geometry, one can consider finite element analysis as an optimum method to model the material behavior. Failure of crack growth under cyclic loading is typically modeled using the CZM. However, finding the constitutive behavior parameters is considered challenging. In this work, the maximum stress, which is difficult to calculate experimentally, is estimated using the virtual closure technique (VCCT) as it is considered less complicated and costy than the conventional methods. The VCCT is a finite element method that is employed to simulate monotonic crack growth. From this model, the maximum stress is recorded and used as the maximum traction stress in the cohesive zone model (CZM) to simulate fatigue crack growth. The bilinear traction separation law was employed to simulate the cohesive process zone. To calibrate the model results, an experiment is conducted on two samples those were treated by two different methods. One sample has a sandblasting surface pre-treatment and the other is pre-treated by peelply. Each pre-treatment enhances different material toughness and hence validity of the results if supported. Both samples were tested under both static and cyclic loadings. The maximum energy release rate and the crack length were selected as comparison parameters between the models results and the experimental observations. Overall, it was noticed that the results are considered having reasonable fit.
A New Approach to Estimate Friction Factor for Horizontal Wells from Production Logging Data
Authors: Gok Ihsan Murat , Cevik Muharrem Hilmi , Cinar Murat 
Published: February 2022

Abstract
Conventional friction factor estimation is a challenging task for high flow rate horizontal wells since the roughness is an unknown parameter. In addition, pipe roughness may change with operational time due to the development of scale and corrosion in the horizontal section. This study aims to propose a methodology to estimate frictional pressure losses for horizontal wells by using production logging (PL) data. Prediction of pressure loss in horizontal well along perforations or open-hole is quite complicated due to complication in pressure drop. Different components of the pressure drop along the horizontal section are exist: Gravitation, acceleration, inflow/outflow, and finally friction. Estimation of frictional loss in horizontal wells needs to decompose of each term from total pressure drop in horizontal well. Data acquired during production logging provides an opportunity to determine friction factor since it indicates inflow/outflow zone with individual downhole flow rates of each phase. We clearly showed that friction pressure losses can be estimated for horizontal wells using PL data in certain cases. We verified this approach with synthetic PL data.
Developing Live RAM Model for Production Availability Evaluation
Authors: Mossa Walid 
Published: February 2022

Abstract

Objective
To build live-RAM (Reliability, Availability, and Maintainability) model to enable evaluating System Production Availability (PA) associated with variety of shutdown scenarios, with an objective to ensure Production optimization, Reliability improvement, and to support system de-bottlenecking. This Model is complemented by web-based updating tools to reflect changes in Production Profile, Maintenance plans, Reliability and Maintainability data, and equipment modifications.
New Type of Fluidic Oscillator Made Clean Out Operation Environment Friendly and Cost Effective – A Case Study that Converted Failure into a Success
Authors: Ahmed Barzan , Abdulrahman Khoshnaw Farhad , Raza Mustansar , Elmoneim Hossam , Dar Afnan Ahmed , Shakeel Ahmed 
Published: February 2022

Abstract
Untreated disposal of effluent water has the potential of scaling and plugging the in and near-wellbore regions. A case study and methodology adopted for the clean-out operation of water disposal well of Khurmala Field of Iraq is analyzed in the paper. Previous attempts of clean-out using high-pressure hydro- jetting tools along with acid treatment proved futile effort. As last resort, Fluidic Oscillator (SFO) was deployed for clean-out to regain access of TD and plugged fracture network before the eventual decision of work-over is made.
Combination of SFO having pulsing, cavitation, and helix jetting action in conjunction with train of fluids consisting of diesel, 28% HCl and gel were utilized. The operational sequence of clean-out was in stages of 10m to clean 79m interval, comprising of slotted liner and open hole, filled with detritus. Low bottom pressure required a dynamic approach for treatment-fluid nitrification based on the success of clean-out and access to liner and open hole. Annular velocities required nitrification once the slotted liner and open hole were open for in-take. Rate of penetration, sequence and volume of fluid-trains, nitrification, and batch cycling were designed in accord to changing downhole dynamics during clean-out.
A thorough investigation of detritus, designing of fluids, the accuracy of downhole hydraulics, and application of SFO proved to be an effective solution. It regained access to TD and connectivity between the wellbore and the injection zone. Injection increased from none to 15 bpm at 200 psi. The combination jetting effect of SFO (acoustic pulse (alike), cavitation, and helix) demonstrated to be more effective than rotating jetting tools. Moreover, the merits of operational efficiency supplanted conventional operations and environmental impacts were considerably low in terms of operating time, spent additives, and avoidance of work-over operation. The matching injection parameters post-operation with native parameters post-completion indicated that detritus is removed from wellbore and damage from the critical matrix is removed/bypassed.
Currently, SFO is the only technology that has pulse, cavitation, and helix jetting structures. It has an effective jetting for in and near wellbore region while the kinetic energy transferred via fluid makes the impact stronger in the deeper region. The internal mechanism of the tool allows it to handle high pumping rate and pressures while external finishing offers multi-port orientation for outflow that allows targeting the fill in desired directions. The tool does not require redressing, thus it proves to be an efficient, safe, and cost-effective alternative
Online Measurement and Analysis Technology of Oil & Gas Multiphase Flow by Magnetic Resonance
Authors: Deng Feng , Chen Shiwen , Chen Guanhong , Wang Mengying 
Published: February 2022

Abstract
The measurement and testing of oil, gas and water production accompany the entire oil industry from upstream to downstream. Oil and gas production, oil and gas testing, gathering and transportation, and economic transfer all need to be measured. However, the current production metering technology in oilfields is not perfect, and there are many problems such as poor accuracy, demanding phase separation, data delay, non-full range, additional pressure drop, huge equipment and high cost. In order to solve the above problems, since the 1990s, the development of multiphase flowmeters has been the goal of various oil companies and service companies in the world. A batch of non-separation or gas-liquid separation detection methods and commercial equipment based on electromagnetic waves, capacitance/conductance, ultrasonic waves, and gamma rays have emerged. The emergence of these new technologies has greatly improved production measurement accuracy and measurement frequency, and gradually replaced a batch of three-phase separators and measurement rooms. However, in the face of increasing production stimulation wells (wells with EOR measures), unconventional wells (high salinity, with condensate, high gas, high water cut, heavy oil wells) development, as well as special projects such as oil and gas testing. The demand for multiphase flowmeters is becoming more and more urgent. The application scenarios of commercial multiphase flowmeters are limited, non-three-phase full range, short maintenance period, high cost, and other problems have become prominent.
Magnetic resonance (MR) technology is considered to be the most promising multiphase flow measurement technology, but at present it also needs to solve technical problems such as low measurement frequency, static measurement of phase holdup, poor environmental adaptability of the instrument, and high cost. However, there is no precedent for the application of MR technology to the phase holdup detection of fast flowing fluids, which is mainly limited by the signal loss under fast flow, low signal-to-noise ratio, and low magnetic susceptibility.
In the previous work, we proposed a multiphase flow measurement method of "dynamic flow velocity + static phase holdup". On this basis, this paper further innovates and proposes a dynamic phase holdup detection method, which in a real sense realizes the online magnetic resonance measurement and analysis of multiphase flow. At the same time, a set of industrialized MR multi-phase flowmeter was developed, and the error of the liquid phase in the field test was less than 5%, and the error of the gas phase was less than 10%.
A Pilot Demonstration of Flaring Gas Recovery During Shale Gas Well Completion in China
Authors: Xue Ming , Li Xingchun , Cui Xiangyu , Wang Qi , Liu Shuangxing , Zheng Jiale , Wang Yilin 
Published: February 2022

Abstract

Objectives/Scope
As one of the largest emitters in the world, the oil and gas industry needs more efforts on greenhouse gas reduction. Methane, as a potent greenhouse gas, could largely determine whether natural gas could serve as a bridging energy towards a sustainable future. In the past decade, the oil and gas companies in China has significantly enhanced casing gas recovery and reduced large volume of flaring (&gt;20k m3/day). However, the remaining low- to mid- volume flaring gas were left for further recovery.

Methods, Procedures, Process
Shale gas production in China has met a surge in the number of drilling wells. Those new wells were characterized by a relatively low gas production rate (&lt;1 mill m3/day), in comparison with the shale gas well in the US. As a result, flaring gas during well completion needs to be recycled or used so as to enhance the gas recovery rate. In this study, a pilot demonstration project of flaring gas recovery was carried out to reduce greenhouse gas emission in Weiyuan shale gas region in Sichuan province, China. The technical route of dehydration and natural gas compression was adopted. The recycled natural gas was transformed into compressed natural gas (CNG) and transported to the nearest CNG station for further use.

Results, Observations, Conclusions
The inlet gas pressure were between 2.85 to 5.82 MPa and the outlet pressure were kept stable around 20 MPa to meet the standard of CNG. The minimum dew point temperature was -65.5 °C and the outlet temperature rise remained below 23 °C. The manufactured device also showed a sound flexibility with recover rate between 523.22 to 1224.38 m3/h, which was the 28% to 157% of the designed capacity. An overall of 21k of natural gas was recoverd.

Novel/Additive Information
For a single well completion event, a total of 50k of natural gas could be recovered by this device. The device applied in the pilot demonstration has well matched with the local transportation, gas composition, and surface engineering of the well completion and has the potential of popularization and application in the shale gas region in Sichuan. In that case, it could reach a future economic return over 0.6 billion RMB.
A Multidisciplinary Approach to Production Optimization through Hydraulic Fracturing Stimulation and Geomechanical Modelling in Clair Field
Authors: Dumitrache Liviu , Roy Alistair , Bird Anastasia , Goktas Baris , Sorgi Claudia , Stanley Reginald , De Gennaro Vincenzo , Eswein Edmund , Abbott Jonathan 
Published: February 2022

Abstract
The integration of data and discipline specific knowledge is a common challenge when attempting to optimize or accelerate an asset's recovery through hydraulic fracture stimulations. Any potential omission of data or understanding will increase uncertainty and a project's chance of failure. Therefore, when looking to optimize the production of a given asset, it is key to take a holistic approach that breaks down any technical and organisational barriers.
This project couples the output of the different subsurface and stimulation disciplines to reduce the uncertainty associated with the production forecast of planned stimulation designs. The following paper presents the integrated approach for the Graben sector of UK's North Sea Clair oil field, largest oil field currently in Europe.
Geophysicists, petrophysicists, and geologists generate a static model which is calibrated and validated by reservoir engineers through dynamic reservoir simulation. This model is used to identify the optimum exploitation scenario for a hydrocarbon reservoir and is assessed by the geomechanics engineer to deduce the subsurface stresses and strains to create a 3D mechanical earth model. The multidisciplinary validated representation is handed over to the stimulation engineer to implement various treatments, either performed or to be performed. Once these treatments are designed, the reservoir engineer produces a production forecast which is then fed back to all team members involved in the process, enabling an optimization loop. Considering that this is a multi-well (producers and injector) study, any inference is reflected by the analysis and the optimum hydraulic fracture design is chosen for implementation by an offshore stimulation vessel.
Traditionally, for forecasting purposes, hydraulic fractures can be implemented using conventional reservoir simulation; however, these are very much approximated models of what the stimulation engineers are designing and implementing. Often, the reservoir, production, stimulation engineers can come up with individual forecasts that are obtained independently and omit basic information. A typical example is the way stresses might change due to stimulation and production and the possibility to account for them in an integrated way. The proposed workflow eliminates these shortcomings, and the asset team delivers a single forecast of the exact fracture design considering a fully consistent model of the subsurface, which is to be implemented by the stimulation vessel for the different wells.