bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ensuring High-Quality LWD Sonic Data to Emplace Radioactive Compaction Monitoring Markers in an UHPHT Setting
Authors: Banks John , Shotton Peter , Di Tommaso Davide , Anderson Claire 
Published: November 2020

Abstract
The Culzean field is an ultra-High Pressure, High Temperature (uHPHT) gas-condensate accumulation and is one of the largest development projects of recent years in the UKCS. From experience in analogue fields, compaction is likely to occur and negatively impact the deliverability of wells. With accurate geomechanical modelling such issues can be assessed and proactively mitigated.
Measurement of changes in distance between radioactive markers is a recognised technique for compaction monitoring. The measurement is undertaken throughout the life of the well and is used in the calibration of field geomechanical models. Markers were emplaced in two wells in Culzean. To ensure safe and successful emplacement of the markers a real-time estimation of rock strength was undertaken using logging-while-drilling (LWD) sonic data. Key to success was obtaining the correct data for timely decisions on the depth of radioactive markers.
The paper describes the process used to validate sonic data from an LWD sonic tool by comparison with a wireline acquisition and its later application in two additional wells where markers will be emplaced. A unipolar LWD sensor was included in the drilling assembly to transmit semblance image in real time, which was manually picked on surface for compressional and shear slowness. Rather than automatic downhole picking, this approach allowed immediate offset wells comparison, improved reliability and quality checking which increased confidence in the final product. In the initial well, the resulting logs were compared with data acquired from a wireline dipole sonic tool showing a very good match and proving "equivalent-to-wireline" quality of the measurement.
In two subsequent wells once total depth was reached, raw memory and diagnostic data were downloaded from the tool for functional and quality checks and processed to generate semblance images. After undergoing quality check, evaluation and post processing, when needed for improvement, the acoustic data was used to calculate Unconfined Compressive Strength (UCS) estimates. This then guided the selection of depths for the radioactive markers.
The use of a LWD sonic tool, providing reliable acoustic data to generate a UCS, allows a quick turnaround for mobilisation of equipment (i.e. markers) and enabled the operator to acquire data in an uHPHT environment.
Water Flooding Performance Prediction in Layered Heavy Oil Reservoir
Authors: Liu Yigang , Han Xiaodong , Chen Cunliang , Wang Hongyu , Liu Hao 
Published: November 2020

Abstract
Prediction of oilfield development data is one of the important technical indicators for oilfields to achieve maximum economic benefits. Numerical simulation method is the most commonly used method. However it has been widely used with a long run time and too much information to solve this problem. With the continuous development of big data technology and artificial intelligence technology, there is an urgent need to form a development index prediction method based on such technologies.
This paper proposed a new method to predict water flooding performance in layered reservoir. The method regards layered reservoir as a vertical superposition of a series of single layer reservoirs. An injection-production analysis model is established in each single layer reservoir respectively, which considers invasion of natural water and the start-up pressure gradient of heavy oil reservoir. And then a composite model is established only by production data. Finally, the least square principle and artificial intelligence algorithm are used to optimize the model. Then the Gentil's correlation method is used to predict production performance. As development progresses, the production data became more and more abundant, and they replaced the model and re-optimized it. Oilfield applications showed that this technique has capability to predict oil performance in layered reservoir.
Understanding Sand Control Installation Failures
Authors: Tibbles Raymond , Govinathan Kesavan , Mickelburgh Ian , Jain Samyak , Wassouf Philip 
Published: November 2020

Abstract
The sand control completion is the last step in the well construction. It is the step that turns the well from an expense to a revenue generating asset. While every sand control completion is designed for success, things don't always go to plan during the installation, and the technical and commercial results are sometimes less than perfect. Failures can range from minor issues that can be easily remedied to catastrophic events that put the entire well, and investment, at risk. Regardless of severity, it is critical that all failures are analyzed to determine the root cause, prevent them from being repeated and protect asset value. The success of a sand control installation should not be assumed and can only be confirmed with a thorough review of all available job data.
This paper introduces several case studies of failures that occurred during sand control installations and details the investigative process and techniques used to identify the root causes. Examples include events such as screen/wash-pipe damage, bridging, hole collapse, and packer seal failure. This analysis provides key insights into downhole events and mechanisms that can be used to minimize risk and improve future completions.
Innovative Solution for IWAG Injection Monitoring Using Fiber Optic Cable Cemented Behind Casing in an Intelligent Well: A First in Malaysia
Authors: P Mosar Nur Faizah , Ceccarelli Tomaso Umberto , Tan Chee Seong , Arsat Maisara , Mohd Yaacob Mohd Khairul , Sinanan Haydn Brendt , Fabian Oka , Suratman Muhamad Farhan , Samuel Orient Balbir 
Published: November 2020

Abstract
Water and gas injection are widely used techniques to alleviate pressure decline and improve sweep efficiency in brownfield reservoirs. When variable reservoir properties exist, such as permeability, pressure, and thickness, the requirements for real-time monitoring and control become crucial to ensure zonal injection target rates and volumes are achieved.
The Bokor Field is located in the Baram Delta area of the South China Sea, 45 km from the shore of Sarawak, Malaysia, in a water depth of approximately 70 m. This marks the initial use in Malaysia of a distributed temperature sensing (DTS) fiber optic cable installed and cemented behind casing in a multizone immiscible water alternating gas (IWAG) injection well. Injection profiling was monitored via the DTS across multistacked reservoirs having different horizontal permeabilities. The DTS detected injection profile patterns within each zone and enabled identification of high permeability streaks and thief zones. Inflow control valves (ICV) were then used for injection management and control.
For Bokor well, offshore Malaysia, an intelligent completion system was chosen. The well comprised downhole flow control valves with 8 choke positions, permanent downhole gauges, and a DTS cable to enable optimum injection conformance. DTS provides real-time temperature measurements along a multimode optical fiber encased in a ¼-in control line. Enhanced measurement accuracy can be achieved by placing the DTS cable as close as possible to the reservoir by installing it behind the production casing in direct contact with the reservoir formation.
Deployment of the DTS in such a way presents several challenges in the design and operational phases. The first challenge is to ensure the integrity of the cable while running and cementing the casing in a highly deviated trajectory. Special equipment was designed to ensure mechanical protection of the fiber while safeguarding the quality of the cement-to-casing bond. An innovative TCP perforating technique and cable detection system had to be developed to prevent damage to the DTS when perforating the casing. Several design interfaces and system integration tests were identified and carried out between multiple providers to guarantee a smooth and successful installation.
Preliminary results demonstrate intelligent technology for real-time monitoring of the actual injection profile behind casing, and for controlling it remotely via an RTAC (real-time acquisition and control) software solution.
Fluid Contact Monitoring Using Pulsed–Neutron Logging in Challenging Gas–Filled Boreholes for Production Planning in a Mature Carbonate Gas Field
Authors: Phettongkam Numan , Zakeria Ahmad Fakrudin , Mohamed Razman Nur Faradilla , Mohamad Amin Mohamad Farid , Purlya Chesci , Mohd Jumat Norhazilla 
Published: November 2020

Abstract
Fluid contact logging using pulsed neutron (PND) tool in challenging gas-filled boreholes is essential for gas field life monitoring, especially following sustained production. The acquired data is used to identify the remaining gas column and pore fluid contact movements for future planning to optimize production. In this field, wells were logged with the PND tool to identify the current GWC.
The gas-filled boreholes with unknown liquid levels was logged with the PND tool in sigma mode. Sigma, near and far count, and its ratio were used to identify the gas-water contact. A minimum of 2 passes were required for quality control using repeatability, which increased the confidence in the interpretation. Ideally, it is always recommended to run PND tool in a liquid-filled borehole to establish confident gas and liquid differentiation. Due to operational constraints, the wells could not be filled up with water. Thus, the PND tool was run in challenging conditions to detect gas/water contact movement after many years of production.
Sigma data revealed the fluid contact changes in the target carbonate reservoir regardless of the borehole fluid variation in all 4 wells, allowing mapping of the remaining gas level. Due to fluid level uncertainty in the borehole, liquid level variation in each well was observed for all wells based on early time period, burst measurement. Despite the variation of borehole fluid, the great depth of investigation of the sigma measurement enabled the fluid contact to be determined. Also, the top of the carbonate could be determined from the high to low deflection, which indicates the transition from shale to carbonate in the upper gas zone. The fluid contact could be identified by the increasing trend from the low sigma gas zone to a higher sigma in the liquid zone. The near and far count also suggest a similar response, though with some effect of gas borehole fluid on the measurement. Repeatability between 2 passes increases the confidence in the interpretation, even in challenging wells where borehole fluid-level changes has been observed. The fluid contact could be determined in all 4 wells that were logged using both measurements (sigma, near and far count). In addition, by running a gamma ray sensor with this tool, the gamma ray log suggests the possibility of scale build up from produced water, which is essential input for future reservoir management.
The fluid contact could be determined despite a challenging logging environment for the pulsed neutron tool using sigma measurements without the need to fill up the gas well with water for ideal logging conditions. The current identified contact, together with possible scale buildup, are then used by the reservoir management team to facilitate future production planning.
A New Mathematical Workflow to Predict Permeability Variation using Flowing Gas Material Balance
Authors: Haq Bashirul , Al Shehri Dhafer Abdullah , Mohammed Isah , Olayiwola Teslim , Muhammed Nasiru Salahu , Hasan Zahid 
Published: November 2020

Abstract
In the dynamic approach, production data including the flowing wellhead or bottomhole pressures are used to conduct the material balance analysis to determine the gas in place at any time during the life of well. However, the procedure did not extend to identify the well health issues such as permeability variation. The objective of this research is to develop a simplified mathematical workflow to identify and verify permeability variation using flowing gas material balance.
In this approach, a new form of flowing gas material balance equation is derived by adding permeability variation term. In this new mathematical workflow, linear and exponential curve fitting tools along with the flowing material balance analysis are used to predict well expected behavior. The prediction is then compared with initial well production behavior. The deviation of the prediction and the expected production behavior formed the basis of permeability variation.
The component of the model is tested with known data and then the total model is verified with known values. After that, the workflow is applied in the gas well. The new model prediction is validated using field data and the prediction compares quite well. The well health diagnostics are successfully compared with known well issues from an active gas field. Results presented in this paper will show that the novel workflow is able to accurately predict permeability variations in both constant and variable production rates. In addition, the new workflow enables the production engineers to send an alarm to take corrective measure about the issue and to diagnose production issues like permeability variation.
Thermal Energy Harvesting from Oil and Gas Flow
Authors: Arsalan Muhammad , Ahmad Talha Jamal , Saeed Abubaker S. 
Published: November 2020

Abstract
This work describes the need for energy harvesting in horizontal wells and demonstrates a novel concept of thermal energy harvesting. The concept utilizes temperature differences in compressible fluids generated by vortex tubes using thermoelectric generators (TEGs). The method is ideal for fluid environments where thermal gradient is either lacking or is negligible such as horizontal portion of the multilateral oil and gas wells. Laboratory-based experimental validation of the concept is presented in this paper showing the potential of a significant amount of energy harvesting in difficult to access locations and environments including downhole in multilaterals where limited usable energy sources are available besides the flow to power autonomous circuits and systems for monitoring and control applications.
Lazy Wave Steel Catenary Riser Design Optimisation in Digital Field Twin
Authors: Bhowmik Subrata , Naik Harit , Noiray Gautier 
Published: November 2020

Abstract
The objective of the paper is to optimise the Steel Lazy Wave Riser configuration based on an analytical approach and implement the riser design automation in cloud-based digital subsea field. The methodology demonstrates the effective implementation of multi-objective optimisation methods based Genetic Algorithm (GA) and hybrid GA with Radial Basis Function(RBF).
Steel Lazy Wave Riser (SLWR) configuration is considered for the riser design optimisation and automation. The configuration consists of multiple design variables such as top angle, sag bend elevation, hog bend elevation, length of the buoyancy section and the module diameter. The riser configuration optimisation is time-consuming and exhaustive method due to nonlinear time domain analysis and a large number of load cases. Therefore, a novel analytical optimisation technique is developed to reduce the computational cost as well as the complexity using automation. The riser design automation procedures consist of the following steps: 1. The multi-objective optimisation algorithm is used to find the optimal configuration of the riser systems in static condition 2. The optimised configurations in the static state are used for further optimisation based on fatigue and extreme load conditions. 3. Use the final optimal configuration for generating the orcaflex simulation file and perform the design automation in the cloud-based subsea digital field.
The proposed optimisation and design automation method minimises both the maximum riser stress and the cumulative fatigue damage of the SLWR configurations. It also demonstrates the significant reduction in computational cost as well automation helps to reduce the standard error occurs due to manual inputs. The all necessary design data are received from the cloud-based field development and perform the calculation in the cloud. The whole procedures are presented in a very efficient and time-saving manner in cloud-based field platform.
The traditional design of the riser configuration is very experience-dependent as well as very time-consuming. But the riser design optimisation using the optimisation algorithm based on GA can save considerable computational time and also less need for design experience.
Sand Dilation Study and its Effect on Porosity and Permeability During Cyclic Steam Stimulation by In-Situ Imaging Technique
Authors: Bashir Arsalan , Hashmet Muhammad Rehan 
Published: November 2020

Abstract
Cyclic Steam Stimulation (CSS) is an effective and widely used technique to recover the heavy oil/bitumen. However, due to its complex nature, it has not been studied in detail experimentally. Most of the Canadian bitumen reservoirs have negligible steam injectivity, therefore to recover oil from such reservoirs, steam is injected at pressure higher than the overburden causing the pore pressure to increase and allow the disturbance in the sand, referred as sand dilation.
This study aims to investigate changes in permeability and porosity of sand pack while varying net stresses occurring during CSS. New coreflooding equipment was designed, fabricated and commissioned aided with mechanical clamps to prevent leakages specially while reaching minimum net stress through providing strong grip between mandrels and rubber sleeve. To understand flow mechanism at the prevailing conditions, real time visualization study was carried out by using CT scanner. The images of in-situ fluid flow patterns with specific CT numbers were used to obtain a density map over the entire length of sand pack which was translated to porosity.
Ottawa's sand with the highest concentration of 100-140 mesh was used for sand pack preparation by following the wet packing procedure. Methanol was used for this purpose. During the flooding test net stresses were increased and decreased in cycles by injecting steam and later hot water and at every phase scanning was done to apprehend the changes in the CT numbers and density. Permeability was also measured to understand the changes resulted due to varying net stresses. At minimum net stress the sand pack was fractured and the flow paths were confirmed from the CT images causing a radical change in permeability of 22.13% increase. This disturbance in sand during pore pressure variation was irreversible. However, not a considerable change in porosity was observed once the flow took place through the fractures.
This research work has helped to understand the disturbance of sand by steam and hot water injection during CSS and identification of possible flow paths with help of CT images at real time. The changes reported in permeability are for the specific range of sand particle size, pressure and temperature conditions under which this study was conducted.
Seamless Integration of Well Test Interpretation Results into Reservoir Simulation Model
Authors: Chouya Smail 
Published: November 2020

Abstract
Reservoir rock properties characterization using well test data is crucial for the success of field exploration and development phases. Unfortunately, the conventional well test interpretation approach is based on analytical models (Horner plot, Gringarten type curves, and Bourdet derivative) which does not consider the reservoir complexity and the actual geological information used in reservoir simulation models. This may lead to non-geological interpretation and inaccurate reservoir description. Various testing methods are generally used in the oil and gas industry to evaluate the reservoir performance and acquire useful information to reduce uncertainties in reservoir characterization. The two common methods are interval pressure transient testing (IPTT) and drill stem test (DST). Integration of the DST/IPTT interpretation results into the reservoir simulation model is required to better characterize the reservoir properties and help minimize the uncertainties in rock property distribution around the wellbore. Unfortunately, this integration is not done automatically and systematically.
A grid-based inversion techniques of the pressure transient test is introduced to allow seamless integration of well test data into a reservoir model. This technique uses the same grid for the dynamic simulation model to discretize the reservoir properties. It is based on data assimilation, represented by Ensemble Kalman Filter (EnKF) and maximum likelihood techniques such as gradient-based methods. The main challenge of this technique is how to deal with large unknowns in reservoir parameters. This requires the use of Bayesian framework technique (similar to seismic inversion) to overcome the challenge of large unknown parameters.
A workflow that allows a seamless integration of well test interpretation results into the reservoir simulation model is used considering the prior geological knowledge of the reservoir that provides an efficient way to integrate IPTT/DST results and geological information. The grid-based inversion technique has been successfully tested and used to better estimate the reservoir parameters using well test data. The integration of the IPTT results into the reservoir model helped to reduce uncertainties in near wellbore permeability distribution, which ultimately allowed to achieve better history match of the pressure data.
The new integration workflow reconciles static and dynamic reservoir data to update the geological reservoir model with meaningful parameters. It also allows seamless integration (which was not possible before) of well test data into reservoir simulation model which is key for successful reservoir management.