bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Application of Multistage Completion & Acid Fracturing in Deep Carbonate Reservoirs in Kuwait
Authors: Al-Muhailan Mohannad , Juma Shehab Adnan , Aljarki Jasem , Sounderrajan Mahesh , Hiray Niranjan , Patil Dipak , Desai Ankur 
Published: March 2016

Abstract
Drilling horizontal wells into a heavily fractured sour Jurassic reservoir and resorting to acid fracturing may be the key to unlocking substantial reserves of oil for Kuwait. Horizontal wells, while more technically challenging and expensive, will ensure fractures are encountered and acid fracturing will penetrate multiple large, oil bearing fractures to improve productivity. This paper highlights the well design, planning, challenges, operational complications and results of the application of multistage completion & acid fracturing in a deep carbonate reservoir in one of Kuwait's field. The aim of the application of such a distinctive completion was to enhance the production from horizontal well in low permeability carbonate reservoir in West Kuwait.
A series of directional technologies and techniques were used in this application. These included a benign build profile, use of RSS motors in kick-off, curve and drain hole for enhanced steering capabilities, lateral drilling with PDC bits. The ability to drill the well without gains or differential sticking was a major challenge and one which was addressed with the close control of fluid design, mud weight window and hole cleaning policy.
A horizontal well was drilled to a TD of more than 15,500 ft with 7 casings policy with one sidetrack. In view of the multistage completion, which requires the hole to be clean of any debris so that the hydraulic ports and ball seats remain obstruction freefor allowing droping of balls, a conscientious decision was made to lower a 7 ¾? tie-back prior to lowering completion. The operations involved a series of steps performed for the first time in Deep Drilling with primary consideration to limit generation of metallic debris while employing judiciously the use of cleanup tools to get rid of the drilling generated metallic fines. This was followed by a simulated reamer assembly trip performed to ensure the successful lowering of completion assembly.
The paper discusses the challenges of horizontal drilling through formations prone to differential sticking, preparation of the hole for and lowering of multistage frac completion and fracturing. The well yielded favorable results with high oil production which showed great potential for increasing Productivity. While such completion will lead to enhanced productivity, lessons learned include among others a step ladder process to make lowering such a completion consistently successful.
Being the first application in deep reservoirs, the lithology has opened up a new dimension for tapping the full potential of the horizontal wells being drilled. This is likely to enhance production in future.
Non-Parametric Adaptive Regression Splines for Multisource Permeability Modeling in a Sandstone Oil Reservoir
Authors: Al-Mudhafar Watheq J. , Al-Khazraji Ahmed Khalil 
Published: March 2016

Abstract
Different from the imposed linear-relationship in multiple linear regressions, Multivariate Adaptive Regression Spines (MARS) is a nonparametric regression procedure that automatically fits the relationship between variables taking into account non-linearity. In this paper, MARS was adopted for multiscale construction of a relationship between core permeability given the Computer-Processed Indicators (CPI) of multiple well log records in a sandstone reservoir.
In MARS, a set of coefficients and basis functions, which are driven for the regression data, are used to construct the relationship between response variable (core permeability) and predictors (well log data and lithofacies). Different from other techniques, MARS is suitable for high dimensional predictors (multiple predictors) because the basis functions partition the input data into regions, each with its own coefficients set. Additionally, MARS has the ability of overcoming the possible outliers that might be available in the given data set. Likewise, MARS automatically eliminates the predictors that have no influence on the response.
The Computer-Processed Indicators (CPI) encompass: water saturation, shale volume, and neutron porosity. Lithofacies of sand, shaly sand, and shale were also included, in the modeling, to provide three different models given these discrete lithofacies classes. Consequently, MARS algorithm has proven its efficiency to model the distinct scales and construct the non-linear relationship between core permeability and CPI log data, given the lithofacies, by providing accurate coefficient estimation and prediction.
The MARS results were compared with the common approach of Generalized Linear Model (GLM). MARS led to much more accurate modeling and prediction than GLM as the coefficient of multiple determination was much higher and the root mean square prediction error was much less than the GLM. Accuracy of MARS algorithm came from taking into account the non-linearity between data into modeling; GLM consider simple linear relationship to fit the distinct scales data.
Eliminating Sustained Casing Pressure in Well Abandonment
Authors: Obodozie Ikenna E. , Trahan Scott J. , Joppe Lambertus C. 
Published: March 2016

Abstract
Sustained casing pressure (SCP) in oil and gas wells can result in leakage to the seabed if not properly checked during the final phase of the well life cycle. The escape of well fluid to the seabed as a result of SCP can lead to significant environmental damage, if not properly managed by the operator.
A recently developed innovative technology can drastically reduce the cost of sustained casing pressure mitigation during well plug and abandonment (P&A). The non-removal of the inner casing string before potential SCP sections are milled translates into savings for the operator. This specialty tool is designed to go through riser restrictions and pass through restrictions in the production casing internal diameter to mill the sustained casing pressure section in the intermediate casing. The mitigation of SCP in a single annulus is a challenging operation. In some cases, SCP exists in multiple annuli and can be more challenging because the removal of steel from the well is an expensive operation. The high-expansion section mill has been deployed in combination with improved milling technology in offshore well abandonment and has lowered the cost of well P&A.
The catastrophic impact of losing well barrier elements as a result of sustained casing pressure migration must be prevented. The cost of achieving this in some cases can be more than the cost of constructing a new wellbore. Moving forward, the industry will benefit from this technology by having the ability to mill a casing string section within a section. This capability eliminates the existing practice of performing several cut-and-pull attempts and/or casing milling, followed by a section milling operation.
Study on Longitudinal Vibration of Casing String in Deepwater by Riserless Drilling
Authors: Deng Song , Fan Honghai , Liu Yuhan , Liu Jinge , Tian Deqiang , Peng Qi , Ren Weiyan 
Published: March 2016

Abstract
The paper reviews the whole project and introduces the casing string structure of Riserless Drilling. Then it establishes the shallow Riserless Drilling longitudinal vibration model based on vibration theory, soil mechanics, fluid mechanics. We assume the soil layers around the casing are homogeneous, isotropic and saturated cohesive soil, and the earthquake force is harmonic excitation force. And the harmonic excitation force is at the bottom of the soil layers. Meanwhile, it also considers flow friction of drilling fluid in well bore. Based on this, this paper analysis the longitude forced vibration load of casing string by Riserless Drilling and gets its results. At the same time, this paper simulates the results through Abaqus software and compares it to the calculation results. And the results show that the earthquake degree, and the depth of casing is the main factors of longitudinal vibration of casing string of Riserless Drilling while the rate of drilling fluid has little effect on the vibration.
Integrated Simulation Based on Multiphysics Analysis, Virtual Reality, and Hardware for Offshore Installation, Operation, and Maintenance
Authors: Roh Myung-II , Ham Seung-Ho , Kim Ki-su , Zhao Luman 
Published: March 2016

Abstract
The simulation is being widely used to asses the safety and applicability of various offshore works. For this, some technologies can be considered to implement a simulator for offshore applications such as installation, operation, and maintenance. For more realistic simulation, an integrated simulation interface is proposed in this study by incorporating three different kinds of technologies; multiphysics analysis, virtual reality, and hardware. The proposed interface consists of an analysis module, a visualization module, a motion platform module, a network module, and so on. Using the proposed interface, we can synchronize the simulation time and exchange data on the network through the middleware with a standardized data structure. To verify the efficiency and applicability of the proposed interface, it is applied to various simulations for offshore works. As a result, we can see that the proposed interface can be used to perform the realistic simulation for various offshore works in less time and effort.
Application of Artificial Intelligence for Water Coning Problem in Hydraulically Fractured Tight Oil Reservoirs
Authors: Kalam Shams , Alnuaim Sami Abdulaziz , Rammay Muzammil Hussain 
Published: March 2016

Abstract
Artificial intelligence is playing a vital role in oil and gas industry. In this paper a new procedure and a unique statistical model has been developed to predict critical oil rate at any hydraulic fracture perimeter and reservoir property for Tight Oil Reservoirs (TOR) containing hydraulic fracture under water coning issue. The new approach uses numerical simulation and Artificial Neural Networks (ANN). Simulating the coning behavior is an expensive and time consuming technique. Therefore, there is a need for a readymade correlation which can help as a good quick estimate.
This research work exhibits a 3D simulation model, which has run for different ranges of fracture conductivity, kf*w (md-ft), reservoir permeability, k (mD), anisotropy ratio, kv/k, density difference, ?w-?o (lb/ft3), water oil contact, WOC (ft), fracture length, Lf (ft), fracture height, hf (ft) and oil viscosity, µo (cp) to find critical oil rate. Total number of 20,000 data points are obtained by the 20,000 number of simulation runs by coupling the commercial reservoir simulator with MATLAB. ANN is employed to obtain generalized correlation for critical oil rate in hydraulically fractured tight oil reservoirs.
Seventy percent of the simulated data points are used to develop the correlation and rest of them are used to validate and test the proposed correlation. Results show the good agreement with the unseen data. Correlation parameters are transformed to dimensionless form in order to get generalized correlation. Nonlinear regression technique was also applied to find the correlation, but ANN gives good results with lesser error as compared to non-linear regression. It is observed that critical oil rate highly depends on fracture half length, fracture height and fracture conductivity in the hydraulic fractured vertical oil well.
MWCNT for Enhancing Mechanical and Thixotropic Properties of Cement for HPHT Applications
Authors: Rahman M. K. , Khan W. A. , Mahmoud M. A. , Sarmah P. 
Published: March 2016

AbstractGrowing demand to drill high-pressure, high-temperature (HPHT) wells requires improved technology to overcome the HPHT challenges. Designing and testing for cost-effective cementing at simulated downhole conditions for HPHT gas and oil wells poses a challenge necessitating special consideration in the choice of cement slurry. A successful cementing job is dependent on how quickly and efficiently cement achieves its strength. Another critical aspect is to efficiently displace the mud out of the annulus by designing the cement slurry with desired rheology. Achieving desired mechanical and rheological properties of cement becomes harder and more complex at HPHT conditions.A wide variety of admixtures are commonly mixed with the oilwell cement slurries to accommodate the extensive range of pressure and temperature and achieve enhanced mechanical and rheological properties. Carbon nanotubes are one of the most recent admixture options. This paper describes a study carried out to examine compressive strength and rheological properties (plastic viscosity, yield stress and gel strength) of oilwell cement slurries integrating chemical additives and multi-walled carbon nanotubes (MWCNT) at HPHT conditions.The study determined that integrating MWCNT in oilwell cement led to substantial increase in the compressive strength values. The rheological properties of oilwell cement slurries are greatly reliant on temperature, water/cement ratio and the admixture used. The study indicated that using MWCNT in cement slurries improved the rheological properties of cement slurries and therefore their displacement efficiency in challenging conditions.
Tethered Steel Lazy Wave Riser Configuration for FPSO with Disconnectable Turret in Deepwater
Authors: Karunakaran Daniel , Sankar Subramanian , Frønsdal Magne , Baarholm Rolf 
Published: March 2016

Abstract
Recently turret-Moored Floating Production Storage and Offloading systems (FPSO) have been used in many deep water developments worldwide, with consideration of disconnectable turrets for harsh environment applications. This trend makes the interactions between FPSO and riser system more important. Further, Steel Lazy Wave Riser (SLWR), which is a compliant variant of the most commonly used Steel Catenary Risers (SCR), is becoming an attractive riser option.
The paper provides a review of the various riser systems that can be considered for turret-moored FPSOs, and specific emphasis on SLWR. A detailed case study of SLWR for a typical turret moored FPSO with disconnectable turret is presented. This system is described in terms of design and functionalities, the fabrication and installation methods are presented. The case study shows clearly that an improvised SLWR is an attractive alternative to be used for FPSO with disconnectable turret and is very efficient to fabricate and install in a very cost effective manner.
Pros and cons for SLWR are discussed, with consideration of the particular challenges of turret-moored FPSOs with large floater motions, hang-off geometry constraints at turret, hang-off loads, riser interferences, risers pre-installation, and turret disconnection constraints.
Heavy-Duty Cleanup: Caesium Formate-Based Microemulsions Make Light Work of a Tough Job
Authors: Moroni L. P. , Davidson M. , Lam J. , Goonoo A. , Twycross J. , Howard S. K. 
Published: March 2016

Abstract
Minimising drilling costs is an ongoing concern, especially with global uncertainty and volatile oil prices. One area in which costs can be reduced is in the wellbore cleanup phase. Inefficient cleanup can result in large volumes of liquid waste that must be treated or disposed of, particularly if a non-aqueous drilling fluid (NADF) is used. In addition, completion fluid costs can be significant, especially where high-density brines are required for wellbore safety. Improved cleaning efficiency can lead to significant cost savings.
Wellbore cleanups in high-temperature, high-pressure (HTHP) wells can be particularly challenging. Not only is high-density brine required to maintain hydrostatic overbalance to control formation pressures, the brine is often at or close to its saturation point. The selection of surfactants that function effectively in high-salinity fluids can be very challenging. Extensive laboratory testing must be performed to ensure compatibility between the cleanup spacer and the drilling fluid. The performance of the cleanup is then assessed through a series of bottle and viscometer sleeve tests to ensure the solids and metal surfaces were rendered fully water-wet.
A significant challenge when designing cleanup spacers is balancing excellent performance of oily residues and solids removal with thermal and chemical stability. Microemulsion cleanup spacers have been used to perform efficient wellbore cleanups in deepwater applications, resulting in reduced volumes of waste fluids. This paper describes the field application of a high-density caesium formate brine microemulsion cleanup spacer to efficiently displace and remove a high-density barite and manganese tetraoxide-weighted NADF. Results show that microemulsions exhibit excellent displacement and cleanup performance of a challenging drilling fluid. Microemulsion technology results in a quicker cleanup with reduced waste volumes, thereby minimising costs.
The high value of caesium formate brine means that maximising the recovery of this valuable asset is essential to justify the economics of the cleanup process. This paper describes the transfer of microemulsion cleanup technology used in deepwater environments to HTHP applications.
Structural Interpretation Based on the Application of Seismic Attributes - A Case Example in the Offshore of the Peninsular Malaysia
Authors: Shamsuddin A. , Shahar S. , Ghosh D. P. , Ngoc N. H. 
Published: March 2016

Abstract
Geological interpretation based on the seismic attributes can enhance the accuracy of the interpretation. According to Chopra and Marfurt (2007), seismic attribute is any measure of seismic data that can help in enhancing or quantifying features of interpretation interest. There are a lot of seismic attributes and it is hard to choose. The results are based on the computation of the seismic attributes on the offshore of the Peninsular Malaysia. The methodology of the seismic attributes starting from the condition of the data in order to get the best results from the computation of seismic attributes. The condition of the data might give high influence to the seismic attributes computation. Seismic attributes were computed based on the previous researchers' suggestions on the best seismic attributes that can be used to compute the structural features. Interesting structural features which are important in the geological interpretation like fault can be defined in this study area. Based on the results, there are a few types of the seismic attributes which were suggested are suitable and can be applied to the study area and there are a few types which are still can be in doubt and can be in debatable. As a conclusion, the applications of the seismic attributes need to be handled attentively as it might show artifacts. In this case, a few key wells need to be applied in order to validate the geological features especially structural features in this study area. The accuracy of the features can only be confirmed based on the well data for example FMI log. The approach of using various seismic attributes will introduce different types of interesting features for structural study, which might be beneficial in geological interpretation.
Multilateral Gravel-Pack Solutions for Single Wellbore Branches
Authors: Durst Doug G. 
Published: March 2016

Abstract
Drilling, completion, and production monitoring and control of multilateral wellbores in highly unconsolidated sandstone formations have been successfully achieved both technically and operationally in the recent past, helping to ensure that planned production rates and reserves are achieved.
Gravel packing lateral branches on multilateral wells is no longer challenging. Sound isolation of the main branch can preserve the mainbore of debris when milling the window and drilling the lateral, helping ensure seamless gravelpack operations. Stable junction isolation exists to support sand placement and subsequent reverse-out gravel pack operations in the main and lateral branches.
With respect to multilateral wells, one of the key factors in terms of determining whether or not a multilateral wellbore might be suitable for a given project is the size and type of sand control completion and technique that might be necessary. The use of conventional standalone screens combined with multilateral technology has a long and highly successful history. Where more sand control reliability is necessary, the use of gravel packs or frac packs in combination with multilateral wellbores, technology is now available and beginning to develop its own successful history.
In its current form, when combining advanced sandface completions with multilateral completions, gravel pack operations are subsequently followed by the installation of the multilateral and upper completions. As a result of a newly developed system, the junction completion can now be interconnected with the sand control operations in a single seamless operation.
Application of Test Simulation Technique in Deepwater Heavy Oil Reservoir
Authors: Zhang Junbin , Duan Yonggang , Chen Feifei , Li Zhenglan 
Published: March 2016

Abstract
Heavy oil reservoirs have became a key and difficult point as exploration and development of oil and gas goes deeper. Since deepwater heavy oil reservoirs are characterized by adverse fluid property and poor flowability resulting from low seawater temperature, conventional well test usually fails to gain expected crude sample and real formation data, leading to some problems for subsequent development. In view of two difficult issues during the deepwater heavy oil reservoirs test – flow assurance concern and decision-making difficulty in testing system, application of appropriate test technologies and techniques are of great importance.
Prior to the offshore test, an integrated approach to modeling and designing operating conditions was described. The feasibility of available technical solutions in relation to enhancing the low wellhead temperature conditions was discussed based on the wellbore temperature and pressure features derived from the analytical modeling, and a test technique (integrated progressing cavity pump (PCP), heating sucker rod and insulated tubing) applicable to deepwater heavy oil reservoir was recommended. Then, drilling-stem test (DST) was carried out to an exploration well with two oil layers and one gas layer which is located in southwest of Congo sea with the recommended test technique.
Simulation results demonstrate that the advantages of the compound technology – electric heating, PCP and insulated tubing are far greater than using insulated tubing or heating sucker rod alone. Compound technology decreases the frictional pressure loss of the producing fluid due to its capability of maintaining high and uniform wellbore temperature. Interactive tubing conveyed perforating (TCP) and DST was conducted with a testing program of thrice flow well and twice shut-in well. Insulated tubing assembly was employed from progressing cavity pump stator to the wellbore and the setting depth of the heated sucker rod was down to about 10m above the pump. Productivity information, representative crude samples and pressure/temperature information of the testing zone were obtained successfully.
The simulation technology and pilot test proved the feasibility of insulated tubing and electric heating PCP in deepwater heavy oil testing, providing technical guidance for further appraisal and development of deepwater heavy oil fields.