bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field Optimisation of Acid Concentration of Visco Elastic Based Acid Using Fiber Optic Enabled Coiled Tubing (FOECT)
Authors: Dhufairi M.A. , Al-Mutairi S.H. , Ahmed D. , Bal Moustapha 
Published: March 2015

Abstract
Success of matrix stimulation treatments depend on the uniform distribution of treating fluids over the entire production/injection interval. Thus, when acid is pumped into a well, it naturally flows to the most permeable/least damaged zone. To avoid improper placement of acid into one interval of a zone of different injectivities, diversion techniques can be applied. Diversion can be accomplished by either mechanical means or chemical means.
Diverting chemicals are deposited over the perforations or the formation. When deposited, they form a layer with a lower permeability than the formation it is covering. This imposes an additional pressure drop needed to penetrate the cake will cause the fluid to divert to another part of the perforated interval. Eventually, uniform injection is accomplished across the whole interval.
Different concentrations of diverting agents can be used to get the required diversion, but how to know if the diverter pumped is indeed diverting or not is a challenge. Bottom-hole pressure or temperature responses can be checked during the job to get an idea if diverter is working properly. Thus, Fiber Optic Enabled Coiled Tubing with Fiber Optic Enabled Bottom-hole Assembly(FOEBHA) with pressure and temperature sensors for real-time downhole measurements and Distributed Temperature Sensing (DTS) is the best solution available.
This paper describes the use of different concentrations of diverter i.e. visco elastic diverting agent and the behavior responses of downhole parameters with their usage.
Joint inversion of time-lapse crosswell seismic and production data for reservoir monitoring and characterization
Authors: Liang Lin , Abubakar Aria , Habashy Tarek M. 
Published: March 2015

Abstract
We present a fluid-flow constrained inversion approach for joint interpretation of time-lapse seismic and production data. In this approach, the full-wave formseismic inversion is integrated into the traditional history-matching process. Hence, the interpretation of time-lapse seismic data is constrained by the fluid-flow physics in the reservoir. The key component in the workflow is a fluid-flow simulator, which computes not only the production data in the wells, but also the temporal and spatial distribution of fluid properties, such as fluid saturation and pressure. These fluid properties, together with prior rock properties, can be transformed to acoustic properties using the prescribed petro-elastic model. A finite-difference frequency-domain acoustic solver is then used to simulate the time-lapse seismic responses on the reservoir. We use a multiplicative-regularized Gauss-Newton scheme to update the reservoir mode literatively until good match between measured and simulated data is achieved. The derivative of seismic data with respect to acoustic properties is calculated using the adjoint method, and then connected to reservoir parameter susing a chain rule derived from the petro-elastic model, while the derivative of production data with respect to reservoir parameters is calculated using the gradient- simulator method. A synthetic crosswell example is employed to demonstrate that the estimation of permeability and flooding front movement can be significantly improved from the joint inversion of time-lapse seismic and production data.
The Approach of CT-Dragged Hydrajet Perforating and Annular-Delivery Sand Fracturing Applies in Horizontal Wells
Authors: Yuxi Liu , Xianggang Yue , Guoliang Zhang , Long Yu , Chengyu Lan , Peng Liu , Minghui Luo , Shanjun Zheng , Hong Xia , Liguo Li , Xianlong Liu , Yunping Chi , Yuebao Liu , Shifa You , Jibao Ma , Tingting Zhou , Wei Liu , Xinyou Wu 
Published: March 2015

Abstract
Multi stage fracturing of horizontal wells is quickly creating the same'step change' as when vertical wells first went horizontal (Rob Hari, 2010).Following the implementation of multistage fractured horizontal well, the operation scale enhances unceasingly.
The new technique need to be complied with some characteristics, such as high fluid delivery capacity, large fluid amount per well and uninterrupted multi-stage execution. But small open area and big friction drag of tubing or CT become the vital constraint in increasing displacement.
This paper will show the new approach of CT-dragged hydrajet perforating and annular-delivery sand fracturing applying in horizontal wells, and discuss technical measures for estimating and optimizing some construction parameters in two stages of the approach, finally describe two targeted operations.
Development Strategies of JZ25-1S Thin Oil Rim Reservoirs with Big Gas Cap
Authors: Ge Lizhen , Yang Qinghong , Tong Kaijun , Fang Liwen , Su Yanchun , Zhang Yingchun , Cheng Dayong 
Published: March 2015

Abstract
JZ25-1S oil field located in Bohai bay which has a thin oil rim with a gas cap on top and aquifer below, and this field has to supply fuel gases to the residents. To achieve maximum oil recovery, force balance between aquifer drive, gas cap expansion, and viscous withdrawal shall be carefully studied for this type of reservoir at various stages of the production lifecycle.
Available methodologies including analytical, and simulation are used to optimize the development strategies, including well type, the well location, drawdown and so on.
Using horizontal wells to develop the thin oil rim, the horizontal length parallels with the GOC and OWC, the horizontal section length is 300–400 m nearby, the stand off over the OWC is 1/3 of the oil column if the gas capindex is more than 1.5, and the optimized drawdown of the horizon well is recommended 0.3–0.6MPa ; while the gas capindex is less than 1.5 and the aquifer is stronger, the stand off over the OWC is 1/2 of the oil column, the drawdown is recommended 0.5–0.8MPa; And making good use of the gas and aquifer energy at initial stages of production, then using water flooding for the reservoir which gas cap index is less than 1.5 and the aquifer is weak.
A number of horizontal wells were optimized and drilled in JZ25-1S field after optimizing the development strategies. The initial oil rates are from 943-2830bbl/d under the optimized drawdown.
The management of GOC and OWC movement is extremely critical in this kind of oil field. Based on the achieved parameters, these wells display significant higher oil production with delayed water coning and slower gas channeling.
Both simulations and production data demonstrate that the JZ25-1S development strategies gain success, using horizontal wells balance GOC and OWC to explore hydrocarbon, and achieve maximum results, which provides the theoretical and production data for development optimization of thin oil rim reservoirs with gas cap in Bohai Bay.
Sichuan Shale Gas Microseismic Monitoring: Acquisition, Processing, and Integrated Analyses
Authors: Dwan Fa , Qiu J. , Zhou M. , Yuan R.S. , Zhang Z. , Jin L. , Wang S. , Li X. , Lin M. , Liang B. , Deng C. , Liang S. , Englebrecht L. , Van Dok R. , Walter L. 
Published: March 2015

Abstract
The ability to estimate the stimulated reservoir volume and to enhance the effectiveness of hydraulic fracturing operation is fundamental in field development planning and critical to optimizing well completion in unconventional gas exploration and production. Microseismic Monitoring (MSM)survey provides essential observations study how induced rock volume responds seismically under field hydraulic fracture stimulation. Recent advanced microseismic technology with further development can provide real-time monitoring and interpretation which will improve hydraulic fracturing efficiency and better EUR, stop induced fracture development toward fault zones, and avoid connecting water-bearing layers. Advanced processing can enhance weaker microseismic signal, which provides a more complete Microseismically-Stimulated Reservoir Volume (M-SRV). M-SRV is essential to build the 3D understanding of the induced fracture network under various stimulation designs in volumes and in patterns from each fracturing stage.
Modelling the Transient Behaviours of the Kinetics in the Transesterification of Palm Oils Reveals Prospects for Customisation of Esters for Drilling Fluids Formulation
Authors: Okeke Eric O. 
Published: March 2015

Abstract
This paper discusses the prospects for customizing esters derived from palm oils as part of the first phase of a study to develop new drilling fluids. This phase evaluates the feasibility and prospects for customizing such esters in order to fully define experiments and all analytical conditions for realizing the objectives of the entire study. Published studies in transesterification show products from various vegetable oils for different applications including biodiesel production. Vegetable Oils consist of triglycerides (TG) 90 - 98 % by weight, small diglycerides (DG) and monoglycerides (MG), while palm oil contains TG 95.7%, DG 3.7%, and MG 0.6%. Transesterification of vegetable oils with alcohol is characterized by multiple consecutive and reversible reactions. TG is converted stepwise to DG, MG and finally glycerol (GL). We are particularly interested in palm oils (developed in large plantations in Nigeria). ASPEN HYSYS 7.3 was used to model the non acid catalyzed transesterification involving three reactions each with methanol for conversion of TG, DG and MG under steady state and transient conditions in a CSTR at varied reaction conditions and time to produce varied esters properties. Results from the model show prospects for customizing esters derived from the transesterification of palm oils and realizing their application in drilling fluids formulation.
The World's First Real Time Logging with Tractor in an Extended Reach Horizontal Well with Proof of True Stimulation
Authors: Arukhe J.O. , Ghamdi S. , Dhufairi M. , Duthie L. , Omairen K. 
Published: March 2015

Abstract
Although engineers have employed tractor interventions relatively extensively in well stimulation of extended reach wells in this field, an outstanding challenge in the field and even in the industry has been to conduct real-time acquisition of inflow or production profiles and to evaluate treatment effectiveness in extended reach open hole horizontal wells. This challenge was overcome from real-time electrical to optical (EtO) water injection profile measurements simultaneously with running a tractor. The motorhead assembly (MHA) of coiled tubing (CT) was successfully wired through a tractor to allow the world's first successful real-time acquisition of an inflow profile in an extended reach open hole horizontal power water injector in one of the current largest field development projects in the world. The well, located on one of two finger islands, was completed to a total depth of nearly 30,000 ft (over 9.10 km) MD; making it the deepest open hole section logged in the field development outside the normal reach of tapered CT for well intervention. The intervention on the well was successfully carried out through the application of a 2-in. tapered CT and well tractor.
The well's treatment involved 3,850 barrels of emulsified acid recipe in 14 stages. A comparison of the pre- and post-stimulation injectivity indices showed an eightfold injectivity index improvement from 53 bpd/psi to 400 bpd/psi. The resulting marked improvement in injectivity from acid stimulation also revealed the benefit of informed decisions from the real-time fiber optic distributed temperature sensing (DTS) in fluid placement.
Effective stimulation was critical for increasing injectivity and creating conductive flow paths between borehole and the reservoir. Relatively good transmissibility between the injectors and producers during the commencement of a field-wide waterflood was crucial because of a relatively high viscosity tar layer between the overlaying oil column and aquifer. This tar layer was a challenge for assuring adequate aquifer support to the producers because of their partial sealing nature. For reasons of optimizing sweep and recovery, the placement of water injection wells and requirements was focused around the flanks of the structure. The ability to employ real-time information to effectively stimulate and log inflow profiles in extended reach wells has provided assurance that stimulation can serve as a technical and an economic solution for addressing the relatively high skin damage post drilling and completion. Other practical applications of the success outcome from the real-time acquisition of inflow profiles includes the reduction in the transmissibility uncertainty between the producers and injectors in the field development partly because of the availability of better quality data for reservoir simulation or characterization purposes.
Application of Walkaway VSP for Improving Seismic Imaging of Fractured-Cavernous Carbonate Reservoirs
Authors: Liu Yimou , Liang Xianghao , Zhou Yi , Liu Shiyong , Wang Xiaofeng , Li Yanpeng 
Published: March 2015

Abstract
Ordovician carbonate rocks are widely distributed in Tarim basin, western China, and they are the important yet very difficult targets in the oil and gas exploration and development. The carbonate reservoirs are ultra-deeply buried and their storage spaces are mainly secondary dissolved caves, holes and fractures of various sizes. The main challenges for seismic imaging are that the target formations are usually in very low signal-to-noise ratio due to the seismic attenuation, and the reservoir media are strong heterogeneous (caused by caves and holes) and having varying degrees of anisotropy (caused by fractures). Conventional processing techniques fail to image and identify the fractured-cavernous reservoirs accurately. In order to better image and identify the reservoirs, an 8-azimuth walkaway VSP (with a maximum offset of 6600m from the wellhead and covers the 510m-6470m depth interval with receiver spacing 10m) was carried out to estimate the true amplitude recovery (TAR) factor, Q factor and VTI anisotropic parameters, and then proper energy compensation approaches and VTI anisotropic migration algorithms are introduced in the seismic processing flow. The results show remarkable improvement in seismic imaging, and the depth errors of the geological targets are reduced considerably.
Fill Cleanout Operations in Offshore Saudi Arabian Fields: Case Histories toward Improving Economics and Operational Logistics
Authors: Yateem K.S. , Qahtani H.B. , Saeed S.S. , Li J. , Aitken B. 
Published: March 2015

Abstract
Coiled tubing (CT) fill cleanouts have been in existence for over four decades and today account for approximately 30% of the services performed. Both CT and conventional jointed pipe offer a forward or reverse circulation mode to remove solids; however, using conventional water-based fluids, a sand cleanout method may apply excess hydrostatic pressure to the formation, resulting in some lost circulation to a sub-hydrostatic reservoir. Nitrogen (N2) can be used to reduce hydrostatics, but this requires a very precise job design and execution. Moreover, N2 use can have adverse logistical and economic implications - large amounts of N2 may be needed, especially in larger diameter wellbores and in horizontal wells.
Several cleanout methods have been utilized in the past, employing a variety of different approaches. CT historically has incorporated limited circulation rates, exotic/costly fluids and reversing circulation to remove solids. The use of CT to remove sand from wellbores was one of its earliest applications and continues to be an important service today.
This paper will discuss cost-effective solutions in Saudi Arabia, highlighting field cases and job optimization. The selection of the most appropriate sand cleanout method has to be based on both logistical and technical issues. This paper shows how to select the most cost-effective fills cleanout method for these wells. A few field cases are discussed to demonstrate the proper operational procedure, challenges and lessons learned. The combination of how to utilize the sophisticated solids transport software, downhole switchable nozzle, and proper operational procedure with the frequent evaluation of downhole conditions on site is essential to insure the fills cleanout is executed 100% successfully.
The Production Enhancement of NGL and Reduction of Pipeline Liquid Condensate Flaring with the Successful Implementation of Triethylene Glycol Dehydration Unit
Authors: Peng Kuang-Yao Brian 
Published: March 2015

Abstract
To meet the future sustainability requirement(1,2), major energy suppliers in the world have been pursuing the highest standards of environmental policy to contribute the conservation of natural resources through operation excellence and energy optimization.
Abqaiq Plant is the largest oil stabilization plant in the world. A small improvement in separation process could lead to significant energy saving and reduction of CO2 release for its large scale. The crude oil processing units at Abqaiq Plant have two major functions. First, crude feeds from oil field are stripped with steam which increases the moisture content of offgas from the oil stabilization column. Second, the low pressure offgas is pressurized to 450 psig for separation of NGL products. The final NGL product is transferred to the downstream refinery for further processing and the offgas from the NGL facility is transferred to the downstream gas plants for sulfur removal. For years, gas pipelines have been suffering from back pressure caused by liquid condensate accumulation in the pipeline. To reduce the back pressure, enhancement of NGL recovery is required but the challenge is to lower the deethanizer operation temperature without hydrate formation. As a part of the global downstream pipeline and plant optimization program, Saudi Aramco has invested $65MM capital expense for triethylene glycol (TEG) dehydration unit(3,4,5) at the world largest oil stabilization facility to reduce the frequency of pipeline scraping. The success of this project would eliminate 2 million pipeline scraping cost and 40 million of liquid condensate reprocessing and liquid flaring every year. The liquid condensate flaring has imposed a serious adverse environmental impacts and risk to operator exposure to hydrogen sulfide. Commissioning of the TEG dehydration unit was initially unsuccessful for the issue of plant piping network back pressure. To achieve the full benefits of the newly implemented TEG unit, the Abqaiq Plant operation engineering unit has utilized the advanced real time optimization (RTO) model to identify the root causes of failure. Process studies including the feasibility of steady state normal operating conditions and the piping flow estimations were completed by RTO data reconciliation model. Further offline studies for pressure drop analyses on piping networks were completed with additional pipe diameters and roughness data. The location of back pressure was identified by the advanced engineering tool.
Multi-Azimuth Seismic Data Imaging in the Presence of Orthorhombic Anisotropy
Authors: Xie Yi , Birdus Sergey , Sun James , Notfors Carl 
Published: March 2015

Abstract
Orthorhombic anisotropy is considered to be the simplest realistic symmetry for many geophysical problems. Orthorhombic anisotropy exhibits both HTI (Horizontal Transverse Anisotropy) and VTI (Vertical Transverse Anisotropy) effects, making seismic velocity varying with azimuthal direction as well as polar direction. In many cases, these effects are important by themselves and can be a target of special studies.
The presence of orthorhombic anisotropy poses challenges in wide azimuth imaging which has been rapidly developed for better illumination, better imaging, and better multiple elimination. Analysis of multi-azimuth (MAZ) data often reveals noticeable fluctuations in moveout between different acquisition directions, preventing constructive summation of MAZ images due to the azimuthal dependency nature of wave propagation in orthorhombic medium. On the other hand, the co-existing VTI effects of orthorhombic anisotropy can also cause well misties and higher order moveout.
Orthorhombic anisotropy can take into account the co-existing HTI/VTI effects. We have developed an approach for imaging in the presence of orthorhombic anisotropy, including orthorhombic velocity analysis and orthorhombic migration. Following Tsvankin's work, we put forward a ray tracing approach suitable for both weak and strong anisotropy which applies to both Kirchhoff and Beam PSDM. Aimed at the challenge in orthorhombic anisotropy model building, we have developed a practical workflow which combines the co-existing HTI/VTI anisotropy estimated through multi-azimuth tomography to form the orthorhombic model.
In this paper, we first describe our approach for imaging in the presence of orthorhombic anisotropy, including the newly developed orthorhombic ray tracing method and the newly developed practical method for orthorhombic anisotropy model building. We then demonstrate with both synthetic and real data from offshore Australia that our approach can successfully take into account the co-existing HTI/VTI effects, reduce the structural discrepancies between seismic images built for different azimuths, hence produce constructive summation of MAZ dataset, resolve well mistie to match with geology, and deliver a step-change in the final seismic image quality.
Seismic Interpretation Based on Mechanical Deformation Process
Authors: Pussacq Alice , Fu Qiang , Malvesin Emmanuel , Panhaleux Solene 
Published: March 2015

Summary
It is a common workflow in commercial software packages to identify stratal features through flattening techniques. However, classic and proportional flattening methods have inherent drawbacks because they do not allow for use of physical laws and rock properties. The use of common mechanical-based restoration methods is also limited because of their low performance. In this paper, we propose use of a mechanical deformation technique based on the finite element method (FEM) to balance seismic data to a hypothetical domain. The conversion makes the interpretation process more reliable for quality control (QC) of structural analysis in an interpretation-friendly environment.

Introduction
One basic step of the seismic interpretation is picking horizons, which can be auto-tracked or performed manually. The fundamental principle behind this operation is the seismic events that are relict depositional surfaces or bedding planes formed nearly instantly in terms of geologic time and that follow geologic boundaries (Catuneanu, 2010; Zeng, 1998). As results of the tectonic deformation and the effect of deposition (for example, sigmoid shape for shore-face depositional pattern), horizons are no longer flat. To remove the effect of the structural deformation (folding and faulting) in the geologic time space, several techniques have been proposed and various software packages have been developed to un-fault and flatten the depositional sequences (Stark, 2004; Stark 2005; De Bruin, 2006).
A classic flattening method can be performed by applying a simple vertical shift, based on one particular continuous horizon, for every trace in 2D seismic sections or 3D cubes (Fu, 2010). Its use is very limited. The proportional layering technique, an improved classic flattening approach, was proposed in the mid-1990s to create approximately paleo-depositional data. It is based on the assumption that the thickness between layers (time or depth domains) follows a linear relationship. Both methods are purely geometrical and very convenient because of their computing efficiency. Their biggest issue is that there is no consideration for tectonic events and geologic depositional trends. They are just converting to an artificial domain to make the interpretation easier. This process can smear the chronostratigraphic information inside the fault zones or even in the whole section (Figure 1). Essentially they are a 1D shifting technique and no attention is paid to the fundamental principles used to govern rock deformation.