bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uncertainty Analysis of an Integrating Two Structural 3D Sthochastic Geological Models of a Siliciclastic Reservoir: Potiguar Basin, Northeast of Brazil
Authors: Fanha Ana Beatriz , Cavalcante Jose Sérgio , Reyes-Pérez Yoe Alain 
Published: July 2010

Abstract
The studied field is located in the Brazilian Continental Shelf, the Potiguar Basin. These reservoirs are Eo–Cretaceous sandstones, which correspond to the gradual passage from the continental to marine depositional environments.
The workflow used was chosen in order to reflect the concern in trying a more effective representativeness of the structural complexities of the studied field. It consists in building several three-dimensional stochastic reservoir models and in recalculate the STOOIP (Stock Tank Originally Oil In Place), based on the integration and the interpretation of available data. Two structural geological models were built with distinctive geophysical interpretations based on a seismic reference surface. These tectonic differences can modify the stratigraphic distribution of the reservoirs and change drastically the fluid flow on the petrophysical system of hydrocarbons distributions on the reservoirs.
The uncertainty analysis was built and the parameters that impacted the most the STOOIP were varied under each considered structural model. These parameters were: the range of the porosity values and the cut-off of oil. A risk curve of 520 simulations was developed, that identifies which models corresponds to the respective percentiles and obtain the respective realization to simulate on the flow the many probabilistic sets.
We create the Hydrocarbon Pore Volume maps – HPhiSo, for each percentile of each structural model. The percentiles P50 of these maps of the two models were superimposed, and it was defined a set of planned wells to the reservoir drainage. This permits to relate the biggest hydrocarbon column with the highest structural map, reducing the risk. The geological uncertainties analysis results from numeric numbers varying the STOOIP until 37%, while oil was considered in all blocks. Eight realizations of each 3D geological model will be submitted to flow simulation and the planned wells will be ranked according to their productions curves.
An Appraisal of Soil Pollution in Oil and Gas Production Environment: A Case Study of Heavy Metals Concentration in Ebocha and Akri Oil Fields
Authors: Ossai C. I. , Duru U. I. , Ossai I. A. , Arubi I. M. 
Published: July 2010

Abstract
The concentrations of heavy metals in the soil at oil and gas production areas were appraised at Ebocha and Akri communities in Niger Delta region of Nigeria. The pollution/contamination loading indexes of Zinc (Zn), Nickel (Ni), Copper (Cu), and Lead (Pb) in the two communities were determined from soil samples collected in eight locations (in triplicate) in each community using Atomic Absorption Spectrophotometer (AAS).
It was observed that Ebocha was slightly polluted with lead (contamination/pollution index, c/p = 1.3), severely contaminated with zinc (c/p = 0.642) and slightly contaminated with copper(c/p = 0.123). Omoku was also slightly contaminated with zinc (c/p = 0.225) while all other sampling locations at Ebocha were very slightly contaminated with zinc, copper nickel and lead (c/p &lt;0.1). Akri was very slightly contaminated in all the sampling locations except for Afia-afor where lead slightly contaminated the soil (c/p = 0.113).
A significant correlation (p &lt;0.01) was obtained for zinc (r = 0.65) while there was no significant correlation (0.05 &lt;p &lt;0.01) obtained for Ni (r = −0.14), Cu (r = 0.22), Pb (r = −0.08), Mn (r = 0.38) and Fe (r = 0.54). This correlation showed that the sources of the heavy metals in both communities are different. It was also observed that the increased concentration of heavy metals in oil and gas production areas is more due to other associated human activities in the areas than oil and gas core production activities.
Successful Perforating Campaign in Extended-Reach Wells Offshore Malaysia
Authors: Noya J. V. , Wibsono R. , Parta I. P. , Connell C. , Oettli M. , Erkol Z. 
Published: July 2010

AbstractIn offshore Malaysia, the use of coiled tubing (CT) e-line has become a viable alternative to perforate new wells as it eliminates the use of an expensive offshore drilling rig for the completion process. The CT can convey long gun strings in horizontal completions in a single run, while creating the necessary underbalanced conditions.As the field development evolved, it required drilling complex extended reach wells (ERW) to access reservoirs farther from existing platforms, imposing more difficulties for the operation. The CT is predicted to lock up before reaching the target depth in some of the new wells. In addition, operational inefficiencies in past campaigns were common, primarily due to the design of CT e-line equipment used. Occasionally, the disconnect tool was actuated accidently due to sensitivity to pumping flow rates.A solution based on the combination of a hydraulically actuated CT wired tractor and a new CT e-line head design with unique features was proposed and implemented during a recent perforating campaign. In this solution, the tractor provided the force necessary to overcome the CT lockup and conveyed the guns to total depth (TD). Unlike most CT e-line head designs, the one used had the ability to circulate fluids through the assembly down to the CT tractor, enabling its actuation. The technical solution, field experience and results are presented.The perforating campaign included six highly deviated wells and two highly ERW [TD to true vertical depth (TVD) ratio of 3:1] for which the CT wired tractor was needed. All wells were successfully perforated under balance, with no observed sand production. The longest gun string conveyed to TD was 597 ft in length. Zero incidents were recorded in a total of 16 runs, in spite of the limited field test status of the CT e-line head design.This is the first recorded use of a CT e-line application with CT wired tractor for perforating purposes in ERW. Thus, the operational envelope of CT e-line applications is expanded, addressing the intervention needs of the future field development plans based on the ERW design in the area.
Novel Methodology to Understand Wear Mechanism in High Gas Rate Production Tubing
Authors: Maschio Leonardo , Hochenfellner Federico 
Published: July 2010

Abstract
The San Martin field is east from Lima, in the heart of the Peruvian tropical forest (see Fig 1). It is home to one of the most important non-associated natural gas reserves in Latin America, a vital resource for the energy needs of the country.
Tubing integrity in San Martin area has been a concern and a subject of continuous control due to the wells high gas rate, difficult logistic and economic importance. Multi-finger caliper logs were run in all the wells in San Martin field to control and assess tubing condition and integrity. Although the wells produced with low carbon dioxide (CO2) and water content, and no solids, preliminary reviews of the logs showed that only the wells with the highest production rate have wear signs of material loss.
This paper recap an extensive investigation performed in all the wells in the San Martin area. In this document logs reports, calculation as well as the ASCII files revision and quality controls are shown. Subsequently, a synopsis of the wear mechanism, its trends, the variables that control it and the extent of the problem using a novel internal processing of the raw caliper data are discussed. Finally, a set of recommendations to reduce the wear effect is presented.
Understanding the wear mechanism and documenting the lesson learnt are paramount not only to improve the operations in the San Martin field, but also to use this knowledge to improve the decision-making and management of the upcoming field completions in the same area.
Dynamic and Static Thermal Well Flow Control Simulation
Authors: Stone T. , Naccache Paul , Neylon Kieran , Edwards David , Damas Carlos Emilio , Rowan David , Raffn Anne Gerd 
Published: July 2010

Abstract
A preliminary investigation is presented on the use of Inflow/Injection Control Devices (ICDs) to control steam placement in the early stages of a Steam Assisted Gravity Drainage (SAGD) process. The two parts of this process that are examined are the steam circulation period and the early stages of injection/production in which the steam chamber is beginning to form. A SAGD case study has been designed that accurately models the initial circulation period in which both wells circulate steam in order to conductively and, to a lesser extent, convectively heat the region around the well pair in order to establish communication after which both wells switch to injection and production. Flow control is examined in a variety of configurations in the steam injection well, the devices being placed to control steam/water flow along the tubing, along the annulus and from the tubing to the annulus.
Estimation of Future Production Performance Based on Multi-objective History Matching in a Waterflooding Project
Authors: Han Y. M. , Park C. , Kang J. M. 
Published: July 2010

Abstract
The paper presents a MOEA(Multi-objective Evolutionary Algorithm) applied to history matching of waterflooding projects, that is to search a feasible set of geological properties showing the reliable future performance. Typical history matching has concentrated on single objective function with linearly weighted terms, even as a realistic field includes many wells and well measurements in time and type. The optimal solution is sensitive to weight factor and competing match criteria of individual term in the objective function often reduces the likelihood of finding an acceptable match. The unacceptable error at a specified well can be observed in a heterogeneous reservoir where shows various well performances.
To overcome the matter, a new history matching approach is developed that allows the performance characteristics of the whole wells. Individual well performance is optimized separately using genetic algorithm coupled with non-dominated sorting and diversity preservation. The fitness is sorted along to the proximity and then the diversity is added by examining the crowding distance as the approach to arrive at the global optimum. Waterflooding is demonstrated in a heterogeneous oil reservoir with multiple production wells. The predictability of unknown future production performance is compared with that of single objective function, the conventional history matching method.
The model represents irregular performance tendency more accurately than the conventional history matching. It improves the predictability of the conventional model. The averaged error converges about 5%, that is much less than that of single objective function. The selection of adequate set of reservoir properties is possible among the feasible solutions unlike the conventional model. The developed method can be applied as a useful tool for uncertainty analyses in waterflooding projects.
Lithofacies Analysis and Modelling of the Kookfontein Deltaic Successions, Tanqua Depocenter, Southwest Karoo Basin, South Africa
Authors: Sonibare W. A. , Mikeš D. 
Published: July 2010

Abstract
Deltaic successions are an important habitat for some of the major world's fossil fuel reserves (i.e. oil, gas and coal). An outcrop analogue study of the excellently exposed Permian siliciclastic Kookfontein deltaic sequence will therefore improve prediction of sandbody geometries and complex internal heterogeneities of subsurface examples.
Preliminary findings from field outcrop log data show the nature of complexity that could be encountered in a deltaic system that fills a basin. The complexity of the Kookfontein deltaic system is reflected in the succession of sedimentary structures (i.e. cross laminations, ripple laminations, Hummocky, massive and homogenous slump layers and horizontal laminations) both in time and space in a more or less an unpredictable manner.
In order to establish a 3D model of the rock record that includes stratigraphic elements and boundaries of all scales, we propose an approach that combines outcrop log, gamma ray log and photo-panel analysis. This approach will allow critical examination of the lateral and vertical variations of facies and their properties regarding fluid flow i.e. geometry and internal heterogeneity. The photo-panel analysis allows 3D high-resolution interpretations of the lithological boundaries both laterally and vertically which cannot be obtained from seismic resolution.
Based on the nature and complexity of the facies association, this study will propose a standard facies model for the deltaic sequence that will test the applicability of Walter's law of facies associations in facies analysis. A 3D reservoir-scale model will then be constructed based on the 3D geological model. The emphasis here will be to depict possible errors that could arise if all the stratigraphic elements and their boundaries (both on small and large scales) are not fully incorporated into reservoir scale modelling.
Advanced Drillable Aluminum Plug Technology Solves Operational Concerns: Pinedale Wyoming
Authors: Lewis Ryan , Hodges David , Crawford Robert , Desai Ankur , Winn Alex 
Published: July 2010

Abstract
Efficiently fracture treating a large number of zones has created a unique downhole tool challenge. In many applications, the operator requires a drillable cased-hole bridge/frac plug to effectively isolate multiple zones for stimulation in a single borehole. The main objective of the drillable plug is to isolate the lower zones so effective stimulation can be performed in the upper zones. This minimizes wellbore interventions while maximizing the number of zones stimulated. During drill-up, the plug must breakdown into small cuttings that can be easily transported utilizing conventional flow-rates to ensure a clean wellbore and unobstructed perforations. The plug must be composed of materials that allow for rapid drill-out using standard downhole motors and milling equipment.
Drillable plugs have evolved due to multiple challenges associated with the escalating number of zones that must be treated. Most recently, the service industry has produced a variety of composite bridge/frac plugs that have advanced performance compared to standard cast iron versions. However operators have experienced multiple problems with composite plugs.
To addresses the issues, a plug was designed and manufactured from precision aluminum alloy. The aluminum plug technology (APT) has significantly increased plug life-span having successfully addressed degradation issues in the application's pressure/temperature range. The new plug stays locked downhole under extreme temperatures/pressures without degradation and a unique anchoring system eliminates spinning of multiple plugs during drill-out. Advanced materials and a compact design have reduced drill-out time to an average of 20 minutes, saving the operator expensive rig time.
Using the APT, the operator has the option to flow back the well for an extended period before plug drill-out. APT has also drastically reduced the incidents of fishing due to partially set plugs. APT has demonstrated reliable performance during stimulation, effectively eliminating the adverse effects of plug movement during treatment.
Proppant Hydraulic Fracturing in Low Permeability and Low Acid-Soluble Carbonate Reservoir: A Case History
Authors: Pujiastuti Silvie , Wijayanti Elisa , Nugroho Hestu Sapto , Istono Noviadi , Wijaya Rio , Komalasari Novi 
Published: July 2010

Abstract
Proppant hydraulic fracturing has been a successful stimulation method used to enhance production in sandstone reservoirs. But for fracturing carbonate formations, the possibility of the existence of natural fractures and the hardness of the rock can be challenging. This paper will elaborate on a carbonate-fracturing pilot project in Soka field, which is the leading carbonate proppant hydraulic fracturing project in Indonesia.
Platform carbonate limestone from the Baturaja formation is the major component of Soka field reservoir. The platform consists of limestone with infiltrate mudstone/packstone and chalky limestone with poor porosity. The limestone mudstone/packstone lithology is dominated by mud, clay, and fine silt carbonates which results in the limestone becoming dirty and causes the low acid-solubility value of limestone in the field.
Stimulation jobs were performed in two wells in Soka field. From log analysis, the carbonate formation in both wells shows a high shale content (20%) and low permeability (6 md). Acid-solubility tests performed on both well cores showed low acid solubility. Matrix acidizing was performed in both wells, but they still showed low influx. Well A, after being perforated and matrix-acidized, only produced 40 BFPD, with a 30% water cut and a high GLR 19,061 scf/STB. Well B, after being perforated and matrix-acidized twice, had very low influx from reservoir to wellbore.
Proppant hydraulic-fracturing stimulation was performed in both wells using hydocarbon-based frac fluid and 12/18-mesh ceramic proppant. After being hydraulically fractured, Well A produced 165 BFPD at 18/64 inch choke, with 60% water cut and a GLR of 700 scf/STB, while Well B produced 173 BFPD at 25/64 inch choke, with a 0% water cut and a low gas rate. Production from both of these wells is maintained at the reservoir critical rate for each well.
Unique Straddle Design for Placement Inside Damaged Down Hole Safety Valve Nipple Seal Area
Authors: Liland Tor Henning , Lund Are , Johanson Therese , Hiorth Espen , Bill Bjørn 
Published: July 2010

Abstract
Up until today operators have been facing a challenge on how to avoid recompletion of wells where the nipple seal area inside the TRSCSSV (Tubing Retrievable Surface Controlled Subsurface Safety Valve) is damaged due to large amount of well interventions or damaged due to corrosion.
Various methods have been used for repairing a TRSCSSV with a damaged seal area. This includes standard insert WRSCSSV (Wireline Retrievable Surface Controlled Subsurface Safety Valve), with normal and oversize swell packing elements. Honing of the upper and lower seal area prior to installing an insert valve has also been performed but with variable success.
To have the DHSV working properly it is vital to maintain barrier control of the well. If the DHSV nipple profile is damaged the alternatives are to repair it using one of the above mentioned methods or to secure the well for later recompletion
Since all the above mentioned methods of repairing a damaged seal area for insert valve have failed, Statoil initiated a development project for a straddle design using well know element technology based on an HPHT Bridge Plug design. The straddle has solid elements, which shape according to the damage inside the seal areas. In addition each element is equipped with expanding anti-extrusion back-up rings on both sides, trapping the element so it has nowhere to go when differential pressure is applied. The straddle uses the existing nipple profile above the no-go for anchoring and is equipped with dogs to fit this profile. A standard insert safety valve is made up to the bottom of the straddle and is then operated by existing surface control line.
This paper will compare the different methods used for repairing a damaged Down Hole Safety Valve nipple seal area and discuss the development process and qualification testing done for the new unique straddle system and setting tool. Case histories will also be presented from several prolific North Sea Wells.
The Diagnosis of Decline and Successful Recovery of PI in a ‘DRY’ HPHT Gas Well That has been Affected by In-situ CaCO3 Scale and Salt Deposition
Authors: Wat Rex , Iversen Anne Marie , Belsvik Yngve Heggheim 
Published: July 2010

Abstract
Over a period of 4 to 6 months one of the Kristin wells had experienced a rapid decline in production. The drop was unexpected and at the time there was no detectable formation water breakthrough in the well. The decline in productivity was interrupted by a number of erratic, but temporary, surges in production that fell off again soon after. By comparing the well performance with other wells having the same downhole completion type, attention was soon focused on the likelihood of in-situ CaCO3 scale deposition. The subsequent discovery of CaCO3 deposition in the near wellbore area was partly anticipated. However, the discovery of halide scale (by precipitation) and salt (by evaporation) deposition came as a major surprise given that the Kristin formation water contains less than 10% of Total Dissolved Solids (TDS). This paper will describe the early diagnostic approach to screen and finally identify the most likely cause of the productivity loss. It will present the multiple well treatments that followed, the logics, the results and their interpretations. In addition to the results from these multiple treatments the paper will provide a mechanistic explanation of such deposition processes. Most interestingly, a novel observation will be put forward in this paper to underline the erratic and temporary surges of production during the decline period and that can be attributed to a ‘self-healing’ mechanism.
Intervention System for the Perdido SPAR Wet Tree Wells
Authors: Larsen H. A. 
Published: July 2010

Abstract
A system has been developed to safely intervene into sub-sea, direct vertical access well from a SPAR with a non- compensated platform rig. The system ensures well integrity and compensation of movement due to heave and tide of all intervention well control equipment. The system will work for wireline, slickline, braided line, and coiled tubing as well as bullhead pumping operations.
The system consists of: Hydraulic latching tool (tree to landing string)High pressure marine riserHigh torque and/or high pressure landing stringRiser tensioner systemSurface BOP'sLanding string hang off toolAnnular slick joint3-Line FlatPack control linesClamps for the FlatPackInline compensator to be suspended from the derrick
Platform movement is compensated with two systems concurrently: the Riser Tensioner System and the Inline Compensator. These systems ensure that no part of the rig-up can be loaded beyond its operational capabilities. Operations are safer and efficient because the systems are passive and minimum real-time human interaction is required once the systems have been rigged up and the operational parameters are set.
Drawings have been prepared to ensure the fit and feasibility of using standard oil field equipment in this environment. Bottlenecks and potential solutions have been identified.