bluuebunny/crossref_metadata_2025_split huggingface dataset:
Case Histories: Post-Frac Fluid Recovery Improvements of Appalachian Basin Gas Reservoirs
Authors: Paktinat J. , Pinkhouse J. , Stoner W. P. , Williams C. , Carder G. A. , Penny G. S. 
Published: December 2007

Abstract
The primary purpose of surfactants used in stimulating sandstone reservoirs is to reduce surface tension of the fracturing fluid, decrease interfacial tension between injected fluid and reservoir rock and increase post-fracturing fluid recovery. However, many of these chemicals when injected at high pressures adsorb rapidly into the sandstone formation, reducing their effectiveness in post fracturing fluid recovery.
This study describes simulated laboratory experiments and case histories of various surfactants used in the oilfield. Several different surfactants including ethoxylated linear alcohol, nonyl phenol ethoxylate and a microemulsion system were investigated to determine their adsorption properties when injected into a sand packed column. A laboratory simulated comparison study of these surfactants versus a microemulsion system was used to identify their water recovery properties from gas wells.
Field data collected from Benson, Balltown, Injun, and Speechley Sandstone formations confirm experimental sand packed column and core flow investigations. Reservoirs treated with microemulsion fluids demonstrate exceptional water recoveries when compared with conventional non-emulsifying surfactant treatments. Case histories reported from several gas wells stimulated in the Appalachian Basin illustrate the advantages microemulsions have over conventional surfactant treatments when faster cleanup, increased post fracturing fluid recovery and well productivity are of concern to the operator.
The Challenge Of Selecting Appropriate Drill String Enhancing Features For Drilling In The Middle East Harsh Environment
Authors: Plessis Guillaume , You Jean Bernard 
Published: December 2007

Abstract
Drilling in the Middle East is challenging and when it comes to drill string selection and design, the drilling engineer has to consider all the parameters that will influence the lifetime of the drill string, among which drilling environment, well geometry, need for drilling deeper wells in an always more economical manner.
As an example, on the environmental side, the presence of H2S in most fields doesn't allow using standard grades of material and could also require adding geometrical features to the string that allows regaining an acceptable lifetime, in conjunction with a control of the drilling fluid characteristics.
The well geometry and the necessity to tap oil in areas that could not be reached easily and are remote from the drilling site will require that the string has the ability to carry substantially higher loads and in particular allows transmitting high torques through the connection. This could be even more challenging when the operation requires that the tool joint diameter be limited to allow fishability.
Larger hole drilling dictates optimization of hydraulic in order to remove the cuttings efficiently and once again the geometry of the drill pipe is to be considered thoroughly. In this case, streamline connections with enlarged internal diameter can be provided without compromising on the torsional and tensile capacity of the drill string.
This paper aims at answering some of the drillers most commonly asked questions when designing drill strings, since it is essential to understand which parameter to play with in order to optimize the string design. We will expand, in particular, on the raw material selection, stress relief features, geometries and connections that allow increasing drilling performances, thus reducing the overall cost of the drilling operation.

Introduction
The objective of this paper is not to define one design that would be applicable across the region but rather to highlight specific conditions or requirements that could apply to drill stem products and the available solutions that allow drilling in an always more efficient and cost effective manner.
At first we will focus on the H2S embrittlement, which is one of the main concerns in this region.
Then we will concentrate on the general requirement for torque before finishing with a few examples of drilling efficiencies improvements that generally are the result of the use of the latest generation of streamlined double shoulder connections.
Application of Subsea O/W Separation: Main Drives and Challenges
Authors: de Figueiredo M. W. 
Published: December 2007

Abstract
Oil production is normally followed by water production in increasing rates, mostly when waterflooding is used as oil recovery mechanism. In order to minimize the impact that high rates of produced water causes to the topside facilities, Petrobras is working on the development of a subsea system for oil-water separation, so that most of the produced water can be separated on the mudline and reinjected in the reservoir or in a bearing formation. Besides the benefit of debottlenecking the production plant, there are gains in flowrate and flow assurance due to the less amount of water in the production stream.
The article also shows how this development has been carried on, the scenario definition for the pilot, the problems associated to an installation in a system already operating and the oil characteristics determination. These data constitute the base for the survey to detect the technologies with potential application on the separation system to be developed.
The special characteristic of the oil, with high tendency to form stable emulsions with water, are also analyzed, as well as the difficulties it brings to the process in the subsea environment, where there are vessel size and fluid heating limitations.
The Exploitation of Heavy Oil From Middle-Deep Reservoirs: Horizontal Well Completions at the Oritupano-Leona Field In the Eastern Venezuela Basin
Authors: Riera L. , Castillo J. , Bellorin W. 
Published: December 2007

Abstract
Since Petrobras Energía Venezuela took over the Oritupano-Leona Unit by agreement with PDVSA in March 1994, turned out a great challenge for the company about how to increase and improve not only the field potential but the reserves enhancement too. Low to high liquid rates horizontal wells were implemented in order to defeat one of the most challenging issues at the company: The exploitation of heavy oil from middle-deep reservoirs.
Numerical simulations along with geological studies were conducted to define the best strategy for performing new horizontal wells. Drilling and completions started five years ago making the first steps to get a technical and economical performance for well productions and at last, three stages were done. Stage I considered low liquid rates horizontal well completions ranging from 1,500 BFPD through 4,000 BFPD. Stage II was a little bit aggressive increasing rates from 7,000 BFPD through 10,000 BFPD and finally we went Stage III, where our goal was to reach more than 20,000 BFPD.
All cases observed that transient flow regime where water conning threats have to be faced before reaching semi steady state flow, lasts between 8 to 10 months. During these periods, different productions strategies were implemented.
Looking at adverse factors such as oil gravity ranging from 8 API to 12 API, reservoir depths from 7,500 feet to 9,000 feet, scales precipitation possibilities and a very strong aquifer presence with similar physical-chemical properties throughout the geological column, let anybody to think that it was obvious that obtaining these 20,000 BFPD, not reaching water conning effects, represented a very risky feat for the company.
The R sands in the Oritupano C field, one of the most productive blocks at the main Oritupano-Leona System, became as a remarkable experience after the nation wide largest horizontal well completion (Hz-13) with more than 20,000 BFPD; 12 API; 800,000bls cumulated oil and no water conning effects in the last 10 months. Some other areas are giving same results such as TU sand in the Oritupano B field.
Results show that improve oil recovery (IOR) from middle-deep horizontal wells in Eastern Venezuela have boosted the heavy oil production with no steamflooding and diluent injection techniques. Yet there are some issues to face such as emulsion formation in the early production during transient flow and the reservoir fingering or channeling effects that might prevent a second line of well construction. More statistical information together with more simulation studies will contribute to reduce the uncertainty in forecast for heavy oil produced horizontal well projects: The challenge is still ongoing.
Using the Link Between Diagenesis and Fracturing to Accurately Predict, Characterize, and Model Fluid-Flow in Fractured Carbonate Rocks
Authors: Gale J. F. W. , Laubach S. E. , Olson J. , Marrett R. 
Published: December 2007

Abstract
By taking diagenetic processes into account we improved quantitative fracture population description. Using diagenesis information also allows more accurate geomechanical modeling and creation of more realistic fracture patterns for use in fluid-flow simulation. Mechanical rock properties and fracture attributes change with diagenesis and fracture architecture depends on rock properties (particularly subcritical crack index) at the time of fracturing. Preservation of fracture void space depends on cement precipitation synchronous with fracture opening that obeys systematic rules. The greatest effect on large fractures is from later cements, which are typically heterogeneous in distribution.
Feasibility Study of CO2 Injection for Heavy Oil Reservoir After Cyclic Steam Stimulation: Liaohe Oil Field Test
Authors: Luo R. , Cheng L.-S. , Peng J.-C. 
Published: December 2007

ABSTRACT
Because of the favorable properties of CO2 it has been used to enhance the recovery of oil for a long time. But this technology is under slow development in China for lack of rich CO2 resource until some CO2 reservoirs were found in recent years.
Using simulation and reservoir-engineering method, this paper presents the feasibility study of CO2 injection for heavy oil reservoirs following cyclic steam stimulation. Pilot tests were conducted to several wells in Lengjiabao heavy oil reservoirs in Liaohe oilfield, China. Some wells got good effect, while some wells got poor effect. And the results from the simulation and field pilot tests are evaluated economically. Study shows that for common heavy oil reservoir after cyclic steam stimulation, the higher the oil viscosity, the greater the CO2 utilization ratio, and the more feasible CO2 stimulation process; for extra-super heavy oil, 1-3 cycles steam huff-n-puff were performed as necessary, followed by CO2 stimulation process so that good benefit could be gained. These results are of significance for field operation and production of heavy oil.
Field Pilots of an Innovative Real-Time Testing Technique for Separate-Layer Water Distribution
Authors: Wang Zhongguo , Wang Qingfa , He Guixin , Zhang Huishu , Li Ning , Zhang Huixin 
Published: December 2007

Abstract
Based on the traditional water injection technology using off-center choke mandrels for separate layers, an innovated technique for real-time downhole injection-rate adjustment for multiple separate layers was studied, which achieved real-time stepless and continuous adjustment of the desired downhole injection-rates for different separate layers. The technique enhanced the injection-rate adjustment efficiency for a more qualified water flood program and improved the overall production effect in a water-injection field.
Redevelopment of a Matured Multilayered Carbonate Offshore Field through High Technology Horizontal and Multilateral Wells
Authors: Kumar R. , Ramanan S. , Narasimham J. L. 
Published: December 2007

AbstractOil productivity from Mumbai High field, an offshore multilayered carbonate reservoir, increased significantly through implementation of a major redevelopment programme. High technology drilling viz. horizontal/ multilaterals for the new development wells was adopted on field scale to effectively address typical complexity of the layered carbonate reservoirs. Since the commencement of the project in 2000, around 140 new wells were drilled, mostly with horizontal and multilateral drain holes. Besides these, more than 70 sub-optimal producers were also converted as horizontal sidetracks under brown field development. The horizontal sidetracks were drilled as long drift sidetrack (LDST), LDST-ERD, short drift sidetrack (SDST) and medium radius drain hole (MRDH) type of wells through application of innovative and emerging drilling technologies with non-damaging drilling fluids, whipstocks to kick off sidetrack wells, rotary steering systems, expandable tubulars to complete horizontal sidetracks in lower layers etc. With the implementation of this project, the declining trend was fully arrested and a significant upward trend in production could be established.
Investigation of a High Temperature Organic Water Shutoff Gel: Reaction Mechanisms
Authors: Al-Muntasheri G. A. , Nasr-El-Din H. A. , Peters J. A. , Zitha P. L. J. 
Published: December 2007

AbstractWater production during oil and gas recovery is a longstanding problem that is becoming critical with maturing fields worldwide. Lifting, processing, treating and re-injection of the unwanted water add to the overall oil production costs. Also, water disposal may pose environmental problems. Recent statistical studies indicate that processing unwanted water costs the oil industry nearly 40 billion dollars per year.Polymer gels have been widely used as blocking agents for excessive water production. In this study, a copolymer of polyacrylamide tert-butyl acrylate (PAtBA) and polyacrylamide (PAM) crosslinked with polyethyleneimine (PEI) have been investigated. This PAtBA/PEI system was previously shown to be stable at temperatures up to 160°C, typical of those encountered in deep oil and gas reservoirs. However, the crosslinking mechanisms of this system at high temperatures have not been well defined.This study examined the structural changes of PAtBA and PAM using C-13 Nuclear Magnetic Resonance (NMR) spectroscopy. Understanding these changes is a first step towards the identification of the crosslinking mechanisms of PAtBA and PAM with PEI. This will have a strong impact on the design of water shut-off treatments utilizing these systems.
An Investigation of Minimum Miscibility Pressure for CO2 - Rich Injection Gases with Pentanes-Plus Fraction
Authors: Bon J. , Sarma H. K. , Theophilos A. M. 
Published: December 2007

Abstract
A miscibility study was conducted to investigate the effects of the C5+ content in injection gases on Minimum Miscibility Pressure (MMP). Currently available common MMP correlations are based on data from injection gases containing no C5+ fraction. However, laboratory analyses suggest that having a small (and yet relatively significant) C5+ fraction could have a large effect on reducing the MMP to considerably below the predicted values from existing correlations. This paper aims at investigating possible benefits for miscibility and CO2 EOR flooding with impurities, particularly with C5+ fraction.
Previously, a PVT and miscibility study was conducted on a Cooper Basin (located in central Australia) reservoir fluid, including solubility-swelling and viscosity studies. Slim tube tests were performed using two injection gases – pure CO2 and a CO2-rich synthetic gas (80mol% CO2), which contained a small amount of C5+ fraction (0.3mol%). The MMP was expected to increase substantially due to the presence of a large amount of methane (15mol%). Correlations from literature predicted the MMP to be above 3433psia, but the MMP was measured to be 2880psia1. As most currently available correlations are based on injection gases with no C5+ fraction, a major contributing source to error with these correlations may have been the C5+ content of the gas.
In order to investigate the effects of the C5+ fraction in the injection gas, a series of Rising Bubble Apparatus (RBA) experiments were conducted on the reservoir fluid with three injection gases at three different temperatures to investigate the effect of C5+ in the injection gas stream.
Results indicate that the C5+ fraction does have a significant effect on the MMP that needs to be factored into current correlations when the injection gas has a C5+ content.
Optimizing Wireline Formation Evaluation in HP/HT Wells
Authors: Larson Roderick A. , Duhon Lamar L. , Benavides Simon P. 
Published: December 2007

Abstract
Evaluating high-pressure high-temperature (HP/HT) wells has become increasingly challenging. As the wellbore temperatures exceed the continuous operating specification of available sensors and electronic components, standard deployment and data acquisition methods are no longer sufficient. Nearly all practical methods of protecting the sensors and electronics from temperature are time constrained. Therefore it is necessary to explore all options to acquire a maximum amount of data in a finite amount of time downhole. This paper will discuss the equipment and processes necessary to provide critical formation evaluation in the formidable HP/HT environment.
Selecting Representative Laboratory Test Conditions for Fit-For-Purpose OCTG Material Evaluations
Authors: Nelson Jocelyn L. , Reddy Ramani V. 
Published: December 2007

Abstract
The sulfide stress cracking resistance of steel oil country tubular goods (OCTG) is commonly correlated to the hydrogen sulfide (H2S) partial pressure, calculated by multiplying the mole fraction H2S by the total system pressure. However, sour gas mixtures exhibit non-ideal behaviors at high system pressure. Neglecting these non-ideal effects causes large over-conservatism at total system pressures above 5000 psi. It is important to compensate for non-ideal gas and solution behaviors in order to select representative laboratory test environments for sour service fit-for-purpose materials evaluations.
Connections for HPHT Well Applications and Connection Leak Probability
Authors: Valigura Gloria A. , Tallin Andrew 
Published: December 2007

Abstract
HPHT wells bring new challenges to the well design engineer. One of these challenges is connection design and selection. Connections for HPHT wells must be high performance connections that have been fully tested to demonstrate high reliability and fitness for service.
Our objective is to discuss the impact connection design and selection have on these challenges, the reasons for using two seals and the need to test each of the seals independently to ensure an acceptable connection leak probability. Shell uses the industry test standard, ISO 13679:2002 "Petroleum and natural gas industries – Procedures for testing casing and tubing connections"(1) to qualify connections. We will discuss our method for determining reliability of a connection – a probabilistic calculator-its assumptions, and how sensitive the results are to those assumptions.
A New Method of Material Categorisation for Super-Duplex Stainless Steel Tubulars
Authors: Renton Neill , Seymour Dave , Hannah Irene , Hughson William 
Published: December 2007

Summary
Following the failure of a super-duplex stainless steel (SDSS) production tubular in an HT-HP well in the Shearwater field, Shell Exploration & Production in Europe have developed a new method of categorizing SDSS material using an eddy current inspection technique. The technique is designed to identify areas of hardened material with modified microstructure on the external surface of the tube, which are believed to have contributed to the Shearwater failure. This paper describes work carried out over the last 18 months into the development of the inspection technology and appropriate assessment criteria. The assessment criteria are based on a combination of numerical cut-off's and eddy current trace signature identification, newly developed as a result of this work. The technique successfully identified all tubes of concern with a rejection rate of 0.5%.
Significant Reduction of Imperfection Depth Tolerance during Ultrasonic Inspection of Oil Country Tubular Goods
Authors: Prejean Hilton , Mason Dave , McGill Randy 
Published: December 2007

Abstract
This paper summarizes the results of a series of demonstrations used to evaluate the effect of various conditions on conventional automated full-length ultrasonic inspection of heavy wall tubular goods using reference indicators with depths significantly less than 5% of the specified wall thickness.
The Use of Phased Array UT Inspection of OCTG
Authors: Glascock David , Brassard Michel , Mason Dave , McGill Randy 
Published: December 2007

Abstract
This paper covers the use of Ultrasonic (UT) Phased Arrays for the automated full length ultrasonic inspection of tubular goods. The technology provides increased flexibility to adapt to varying defect locations, shapes and orientations.
Demanding inspection parameters can be optimized for tubulars such as those used in High Pressure/High Temperature Sour Wells.
Umm Gudair Production Plateau Extension, the Applicability of FullField Dumpflood Injection to Maintain Reservoir Pressure and Extend Production Plateau
Authors: Quttainah R. , Al-Maraghi E. 
Published: December 2007

Abstract
More than 40 years of production has confirmed that the UG (MO) reservoir receives very little natural pressure support in some areas. The introduction of a new Production gathering center has increased the field production 6 folds. At current reservoir conditions and production strategy, the production will stay on plateau for only 3 years. This is mainly due to the rapidly falling reservoir pressure. The remedial plan is to initiate a full field water injection project to maintain reservoir pressure.
The primary objective of this project was to extend production plateau as long as economically possible. The reservoir pressure for the field, as well as different areas within it, is declining rapidly. The most important cause of this reservoir pressure decline is the high off-take rate (compared with the aquifer influx rate) and the lack of a reservoir pressure support such as water injection. This suggests that the water injection option is needed to support the reservoir pressure and extend the oil production plateau.
In this project, many development options were considered. These options can be grouped into three main groups: water injection, infill drilling and combined development options. In the water injection option, comparisons were considered. These options are surface injection vs. dumpflooding, pattern vs. peripheral injection, injection into the oil column vs. injection into the water zone. In the drilling option, comparison between infilling and sidetracking was done. Basically, within each option there was an optimization process, which consists of many sensitivity cases. The purpose behind these many cases is to optimize each option before being combined and get better results than when used alone. For example, in the water injection option, sensitivities were run to see the impact of number and location of injectors. Also, within that case, sensitivities were run to see impact of not achieving a target injection rate. For the infill drilling option, many cases were run to optimize the number of producers. For the combined development options, sensitivities were run to determine best-combined option and to study impact of water injectivity issues.
Technical Contributions: Will demonstrate the design of a fullfield water injection scheme to maintain reservoir pressure.Will demonstrate the applicability of dumpflood to repressurize a constantly depleting reservoir.Will demonstrate a cost-effective technique to maintain reservoir pressure.