bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving the Quality of Production Data and Its Effect on Allocation Factor and Reserves Estimation
Authors: Ghaempanah B. , Mehdizadeh P. , Scott S. L. 
Published: December 2007

Abstract
It is usual for production and reservoir engineers to consider measured well test data as exact values. In practice well rate data has different levels of uncertainty. A more realistic decline analysis and reservoir simulation can be done if these uncertainties are taken into consideration. The Process Capability Index (PCI) method, developed for quality control management, has been used in this paper to establish a protocol to quantify the "quality of well test data" and calculate the corresponding level of uncertainty. To obtain the uncertainty level corresponding to a field with any number of wells, Monte Carlo Simulation (MCS) has been used. The MCS is a robust numerical method in calculating the combined level of uncertainty of multi-component systems. In this paper a field with different wells has been considered. Finding the appropriate test data distribution function for each well, the final level of uncertainty of the production has been obtained. Then the impact of the uncertainty in well test data on decline analysis has been expressed and monitized. We believe the type of analysis developed in this paper would be a useful tool to evaluate the cost/benefits of any new technology, such as multiphase metering, for improved production measurement quality.
Application of a New Data-Driven Processing Method to LWD and Wireline Dispersive Compressional and Shear Waveform Data
Authors: Zheng Y. , Huang X. , Tang X. , Patterson D. , Yin H. 
Published: December 2007

Abstract
A challenge for acoustic logging data processing, especially LWD (logging while drilling) data, is how to realistically handle the dispersion effects of the waveform data. Significant dispersion is often encountered in the LWD compressional wave data acquired in an unconsolidated slow formation and in the quadrupole shear wave data with a heavy drilling mud. In the presence of dispersion, formation slowness computed from the waveform data is generally higher than the true slowness value. Correction for the dispersion effect usually uses an idealized theoretical model that may not be adequate to handle the actual wave dispersion in the varying LWD environments. To accurately handle the dispersion effect, a new data-driven method has recently been developed. The process is based on the actual dispersion computed from the data. The dispersion data are also used for quality control of the computed wave slowness. This new method is applied to extract compressional and shear slowness from the dispersive LWD and wireline acoustic waveform data from several wells. The results show that the new method realistically accounts for the dispersion effect in the waveform data and obtains more accurate estimates of formation slowness.
Drilling and Testing of an HP/HT Deep Gas Prospect from an Existing Well: Case History of Kra Al Maru 3 Deepening
Authors: Al-Saeedi M. J. , Singh J. R. , Mahesh V. S. , Al-Ajmi H. S. , Mckinnell D. 
Published: December 2007

Abstract
Kra Al-Maru 3 (KM-3) is a deep vertical exploration well originally drilled to investigate the hydrocarbon potential of the Jurassic formations. Investigation of the open hole logs/cores indicated that there was limited porosity development in the Marrat zones of interest. Therefore an operational opportunity became available to deepen the well to explore the deeper Triassic horizons which had gas bearing potential.
The main challenges of this well were to design an extended casing program within the constraints of the present wellbore to allow for drilling/testing of the well with a wellhead rating of 20,000 psi whilst assuring the collection of maximum amount of useable data (cores, logs, rates, pressures and samples).
In order to meet these challenges a special casing design was employed, based on the experiences of other deep wells. Special HPHT cement additives were specified for the cementing of the deep liner strings. Application of turbine and slim hole motor technology was tried and a HPHT well test operation was planned including the use of a state of the art 20,000 psi surface test package.
During the well re-entry major complications were encountered due to high pressure profile, high mud weights, severe losses and well control situations. During the initial short term test the well produced gas, condensate/light oil along with highly saline water which caused salt plugging of tubing and surface lines. Plans are in hand to re-enter the well for long term test after solving the problem of salt plugging.
This paper will present a case history of the well including the planning, design process, implementation and lessons learned from the drilling and testing operations. These conclusions will then provide the basis for future optimization in the design of these types of wells.
Nature Had It Right After All!—Constructing a "Plant Root"-Like Drainage System With Multiple Branches and Uninhibited Communication With Pores and Natural Fractures
Authors: Moss P. , Portman L. , Rae P. , Di Lullo G. 
Published: December 2007

Abstract
If reservoirs engineers could drill wells, they would surely not drill a single, small diameter hole, with the walls of that hole damaged to the point they are initially impermeable! They would probably drill a hole with no damage to the walls, preferably with open fractures or wormholes emanating from that main hole. They would further likely construct more of a network of branches, mimicking the root structure of plants, evolved to efficiently drain nutrients from a soil reservoir.
The problem, of course, has been that the technology required to create such a drainage system has been commercially unavailable. This situation changed, in Venezuela, in late 2005.
This paper describes several wells where multiple, relatively short-length laterals were constructed, maintaining communication with the natural fracture network of the formation, imposing no damage. The paper details the target reservoir's properties and its history of poor production. The new production figures are contrasted to the historical field numbers.
The method used was to simply dissolve a system of short laterals. This was achieved by pumping hydrochloric acid though a specially designed jetting assembly, attached to the bottom of a 1 ½″ coiled tubing unit. This revolutionary method not only creates a "reservoir engineer's" hole, it does so using simple equipment at a low-cost. Further details on the equipment are provided in the paper.
Drilling Fluids in an HP/HT Reservoir: Experiences With Three Different Systems on the Kristin Field Development
Authors: Hansen S. A. , Breivik D. H. , Gjønnes M. , Svanes K. , Vujovic M. , Svela P. E. , Sørheim O. I. 
Published: December 2007

Abstract
Kristin is a HP/HT field developed on Haltenbanken offshore mid-Norway. The Kristin development consists of 4 templates with a total of 12 subsea wells. The inclination through the reservoir ranges from 28 to 85 degrees. The reservoir at approx. 4600mTVD (15092 ft) has an initial pore pressure corresponding to 1.96sg EMW (16,36 ppg) and a temperature of 172°C (342°F). With a water depth of approx. 360m (1181 ft), a MW of 2.05sg (17,11 ppg) is needed to be able to maintain a riser margin.
Three different drilling fluid systems have been used in the reservoir section: 1) Cs/K-COOH clear brine system. 2) Invert emulsion HP/HT OBM. 3) Invert emulsion HP/HT OBM with ultra fine weight particles.
Challenges such as ECD management, hole stability, formation damage, weight material sag and operating on subsea HP/HT wells during harsh winter conditions had to be addressed both in the planning and the operational phase.
In this paper the background for selection of the drilling fluid is briefly described and especially the rationale behind using three different systems. The paper highlights operational experiences to illustrate how the drilling fluid systems influenced and coped with the challenges of drilling subsea, high angle HP/HT wells.
The paper provides a discussion of the pros and cons of the different fluids systems. Finally the paper identifies some of the challenges that lie ahead as the production has started and the reservoir starts to deplete.
Storm-Safe Deepwater Drilling
Authors: Nguyen Chau , Thethi Ricky , Lim Frank 
Published: December 2007

Abstract
The recent hurricanes that battered the offshore facilities in the Gulf of Mexico have prompted many operators and drilling contractors to rethink the way their drilling risers are designed for disconnection and retrieval before the hurricane arrives.
When drilling in very deep water depths, retrieval of the drilling riser is time consuming and tedious; and in emergency situations like the imminent arrival of a hurricane, the drilling rigs risk not being able to recover the drilling risers in time before the evacuation of personnel or sailing for shelters, with potentially devastating consequences.
A solution to overcome this concern is to modify the existing drilling riser to make it disconnectable closer to the surface and leave the long riser string below (and subsea BOP) in a safe and freestanding mode to survive the storm.
This paper presents the feasibility of such a modification, and describes the simple buoyancy system and additional components required. The study also outlines hydrodynamic and structural analyses required to demonstrate integrity of the freestanding drilling riser.
Limitations to Storage Pressure in Finite Saline Aquifers and the Effect of CO2 Solubility on Storage Pressure
Authors: van der Meer L. G. H. , van Wees J. D. 
Published: December 2007

Abstract
CO2 storage in aquifers is an attractive option for reducing CO2 emissions into the atmosphere. The successful example of CO2 storage in the Sleipner injection project proves that large volumes of CO2 can be stored in a water-bearing subsurface formation. In general, most of the injected CO2 will displace water and will accumulate as free gas at the crest of the aquifer.
On the other hand, CO2 is also soluble in water. Therefore, the aquifer or depleted reservoir will eventually be saturated with CO2. The present paper explores various aspects of the solution process, based on numerical simulation studies for a Norwegian type of open aquifer storage location and other types of storage structures. The case studies indicate that only in the long term (&gt; 1000 yrs), solubility may offer a storage mechanism for most of the CO2 stored in depleted fields. This is due to the accumulation of CO2 in the gas phase, which has a limited contact area with the water phase. However, if injection strategies focus on exposing the injected CO2 to as much "fresh water" as possible (i.e. through extended and dispersed migration paths) the amount of CO2 in the free gas phase can be reduced significantly and within a shorter time.
It is commonly believed that all CO2 will eventually disappear because it will dissolve in water. We agree with the fact that all CO2 will dissolve if there is enough water, but when a lot of material (CO2) is added to the system, this will affect fluid volumes and pressures in the total storage system. By studying a practical, real storage location, we try to find out some of the pressure effects of CO2 solubility on the total storage capacity of the selected storage site.
Software Agents—An Emergent Software Technology That Enables Us To Build More Dynamic, Adaptable, and Robust Systems
Authors: Landre E. , Ølmheim J. , Wærsland G. O. , Rønneberg H. 
Published: December 2007

Abstract
The oil and gas industry need to improve operational efficiency, and to address more demanding government issued requirements with respect to environmental safety in vulnerable areas such as the artic north. These requirements drive for new IT solutions, solutions not possible to implement using the more traditional approaches to software development.
These new solutions must be able to sense the environment, make decisions without human intervention, and involve humans when needed. In the latter situation the software can be used to prioritize problems that need human attention and assist the human in making better decisions with respect to the available information and situation at hand.
Software agents provide the capabilities needed to build the necessary IT systems, and they have during the last 15 years been applied successfully in safety critical systems such as military target prioritization [9] and space shuttle operation [10]. Less dramatic solutions involve optimization of air field runways and scheduling of transport capacity in terms of ships and vehicles.
To explore the capabilities of software agents, Statoil has implemented several demonstrators addressing problems in constraint-based planning and business process support.
In this paper we will present how software agents can be used to improve decisions in core oil industry processes such as drilling, production, processing and operation & maintenance. The main focus will be the on production, processing and operation & maintenance as these three processes can be directly supported by the same software agents. Drilling must be supported by another set of agents because drilling operations are conducted during a different phase of the development using different infrastructure.
An interesting observation from our own prototyping effort illustrated in figure 3 is that the three processes production, processing and operations & maintenance can be supported by less than 10 software agents in its initial outline. This is as expected, according to Dr. Ronnquist, and illustrates the power of software agents as a software design tool [11].
Gas-Injection Redistribution Revitalizes a Mature Volatile Oil Field: Cusiana Field Case Study
Authors: Soto L. , Penuela G. , Benavides I. , Martinez M. , Castiblanco I. , Chaves I. 
Published: December 2007

Abstract
Cusiana is a field of three stacked reservoirs (Mirador, Barco and Guadalupe) of volatile oil with a rich gas cap at the top. After a decade of gas re-injection at the crest of the main reservoir, Mirador, the fluid composition has changed as a result of production/injection. The static framework of this highly heterogeneous reservoir has changed too. For instance, minor faults that were proved to be seals at initial conditions are leaking and fractures that used to be passive have been reactivated today.
Initial miscible gas injection strategy in Mirador delivered so far an oil recovery factor (RF) of 50% with remaining oil in areas difficult to access such as an oil rim between the producers and a weak aquifer, poor quality rock layers, and bypassed between the producers and the gas injectors. In Barco and Guadalupe, initial water injection successfully provided pressure support but did not sweep oil as expected (RF= 25%).
A strategy was designed to recover additional oil by moving gas injection points to deeper formations, the flank of the structure, injecting at low flow rates from distributed injection points and maintaining a favorable voidage replacement. This strategy was based on a synergy among the three reservoirs, which allowed well conversions, rehabilitation of 9 shut-in wells to be injectors or producers and conversion of 10.5 km of water injection flowline, which expanded the gas injection network.
After 40% of the strategy implementation by the end of 2005, 1.8 MMSTB of incremental oil has been recovered, reducing the monthly field oil rate decline by half. This success has "boosted" the continuation of the gas injection redistribution strategy for 2006.
This paper describes the geological and reservoir engineering modeling that was performed to design the gas injection redistribution strategy in this mature field.
When Does a Longer Shut-In Lead to a Larger Radius of Investigation?
Authors: Ewens S. , Pooladi-Darvish M. 
Published: December 2007

Abstract
While the concept of radius of investigation is better understood for drawdown tests, its applicability to buildup tests is less certain. For example, a rule of thumb is that "one cannot see a particular feature in a buildup unless the radius of investigation during the preceding flow period has seen that feature". In this paper, we clearly illustrate that the radius of investigation of a buildup can be larger than that of its previous flow period.
Another common contention is that the radius of investigation of a buildup is limited by noise dominating the late time pressure behavior. Oliver1 and later Thompson and Reynolds2 defined the radius of investigation based on the distance from the well to the region of the reservoir which has the greatest impact on the pressure derivative. We have used this approach to calculate the derivative and show that the ratio of noise to the signal from the reservoir does not necessarily increase. We show that when data is sampled appropriately, the radius of investigation of a buildup can easily go beyond that of the preceding flow period, and clearly demonstrate when this may remain unaffected by noise.
Cement Shrinkage Measurement in Oilwell Cementing—A Comparative Study of Laboratory Methods and Procedures
Authors: Reddy B. R. , Xu Ying , Ravi Kris , Gray Dennis , Pattillo P. D. 
Published: December 2007

Abstract
Cement sheath shrinkage after placing the cement slurry in the annulus has been of concern in oilwell cementing because of the potential detrimental effects that shrinkage can have on long-term zonal isolation.
This paper compares several methods for measuring cement shrinkage under a variety of conditions including those downhole. Using the various methods, cement shrinkage in environments where the cement slurry is either closed to or open to external water sources was measured and the values were compared. The methods used for measurement under atmospheric conditions were based on API test apparatus (balloon and ring-mold) and flask methods currently used in field labs. Measurements under pressure and temperature were performed using the ring-mold method, in-house designed equipment, and newly available commercial equipment.
The values obtained by the different methods are discussed. Procedure modifications are proposed for measuring volume changes to cement slurries based on placement time, shear history, and gel-strength development.
The results presented in this work can be used to test shrinkage characteristics of cement slurries in the lab, under downhole conditions, and to select a cement system that is fit for purpose.
Qualifying Proppant Performance
Authors: Freeman E. R. , Anschutz D. A. , Renkes J. J. , Milton-Tayler D. 
Published: December 2007

Abstract
Qualifying proppant performance prior to a frac job, or simply verifying proppant performance after a frac job, can add significant value to propped fracture stimulations. Through a blend of established practices and new technology, data can be generated that will give an engineer insight into how specific proppants are designed to perform. This is without running expensive and time consuming conductivity and permeability tests on every job.
A primary objective is to establish representative, reliable and reproducible data via a sample collected from a large mass. American Petroleum Institute (API) Recommended Practices (RP) identifies three primary tenets: 1) representative sampling from a flowing stream, 2) standardized testing with calibrated equipment, and 3) sample retention for follow-up evaluation. Application of these practices ensures that proppant test data is valid (e.g. representative, reliable, and reproducible). Yet, these practices alone typically quantify quality but do not qualify proppant performance.1,2,3
Correlation of valid well-site proppant data with published information (literature, web-sites, or fracturing simulators) enables one to identify disparities. Any differences in part may be the result of mining anomalies, manufacturing defects, transportation abuse, and/or contamination. These can directly impact the delivered performance of your chosen proppant. Since proppant flow capacity or conductivity is a key measure of that performance, some empirical results have been assimilated for well-site and public data.
As a consumer, having information that describes the proppant at the well-site is important to deciding application and value. By compiling historical well-site proppant data one can set a minimum threshold of required properties or specification. This provides the opportunity to identify a greater range of proppants (e.g. substitutions) that meet reservoir, economic, and supply chain needs.
Lastly, this paper introduces new patent-pending technology that enables well-site proppant sampling and evaluation before the fracturing treatment. Having pre-frac data gives one the opportunity to make any necessary changes in fracture design and implementation to get the most from available proppant. It also provides for a detailed inspection of the well-site delivered proppant supply. For instance, one can isolate and sample each pneumatic trailer, monitor associated pneumatic discharge pressures, provide representative split samples for fracturing fluid compatibility testing, etc.
Case histories, onshore and offshore, support "qualifying proppant performance".
Drilling and Completions Waste-Management Strategy in Deepwater Angola
Authors: Klein R. J. , Walls A. H. , Page P. , Chambers B. , Gallagher R. , Burt D. 
Published: December 2007

Abstract
BP's recent exploration success in Angola is expected to result in a number of significant subsea developments in water depths ranging from 1200metres to in excess of 2000metres. Our understanding of the environmental impact of discharges associated with drilling and completions operations in deepwater Angola is immature at scale. Studies around single wells have been presented (Reference 1) but this type of work has not been considered for the development of a portfolio of subsea projects. A strategy and implementation plan has been developed by a multidisciplinary team to better understand the extent/impact of discharges and evaluate currently available and future waste management options, incorporating lessons learned from more mature deepwater operating areas where appropriate. This will enable informed decisions to be made on future implementation of best practicable waste management solutions.