bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geomechanical Assessments for Underground Gas Storage and CO2 Sequestration in Depleted Hydrocarbon Reservoirs
Authors: Fang Zhi , Khaksar Abbas 
Published: February 2011

Abstract
Depleted hydrocarbon reservoirs are attractive targets for gas storage and CO2 disposal because of proven storage capacity and seal integrity, existing infrastructure, etc. Optimum well completion and injection design in depleted reservoirs would require understanding of important rock mechanics issues such as: 1) drillability and completion of new wells, 2) maximum sustainable storage pressures avoiding fracturing and fault reactivations considering rock-fluid interaction effects. Building a field specific geomechanical model calibrated with well and production data is a pre-requisite for addressing these issues. Through a case study from a North Sea field, this paper demonstrates a systematic approach for geomechanical risk assessments for CO2 storage in depleted reservoirs.
A depleted gas reservoir at 4,265ft depth with current pressure of 45psi is considered in this study for CO2 sequestration. Historical well and production data are used for geomechanical modellings and defining the change of earth stresses associated with depletion and injection. Analyses show that because of the low fracture gradient within the depleted sandstone reservoir and the presence of non-depleted overburden shale, the inclination angle for new injectors should be kept below 50° to avoid hole failure or mud losses. Field data and analytical sanding evaluations indicate no sand control installation would be needed for injectors. Fracturing and faulting assessments confirm that the critical pressures for fault reactivation and fracturing of intact rocks are, far beyond the planned CO2 injection and storage pressures up to the original pressure 1,962 psi; hence no leakage due to faulting or fracturing is expected over the life of CO2 storage.
The methodology and overall workflow presented in this paper is expected to assist well engineers and geoscientists with geomechanical assessments for optimum well completion and injection design for gas and CO2 storage in depleted reservoirs.
Reserves Overbooking: The Problem We’re Finally Going to Talk About
Authors: Olsen Grant T. , John Lee W. , Blasingame Thomas A. 
Published: February 2011

Abstract
Oil and gas reserves estimates which honor disclosure requirements of the U.S. Securities and Exchange Commission (SEC) are critically important in the international oil and gas industry. Unfortunately, a number of E&P companies have allegedly overstated and subsequently written down certain reserves volumes in recent years. In some cases, the consequences have been quite adverse. We document some of these cases of reserves overstatements and summarize the consequences. Reserves write-downs are of obvious interest to numerous groups involved in the reserves estimation process and outcome, including estimators, managers, investors, creditors, and regulators. The magnitude and nature of recent overstatement cases, relative unfamiliarity with the SEC's inner-workings, and the Commission's new reserves reporting requirements, increase the need to examine critically reserves disclosures and reserves overstatements.
Drainage and Imbibition CO2/Brine Relative Permeability Curves at Reservoir Conditions for Carbonate Formations
Authors: Bennion D. Brant , Bachu Stefan 
Published: February 2011

Abstract
Proper modeling of the multiphase flow of supercritical CO2 in deep saline aquifers for CO2 sequestration (both cycles of drainage during injection and imbibition during CO2 migration) is critical in being able to understand and predict both the short and long term fate of the injected CO2 over extended time periods (hundreds to thousands of years). Current numerical models require the use of accurate two-phase CO2/brine relative permeability data at representative in-situ conditions in order to be able to accurately conduct these calculations. However, there are virtually no published data in the literature on the high temperature and pressure displacement character of CO2/brine systems in actual reservoir rocks, except for the data published by the authors in the June 2008 issue of the SPE Reservoir Evaluation and Engineering Journal. That data set, although it included a few carbonate cases, contained mostly measurements on clastic rocks. This paper presents a new set of nine relative permeability measurements (both drainage and imbibition) for carbonate rocks (limestone and dolomite) of higher permeability values than those in the initial work (which are thus more likely to be representative for candidates for CO2 sequestration in deep saline aquifers). The new data set to be presented includes also pre and post-test CAT-scan imaging of selected samples to illustrate potential effects of CO2 contact on potentially soluble carbonate matrices. The paper compares the new data set of measurements for carbonate rocks with the limited set of data available for carbonates from the previous work, and attempts to determine if specific relative permeability and residual saturation trends can be defined based on other rock characteristics that are easier to measure in routine core analyses, to allow extension of the data set to other carbonate facies elsewhere which have not been tested.
Has the Safety Case Failed?
Authors: Fitzgerald Brendan , Breen Paul , Patrick Joe 
Published: February 2011

Abstract
The paper examines the performance of the oil and gas industry, in particular in Australia and New Zealand, since the introduction of the Safety Case regime. Emphasis is placed on identified project issues and conclusions are drawn related to the current status of the industry, its maturity and its ability to apply the Safety Case regime in the manner required to achieve anticipated results. The paper examines whether issues that have led to project failings in recent years are inherent in the way the industry operates.
The paper discusses the experience of the offshore oil and gas industry in Australasia, in comparison with other parts of the world. The experience of other industries that apply the Safety Case approach is also discussed.
The core issue that is highlighted relates to the manner in which the Safety Case is applied, including issues of lack of understanding of the Safety Case process by management, the effect of contracting strategy on the effectiveness of the Safety Case and the lack of a common understanding of the role of the Safety Case. The paper is based on cumulative experience since the beginning of the Safety Case in the oil and gas industry, drawing in particular from experience on major projects within the last few years.
The paper highlights the manner in which the industry undertakes development projects, in particular, with some observations about the legacy that this leaves for the operating company and its personnel. More than 20 years after Piper Alpha, the industry has moved on and this paper seeks to provide a re-appraisal of the effectiveness with which major accident hazards and risks are managed.
The paper also seeks to draw conclusions that illustrate a way forward for the oil and gas industry.
An Intergrated Analytical Method in Identifying the Remain Potential of Thin Bed Reservoir on Deltaic System, Sengata Field
Authors: Demak Riswan Kiay , Alkaff Mohamad Hafiz , Ira Yashinta , Prasetiyanto Febri 
Published: February 2011

Abstract
This paper presents an integrated and simplified method with some field cases that can be applied to delay rapid production depletion and it focuses on the occurrences of the potential bypassed oil zone. The method that we used in here is by combining geological approach, with reservoir production history map as a result of data obtained during infill drilling and subsequent well work activities in the wells in the aim to get the remaining potential of reservoir. The primary benefit is to extent the field life as long as possible before it become a Marginal Field.
Well services are the common ways in maintaining production in every field, in this case Sengata Field. This aging onshore field has been developed by PT PERTAMINA EP since 1973 and the production reached its peak of 6000 BOPD in 1979 and with average decline rate of 60%, the field is on a fast declining trend. Like many other deltaic environment reservoirs in the world, the structures of this field is extremely sophisticated and consist of large number of reservoirs and most of them are thin bed reservoir and multiple stacked channels that contain oil, gas and formation water. The observed drive mechanisms consists of a combination of Solution Gas Drive and Water Drive The complicated geometry is a serious challenge for engineers who are responsible for determining lateral and vertical communication between the individual sand units.
Recent analytical method has been proven very successful in sustaining and revitalizing production shown by the oil increment up to 110% for it's target and allows PERTAMINA EP to optimize and prolong the field life.
Case History: Overcoming the Challenges of Deepwater Gravel Packing by Using Viscoelastic Fluids in Wells with Concentric-Annulus Completions
Authors: Joseph Kevin Peter , Cawiezel Kay E. , Wood Neil 
Published: February 2011

Abstract
Viscoelastic Surfactant (VES) Fluid technology was applied in the gravel packing of 18 deviated open-hole wells, having concentric annular completions, in Deepwater offshore India, with excellent results. The formation is unconsolidated, friable and highly permeable with very little margin between pore pressures, wellbore breakout pressures and fracture pressures. A preperforated liner was placed in the under-reamed open-hole section to protect against wellbore instability, and the sand control screens were landed inside the liner forming a dual annuli or concentric annulus, which was then gravel packed. Conventional gravel packing strategy suggests manipulating pump rates to minimize downhole pressures. However, with VES fluids, surface and bottom-hole treating pressures are easily kept to a minimum until screenout. This paper summarizes the challenges encountered; lessons learned and highlights the key advantages of the viscoelastic fluid systems used in these applications. The superior proppant-carrying capabilities of the viscoelastic system was proven showing higher success rates in complete packing of the open-hole sections compared to wells gravel packed using HEC-viscosified fluids. This paper also includes the details of the laboratory development and optimization of the VES fluids for both formate and calcium chloride based gravel pack carrier fluids. This involved screening of possible viscoelastic surfactants by compatibility tests, VES fluid rheology tests, internal breaker tests for the specific well conditions and friction pressure tests. The VES fluids’ superior proppant carrying capabilities, friction reduction properties, cost effectiveness, and non-damaging effects were the key success factors in overcoming the gravel packing challenges. The lessons learned from this project can be utilized in similar deepwater or extended reach applications to assist in improving success rates in gravel packing long open-hole intervals.
Three-Phase Flows Simulation for Improving Design of Gravity Separation Vessels
Authors: Vilagines Régis D. , Akhras Abdul Rahman 
Published: February 2011

Abstract
Computer simulation of gas/water/crude-oil flows inside gravity separators was developed. A three-dimension Eulerian model is used to describe flow features, including liquid free-surface, phase-mixing and droplets settling.
The simulations were conducted for a 45.5 meter long production trap operated in Saudi Arabia, required 105,000,000 mesh cells and ran on 93 parallel processors. The adjustment of the computation parameters and a technique to ensure constant liquid level in the vessel during the computation are described.
Density and velocity distributions in cross sections inside the vessel are presented and discussed.
The flow at nominal conditions was improved with a new inlet device. Computation results show how the inlet geometry effects propagate in the downstream flow, thus affecting the separation of phases.
Keywords: numerical simulation; separation; gravity; multiphase flow.
The Method and Expert System for Risk Assessment of Drilling In High-Sulfur Gas Field
Authors: Zang Yanbin , Wang Ruihe , Zhang Rui , Wang Zizhen , Li Xinzhi 
Published: February 2011

Abstract
The drilling operations had posed great potential threats to the surroundings and the safety of personnel, due to geological complications, lithological complexity, overpressure and acidic gas corrosion in high-sulfur gas fields. In order to accurately identify, evaluate and control the risks of drilling, the comprehensive evaluation index system (CEIS) and model for safe drilling based on fuzzy theory are constructed, and an expert system for drilling risk management is developed based on historical accident cases in high-sulfur gas fields.
The main structure of the expert system built in a framework way is introduced, and the operation principles of risk management by case reasoning for the expert system are discussed. Taking a drilling exploration area in the Northeast of Sichuan Basin as an example, the expert system is developed and then evaluates the drilling risk of Yuanba block. The results show that the comprehensive score of drilling security in YB-1 well is 0.559, which means very high drilling risks. In addition, the geological conditions and natural environment are identified as the two main potential factors that impact drilling security. All these evaluation results align well with the actual drilling practices, and this method of comprehensive evaluation for drilling risks is practical.
The evaluation method and expert system could provide a prime and valuable reference and conduction in rapidly locating the risk sources, accurately assessing drilling risks and improving the overall safety level of drilling.
Artificial Lift Using Impulse Pumping
Authors: Pierre B. , Gudmundsson J. S. 
Published: February 2011

Abstract
Impulse pumping is a new method for transport of fluids that can be applied in drilling and petroleum production. Of particular interest are applications of impulse pumping to artificial lift of liquids. In such situations, the motor driven part of an impulse pump appratus is located at wellhead; hence facilitating ease of operation and maintenance. In addition, no theoretical vertical lift limit applies in impulse pumping; thus simplifying design and applications of an impulse pump. Characteristic curves of impulse pumping first emphasize situations where impulse pumping performs with the greatest energy efficiency. Artificial lift of deep water for depressurization of the Statfjord field is then investigated. Operations, maintenance and performances of impulse pumping are then compared to those of electric submersible pumps and jet pumps based on results from three different industrial test cases.
Introduction of a New Logging While Drilling Resistivity Tool in the Liaoning Province of China
Authors: Lee Jonathan , Zhang Zhi Guo 
Published: February 2011

Abstract
The land drilling market in China has seen a significant increase in the use of gamma and propagation wave resistivity logging while drilling (LWD) tools in recent years, primarily through the offerings provided by major service companies. Although these technologies have been in use for many years, their availability to independent service companies has been restricted to either purchasing older generation tools from the majors or using their services at inflated prices, with limited resources to develop their own LWD technology. The authors describe the successful introduction of an LWD system within China by an independent service company working with an independent tool manufacturer―removing the reliance on technology developed by established international service companies.
The paper details the introduction of the formation evaluation technology and associated measurement while drilling (MWD) system by a local service company, established in wireline logging operations but new to the field of directional drilling, MWD and LWD. Focus will be placed on detailing a series of multilateral wells drilled within the Liaoning Province and the challenges faced with introducing new technology and interpreting data from high angle and horizontal wells.
The studies demonstrate the successful implementation of LWD technology in a field where previous attempts to log while drilling had failed. Through training provided by the tool manufacturer and use of field engineers with wireline logging backgrounds, the service company was able to log nearly 2200 m of lateral sections in the oil company’s most complicated multilateral project to date. The wells were drilled faster than previously with significantly improved system performance.
The availability to local service providers of a resistivity system with proven performance enables them to expand their service offerings without having to rely on technology provided by the majors―in turn allowing construction of more complex wells, designed to increase and optimize production.
Infill Drilling Potential in Tight Gas Reservoirs
Authors: Luo Shu , Kelkar Mohan 
Published: February 2011

Abstract
Many operators of tight gas reservoir fields are interested in determining the infill well potential in these fields. Over drilling may prove to be uneconomical; whereas, under drilling would leave unexplored reserves in the ground. In predicting EUR of a potential in fill well, the operator is interested in knowing what percentage of the production will be from incremental reserves (newly accessed) vs. acceleration reserves (which can be produced from existing wells). Higher the percentage of incremental reserves better is the potential of an in fill well.
In this paper, we present a novel method for determining the incremental vs. acceleration potential for in fill well in a tight gas reservoir. We evaluate the existing wells by plotting the data in a form so that the data can be linearly extrapolated. We predict the EUR for individual wells before and after new wells in the vicinity are drilled. By knowing how much gas is "diverted" from the older wells, we determine the acceleration component of an in fill well. By repeating the process as the field is being developed, we can determine the fraction of acceleration and incremental components of the EUR at each stage of infill drilling. We will also know how the EUR is changing as the well spacing is slowly reduced. To ensure our results are reasonable, we also compare our EUR values with EUR’s reported by the operator as proved reserves. Armed with this information, we can extrapolate in fill well potential for a smaller spacing, including the contribution due to acceleration vs. incremental production.
We developed this procedure for Wamsutter field in Wyoming. Using the procedure, we recommended in fill well locations to the operator. The comparison between actual data and the predicted results will be presented.
Planning and Execution of Highly Overbalanced Completions from a Floating Rig: The Ursa-Princess Waterflood Project
Authors: Stair Craig D. , Hinnant Chuck H. , Hines Natalya O. , Schober Jamie M. , Davis Chris L. , Lizak Ken F. , Pugh Brian A. 
Published: February 2011

Abstract
The Ursa-Princess Waterflood (UPWF) targets the Lower Yellow sand, the main reservoir in the Mars-Ursa basin in Mississippi Canyon, about 60 miles south of the mouth of the Mississippi river in the Gulf of Mexico, USA. The Lower Yellow sand, a world class Upper Miocene turbidite reservoir, has been on production in the Ursa and Princess fields since 1999, and has been drawn down nearly to the bubble point. The waterflood is intended to increase and stabilize reservoir pressure, and to improve sweep efficiency. To accomplish this, four subsea injectors were designed and constructed to inject treated seawater at some 40,000 bbl/day each for a target life of 30 years.
As the Lower Yellow reservoir was already highly depleted, unique risks were identified in the planned subsea completion operations, to be conducted from a Mobile Offshore Drilling Unit (MODU). Seawater, used as a completion fluid, was expected to be up to 4000 psi overbalanced to the reservoir, depending on the well location. This created the risk of either uncontrollable fluid level drop in the marine riser or extreme impairment to the sandface completion. In order to maintain well control with a fluid level at the surface and still deliver low skin completions, multiple design and procedural issues needed to be addressed, including:
Control systems on the rig and riser system to prevent uncontrollable fluid level drop, Perforating systems to minimize impairment in a high overbalance environment without adding undue risk to well control, Pill designs that could both control fluid loss at the sand face and clean up effectively, Downhole completion systems capable of functioning either under very high pressure differentials or against very high loss rates, Development of high burst screens that could withstand pilling in the event mechanical fluid loss devices failed.
As more Deepwater reservoirs approach depletion, specialized tools and procedures will be required to continue to deliver safe and effective sandface completions from floating rigs. This paper details many of these considerations, and summarizes the execution experience and results for one such reservoir.
Producing High CO2 Gas Content Reservoirs in Pertamina Indonesia Using Multi Stage Cryogenic Process
Authors: Suarsana I Putu 
Published: February 2011

Abstract
High CO2 reservoir gas in Pertamina is considered as unconventional gas reservoir since the gas has low heating value. The high concentration of CO2 in the gas caused the low heating. The gas need to be processed to make it marketable gas.
PERTAMINA has lots of sources of reservoir gas which content high CO2. The gas sources will be produced in the future since the gap of gas supply and demand in Indonesia is getting bigger mean while the hydrocarbon gas reservoir is diffucult to discover. There is no choice that the high CO2 gas content reservoirs will be produced in the future.
The high CO2 gas is considered as unconventional gas reservoir, corrosive gas, and unvaforable to be produced. High CO2 gas produced is not only has low calori but also will affect the global warming. In this case Pertamina has dilemma in producing the reservoirs.
In this paper will present about: alternative research about producing high CO2 gas content reservoirs. Determination of how to characterize reservoir fluids with high CO2 concen- trations for applications in compositional reservoir simulators.
Determination of separator conditions to obtain marketable gas by introducing a cooling process in a multistage separator.
A method to process high CO2 gas content to an environmentally friendly fuel gas which can eliminate the possible climate change caused by CO2.
Multi stage cryogenic process will separate CO2 gas reservoirs using cryogenic reservoir stage step by step. The number of stage will be define the effective pressure and temperature of the vessel to separate the CO2 from the gas reservoir. The Final goal is to obtain marketable gas which contain CO2 less than 10%mol, heating value more than 1000 btu/Mscf.