bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiphase Transportation: A Kinetic Inhibitor Replaces Methanol to Prevent Hydrates in a 12-inc. Pipeline
Authors: Leporcher E.M. , Fourest J.M. , Labes-Carrier C. , Lompre M.
Published: December 2007

This paper describes how a kinetic inhibitor has been selected and then deployed in a gas pipeline in operation. Elf has performed a lot of research about new alternatives for hydrate inhibition in order to extend the area of multiphase transportation. Kinetic inhibitors can act at much lower concentration than thermodynamic inhibitors (alcohols). These new chemicals do not prevent the nucleation but significantly delay the growth of hydrate crystals. The duration of inhibition, which determines the chemical efficiency depends on the rate of sub-cooling. The understanding of these key parameters allows to contemplate multiphase transportation in the thermodynamic domain of hydrate formation. Within the family of kinetic inhibitors issued from research programs and proposed by manufacturers, three chemicals were pre-selected. Hydrodynamic conditions of the liquid phase were assessed on a pilot laboratory loop 1" × 22m. A lot of specific tests including compatibility with the field injected chemicals, modification of physical properties of the liquid phase were performed in order to anticipate any operational disturbance. From this test program, the overall most efficient chemical was selected.

Then this chemical was injected instead of methanol during three weeks. The onshore gas pipeline 12" × 17km was continuously monitored with eight pressure transducers located along the pipeline. The conditions of deployment, hydrodynamic observations and induced consequences on the downstream process are presented. The main conclusion is that a kinetic inhibitor injected at a rate of 170l/d in a pipeline carrying 1 MSm3/d of gas (with its condensate and condensed water) replaced methanol, with sub-cooling conditions up to 8 C.

P. 455
How do Anions in Water-Based Muds Affect Shale Stability?
Authors: Carminati S. , Del Gaudio L. , Zausa F. , Brignoli M.
Published: December 2007

The effect of different anions on shale behavior has been studied. Viscosity effects, pore blocking mechanisms and osmotic phenomena have been evaluated by pressure transmission tests under high pressure and high temperature conditions. Parallel to this short term experiments, mechanical (indentation) tests on cuttings aged for 12 days at 80°C have been run. In addition to organic and inorganic sodium and potassium salts, two commercial glycols (with and without Cloud Point) have been selected and analyzed. All the experiments have been carried out at alkaline pH. It is shown that different anions induce different shale hardening and different unbalance (related to osmotic phenomena) between pore and drilling fluid pressures. Besides that, some conclusions on the role of glycols have been drawn.
Gel Treatment Optimization by Rheological Measurements
Authors: Broseta Daniel , Marquer Olivier , Baylocq Pascal , Féry Jean-Jacques , Zaitoun Alain
Published: December 2007

This paper gives some recommendations of the pertinent rheological measurements for an efficient gel screening in water shut off and conformance improvement treatments. The proposed methodology is based on measurements of gelation time and final yield stress, which are related, respectively, to the pumping time and to the maximum differential pressure the gel can withstand in the reservoir (matrix or fracture).

A laboratory study has been carried out with two polyacrylamide/chromium (III) formulations, one of which, involving a high-molecular-weight polyacrylamide, is adapted for plugging fractures, and the other one, involving a low-molecular-weight polyacrylamide, is usually employed for plugging porous matrices. These formulations have been used in some specific field applications. A series of viscosity, storage modulus and yield stress measurements on the gelling solutions are presented in this paper, with the purpose of quantitatively characterizing the gelation kinetics and final strength of the gel formed. The proposed methodology is utilized for investigating in detail the influence of shearing on the gelation time and final gel strength. In practice, the gel formulation is in fact subjected to hours of strong shearing in the surface facilities (i.e., pumps, tubings….) and in the near-wellbore part of the formation before being left under quiescent conditions (well shut-in).

The results demonstrate that shearing has for effect to restrain gelation and, in particular, to limit the viscosity rise due to the formation of aggregates of crosslinked polymers (microgels). The gelation time, defined in relation to this viscosity rise, strongly increases with shear rate for the high-molecular-weight (non-Newtonian) formulation, but is unaffected by shear for the low-molecular weight (Newtonian) formulation. Experiments have also been conducted in which an extended initial period of strong shearing was followed by another extended period of rest. The final gel strength of both formulations, evaluated from yield stress measurements, turned out to be independent of the shear rate history.
Optimization of Hydrogen Sulfide Scavengers Used During Well Stimulation
Authors: Al-Humaidan A. Y. , Nasr-El-Din H. A.
Published: December 2007

Many water injectors and oil producers are damaged due to the accumulation of iron sulfide deposits near the wellbore area. For example, iron sulfide is present in water supply and injection wells as a product of sulfate reducing bacteria (SRB). Hydrochloric acid can be used to remove iron sulfide, however this process can result in the release of hydrogen sulfide, a toxic and corrosive gas. Moreover, hydrogen sulfide reacts with ferric ions and precipitates elemental sulfur. Elemental sulfur is insoluble in acids, practically impossible to dissolve, and can damage the formation. The objectives of this study are to screen hydrogen sulfide scavengers, which can be used during well stimulation, and assess the performance of the selected chemical in the field.

A simple, fast procedure was developed to evaluate hydrogen sulfide scavengers. Several types of scavengers, all aldehyde-based chemicals, were examined. The concentration of hydrogen sulfide scavenger was varied from 0 to 10 wt%. Reaction temperature was kept constant at 25°C.

A simple, fast procedure was developed to screen hydrogen sulfide scavengers used during well stimulation. The efficiency of capturing hydrogen sulfide was found to be a function of scavenger type and concentration. At scavenger concentrations greater than 0.5 wt%, a polymer-like material was observed with most scavengers examined; this material adversely affected acid reaction with iron sulfide and could cause formation damage. Low sulfide concentrations were obtained in the acid returns when S-1 was added in the acid formulation.
Improvement of Low-Permeable Cement for Zonal Isolation at High-Temperature Conditions
Authors: Dubois N. , Noik Ch. , Rivereau A. , Vernet Ch.
Published: December 2007

The development of new drilling technologies and the increase of severe operation conditions related to deep water applications lead to enhance the performance of drilling fluid and cement formulations. Success of cementing operations depends on slurry placement and then on the material properties under temperature and pressure conditions. A novel cement developed for high temperature wells is proposed. This material issued from civil engineering is composed of classical Portland cement and silica particles. The major problem in these formulations was to manage with the compacity of dry powders by a better choice of the particle size distribution of cement and silica grains. At least two types of silica were used, one was a crushed sand and the other a silica fume. The control of the initial homogeneity of the dry mixture allowed to adjust the rheology of the granular media in water. The slurry fluidity is finally adjusted by an optimum in the concentration of the dispersant additive leading to a minimum in viscosity.

Other additives such as retarders and fluid loss reducer were selected according to the temperature range of use. Properties of the setting material were evaluated by compressive tests on crashed core and water permeability measurements. Test results indicated good relation between mechanical properties and initial compacity of the cement systems.
Application of Multiphase Flow Methods To Horizontal Underbalanced Drilling
Authors: Smith S. P. , Gregory G. A. , Munro N. , Muqeem M.
Published: December 2007

Multiphase flow can be present in all aspects of underbalanced drilling. This paper outlines the ways in which multiphase flow pressure loss calculations can be used by drilling engineers in the design and optimization of underbalanced drilling operations. Then, detailed field measurements for several horizontal wells drilled underbalanced with coiled tubing are used to evaluate the application of existing pressure loss calculation methods to this unique application.
A Massively Parallel Reservoir Simulator for Large Scale Reservoir Simulation
Authors: Dogru A. H. , Li K. G. , Sunaidi H. A. , Habiballah W. A. , Fung L. , Al-Zamil N. , Shin D. , McDonald A. E. , Srivastava N. K.
Published: December 2007

A Massively Parallel reservoir simulator (POWERS) has been developed and fully integrated with Suadi Aramco's pre and post processing graphical environment. The simulator has been validated against published results and other industrial simulators. Three different giant oil field studies using million grid blocks were carried out by using the new simulator. Benchmark runs indicated near linear performance improvement with linearly increasing number of processors. With the current capabilities mega cell construction, preprocessing and post processing is quite fast. History match runs involving over million grid block and 30-50 years of history is obtained in less than one hour on a low cost parallel computer.
A Total-Velocity Sequential Preconditioner for Solving Implicit Reservoir Simulation Matrix Equations
Authors: Watts J. W.
Published: December 2007

The total velocity sequential semi-implicit method has received significant use since it was originally developed in about 1970 by Spillette, Hillestad, and Stone1. Its advantage is a reduction in the per-timestep computational requirement. It comprises two major steps: a solution of the IMPES pressure equation, then a solution of coupled saturation equations. Since the pressure solution is for a single unknown at each gridblock, it requires less work than solving fully implicit equations. Since the set of saturation equations does not have the elliptic nature of the pressure equation or of the fully implicit coupled set of equations, the saturation solution converges rapidly. Overall, the per-timestep computational work required is typically a half to a fifth that required for fully implicit computations.

The sequential semi-implicit method is far more stable than IMPES, and it can be effective in a wide variety of reservoir problems. However, there are problems in which it does not work as well as the fully implicit method, its per-timestep economy being more than offset by a requirement to perform more timesteps.

This paper describes an attempt to get the best of both worlds by using the total velocity equations in a preconditioner for the implicit matrix equation. The resulting method, which is similar to CPR2, has performed effectively in a variety of problems. However, its performance has not yet been compared to that of competing methods.
Implementation of the Modular Magnetic Tool in Air Drilling Systems
Authors: Morsy Hatem , Shale Les
Published: December 2007

Conventional methods used to steer the BHA when drilling with air are primitive and time consuming. Usually, a single shot survey tool is the most convenient option for steering the BHA.1 Survey tools, however, are not designed for the harsh environment. Consequently, they are prone to early failure in this application. To improve reliability and drilling efficiency in air and gas drilling, the Modular Magnetic Tool (MMT) was developed. The MMT employs a rugged steering tool with a wet-connect system. This MMT/Wet Connect System allows orientation of the drilling motor in a particular direction while still allowing drilling straight ahead with drill string rotation.

The steering tool was specially designed to handle the high shock and vibration when drilling with air and gas. It provides continuous surface readout of drift angle and azimuth of the hole as well as tool face orientation while drilling ahead.

The wet-connect system allows the wireline to be run through the drill string from the top of the Kelly. Connection of the wireline employs a male end (rocket) that sits in a special sub in the drill string. A female end stabs onto it whenever it is desirable to orient or survey. The female end can be tripped out of hole inside the Kelly, either to make a connection or to allow rotation of the drillstring. This configuration minimizes both down time and damage to the wireline that could be critical when drilling in certain formations.

This paper discusses system design and performance, and presents case studies of wells drilled utilizing this system.
Novel Completion Brine Applications at Viosca Knoll in Hot, H2S and CO2 Environment
Authors: Darring M. T. , Moore K. R. , Ali S. A. , Vollmer D. P. , Ke M.
Published: December 2007

A novel non-halide completion brine has been developed and field tested in the Viosca Knoll field, offshore Mississippi and Alabama in the northeastern Gulf of Mexico. Laboratory testing was performed to confirm the non-corrosive nature of the novel completion brine in a high-temperature acid-gas environment. Testing was performed on 4130 carbon steel and 13 chrome stainless steel at 320°F to simulate conditions anticipated in the 15,000' Viosca Knoll wellbores. These conditions include up to 3.5% CO2 and 35 ppm H2S in the produced gas. Results of long-term weight-loss corrosion tests are presented, as are data from return permeability core-flow studies.

Case histories for three wells are presented, specifically those in which the non-halide completion brine was used as a packer fluid and as a perforating fluid. Some of these wells were first flow-tested by perforating in water-base drilling mud. An examination of the data from these wells confirms the benefits of perforating in the non-halide completion brine into the limestone reservoir.

Unusual precautions are required in blending, handling and transporting the brine. This paper also outlines some of the special measures used and recommended for handling.
ESP's: On and Offshore Problems and Solutions
Authors: Lea James F. , Bearden John L.
Published: December 2007

This paper is a follow-on to SPE 28694 (Ref. 180) which summarizes and categorizes ESP literature by a number of different topics. The intent is to list problems mentioned in various papers and a quick mention of the solutions, which are discussed in the given references. As mentioned in the previous reference, it is also an attempt to relate problems to various field conditions, however many of the field papers do not include a complete listing of field conditions, so to be able to do this from using the literature is often not possible.
Can Electrical Insulation and Conductor Performance Be Predicted?
Authors: Durham Marcus O. , Durham Robert A.
Published: December 2007

Long power cables and large machines require different application techniques from most electrical wiring. The first topic discussed is a new technique for evaluation of insulation for continued use. The second area is a different method for selection of conductor size considering temperature and voltage drop. The hi-pot evaluation is primarily a maintenance function, while the voltage drop procedure is primarily a design practice.

For the first topic, high potential (hi-pot) tests are often conducted on power cables and large machines. However, there has been no standardized method of determining if the insulation is acceptable. Various methods have tried to compare leakage current between conductors, use a fixed limit on leakage current, or compare with previous tests. Each has its advantages and limitations.

From empirical data and diverse experience, we have developed a numeric technique that will indicate impending failure. The procedure is mathematically rigorous but can be practically applied. It is very applicable to computer controlled hi-pot systems as well as manual systems.

The second topic is the voltage drop for long conductors. We have applied numerous considerations to develop a simple relationship that can be readily applied. It incorporates wire diameter, length, current, number of phases, and temperature correction, with permissible voltage drop.
Quantitative Model of Wormholing Process in Carbonate Acidizing
Authors: Gong M. , El-Rabaa A. M.
Published: December 2007

Wormholing in carbonate acidization is a dynamic process that involves competition between a couple of physical and chemical processes such as convection and mass transfer as well as surface reaction. Acid injection rate, reaction rate, and molecular diffusion rate all affect the wormhole creation and penetration.

A new quantitative wormhole model is presented to describe the wormholing process in carbonate acidizing. Unlike other models, this comprehensive model deals with the wormholing process by introducing various acidizing dynamics, including acid reaction, diffusion, and convection. Therefore, both the Damköhler number and the Peclet number are involved in the model.

With pertinent physical parameters, the model predicts the wormhole length as a function of acid injection rate when both rock and acid properties are known. Comparing with extensive experimental data of linear core flood in both limestone and dolomite, the model accurately predicts the wormhole breakthrough time. More importantly, the critical injection rate (or optimum injection rate) is obtained with the model by differentiating the equation with respect to the injection rate. The ability to estimate the critical injection rate enables field carbonate acid treatments to be more efficient.

For practical applications, the model is properly extended to 2D and 3D radial flow geometry by introducing fractal dimensions. At last, the paper presents examples applying the wormhole model to field applications including open hole and perforated hole. Based on theoretical and experimental studies, suggestions are given for the optimization of field carbonate acid treatment.
Production Optimization at the Kuparuk River Field Utilizing Neural Networks and Genetic Algorithms
Authors: Stoisits R. F. , Crawford K. D. , MacAllister D. J. , McCormack M. D. , Lawal A. S. , Ogbe D. O.
Published: December 2007

The Kuparuk River Field, located on the North Slope of Alaska, contains approximately 6.4 billion barrels of oil. Total cumulative production to date is approximately 1.4 billion barrels, and current average daily production is 270,000 barrels of oil. The total number of wells in the field is approximately 900. Oil, water, and gas are separated at three Central Processing Facilities. Gas is compressed at each facility for use in gas lift operations and for miscible and immiscible water alternating gas pressure support projects. Kuparuk is production facility limited, which imposes gas, and water handling constraints on the field. Allocation of wells to the production facilities as well as allocation of lift gas are key elements in maximizing oil production rate. An optimization program utilizing formation gas oil ratio and incremental gas oil ratio computations for well and lift gas allocations is currently in use.

The objective of this work was to develop an optimization model which would be an improvement over the current model and also be superior to commercially available optimization software. This required the development of a field production model which included well performance, surface line, and facility models. For each iteration in the optimization model oil rate from the field production model is computed. Two major impediments to the rigorous optimization of large producing fields are the effectiveness of the optimization algorithm and the cost of computing the state of the objects being optimized. In order to successfully solve for an optimal solution to this large highly nonlinear allocation problem a technique based on genetic natural selection process is used. In order to address the problem of excessive computation time neural networks were developed to replace the surface line hydraulics simulation.

The new optimization program was evaluated using twenty-seven days of field data. The average daily production rate based on the 27 days of information was 273,000 bopd. The program was run in predictive mode and yielded an average 272,000 bopd for these 27 days. This indicated the field production model was reasonably accurate. The program was then run in optimization mode to generate recommendations for allocation of wells to production and allocation of lift gas. Average forecasted optimized rate for the 27 days was 292,000 bopd, which is a 7% increase in production over the current optimization forecast method.
Economic Pilot-Floods of Carbonate Reservoirs Using a Pump-Aided Reverse Dump-Flood Technique
Authors: Yao C. Y. , Hill N. C. , McVay D. A.
Published: December 2007

Successful waterflooding in carbonate reservoirs depends greatly on the ability of the operator to make technical and economic adjustments in a specific area, due to the heterogeneous nature of carbonate reservoirs. It is important to systematically consider all tools available in waterflood system design, including laboratory testing, waterflood design using computer simulators, pilot flood tests and waterflood monitoring 1.

This paper presents a case study of a 5-injection well pilot flood in three carbonate reservoirs in the Onbysk oil field using a pump-aided reverse dump-flood technique. This technique was optimal given the conditions at the remote Onbysk field: no surface injection facilities and little data available on water flooding carbonates in adjacent fields. The feasibility study includes laboratory core flood tests, waterflood computer simulation using a 3-D reservoir simulator, and a 5-injection well pilot flood in three domes. This 1-1/2 year reverse dump-flood pilot project indicates that water flooding is economically feasible in these carbonate reservoirs; thus, a large-scale surface water injection program was started to maintain reservoir pressure and to increase reserves.
Effect of Wettability and Matrix to Fracture Transfer on the Waterflooding in Fractured Reservoirs
Authors: Civan Faruk , Wang Wei , Gupta Anuj
Published: December 2007

Effect of matrix-to-fracture transfer on oil displacement by water imbibition in naturally fractured porous media is investigated in terms of the wettability effects and the governing rate processes. A mathematical model is developed by coupling the two-phase flow in the fracture network and in the porous matrix via an oil-water exchange function that incorporates the rates of transfer of oil from the dead-end pores to the network of pores and then to the network of fractures. The resulting integro-differential equation is solved numerically. The parametric studies carried out utilizing this model indicate that the rate constants and matrix wettability play important roles in obtaining an accurate description of the oil recovery during waterflooding in naturally fractured reservoirs.
Improved Blowcase Operation and Design
Authors: Elmer William G.
Published: December 2007

Blowcases have been used in the oilfield for many years to transfer fluids, but how do they work? What characteristics distinguish a well-designed blowcase? Do blowcases have a future? This paper answers these questions by:

Discussing the role of blowcases, and in what circumstances they may be preferred to pump operation, Explaining the process flow diagram for a typical blowcase, Reviewing typical styles of level controls, floats, and motor valves used for blowcase operations, Calculating the ratio of displacement gas to fluid removed for two level control designs, Calculating blowcase efficiency for two level control designs, and Discussing the advantages and disadvantages of small versus large volume blowcases.

The conclusion will be made that blowcases will continue to play an important part in oilfield operations, and that better understanding of blowcase "Best Practices" would be beneficial to industry.
Static/Dynamic Settling of Proppant in Non-Newtonian Hydraulic Fracturing Fluids
Authors: Asadi Mahmoud , Shah Subhash N. , Lord David L.
Published: December 2007

Experimental data and analysis are presented on the static and dynamic settling of proppant in non-Newtonian hydraulic fracturing fluids. A unique High Pressure Simulator (HPS) that closely models reservoir hydraulic fractures is used to study proppant-settling behavior under both static and dynamic conditions. A system of optical fibers and Light Emitting Diodes (LED) acting as a vision system were imbedded in the platens representing fracture walls for quantification of proppant settling under various fluid injection conditions.

Hydraulic fracturing fluids tested include slurries of 35 lb/Mgal guar linear gel with 6 ppg 20/40 mesh sand, 60 and 40 lb/Mgal hydroxypropyl guar (HPG) linear gels both with 4 ppg 20/40 mesh sand, and borate-crosslinked 35 lb/Mgal guar gel with 7.3 ppg 20/40 mesh sand. Test conditions cover a shear rate range of 60 to 120 sec−1. In addition, the effect of an enzyme breaker on proppant settling rate under static conditions was studied. Tests were conducted with a fracture gap width of 0.375 in. under ambient conditions.

Analysis of the dynamic condition indicates that proppant settling within the linear and crosslinked gels investigated is non-linearly dependent on shear rate. Under static conditions, linear gel slurries settled 40 to 50 times faster than the crosslinked gel containing breaker. It is also shown that an increase in shear rate induces proppant settling in borate-crosslinked 35 lb/Mgal guar gel while it reduces the settling rate in 35 lb/Mgal guar linear gel.
Use of Soil Venting for Remediation of Condensate Contaminated Soils
Authors: Wittenbach Stuart , Lower Steve , Biagi Chris
Published: December 2007

Although the oil and gas industry has a good environmental spill record, sometimes a spill of condensate occurs on oil and gas leases, flowlines/pipelines, gas plants and other sites. Due to the different characteristics of condensate, when compared to crude oil, the remediation of these spill sites varies. Many of the typical options in use today are soil removal, soil venting, soil farming, bioremediation, and thermal-desorption. The challenge for the environmental and operations managers is to select the best system for the each particular site.

Costs and liability for off-site disposal and potential groundwater contamination are ever increasing. Kerr-McGee conducted a study of passive and mechanized soil venting of condensate contaminated soils in the panhandle area of Texas. Both systems proved to be practical and effective.

Goals of the project were to: Remediate the contaminated soils to the Railroad Commission of Texas limits.Determine the effectiveness of both systems.Remove the possibility of any groundwater contamination by remediation of the soil profile.

All three goals were met and this paper summarizes the results of this project and provides another tool for remediating condensate-contaminated soils.
New Tricks for an Old Tool: A Case Study of an Unconventional Use of Temperature Logging
Authors: Robin George J. , Pontoriero Pat
Published: December 2007

The plugging and abandonment (P&A) of a Class 1 Hazardous injection well (previously a Class II, oil and gas well) in California was dependent upon satisfying state and federal requirements, which included placement of cement plugs inside the casing and, if needed, in the annular space between the casing and the original drilled hole. Pressure which had built up inside the annular space between the tubing and casing during the ten year shut-in period was suspected to be caused by a very small casing leak. The concerns regarding the unconfirmed existence and unknown location of this suspected leak in the casing made the P&A Plan more complicated and potentially more expensive to account for all the possible scenarios that could occur. The U.S.E.P.A. required that the P&A Plan include locating the cause of the casing pressure and either remediating the leak or preventing any future harmful effects to the environment. Since a temperature tool would be utilized to establish External Mechanical Integrity in the well, it was decided that the same tool could possibly be used to locate the casing leak. The development of these "alternate" procedures were based upon the principles of the temperature tool's ease of operation, its sensitivity and resolution, and its reliability. The temperature tool was used to reflect a disturbance of fluids in the tubing/casing annulus that were previously stable. This paper discusses those procedures, the results and conclusions of that portion of the P&A operation, and the rig time cost savings from conventional methods.
Innovative Regulatory Approach for Synthetic-Based Drilling Fluids
Authors: Veil J. A. , Daly J. M.
Published: December 2007

The oil and gas industry has historically used water-based muds (WBMs) and oil-based muds (OBMs) in offshore drilling operations. WBMs are less expensive and are widely used. Both the WBMs and the associated drill cuttings may be discharged from the platform to the sea provided that U.S. Environmental Protection Agency (EPA) discharge limitations are met. In some wells, however, difficult drilling conditions may force a switch from a WBM to an OBM. Neither the OBM nor the associated drill cuttings may be discharged. The OBM is hauled to shore, where it is processed for reuse, while the associated cuttings are injected in a disposal well at the platform or hauled to shore to a disposal facility. Both of these options are expensive. Synthetic-based muds (SBMs) are drilling fluids that use synthetic organic chemicals as base fluids. SBMs were developed to replace OBMs in difficult drilling situations. SBMs are more expensive than OBMs; however, they have superior environmental properties that may permit the cuttings to be discharged on-site. Like OBMs, SBMs are hauled ashore for processing and reuse after the well is drilled.

The existing national effluent limitations guidelines (ELGs) for the offshore industry do not include requirements for SBM-cuttings since SBMs were not commonly in use at the time the ELGs were adopted. In late 1997, EPA announced that it would modify the offshore ELGs to include requirements for discharges of cuttings drilled with SBMs. For the first time in the history of the ELG program, EPA is following an innovative expedited rulemaking process that will lead to development of draft regulations in one year rather than the 4- to 6- year period usually needed. With direction from the federal government to stakeholders concerning information needs for the regulatory development, the industry has established sev eral working groups to collect new scientific information on SBMs. This paper describes the expedited rulemaking process and summarizes the findings of the workgroups to date.
Using Remote Sensing for Environmental Baseline Studies
Authors: Henderson Douglas R.
Published: December 2007

Remote sensing is a powerful tool for environmental baseline studies related to oil and gas operations. Oil and gas lease blocks are frequently too large, or their terrain too difficult, to study and map from the ground in a timely, cost-effective manner. The use of remotely sensed imagery allows for rapid, inexpensive analyses. This paper reviews the basics of remote sensing technology while highlighting innovative examples of environmental projects concerning oil and gas exploration and production sites that successfully used remotely sensed data. Case studies presented span a range of approaches covering regions in Peru, Ecuador, and California. Several of these projects used remote sensing in challenging rainforest environments.

A variety of technologies—panchromatic and multispectral satellite images, aerial photography, radar data, and GPS—are employed to address different environmental assessment needs. Such needs often include assessments of lease blocks during ownership transfer, or periodic environmental monitoring of discharge zones, pipelines, well pads, and associated infrastructure. Remotely sensed data can also provide the backbone for environmental impact assessments and change detection studies.
Producing Interactive Environmental Impact Assessments on CD-ROM
Authors: Rabin Karen M.
Published: December 2007

Environmental Impact Assessments (EIAs) can be lengthy, complex documents. A typical EIA might contain 250 pages of text, 10-20 color figures, 30-40 tables, and 5-10 lengthy appendixes. These documents quickly become cumbersome for the reader. In addition, pages may easily be lost or damaged. Printing and binding costs for complex EIAs are expensive (hundreds of dollars per copy), and often limit distribution.

To help solve these problems, Walsh Environmental Scientists and Engineers Inc. (WALSH) produces large EIA documents in hypertext markup language (HTML) on a CD-ROM for easy viewing and distribution. The final product contains the entire document, tables, figures, appendices, and laboratory analytical data. Internal links allow the reader to access a figure or table from the place it is mentioned in the text, in the same way one navigates a web page. A linked table of contents enables the user to click on any section, table, or figure and jump to that position.

Reproduction of CD-ROMs is inexpensive (about $25 per copy) and fast, so the EIA can be widely distributed. In addition, data on CD-ROM are virtually indestructible and cannot be altered. Physical storage requirements for CDs are less than for the 4" binders used for printed copies. Another benefit is that once an EIA has been produced in HTML format on CD-ROM, it can be easily transferred to a web server and accessed by people anywhere in the world through the Internet. If desired, password access can protect confidential information.
Transforming Environmentally-Impacted Sites into Optimum Returns
Authors: Daddario David J.
Published: December 2007

Oil and gas companies are looking for new ways to raise cash and remain competitive. However, outmoded or underutilized facilities with environmental problems, such as hydrocarbon-impacted sites, can be a major financial drain. Plus, the public outcry about pollution can be difficult to manage. This session will review the new property divestment strategies that companies are utilizing to reduce liability, foster community support, optimize financial returns, and create economic development.

From a financial and legal perspective, new tools have become available over the last six months to cap costs and raise cash from problem real estate. Understanding the marketing potential of a problem site and identifying reuse opportunities are key to a cost-controlled cleanup effort and creation of a new product in the marketplace.

Using case studies, this session will describe how applying new strategies and tools can help to: –Minimize cleanup costs,–Maintain community support,–Negotiate strategies with regulators, and–Create optimum dollar return and economic development.
Cyclic-Steam Injection Initiation Project in Heavy Oil Reservoir – A Simulation Study
Authors: Rajtar J. M. , Hazlett W. G.
Published: December 2007

In this paper, a short pilot simulation study of new heavy oil cyclic steam injection project in California is presented. The new project is located in the proximity of the current cyclic steam project, which was used as reference for key reservoir data. The heavy oil reservoir is initially at low temperatures. For this reservoir, a number of project inititiation scenarios are evaluated on the basis of cumulative oil production. Scenarios involve evaluation of the number and location of horizontal and vertical wells for the most effective steam placement and oil recovery.

In the first part of the study, ten scenarios are compared for a simple assumed model of the area under consideration. From these, the three most interesting scenarios were selected for further study. In the second part of work, the reservoir model was adjusted to reproduce average observed field rates per well. After this simplified history match, three selected cases were rerun and the fourth case was added. Details and description of the simulated scenarios are presented in the paper. Scenarios are compared on the basis of cumulative oil production. Results indicate strong dependence of the cumulative oil production on the well location with reference to the Water Oil Contact (WOC). Effects of injection rate, and well and injection timing are also illustrated. All the presented strategies result in an increase in cumulative production.
Production Performance Simulation of a Horizontal Well in the Bolivar Coastal Fields, Zulia State, Venezuela
Authors: Perez Carlos A. , Salazar Victor M. , Elias Lopez
Published: December 2007

The objective of the present project is to develop a simulation model for one of the thermal projects of the Bolivar Coastal fields in the Zulia State, Venezuela. For this purpose, a thermal simulator was used in order to model the oil production performance from a 1640 Ft. horizontal well, and also, from infill wells located in the line of the horizontal well. With these results, to evaluate and compare the profitability of both production performances and to optimize the future operation strategy, continuing with the cyclic steam injection (C.S.I.) process.

Taking into account the geological model, recently developed for the thermal project, as a result of an integrated reservoi study, the production performance simulation of the horizontal well was accomplished in the most convenient area, where there are ten oil production wells in operation.

A three-dimensional and multiphase thermal simulator was used. A Cartesian grid of 9x23x12 blocks, representing the 3 objectives (4 layers for each one) was created. Once th history matching was successfully done (for each one of the ten wells), five prediction cases were chosen among different developed cases. The horizontal well was included in three of these cases, with the purpose of determining oil potential. A economical analysis was applied in order to recommend the most profitable case and plan the future exploitation scheme for the area.

It was also recommended to apply the present evaluation methodology to other areas of the cyclic steam injection projects in the Bolivar Coastal fields to identify areas as future steam drive candidates.
Management of Water Alternating Gas (WAG) Injection Projects
Authors: Sanchez Néstor L.
Published: December 2007

This paper summarizes the results of several successful WAG projects presented in many Improved Oil Recovery (IOR) Symposiums, indicating the main technical and operational issues considered in the development and implementation of such projects, and the management strategy for monitoring the process (Refs. 1,2,3,4). The results from these field applications will serve as useful guides and examples for improving reserves from many of our mature fields, and would lead to rethinking our strategy of reservoir development and new technology application for significant reserves enhancement in Venezuela. The paper focus on the selection of the technical aspects that must be consider in the implementation and management of the Water Alternating Gas (WAG) Injection process, providing an useable reference for the front line geoscientists, reservoir engineers, production operation engineers and technical managers who wish to obtain a technical and operational overview of the process as applied in the petroleum industry.

Managing W AG injection projects requires making decisions regarding to the WAG ratio, half-cycle-slug size, and ultimate solvent slug size for each WAG injector in the field. The impact of these decisions affects the capital cost of solvent purchase, water and gas plant loads, fluid handling and lifting operation costs, and ultimate incremental oil recovery. Simulation models provide a tool for examining strategies for these decisions. However, it must be able to address operational impacts such as lift method and problems, injecting plugging, workovers and facilities operations. Project monitoring incorporating actual performance data into the reservoir models provides an excellent diagnostic tool for decision making. The technical considerations for managing WAG projects presented in this paper can be used as a methodology for monitoring projects performance at pattern and full field level, increasing understanding of the process performance, and improving decision making.
A New Small-Diameter, High-Performance Reservoir Monitoring Tool
Authors: Simpson G. A. , Jacobson L. A.
Published: December 2007

This paper discusses a new small-diameter, high performance pulsed-neutron spectrometry tool that has been introduced recently for reservoir monitoring applications. Basic measurement principles are explained, and important operating parameters are presented. Field examples from Western Venezuela and South Texas illustrate multiple applications of the new device and compare the performance of the new instrument with a larger pulsed-neutron spectrometry tool.

The new 2-1/8-inch tool is designed for logging through 27/8-inch or larger tubing. The tool is slightly larger than traditional 1-11/16-inch through-tubing tools. This design accommodates larger detectors, thereby improving the performance of the carbon-oxygen (C/O) measurement. Two bismuth germanate detectors yield high gamma ray count rates with good spectral resolution.

To optimize C/O measurements, one mode of tool operation interlaces 5ms of background measurements with 20ms of 10-kHz neutron pulses. The tool records 256-channel spectra from each detector: during the neutron bursts (for analyzing inelastic events),during the interpulse period (for analyzing capture events), andduring the background period (for analyzing activation and background events).

The tool also provides a simultaneous neutron capture cross section (sigma) measurement. Carbon-oxygen and calcium-silicon (Ca/Si) response characteristics for saturation and lithology analysis are derived from laboratory measurements and are illustrated in the customary fan-chart format. In a second mode of operation, the tool optimizes the sigma measurement and provides high-quality neutron capture spectra for quantitative lithology determination.
Use of Oriented Perforation and New Gun System Optimizes Fracturing of High Permeability, Unconsolidated Formations
Authors: Soliman Mohamed , Dupont Richard , Folse Kent , Mason Justin , Burleson John , Azari Mehdi
Published: December 2007

When designing fracture treatments for high permeability formations, fracture conductivity is a primary factor in attaining maximization of completion economics. Optimum fracture design would dictate the knowledge of fracture orientation and the utilization of oriented perforation to optimally place the fracture. While in many unconsolidated formations, the contrast between horizontal stress is small or even insignificant; taking advantage of this situation often improves the efficiency and placement of a fracture.

It is generally believed that existing spiral patterns used in more conventional slurry pack completions give better radial flow performance because of the uniform perforation distribution around the wellbore. However, when a hydraulic fracture is created, the majority of flow into the wellbore is delivered through the perforations that are communicated to the fracture. This is especially true when many of the unconsolidated formations suffer a high degree of damage around the wellbore. For this reason, it is important to focus fluids injected during the completion directly to the fracture and increase the number of perforations communicating with the fracture. This paper will discuss the justification and theoretical background for a newly proposed design that develops this concept. The paper also discusses the tools and procedures necessary to achieve the stated goals.

A case history will be presented that will discuss the methods employed by an operating company in offshore Louisiana in perforating unconsolidated formations with the new system to obtain highly conductive gravel-pack fractures in deviated vertical wells. Significant to the success of the completions was the use of a high shot density perforating gun, oriented at 180-degree phasing. To facilitate the new approach, an innovative perforating gun system was also developed, and a wide perforation was designed to minimize friction.
Case History: New Gas Flow Computer Design Facilitates Offshore Measurement in Gulf Coast Project
Authors: Bonin Wayne , Chunn Mike , McFarland Danny E. , Jenkins Ken , Fink Kevin
Published: December 2007

Electronic gas measurement has evolved from providing a simple replacement for circular chart recorders to requiring instantaneous remote access of flow information. Coupled with this capability is the need to have simultaneous access to this information from multiple locations. Without existing equipment to meet these requirements, a major oil and gas operator and an oilfield equipment engineering and manufacturing company joined forces to develop a new flow computer that would meet the needs of the operator's present communication system and would adapt to future needs. Installation of the new flow computer has significantly enhanced operating efficiency by requiring fewer trips to offshore locations, providing instantaneous flow information for engineers, technicians, and gas accounting personnel, and providing consistency in measurement instrumentation. These advantages have reduced overall operational costs as well as increased personnel training efficiency.
Gas Production Management Options
Authors: Mochizuki Satoshi
Published: December 2007

The primary objective of this study is to extend an oil production plateau period through gas management when the production is limited by the gas handling capacity. Once gas break-through occurs, we would like to know how we should operate to minimize gas production; how effective existing methods are; how we could delay the break-through time. There are a number of options including rate cutback, completion shut-off, well cycling and drilling infills. Effectiveness of those methods may vary depending on reservoir types. This study evaluates relative effectiveness of a number of methods for an existing reservoir using 3 numerical models and field examples.