bluuebunny/crossref_metadata_2025_split huggingface dataset:
Technique Uses Multilateral, Multisegment Wells To Represent Hydraulic Fractures
Authors: Wilson Adam 
Published: February 2015

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 163644, ’Representing Hydraulic Fractures by Use of a Multilateral, Multisegment Well in Simulation Models,’ by D.A. Edwards, SPE, Schlumberger; N. Cheng, SPE, Statoil; T.P. Dombrowsky (now with Longhorn Technologies) and G. Bowen, SPE, Schlumberger; and H. Nasvik, SPE, Statoil, prepared for the 2013 SPE Reservoir Simulation Symposium, The Woodlands, Texas, USA, 18-20 February. The paper has not been peer reviewed.
Simulating fractured wells is challenging and impractical with local grid refinement (LGR) in full-field models with a large number of wells each with multiple fractures. This paper describes a modeling technique by which hydraulic fractures are represented as part of the well model rather than as any form of refinement in the simulation grid. In this approach, a planar fracture is modeled by the mesh formed from the interconnected branches of a multilateral, multisegment well (MSW).
Introduction
Hydraulic fracturing can dramatically change the flow dynamics of a reservoir, so its correct modeling in reservoir simulation can be critical. However, the presence of hydraulic fractures presents a challenge in flow simulation. This is because these fractures introduce effects that operate on different length and time scales than do usual reservoir dynamics.
To overcome this problem, a multitude of modeling techniques and workarounds has been developed. These include the use of dual-porosity models, enhancement of the productivity index of the fractured wells, virtual well perforations to simulate the fractures, and explicit fine-scale gridding.
In full-field simulations, where an entire reservoir with complex geometry, multiple wells, and possible faults is modeled, LGR is a popular method representing hydraulic fractures. However, this approach introduces its own set of problems. For example, in structured grids, the overall orientation of the grid may not easily accommodate fractures, particularly if they are at arbitrary angles.
This paper investigates the modeling of hydraulic fractures as part of the well model. MSWs are a discretized model of a well where fluid flow inside the wellbore is computed by solving physical flow model equations in one dimension. This domain is made up of the segments of the well that consist of nodes, which are connected by pipes. MSWs allow for lateral branches off the main stem and for looped flow paths; both features are employed here for the modeling of hydraulic fractures.
The Cement-to-Formation Interface in Zonal Isolation
Authors: Bybee Karen 
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 88016, "The Cement-to-Formation Interface in Zonal Isolation," by H.K.J. Ladva, SPE, B. Craster, T.G.J. Jones, SPE, G. Goldsmith, and D. Scott, Schlumberger Cambridge Research, prepared for the 2004 IADC/SPE Asia Pacific Drilling Technology Conference and Exhibition, Kuala Lumpur, 13-15 September.
During the completion and production phases of the well, temperature and pressure variations can cause stresses at the cement-to-formation interface. The ability of the casing cement system to maintain a seal at the cement-to-formation interface depends on the condition of the formation surface before slurry placement. The condition of a shale will depend upon the nature of the drilling fluid used, whereas the condition of a permeable rock will depend upon the presence and nature of the filter cake deposited during drilling. The full-length paper presents an improved understanding of chemical interactions at the cement-to-formation interface and the factors that determine bond strength and the position of the plane of failure.

Introduction
Maintaining zonal isolation for the lifetime of oil and gas wells is critical. Leakage behind casing can reduce the cost-effectiveness of the well and cause health and safety risks from pressure buildup and contaminated aquifers. In the petroleum industry, many studies have been performed on the cement-to-casing interface and bulk cement to improve the isolation efficiency of the cement in the wellbore. Less attention has been given to the cement-to-formation interface. Ideally, samples of set cement and the adjacent formation should be recovered from oil wells to give a better understanding of the chemical nature of the interface under downhole conditions during the lifetime of the well.
Low-level radioactive waste sometimes is encased in cement blocks and lowered into clay beds. There is concern that, over time, alkaline fluids near the clay surface will alter its effectiveness as a barrier to the encased nuclear waste. Studies by the nuclear industry to increase their understanding of the cement-to-formation interface are ongoing.
At an underground laboratory in Belgium, plugs of cement were precured and then placed in cored-out holes in Boom clay. Samples were maintained between 65 and 85°C. After 12 to 18 months test time, the samples were cored out of the clay. Sections of the interface were analyzed by microprobe and X-ray diffraction. Observations from the study using ordinary Portland cement are summarized as follows.
Cementing a Long Horizontal Wellbore Using CT Squeeze Technology
Authors: Bybee Karen 
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 94039, "Cementing a Long Horizontal Wellbore Using CT Squeeze Technology," by W. Rauchenstein and C.G. Blount, SPE, ConocoPhillips Alaska Inc., prepared for the 2005 SPE/ICoTA Coiled Tubing Conference and Exhibition, The Woodlands, Texas, 12-13 April.
Coiled-tubing (CT) cementing has been used widely and has been highly successful for remedial squeeze and plugback operations for more than 20 years. However, most of these wells had deviations less than 90°. A long horizontal well in the Alpine field on the North Slope of Alaska was drilled early in the development phase and was out of pattern. The well required a plugback and sidetracking to maintain desired off-take strategy. On the basis of the successful CT squeeze program in Alaska, the decision was made to use CT cement-squeeze technology to seal the lateral portion of the wellbore and leave a cement base for subsequent sidetracking operations.

Field Overview
The Alpine field is in the Colville River delta a few miles south of the Arctic Ocean and approximately 70 miles west of the TransAlaska Pipeline. The facilities are connected to the North Slope road system by ice road for approximately 3 months of the year. Aircraft provide the only mode of transportation at other times.
As a result of the depositional environment and minor fault offset, excellent vertical permeability is observed, and the productive sands are pressure connected across large distances. A water-alternating-miscible-gasflood is being conducted in the Alpine reservoir. The field is developed with line-drive patterns, using horizontal producers and injectors in a one-to-one ratio.
Given the high mechanical strength of the clean fine-grained Alpine sandstones, the operator elected to leave the horizontal sections of the wellbore uncased, to minimize the chance of formation damage. A 7-in. intermediate casing shoe is set just below the top of the producing formations at high angle. The uncased horizontal production hole typically extends 3,000 to 4,000 ft beyond the intermediate casing shoe. Production and injection tubing is primarily 4½ in., although some lower-rate wells are completed with 3½-in. tubing.
While performing above expectations, this completion practice has proved to be a difficult environment to access. Early attempts at logging these wells using CT memory tools and conductor-line tractors provided less than ideal results in reaching the total depth (TD) in the extended horizontal openhole sections. Drilling and formation debris and abrasive formations combined with wellbore geometry limited the ability to reach the full measured depth (MD) of the lateral sections. Portions of openhole lateral sections with fill or debris are not the only potential challenge to successfully cementing these wells; recent caliper logs suggest that the wells also may have sections that are washed out or significantly out of gauge.
Overview: Seismic Applications (August 2005)
Authors: Gibbons Kate 
Published: February 2015

The age of digital technology has definitively arrived. As an industry, we now are reaping the benefits of many years of technology development as well as becoming mature in our ability to understand and evaluate the value of the data.
In reviewing papers from this past year, I noted several interesting case studies and methodologies for integrating seismically derived attributes with geological and engineering data to improve the characterization and management of fractured reservoirs. Nevertheless, I am primarily struck by the variety of papers related to the development and application of real-time data transmission from seismic while drilling, through crosswell seismic, to methods for acquisition at the seabed.
Much of the push has come from the exploration and development of deepwater reservoirs and the need for real-time integration of data to make well-informed decisions. Although driven by the high-end projects, the advantages of the technology are seen across the industry at large.
We are realizing the benefits of implementing digital technology in life-of-field studies, in the development of green fields, in intelligent drilling and completions, and in automation of decision support processes.
The “digital” toolbox is expanding. The expertise and domain knowledge required to further develop the technology extend across the entire range of classic sciences and will affect the way we work and communicate. Challenges still remain in our ability to integrate data fully and in how we use the information effectively. From the technical point of view, there still is work to do on fully integrated data-management platforms. On the human-resource side, we need great improvements in our ability to effectively manage communication across disciplines and to bridge the gap between onshore and offshore personnel.
The articles selected here represent a taste of the trends and developments in digital technology from drilling and completion, to seismic at the drill bit, to seabed- and marine-seismic acquisition, to life-of-field development scenarios.
Available from the SPE eLibrary: www.spe.org
SPE 89994 - “Seismic Pore-Pressure Imaging in Deep Water Offshore West Africa,” by Banik, N.C., SPE, WesternGeco, et al.
Available at the OTC Library: www.otcnet.org
OTC 17284 - “Remote Reservoir-Resistivity Mapping—Breakthrough Geophysics for the Upstream,” by Srnka, L.J., ExxonMobil Upstream Research Co., et al.
OTC 17669 - “Defining Fault-Exclusion Zones at Proposed Suction-Anchor Sites Using an AUV Micro-3D-Seismic Survey,” by Campbell, K.J., Fugro GeoServices Inc., et al.
OTC 17646 - “LWD for Imaging, Wellbore Placement, and Formation Evaluation,” by Rasmus, J.C., Schlumberger, et al.
Hydrocarbon Exploration Using Marine Electromagnetic Techniques
Authors: Denney Dennis 
Published: February 2015

This article, written by Technology Editor Dennis Denney, contains highlights of paper OTC 17168, "Hydrocarbon Exploration Using Marine EM Techniques," by S. Constable, Scripps Inst. of Oceanography, U. of California San Diego, prepared for the 2005 Offshore Technology Conference, Houston, 2-5 May.
Recent interest in marine electromagnetic (EM) methods has been driven, in large part, by the challenges in deepwater exploration and associated efforts to reduce risk through the acquisition of additional data streams. The catalyst for the latest developments in marine EM technology was the problem of subsalt exploration in the Gulf of Mexico. Investigations were made of the use of controlled-source EM (CSEM) methods for direct hydrocarbon detection. Field trials were carried out offshore Angola.

Methodology
Fig. 1 shows the basic methods of marine EM studies. Seafloor recorders make time-series measurements of the electric and magnetic fields at discrete locations. The ionospheric and magnetospheric marine magnetotelluric (MT) source fields propagate into the sea, and a seafloor MT response can be processed from the data much like a land MT impedance, with two significant differences.
Attenuation in the conductive seawater layer dramatically reduces the electric- and magnetic-field energies at higher frequencies. Although MT responses on land can be processed routinely to several hundred hertz, in 1000 m of seawater it is essentially impossible to obtain MT data at frequencies higher than 1 Hz. Until the development of a broadband seafloor instrument, there were few attempts to collect seafloor MT data at frequencies greater than 0.01 Hz. Attenuation is less in shallower water (signal strength decreases with water depth squared), but the MT source fields decrease in magnitude with frequency, offsetting the shallow-water improvement.
The seafloor 1D MT response is the same as would be observed on land over the same geological structure without the ocean layer. However, the magnetic field is affected significantly by seabed conductivity, even in the 1D case (in stark contrast to land, where the magnetic field is essentially uniform, especially away from lateral contrasts in conductivity). A hybrid MT response obtained with the seafloor electric data and nearby land magnetics (equivalent to a sea-surface magnetic record) was used in the early development of the method to finesse the effects of motional noise in the seafloor magnetic data). This response illustrates the effect of seafloor conductivity on the magnetic field. In the case of 2D and 3D seafloor conductivity structure, a vertical electric field is possible in the seawater layer near the seafloor, although this effect is usually very small.
Discussion of SPE 89325, "Beyond Beta Factors: A Complete Model for Darcy, Forchheimer, and Trans-Forchheimer Flow in Porous Media"
Authors: van Batenburg Diederik , Milton-Tayler David 
Published: February 2015

In SPE 89325, summarized in the March 2005 issue of JPT, Barree and Conway state that “new experimental data, under high-rate flow conditions, showed conclusively that Forchheimer’s equation, like Darcy’s law, has a limited range of applicability.” We agree with Barree and Conway that when flow tests have significant non-Darcy effects, interpretation is not always straightforward. However, we disagree with Barree and Conway that Forchheimer’s equation cannot be used to describe pressure-loss velocity dependency at high rates of practical relevance, and we would like to present data collected in two other laboratories to support our point of view.
At FracTech, high-rate gas-flow tests on proppant packs have been conducted since the early 1990s. The tests are typically conducted with nitrogen at ambient conditions to measure the flow rates accurately. Fig. D-1 shows a Forchheimer graph for 20/40-mesh sand at 2-lbm/ft2 concentration for values of ρv/µ up to 330. The data show a linear trend with a coefficient-of-determination value, R2, of 0.9991. This range for ρv/µ is double that in Fig. 2 of SPE 89325. These data were originally presented in SPE 90406. Fig. D-2 is another Forchheimer graph from SPE 90406. The data presented are for resin-coated lightweight proppant with a 16/20-mesh size distribution. Again, a linear relation with an R2 of 0.9998 is observed over the range of ρv/µ values from 10 to 320.
At Halliburton’s European Research Center (ERC), high-rate flow tests on proppant packs have been conducted with water as the flowing medium. Fig. D-3 shows the results of two such flow tests with 18/30-mesh high-strength proppant at 160°C and 10,000-psi stress. Again, the Forchheimer graphs show a linear trend (R2 of 0.99+) for each test over a similar range of ρv/µ values for which Barree and Conway claim nonlinear behavior.
Last, but not least, we would like to share a Forchheimer graph for a pack of 1-in.-long pins as shown in Fig. D-4. The Forchheimer plot, shown in Fig. D-5, again shows a linear behavior over the entire ρv/µ range evaluated. The shape of the particulate used appears not to affect the linear behavior.
The main difficulty in the use of the Forchheimer graph is illustrated by the two data sets presented in Fig. D-3: Although the slope of the lines is almost identical (meaning identical Beta factors), the intercepts with the y-axis that represent the inverse absolute permeability differ significantly. We conclude that, for practical purposes when non-Darcy effects are important, the Forchheimer equation and graph can be used.
Stand Tall and Speak Up: Let's Make Championing Our Industry's Image a Personal Mission
Authors: Sprunt Eve S. 
Published: February 2015

SPE is about you, the individual member. Over the last year, I have written a lot about how different aspects of industry image impact our industry's ability to operate. Now, let's make this personal and look at how industry image affects us as individuals and what each of us can do.
My daughter is now 25 years old. Recently, she reminisced about how, when she was 9 years old and in the fourth grade, I had visited her class to talk about my work. I was pleased that the visit had created such a strong positive memory. For my visit, I borrowed an SPE Magic Suitcase, which holds simple equipment to demonstrate the fundamentals of porosity, permeability in sand, oil sources and traps, and gas- and waterdrives (www.spe.org/web/suitcase/default.html). One demonstration that I thought these 9- and 10-year-olds would understand illustrated the concept of porosity. You can put it together yourself, using an empty container, granular material such as sand, beads, or marbles, and a container with water. Show the children the empty container. Then fill the container with granular material and ask them if it is now full. Then show them how you can add water to the "full" container. I also talked to them about what I enjoyed about my work.
Your section may have a Magic Suitcase that you can borrow. The Aberdeen Section has an active program using the Magic Suitcase to encourage children to take interest in science and engineering and to promote the oil and gas industry to educators and students at school career events. A slide show that is part of the Magic Suitcase materials is available at SPE.org. We are currently developing new pre-packaged presentation kits that our members can use in classroom visits or with civic groups. We want to make it easy to provide information to today's students about the importance of energy in our everyday lives and about the outstanding career opportunities for young people in our industry.
Talking with your children, other family members, and friends is a good way to start working on improving our industry's image. It also has the benefit of helping them better understand your personal role.
For the last couple of years, in conjunction with my job managing research in alternative energy, I've circulated news tidbits on alternative energy technologies within Chevron. One of my colleagues told me that he had shared some of this information with his daughter, a doctor in San Francisco, who works with the homeless and, with her friends, has modified a minivan to run on used vegetable oil. His daughter had previously chided him about his choice of occupation. However, he shared with her information on energy alternatives and convinced her that Chevron was serious about considering alternatives, thereby making her more favorably disposed towards his employer. This illustrates how little things can make a difference. My friend was pleased that just a small amount of information had made a difference in his relationship with his daughter.
Overview: Unconventional Recovery (August 2006)
Authors: Norris Stephen 
Published: February 2015

I was inspired by a recent broadcast of All Things Considered on Natl. Public Radio and began to think of our industry and what could possibly make a difference in the world—if we, like Bill Gates, had an optimistic belief in technology and management combined with the vast resources of the petroleum industry. Is it possible for us to eliminate some of the top energy-related "diseases"?
The production of greenhouse gases certainly would be high on the list, regardless of whether you believe it is responsible for the recent global-warming trend. (Most of us would agree that it is at least a contributing factor.) So, is it "naïve overreaching" to think that we can affect such a gargantuan problem with current or near-future technology? I think we can help. In this issue, the focus is on technologies that hold at least a promise of a solution, either by offering an alternative to dirtier fuels or by eliminating or reducing some greenhouse gases directly.
Although expensive to produce and technologically challenging, coalbed methane (CBM) is a clean-burning fuel with tremendous potential for replacing some of the more conventional and "dirtier" resources. CBM is found in nearly every sedimentary basin, and current production is limited only by economics, which is negatively affected by water disposal and low production rates. New advances in recovery methods, such as the use of horizontal production and injection wells, could yield huge increases in CBM production.
CO2 storage in deep underground reservoirs is not a new idea, but until recently, very little was known about the storage capacity and viability of such a practice. Recent computer modeling has led to an increased understanding of the trapping mechanisms and suggests optimal injection practices.
CO2 sequestration in gas hydrates may offer a viable long-term storage solution while liberating methane gas to use as fuel. Although still in its infancy, this unconventional technology holds tremendous potential for the industry—and the environment.
I hope you will enjoy reading these paper highlights; and with an optimistic belief in our technology and management and with our vast resources, I know we can make a difference!
Unconventional Recovery additional reading available at the SPE eLibrary: www.spe.org
SPE 100021 "A Screening Model for CO2 Flooding and Storage in Gulf Coast Reservoirs Based on Dimensionless Groups" by D.J. Wood, U. of Texas at Austin, et al.
SPE 100584 "Evaluation of the Technical and Economic Feasibility of CO2 Sequestration and Enhanced Coalbed-Methane Recovery in Texas Low-Rank Coals" by G.A. Hernandez, SPE, Texas A&M U., et al.
SPE 97266 "Depressurization-Induced Gas Production From Class 1 Hydrate Deposits" by G.J. Moridis, SPE, Lawrence Berkeley Natl. Laboratory, et al.