bluuebunny/crossref_metadata_2025 huggingface dataset:
Target Zero: The Challenge of Achieving Sustainable Safety Excellence
Authors: Thanajaro Thananan
Published: June 2014

The Montara incident in 2009 is a wakeup call for Safety, Security, Health and Environment (SSHE) transformation in PTTEP. It has proved that SSHE is a License to Operate and has triggered for SSHE transformation. In 2011, the organization was reformed in an effort to strengthen the corporate oversight and to grow in an international arena. The ultimate goal has been set to achieve Target Zero - zero incidents, zero injuries and zero spills. Achieving this challenging yet achievable goal starts with taking a big step back to identify how SSHE is perceived by the entire organization, including contractors. The "Step Change in SSHE Roadmap" has been developed as a paradigm shift in SSHE culture and to treat SSHE as a core value that must be integrated into every aspect of the business. The roadmap articulates a set of strategies, or 5 Acts, for moving toward Target Zero.

The 4S approach was adopted to drive the Roadmap, i.e. Study, Story, Segment and Strategic Communication & Sustain. The first approach, Study, is to understand the current state and develop clear and concise strategic SSHE direction. With a clear direction, we can paint the picture (Story) of where the company is and what it is going to be. The right campaigns are then need to be delivered to engage staff at all levels (Segment), e.g. cascaded SSHE KPIs, leading and lagging indicators, from CEO to individuals, SSHE plan for all functional groups, SSHE line partners, Service Level Agreement (SLA), etc. Finally, the strategic direction and campaign need to be communicated across the organization.

The roadmap and 4S approach has proved a significant improvement in the overall company statistics. At the end of 2012, LTIF reduced by 45% from 2011. The result from LTIF external benchmarking among OGP members also showed that PTTEP has moved from the bottom quartile in 2008 to top quartile in 2012. This is a remarkable step towards Target Zero.

Achieving SSHE excellence is all about appropriate interventions and sustained focus. It is a task of everyone to move from "SSHE is a burden" to "SSHE is how we do business around here".
SEMS after the Audits
Authors: Sutton Ian
Published: June 2014

Audits of the Safety and Environmental Management Systems (SEMS) rule were scheduled for completion by November 15th 2014. This paper reviews the early results from those audits. It is concluded: Of 84 operators, all but 12 submitted their audits.Some of the non-compliant companies have been required to shut in operations. In some cases the senior managers must state that they are in compliance with the SEMS rule under threat of criminal penalties.Not sufficient information has been provided in the audit reports to allow BSEE to reach in-depth conclusions about overall SEMS issues.
BowTie and Job Hazard Analysis: A Case Study to Communicate the Barrier Philosophy as it relates to Process Safety in Well Operations
Authors: Boncan John Gil
Published: June 2014

The purpose of the case study is to evaluate the BowTie Risk Analysis as an effective communication tool to inform field personnel of the Baker Hughes’ multi-barrier approach to well safety and ways to manage risk during operations. Recent findings highlighted that employee awareness and effective communication are fundamentals for a comprehensive risk mitigation strategy. An evaluation was performed to ensure the current risk assessment tools successfully communicated the multi-barrier approach to field employees. Traditional process safety assessments such as the Hazard and Operability Study (HAZOP) and Failure Mode Effect Analysis (FMEA) are difficult to understand and challenging to communicate. The difficulties led to research for an effective method to succinctly communicate the risks to field personnel. The BowTie Analysis was determined to be the best method, because it provides a clear visual risk assessment. To further define the usefulness of the BowTie, an assessment at the field level was conducted to ensure effective use of the BowTie at the job site. The BowTie and Job Hazard Analysis (JHA) is a technique to introduce process safety along with the existing JHA for personal safety. The tool clearly illustrates the barriers associated with well control to employees and the effect if a barrier is compromised. Additional field-derived recommendations were incorporated to the tool to improve barrier communication. The tool further enhances process safety awareness and identifies risk during pre-job assessments.
One Company’s Upstream Water Resources Management Guide
Authors: Lunn Stuart R.D. , Decatur Mark R. , Allen Michael L. , Mire Rick A.
Published: June 2014

Water is a necessity for society, economic development, and the well-being of the environment. Freshwater is not distributed equally around the world, and consequently many regions experience seasonal or longer-term water shortages or excesses. With increasing population and growth in economic development, stress on water supplies is contributing to natural water shortages in some regions. While water use in the petroleum industry is not intensive on a regional basis relative to other users, it can be material at the local scale. Thus water resource management is increasingly recognized as a priority area for global operations. While water issues are often highly location and situation-dependent, our company has developed a standardized guide to water resource management for Upstream oil and gas production projects and operations. The Guide provides environmental, regulatory and socioeconomic (ER&S) practitioners with a consistent and effective methodology to identify, assess and manage water resources-related risks (and opportunities). The Guide has four steps, each with embedded and scalable tools for application by ER&S advisors, local operations advisors, and Corporate subject matter experts; these are: Data Acquisition, Data Analysis, Risk Assessment and Risk Management. Rather than develop an entirely new management system, the Guide was designed to complement existing internal environmental and socioeconomic management and risk assessment/mitigation systems and processes. Application of the Guide is anticipated to result in the enhanced recognition and management of water resources-related risks, decreased capital and operating costs, fewer project and operational delays, improved environmental performance, and a sustained social license to operate.
Recent Advances in Oil Spill Response Technologies
Authors: Nedwed Tim , Palandro David
Published: June 2014

The use of unmanned aerial systems (UAS) has significantly increased for a variety of tasks over the past decade. ExxonMobil is currently evaluating two applications of these technologies to enhance industry’s oil spill response capabilities.

One of these application is to adapt UAS for offshore spill detection. It is well known that oil slicks are challenging to detect by an observer on an offshore vessel even when the slick is only a few tens of meters away. Aerial observers in planes or helicopters are often used to direct response vessels to remote slicks because of this. During larger marine recovery operations, there is a limit to the number of manned aerial vehicles that can be deployed. In addition, remote observation techniques often cannot determine which part of a large oil slick contains the thickest oil. There is a rule-of-thumb that 90% of the oil is located in 10% of the slick area. Thus directing response vessels to the thickest parts of the slick is critical. One concept we are evaluating is the use of small UAS for deployment on oil spill response vessels to allow each vessel to detect not only the slick location but also determine the thickest part of the slick.

The second application of UAS we are evaluating is for offshore in situ burning. Herders are a product that has been under development for several years to enable in situ burning without the need for fire-resistant booms. Herders are made of surfactants that cause an oil slick to rapidly contract and thicken when sprayed on the water surface around the slick perimeter. Only a small amount of herder is required to thicken even large oil slicks. UAS are commercially available to spray insecticide / herbicide on crops. We are looking at using this commercial technology as a platform to spray herders and then ignite the herded slick for offshore oil spills.

This paper summarizes development activities for these technologies.
Point Thomson Project’s Alaska North Slope Borough Community Engagement Program
Authors: Schmidt Rachel
Published: June 2014

The Point Thomson Project (PTP) is a remote gas cycling project on the coast of Alaska’s North Slope. The closest community to the project site is Kaktovik (population ~300 people), a Native Inupiat village located 60 miles to the East of the PTP. The PTP works with Kaktovik, as well as the North Slope Borough (NSB) municipal government in Barrow, on community engagement activities and project approvals. Maintaining open communication is critical to fostering a good working relationship with the local community, which in turn is essential to the success of the project. This requires frequent and ongoing consultations and action/feedback from the project to address community concerns. A community engagement program was initiated in 2008 and has continued to grow and strengthen as the PTP progresses. The PTP strives to further develop and maintain the robust community engagement program with Alaska North Slope communities to ensure local concerns and issues are effectively addressed, which builds trust, understanding, and strong working relationships. This community engagement program has also been critical to the success of PTP’s local NSB permitting process.
One Company’s Angola Sickle Cell Program
Authors: Andrade Vanda , Arango Margarita , Abreu Suzana , Flores Irene
Published: June 2014

Chevron Angola Sickle Cell Program

Sickle cell disease is an inherited blood disorder characterized by misshapen red blood cells, susceptibility to infection, hemolytic anemia, sporadic blockage of blood vessels, and chronic organ damage. The sickle cell gene arose as a genetic selection against malaria. Currently all newborn infants in the United States are tested for sickle cell disease at birth as part of a national screening program, which allows prompt diagnosis, followed by early identification, and preventive care and treatment. About 3000 infants are diagnosed with sickle cell disease each year in the United States.

In Africa, the problem of sickle cell disease is much greater, due to higher sickle gene prevalence. Newborn screening for sickle cell disease does not exist in most parts of Africa, and affected infants often die from infection or anemia. It is estimated that over 300,000 affected births occur annually, but 50–90% die before age 5 years. Sickle cell thus contributes substantially to the under-5 mortality in most sub-Saharan African countries. In Angola, for example, an estimated 12,000 babies are born with sickle cell diseases each year but most will die without a correct diagnosis. Angola has just one sixteenth the population of the United States, but at least four times the number of babies born each year with sickle cell disease.

In March 2011, the Republic of Angola entered into a public-private partnership with Chevron and Baylor College of Medicine/Texas Children’s Hospital to develop a comprehensive sickle cell program.
Safety Captain: a Safety Leadership Program
Authors: Capote Wilmer
Published: June 2014

One of the major challenges for a company’s health, safety and environment (HSE) organization is to engage a significant part of its workforce in key HSE programs and campaigns. Participation of the workforce may not always meet expectations, and as a result, companies have been reacting in many different ways and have tried to apply various strategies—from recognition programs to accountability initiatives—to try and improve participation in HSE activities.

An oilfield services company’s HSE organization launched a safety leadership program seeking to increase the participation of its employees in specific HSE programs and activities. This paper presents an overview of this Safety Captain, All Leaders program, which was launched in Mexico during early 2013 with potential to expand its application worldwide. The case study presented included participation by rig contracting companies and their employees.
Facility Siting and Routing with a Focus on Sustainability
Authors: Motherwell Jonathan , Weinbel Cory
Published: June 2014

Site selection and pipeline routing has been historically led by facilities engineers with the environmental and social team(s) following with a screening and ranking process. This frequently leads to conflicts within the project development team as both groups tend to pick their favorites early on and then struggle to defend their preferred choices. The lead author, a civil /geotechnical engineer by training, has been involved with siting / routing analyses from both perspectives over a 35 year career.

Ideally, an integrated team of engineers and environmental and social scientists is formed to screen and rank sites / routes such that the selected short list satisfies both project requirements while being sensitive to environmental and social issues and concerns. Both technical and non-technical aspects need to be considered. Desk top studies followed by field visits and preliminary mapping supports this process. Once the preferred sites / routes are identified, detailed investigations (including an environmental, social, and health assessment -ESHIA) are conducted to select the preferred alternative. This approach leads to petroleum facilities which are designed, constructed and operated in a more sustainable manner.

The authors review this preferred siting and routing process using several case studies, including historical and recent projects in Africa and South America. The most recent project in a remote area of Northern Mozambique has used the integrated approach in a proactive and successful manner.

This siting and routing methodology is recommended to project executives and project managers developing facilities in sensitive and / or remote areas.
Oil Spill Response: Captive Balloons Rise Up High!
Authors: de Vals Bruno
Published: June 2014

When an oil spill occurs, time is critical: the oil slick must be identified as soon as possible, followed permanently and its drift must be anticipated as much as possible in order to take the right decision and put the recovery equipment in the right place. That’s the reason why Total decided to develop a captive balloon specifically dedicated to the follow up of drifting oil slicks. The balloon is held in position at 150 m (500 ft) above sea level, above the ship in intervention. Two digital cameras are suspended to it, one of them being an infrared/thermal one. This device leads to visualisation of the hydrocarbons during the day and night. That’s a real plus for the rescue team which until now faced serious difficulties to determine the position of the response boat with regards to the oil slick from the deck due to the acute angle of observation and reflection issues.

The equipment is made of two parts: the balloon itself (8 m3, filled with Helium), and a stabilised turret, equipped with two cameras, which weighs less than 3 kg (6 pounds). Software installed on the ground station which can be positioned on the upper deck on the boat analyses the images from the cameras (transmitted by radio wave) and steers the cameras. Particular attention has been drawn to ease of use and rapidity of unfurling: within 10 minutes the balloon is filled with Helium, and overall the whole equipment is ready within 1 hour. The paper will present the balloon and provide details on the various steps from the reasons to develop such a piece of equipment, the difficulties met during its development, and the results obtained so far.
Critical Measurements for Increasing Effectiveness of Management System Control
Authors: du Preez Anton
Published: June 2014

There is a growing requirement for organizations to implement standardized management systems to reduce non-compliance or non-conformance such as ISO 9000, ISO 1400 and various industry-specific HSE programs such as API RP 75. These standards provide a general system structure and are normally implemented as a "compliance based" system. Their implementation does provide an initial reduction of incidents of non-compliance but in time could provide reduced levels of continued benefit while related cost remain level or even increase. Providing a simple framework for the measurement of critical system variables (leading indicators) will assist management in the alignment of such systems to the risk exposure profile in their respective organizations, thereby increasing the effectiveness of the management systems and the return on investment.

The current status in industry is that the degree of management system effectiveness is based around the measurement of system failures ie. incidents, issuance of non-compliance notification and legal exposures. (HSE Executive – Dec 2001)Ref 1. This is a reactive rather than a preventative measure and by definition not the optimal method in managing risk exposures

Complex adaptive systems are special cases of complex systems, often defined as a ‘complex macroscopic collection’ of relatively ‘similar and partially connected micro-structures’ – formed in order to adapt to the changing environment, and increase its survivability as a macro-structure – (Guptha andAnish 2012). Ref 2
SME Development among Aboriginal Communities in Canada
Authors: Bourgouin France , Oxman Michael
Published: June 2014

After years of tense confrontations between industry and Aboriginal communities in Canada, there is growing acceptance among all parties of the importance of building mutually beneficial development goals. This coincides with global public recognition of the importance of indigenous perspectives in development decisions and consultation processes aligned with the unique needs of Aboriginal communities.

This paper aims to explore trends and success factors in establishing mutually beneficial business practices for the oil and gas sector and Aboriginal communities in Canada. It will specifically focus on challenges and opportunities for extractive industry companies in supporting SME development among Aboriginal communities. Our findings are based on our own experience with companies and indigenous organizations, interviews with business owners and Aboriginal leaders, field observations of peer company practices, insights from conference proceedings highlighting Aboriginal and non-Aboriginal business initiatives and literature review.
Evolving Strategies in Enhancing Preparedness to Oil Spills in Asia Pacific
Authors: O’ Driscoll Declan
Published: June 2014

In the past four years, since the Montara and Macondo oil spill incidents, our industry has become particularly focused in strengthening our preparedness and response capability to upstream incidents.

This is in contrast to the late 1990’s and early 2000’s, when the focus was very much on maritime related oil spills. In Asia, the Evoikos (1997) and Natuna Sea (2001) oil spills in the Straits of Singapore raised particular concerns amongst regional governments on issues relating to transboundary responses, as well as the recovery costs incurred by governments in the cleanup and compensation for those economically impacted by the spills. The Prestige (Spain 2002) oil spill further highlighted the issues of a transboundary response while the Solar 1 (2006) in the Philippines and the Hebei Spirit (2007) in Korea further demonstrated the region’s exposure to maritime related oil spills.

From an industry perspective, the Evoikos and Natuna Sea spills provided a litmus test on how an industry established Tier 3 centre would be of assistance in a major incident. East Asia Response (EARL) was established in 1993 as a regional Tier 3 centre. Singapore was chosen as the preferred location for the centre due to the heavy tanker traffic passing through the Straits of Singapore from the Middle East to north East Asia and for its major oil refining and storage infrastructure.
Improving Land Transport Contractor Driving Safety Performance
Authors: Condor Juan Carlos , Villarreal Gonzalo
Published: June 2014

Driving is identified as the work-related activity with one of the highest risks in the oil and gas industry, and in many countries the annual numbers of driving-related incidents have been rising in recent years. A study conducted by the World Health Organization (WHO) predicts that road-related fatalities will continue to increase, and will become an even higher contributor to global mortality. According to safety performance indicator reports produced by the Oil & Gas Producers Association (OGP), land transport is one of the activities with the highest number of fatalities, and most of these fatalities involved land transport contractors (LTCs). Similar root causes were identified in most of these fatal incidents, and these included not following procedures, poor driving behaviors, and inadequate or defective vehicle safety features.

In 2010, an oilfield services company put in place new guidelines aimed at increasing the levels of HSE compliance among all of its LTCs. The guidelines were designed based on prior experience of LTC weaknesses related to HSE management and risk exposure while en-route. The guidelines defined specific requirements to enhance HSE management and improve LTC HSE performance through compliance with the requirements, such as effective training and vehicle safety features.

This paper describes some of the outcomes of the new guidelines when implemented in Colombia and Peru. These include a new LTC contracting process implemented with the participation of all relevant company departments. Specific processes have been introduced to measure the level of compliance with contractual HSE requirements and performance assessment tools. The authors discuss how results of the guidelines include improving HSE culture among the company’s LTCs, who are more motivated to implement effective HSE management systems over the long term. The company’s automotive incident rate has in Colombia and Peru has improved by more than 20% over the last two years. There has also been an increase in monthly LTC contracts and an associated reduction in the utilization of LTC’s on a call-out basis, which has historically represented the service with the highest risk.
Improvements in Multistage Fracturing, Remolino Field, Mexico
Authors: Gutierrez G. , Ramirez L. , Sierra J. R. , Medina E. , Gutierrez L. J. , Salguero J.
Published: June 2014

During the past few years, the oil industry in Mexico has taken significant steps toward improving the economic performance of hydrocarbon-producing wells in the very low-permeability, heterogeneous, compartmentalized, and hard-to-produce reservoirs of the Chicontepec paleochannel through the application of high-impact technologies used in unconventional wells for drilling, logging, perforating, zonal isolation, completions, fracturing, etc. that unquestionably helped improve well performance. However, the proper integration of these new technologies in the heavy-oil Remolino field, located in southern Chicontepec, has shown the potential to deliver better results in terms of production and recovery improvement.

Some of the production problems of Remolino field include previous ineffective stimulations, low reservoir contact area, poor well productivity, and extremely low recovery factors. These problems were addressed by modifying (i) the well architecture from vertical to horizontal, (ii) the zonal isolation from conventional cemented to engineered cemented and swell-packer openhole, (iii) the wellbore-reservoir connection from perforating to hydrajetting and ball-activated sleeves, (iv) the fracturing fluids from conventional crosslinked to hybrid fluids, and (v) the fracture design and pumping schedule to achieve the required length and conductivity. The application of these completion technologies in Remolino field have evolved, based on production results and operational efficiency, from the simplest perf-and-plug method in vertical wells to more complex coiled-tubing assisted fracturing and faster ball-activated sleeves in horizontal wells. Lowering the completion time also has been a primary driving factor for choosing the proper completion option for each individual well, attempting to achieve faster fracturing and quicker production.

The experience of applying new technologies in Remolino field is presented in this paper, including comparisons between openhole and cemented laterals, fracture stages with single and multiple cluster/ports, number of fractures/fracture spacing, and lateral length required to improve the production without compromising completion costs. To date, the benefit of the overall application has been a five-fold production increase and, as expected, a significant improvement in the recovery factor.
Pumping Balls: A Study on Flow Conditions for Frac Ball Launching and Conveyance
Authors: Dardis M. , Melenyzer G. , Aviles I.
Published: June 2014

The use of ball drop type fracturing tools has been instrumental in the increase of activity in hydrocarbon-bearing reservoirs. These systems rely upon a series of balls that increase in size to progressively isolate stimulated intervals from toe to heel. It is of extreme importance to predict the behavior of such balls as they are pumped into the flow stream and ultimately the completion to avoid undesirable over-flushing of the fracturing stage.

In order to better understand the dynamics of launching these balls, a full scale surface test was performed on a flow loop. Using a ball launching device, balls ranging in size from .795" to 3.0" and composed of magnesium, aluminum, or ceramic material were introduced into flow streams of varying rates. The flow rates were designed to mimic both the flow rate through the ball launching device and the total flow rate after rejoining the treatment line. Various conditions were simulated including competing rates as the balls traveled through a simulated treating line and standpipe.

Computer modeling was utilized to further understand the behavior of fracturing balls displaced by fluid in horizontal multistage completions. The change in fluid velocity through the balls seats was studied to simulate the pump rate necessary for a ball to travel through the completion and land on the intended seat to provide isolation.

The information gathered during this experiment was analyzed to determine optimum flow conditions required to successfully launch fracturing balls. The effect of the ball size and material was studied to determine what influence they had on the ability of the balls to travel with the fluid. Recommendations on minimum rate versus ball size will be presented for both surface and down-hole scenarios.
Laboratory Results of Proppant Transport in Complex Fracture Systems
Authors: Sahai Rakshit (Raki) , Miskimins Jennifer L. , Olson Karen E.
Published: June 2014

With a global paradigm shift towards exploring shale reservoirs, the industry focus has moved towards optimizing hydraulic fracturing in these reservoir types. Low-viscosity slickwater fracture treatments are commonly used as a completion technique in these ultra-low permeability reservoirs. Each shale reservoir is different due to the presence of in situ natural fractures and other geologic complexities, and thus the resultant hydraulic fracture network is distinct and the proppant transport in these "created" complex fracture networks is not clearly understood. Much speculation exists in the industry as to how efficiently the proppant is transported from the primary fracture into subsidiary fractures, if it is at all. A better awareness of proppant movement in complex fracture networks can possibly help with better hydraulic fracture treatment designs by focusing on parameters that enhance transport in the subsidiary fractures and understanding what impacts this transport may have on the resulting production.

This paper discusses a series of tests carried out in a low-pressure laboratory setting to evaluate proppant transport in complex fracture networks. Different slickwater treatment scenarios were simulated by pumping sand slurry through a series of complex slot configurations while varying the slot complexity, pump rate, proppant concentration, and proppant size. Results from twenty-seven tests carried out provide some interesting insights into the nature of proppant transport and settling in complex fracture networks. In the case of a primary slot system, the proppant transport was observed to occur via traction carpet after the creation of a proppant dune. However, in the case of secondary slots, the proppant transport was found to be dependent on the dune buildup in the primary slot. Two mechanisms were observed to be transporting the proppant into the secondary slots: 1) proppant flowing around the corner at pump rates higher than the threshold pump rate (related to the threshold velocity in the primary slot), and 2) proppant falling from the primary slot due to the effects of gravity, regardless of the pump rate.
Microseismic Estimates of Stimulated Rock Volume Using a Detection-Range Bias Correction: Theory and Case Study
Authors: Zhang X. , Holland M. , van der Zee W. , Moos D.
Published: June 2014

Microseismic monitoring is becoming an integral part of hydraulic fracturing. The observed microseismic events reflect the rock failure that occurs during or after the stimulation, and so the events’ spatial distribution is often used to determine the stimulated rock volume (SRV) and the event frequency is used to derive stimulation effectiveness. However, discrepancies are often observed between the production rate (or the flow rate) and the stimulation effectiveness computed using the observed microseismic event locations and frequency. This study presents a multi-step workflow for calculating stimulation effectiveness. The workflow is developed based on two observations. The first is the recognition that the attributes used for calculating stimulation effectiveness must be related to deformation. The second is that it is possible by using a method based on the parameters of the Gutenberg-Richter to correct for spatial detection bias. We first describe the workflow and then apply it to calculate stimulation effectiveness using a microseismic event data set obtained during multistage fracturing stimulation of an upper Devonian shale gas reservoir in southern West Virginia. The workflow provides an improved estimate of stimulated reservoir volume. The approach has been tested here using only the magnitudes and locations of the events. Further improvement is possible using moment tensor / focal plane solutions.
Changes in Shale Fracture Conductivity due to Interactions with Water-Based Fluids
Authors: Pedlow John , Sharma Mukul
Published: June 2014

A sizable amount of literature exists analyzing the effect of confining stress on fracture conductivity in sandstones. This report attempts to answer similar questions with regard to shale formations. The low Young's Moduli and Brinell hardness values characteristic of many prospective shale formations may lead to a great deal of embedment and fines production which can drastically reduce fracture conductivity. Furthermore, shales exhibit sensitivity to aqueous fluids which may cause them to be weakened in the presence of certain fracturing fluids. Previous work analyzing shale fluid sensitivity has failed to preserve the shales’ formation properties by allowing the shale to dry out.

This paper presents a study of propped fracture conductivity experiments at reservoir temperature and pressure using various North American shale reservoir cores. Exposure to the atmosphere can alter the mechanical properties of the shale by either drying or hydrating the samples, so care was taken to preserve these shales in their native state by maintaining constant water activity (relative humidity). Variations in applied closure stress and aqueous fluid exposure were analyzed and in certain cases altered the propped fracture conductivity by crushing proppant, embedding the proppant into the fracture face, and producing fines. The damage to fracture conductivity is correlated to mineralogy for the various shale samples. These findings show that a one-size-fits-all frac design will not work in every shale formation, rather a tailored approach to each shale is necessary.

In the future, the results of this work will be analyzed alongside easier to perform Brinell hardness tests, swelling tests, and other characterization techniques incorporated into the UT Shale Characterization Protocol (Zhou et al., 2013). Correlations were developed to relate the simpler tests to the fracture conductivity experiments will yield an easier method to determine the role embedment and fluid sensitivity have on post treatment fracture conductivity in shales.
Fracability Evaluation in Shale Reservoirs - An Integrated Petrophysics and Geomechanics Approach
Authors: Jin Xiaochun , Shah Subhash N. , Roegiers Jean-Claude , Zhang Bo
Published: June 2014

The identification of fracture barrier is important for optimizing horizontal well drilling, hydraulic fracturing, and protecting fresh aquifer from contamination. The word "brittleness" has been a prevalent descriptor in unconventional shale reservoir characterization, but there is no universal agreement regarding its definition. Here a new definition of mineralogical brittleness is proposed and verified with two independent methods of defining brittleness. Formation with higher brittleness is considered as good fracturing candidate. However, this viewpoint is not reasonable because brittleness does not indicate rock strength. For instance, fracture barrier between upper and lower Barnett can be dolomitic limestone with higher brittleness. A new fracability index is introduced to overcome the shortcoming of brittleness by integrating both brittleness and energy dissipation during hydraulic fracturing. This fracability index considers that a good formation for hydraulic fracturing is not only of high brittleness, but also requires less energy to create a new fracture surface. Therefore, the formation with lower fracability index is considered as a fracture barrier, while with higher fracability is considered as better fracturing candidate. Logging data from one well of Barnett shale is applied (1) to verify the principle of new brittleness and fracability index model; (2) and to demonstrate the process of screening hydraulic fracturing candidates employing fracability index model.
Mid-Continent Water Management for Stimulation Operations
Authors: Tipton D. Steven
Published: June 2014

Water is the most common and heavily used fluid in the petroleum industry. It is produced along with oil and gas from nearly every well. Fresh water is used as a base fluid in drilling, completion, and production operations. Produced water is handled in three primary ways: injected in salt water disposal wells, for pressure maintenance in secondary or tertiary recovery projects, or as a recycled base fluid in hydraulic fracturing.

In unconventional oil and gas operations hydraulic fracturing is the biggest user of fresh water. The focus of this paper is the procurement, conditioning, transportation, storage, reuse and disposal of water for hydraulic fracturing in Newfield's MidContinent operations.

Newfield's two primary fresh water sources are subsurface aquifers and surface water. The transportation of either fresh water or recycled (produced) water can be done by either pipeline or truck. Where possible it is preferable to transport the water through pipelines. For the transportation of smaller volumes of water 3" or 4" poly pipe is used or the water is trucked. Large volumes of fresh water are generally moved through 10" aluminum irrigation line, although polyvinyl chloride (PVC), lay flat hose, and high density polyethylene (HDPE) are also used. For the transportation of recycled or produced water HDPE has been the choice for most operators.

Newfield's preference for storing fresh water is unlined ponds because they can then be used by a landowner for long term water supply on his or her property. Lined pits are used where the soil conditions will not prevent water from leaking out. Fresh water can also be stored in frac tanks (500 bbl), modular tanks (up to 60,000 bbl), or portadams (sized as required). Recycled or produced water is stored in permitted lined pits, frac tanks, modular tanks, or portadams.

After fracturing a well, the produced water used can be recovered, stored, and reused. If the produced water cannot be reused it will be disposed via deep well injection (most common disposal method) or evaporation (limited use). The amount of produced water recovered after stimulation is dependent on the formation characteristics. Usually from 20 to 80% of the water used during the fracturing operation is recovered within the first 60 days of production and can be reused. Depending on the quality of the produced water recovered, it may require some type of treatment prior to reuse. Newfield began recycling water in its Wheeler County, Texas operations during 2005 because it made economic sense and the company is committed to responsible environmental stewardship.
A Methodology for Statistical Propped Fracture Treatment Design in Fluvial Environments
Authors: Smith P.E. , Dunn-Norman S. , Smith M.B.
Published: June 2014

Hydraulic fracturing treatment design historically has been deterministic in nature. In a deterministic design, the required design variables are single-valued and can be established with a reasonable degree of certainty. Additionally, their values are assumed to be laterally continuous. Fulfilling these assumptions is complicated for geologic settings in general, but nearly impossible in fluvial geologic environments, which violate the assumption of lateral continuity.

Recent work has defined a methodology for hydraulic fracturing treatment design using statistical methods to account for the complexity and heterogeneity in fluvial environments. The methodology demonstrates how to use statistics to address treatment design questions such as, “What is the vertical fracturing interval needed to create a well-confined, economical and productive fracture treatment in a highly layered, fluvial environment?” and “What is the optimal fracture treatment in such complex geology?”

This paper presents and describes the statistical-based hydraulic fracturing design methodology, including constructing and calibrating a basic geological model, incorporating geostatistics for the selection of alternate geological models, forecasting production for alternate fracturing treatments, and determining an optimum hydraulic fracturing design using all available information. The methodology is illustrated using geological and well data from a producing fluvial tight gas formation, though the approach should apply to other complex geological settings.

This work is valuable as it demonstrates a method for extending the deterministic approach taken with formation characterization and applying it directly to hydraulic fracturing design (thus, using the data where good values are available) to include statistics, thereby providing a basis for selecting an optimum treatment design when a range of possible design parameters exists for less well defined variables.
Pressurized-Fracture Propagation using a Phase-Field Approach Coupled to a Reservoir Simulator
Authors: Wick Thomas , Singh Gurpreet , Wheeler Mary F.
Published: June 2014

Tight gas and shale oil play an important role in energy security and meeting an increasing energy demand. Hydrualic fracturing is a widely used technology for recovering these resources. Prediction of fracture growth during slick-water injection and final geometry for single and muti-stage hydraulic allows quantitative assessment of frac-job scenarios. A recently introduced phase-field approach for pressurized fractures in a porous medium offers various attractive computational features for numerical simulations of cracks such as joining, branching, and non-planar propagation for heterogeneous porous media. In this study, we employ the phase-field fracture propagation model is used as a pre-processor in order to couple it to a fractured poroelastic reservoir simulator. This offers the possibility to simulate the entire scenario from hydraulic fracturing to the production process. The proposed algorithm is based on a one-way coupling and is therefore easy to adapt to existing legacy reservoir simulators. The phase-field model can be seen as a fracture-well-model in the reservoir simulator. The key idea behind this strategy is the possibility to couple reservoir and fracture flow in the phase-field formulation from which we obtain an initial condition for the reservoir simulator. Our proposed framework is substantiated with several numerical tests in two- and three dimensions.
Poroelastic versus Poroplastic Modeling of Hydraulic Fracturing
Authors: Wang Han Yi , Marongiu-Porcu Matteo , Economides Michael J.
Published: June 2014

With the increasing wide use of hydraulic fractures in the petroleum industry it is essential to accurately predict the behavior of fractures based on the understanding of fundamental mechanisms governing the process. The prevailing approach for hydraulic fracture modeling relies on Linear Elastic Fracture Mechanics (LEFM). Generally, LEFM that uses stress intensity factor at the fracture tip, gives reasonable predictions for hard rock hydraulic fracturing processes, but often fails to give accurate predictions of fracture geometry and propagation pressure in soft/unconsolidated formations. The reasons are that the fracture process zone ahead of the crack tip, elasto-plastic material behavior and strong coupling between flow and stress cannot be neglected in these formations. Recent laboratory testing has revealed that in many cases fracture propagation conditions cannot be described by traditional LEFM models. Rather, fractures develop in cohesive zones. In this study, we developed a fully coupled poroelastic and poroplastic hydraulic fracturing model with cohesive zone method which is able to model crack initiation and growth considering process zone effects. The impact of formation plastic properties on fracture process is investigated for both short term and long term injection and the results are compared with elastic formation. In addition, the main factors that affect the poroelastic backstress and the effects of formation plasticity on a hydraulic fracture are also investigated. The results indicate that both poroelastic backstress and formation plasticity lead to higher net pressure, but they have an opposite impact on fracture geometry. Poroelastic backstress tends to reduce fracture width while formation plasticity tends to increase fracture width. It was also observed that plasticity can reduce closure pressure below minimum horizontal stress. Poroelastic backstress is mostly controlled by the leak-off rate and formation permeability and the effects of plasticity are mostly influenced by in-situ stress, plastic properties and pore pressure. We also found that the effective toughness method which is used to quantify fracture process zone effect in soft formation tends to underestimate the fracture width and overestimate fracture length even if it can match the net pressure. Ignoring plasticity in certain formations can lead to inaccuracy of fracture geometry, net pressure prediction and fluid efficiency calculations. The deviations of real fracture geometry from elastic formation model can have great impact on well production, especially in unconventional, low-permeability reservoirs. So for a more accurate modeling of fracturing in plastic formation, the whole affected region around the fracture should be considered, especially when the plastic deformation area is large.
Diagnosis of Fracture Flow Conditions with Acoustic Sensing
Authors: Martinez R. , Hill A. D. , Zhu D.
Published: June 2014

Distributed acoustic sensing (DAS) is an emerging technology in hydraulic fracture diagnosis. Current uses of DAS systems have been limited to qualitative analyses that pinpoint noise sources, such as injection into formation or production from a fracture. This locating of noise verifies that injection or production is happening and its sound intensities at the different stages give a relative indication as to which stages took more fluid or produced more fluid post-treatment.

In this paper we used signal processing techniques and quantitative analysis to measure flow rates in a simulated fractured well. Production into a 5-½ inch ID well was simulated by injecting fluid through a one-foot long packed bed of 16/30 mesh proppant. Gas was injected at varying rates into the fracture and into the well. The noise produced from production was recorded with a hydrophone. The acoustic signal was transformed from the time domain to the frequency domain through a fast Fourier transform (FFT) for analysis.

The experimental results showed that the frequency of sound and its intensity were crucial in determining the amount of fluid being produced. The sound level of the peak frequencies were found to be linearly related to the flow rate. The results verified that sound alone can be used to measure flow rate through a proppant packed fracture or perforation tunnel.

Determining the fluid properties and flow rate can be achieved with DAS systems if the sound frequencies in addition to sound intensity are monitored. Incorporation of this technique into current DAS systems can give a real time value for injection rates during hydraulic fracture treatments and values for production rates from post treatment measure
Application of Integrated Advanced Diagnostics and Modeling to Improve Hydraulic Fracture Stimulation Analysis and Optimization
Authors: Ugueto Gustavo A. , Ehiwario Michael , Grae Abram , Molenaar Mathieu , McCoy Kelly , Huckabee Paul , Barree Bob
Published: June 2014

Economic development of unconventional resources relies heavily on the effectiveness of propped hydraulic fracture stimulation treatments (HFS or "fracs"). Non-stimulated and/or under-stimulated reservoir continues to be a critical industry concern. Mitigation is expensive and may require refracturing and/or additional wells to be drilled. Techniques to monitor and diagnose the geometry of HFS are limited and analysis typically has large uncertainties. This paper summarizes multiple datasets to demonstrate how complementary diagnostics significantly reduce uncertainties in their analysis, help to calibrate frac models and improve completion design of multi-stage wells. Diagnostics utilized in the datasets include: fiber optic distributed sensing (acoustic & temperature), non-radioactive tracers and production logs. We found that integrating these complementary diagnostics with other subsurface and well information not only confirmed that actual frac heights were different than intended in about half of the monitored stages, but also provided new insights that allow us to modify the HFS treatment design to better match the desired geometries. These diagnostics were used to history match and calibrate our frac models, allowing us to extrapolate results from the few wells with diagnostics to additional wells in the field. Statistics are also provided for the datasets including: percentages of perforation clusters and net sand treated to demonstrate the potential opportunity for improved stimulations and reserves recovery.