bluuebunny/crossref_metadata_2025 huggingface dataset:
The Great Emissions Roundup: Strategies for Permitting Maintenance, Startup and Shutdown (MSS) Emissions at Upstream Oil & Gas Facilities
Authors: Ontko Robert J. , Bradley Donald D.
Published: June 2014

Unconventional development projects follow a general life cycle. Each step in the life cycle has a number of common activities that can have important environmental and social impacts. Managing those activities to reduce/control the impacts can reduce the project’s business risks and improve the overall success of the development program.

As the development activities become more production oriented, facilities will be more likely to undergo regular maintenance, and the potential for air emissions will increase accordingly. In recent years, the EPA has been working to reduce air pollution from stationary sources by closely examining the use of affirmative defense as it pertains to emission events. To this end, the Texas Commission on Environmental Quality (TCEQ) issued rules in December 2005 for permitting planned maintenance, start-up and shutdown (MSS) emissions.

Upstream oil and gas sites have an MSS permitting deadline of January 5, 2014. For the refining, chemical, and utility industries, the TCEQ processed MSS permit applications for 30 refineries, 400 chemical plants, and scores of utility plants. In the coming year, more than 20,000 oil and gas sites are expected to confront this issue. The vast majority of these oil and gas sites are authorized under permit by rule or standard permit.

While TCEQ has published guidance for MSS Best Available Control Technology (BACT) for refineries, the relevance of this guidance to the oil and gas industry is lacking, and additional guidance has yet to be presented. Facilities seeking to utilize existing authorization mechanisms for their identified MSS activities will have to evaluate the equivalent of BACT to meet the emission limits.

Based on the implementation schedule, most companies have not yet attempted to tackle the MSS permitting issue. Early experience in this area indicates that, in order to meet current permit requirements, MSS activities at oil and gas production sites will require a combination of revised operating procedures and application of additional controls. Sites that cannot manage to a tighter set of operating parameters during MSS activities may trigger the need to convert to a new source review permit, which would require BACT.

This paper will look at the permitting and emission control challenges and strategies for complying with this impending requirement using existing mechanisms.
Keeping Up With Rapid Change: Performance Assurance for Operating Assets in Shale Development Areas
Authors: Read H. L , Bradley D. D.
Published: June 2014

Unconventional development projects follow a general life cycle. Each step in the life cycle has a number of common activities that can have important environmental andsocial impacts. Managing those activities to reduce/control the impacts can reduce the project’s business risks and improve the overall success of the development program.

Operations in many shale plays are rapidly shifting from exploration into the longer-term production step of the life cycle. The pace of change presents significant challenges to maintaining compliance with federal and state environmental, health and safety (EHS) requirements.

To reduce the risk that significant noncompliance could result in regulatory issues that could slow or halt development activities, many operators are conducting independent reviews of their assets. Such reviews, which can be conducted in accordance with the Texas Environmental Health and Safety Audit Privilege Act, provide management and owners with an appraisal of potential environmental liabilities and recommendations for managing compliance risk. EPA has also developed a specific audit policy for new owners of assets who want to make a "clean start" at newly acquired facility by addressing environmental compliance prior to or early in the stages of ownership.

These types of audits focus on key questions to identify areas for improve performance and thereby enhance shareholder value:Do the locations have the necessary permits, authorization and plans?Do the permits, authorization and plans represent current operations?Can the operations expand?What capital will be necessary to come into compliance with regulatory permits and requirements?What is the compliance culture? Is there a sufficient management of change program to identify and adjust to different compliance requirements?

ERM’s experience has shown that the most frequent findings from these audits include storm water contamination issues, lack of air permitting or under-permitting emissions sources, failure to use adequate control devices, and problems with spill containment and spill plan implementation. Through the audit privilege process, disclosed civil and administrative violations can be corrected without incurring monetary penalties, in addition to a prescribed time frame to implement corrective actions. An environmental audit can be a beneficial tool for new or experienced owners or operators looking to enhance their asset value and manage non-technical risk at their sites.
Innovative Way to Involve Business Partners in HSE: A Success Story
Authors: Al Abdul Salam Abdullah , Al Qallaf Yousef , Adivi Bala Siva , Kakoty Debasish
Published: June 2014

Business Partners play vital role in achieving world class HSE Performance in any industry. Health, Safety, Environment being one of the key strategic objectives KOC (Kuwait Oil Company), hence, it is of paramount importance to move together with Business Partners to achieve world class HSE Performance. In order to promote a safe work environment at the contractors’ work sites in consistence with KOC HSE Procedural requirements, full cooperation and commitment of Contractors’ workers as well as Contractors’ management are absolutely essential. Also, to address the risks identified in the North Kuwait Directorate Risk Register, an innovative way has been introduced to bring the High Risk items to ALARP level.

The sustained drive and commitment of the management is identified as the most critical aspect of creating and maintaining strong HSE culture. Kuwait Oil Company (KOC), one of the premier Oil &Gas companies in the Arabian Gulf region, gives top most commitment to HSE and considers HSE as a key strategic objective of its business strategy and number one priority towards sustainable development. KOC recognized the importance of Business Partners involvement in HSE in not only just integrating in the policies and procedures, but involves accountability & commitment to the implementation and practicing. KOC strongly believes that Leadership of Client as well as Business Partner coupled with commitment and accountability act as fundamentals to HSE performance, and to business success.

This paper will focus the methods and processes how the Business Partners (Contractors) in KOC North Kuwait Directorate have been brought on board for achieving wonderful HSE Performance.
Identification and Evaluation of Brackish Groundwater Resources and Alternate Water Sources for Hydraulic Fracturing Operations
Authors: Mueller Dan
Published: June 2014

An important aspect of the hydraulic fracturing process is identifying and securing sufficient water resources. With the ever increasing demands for higher quality water resources for domestic and agricultural needs, alternative water sources including brackish groundwater and water reuse options are being evaluated and used for hydraulic fracturing operations.

To access alternate water sources both the availability and suitability of the water resource must be addressed. Available alternate water sources are first identified within a reasonable distance to the wells that will be hydraulically fractured. Once identified, the alternate water source must be evaluated to determine if it is suitable (in terms of both quality and quantity) to meet the hydraulic fracturing requirements. If all conditions are met, the alternate water resource will provide a viable solution to meet the water needs of the hydraulic fracturing operation and at the same time minimize impacts to more sought-after water resources.

Examples of utilizing available groundwater information from public domain sources to identify brackish groundwater resources and to map the horizontal and vertical extent of these resources are presented. The classification of brackish groundwater includes a wide range of water quality parameters and only some of the brackish groundwater falls within the technical specifications needed the hydraulic fracturing operation.

Water reuse in the form of treated wastewater effluent can provide a suitable water resource for the hydraulic fracturing process. Examples of the identification and evaluation of wastewater effluent sources are presented. From initial identification of potential wastewater effluent resources through the evaluation of these identified resources to determine the viability to use these resources for the hydraulic fracturing process is presented.

Sustainable use of water resources is important under all circumstances with heightened concern when drinking water and irrigation quality water is limited from higher demand and/or draught conditions. The effective and appropriate identification and evaluation of alternate water sources is critical to the successful hydraulic fracturing process. This paper presents field implemented processes and procedures used to identify and evaluate brackish groundwater and treated wastewater effluent to meet hydraulic fracturing water needs.
Solving an Acute Problem and Developing a Long-Term Sustainable Solution for an Operational Facility Supporting the Oil and Gas Industry
Authors: Large Alex , Serra Jordi , Letlow Myna , Marczak Janette
Published: June 2014

An oilfield service company has been operating a site in Knowsley, Liverpool, UK for more than 20 years. The site was first developed during WWII as a Royal Ordnance Factory, and since that time has been used almost continually for the manufacture of specialty chemicals (including organic chemicals, organotin compounds, and lead-based compounds) by various companies.

Historical use and disposal practices have resulted in significant subsurface impacts including the presence of free-phase hydrocarbons (LNAPL) and mobile organotins within a complex geological and hydrogeological setting. Despite a number of efforts over the years to characterize and address site contaminants, issues remained and required clarification to resolve the regulatory roadblock that was preventing successful closure of the on-site remediation.

This case study presents the results of the recent successful efforts to develop a robust and defensible conceptual site model, highlighting the key lessons learned in terms of data assessment, integration and visualization. Two important areas of focus include:Engaging with the regulators on a pragmatic, risk-based approach to managing LNAPL remediation. This included developing a remedial strategy focused on understanding whether there are actual risks rather than the mere presence of LNAPL.Understanding the relationship and interaction of tributyl-tin (TBT) with LNAPL, where the LNAPL was acting as a preferential solvent, and enhancing the mobility of the TBT. As such, the risks presented and any subsequent remedial solution could not be considered as two separate problems and an integrated strategy was developed.

The use of risk-based approaches, robust conceptual models and a detailed understanding of contaminant distribution are critical to the development of long term sustainable solutions to remediate contaminated sites.
Effective Strategies for Crystalline Silica Exposure Monitoring and Control in Hydraulic Fracturing
Authors: Benson Brian , Denson Barbara Brandl , Huddleson Steve
Published: June 2014

Accounts of occupational respiratory illness associated with the inhalation of rock dust date from antiquity, and thus the condition known as silicosis is among the oldest known occupational illnesses. Respirable crystalline silica is, and has been, an enforcement priority for OSHA for several years. The current ACGIH TLV (the recommended exposure limit) is roughly one fourth of the OSHA Permissible Exposure Limit, and many regulators believe the current legal exposure limits do not offer adequate worker protection.

There are some technical challenges to monitoring worker exposure for respirable crystalline silica. These technical issues can lead to flawed exposure evaluation and risk assessment, and thus put employers at risk. Options will be presented to supplement traditional NIOSH and OSHA exposure monitoring methodology and exposure data analysis and provide common sense approaches to dust control that can reduce exposure.

There are several techniques that allow gathering more silica exposure data in less time and with less expense. These techniques can provide larger, more representative data sets at lower cost, and enhance employers’ abilities to assess and manage silica exposure at their sites.

The recent OSHA/NIOSH Hazard Alert on excessive silica exposure during oil and gas well stimulation using hydraulic fracturing has put employers on notice that they are responsible for managing this recognized workplace hazard. Employers who can produce records of proactive, robust exposure monitoring programs are rarely targeted for intensive regulatory field in-spections.
Unconventional Technology Performance: Bridging the Technical to the Nontechnical
Authors: Gardner Katherine , Hernandez Maximo
Published: June 2014

As the need for energy independence broadens hydrocarbon exploration to new geographies and involves new and improved techniques, new lifecycle success factors are continuously introduced to unconventional projects which are required to achieve production objectives on schedule and budget. These factors differ somewhat from the ones a traditional drilling and production field development exposes to the view of those beyond the industry, thus generating new challenges. Traditionally perceived technical issues are typically centered on well control, hydraulic fracturing fluid composition and other technical discipline improvements on a well by well basis. However a set of new challenges have developed as a range of social, economic and environmental stakeholder issues. These can significantly support or affect the ultimate outcome of an investment. The following analysis exposes the authors’ views on performance to the technical limit and factors that contribute to the end result which are beyond the technical limit.
Improving Performance of Alarm System by Implementing Effective Alarm Management Philosophy: A Case Study of West Kuwait Field
Authors: Al-Azmi F. , Parikh C. A.
Published: June 2014

The DCS (distributed control system) alarm system of gathering center of West Kuwait field at Kuwait Oil Company was not functioning as required. DCS alarm system was generating around 400 to 700 alarms in one hour which was out of operator’s alarm handling capacity. This was highlighted as one of the key contributing factor to the seriousness of process upsets & incidents. The overall alarm management system was thoroughly investigated to understand root cause of these poorly functioning system and to improve it accordingly. A detailed investigation revealed lack of alarm management philosophy during design stage and subsequent over configuration of DCS alarms as main cause of this poorly functioning system. All DCS alarms were analyzed in detail to eliminate all unwanted alarms to achieve manageable alarm level of around 5-20 alarms per hour.

This paper shares field experience for analysis of DCS alarm system and explains main root causes which resulted in such poorly functioning alarm system at gathering center of West Kuwait field. It also provides guidelines for improving such alarm system & for developing alarm management philosophy to implement efficient DCS alarm system. It also shares some of the actual alarm data and their analysis which supports need of well-developed alarm management philosophy for implementation of efficient DCS alarm system.

It was observed that total 182 alarms were mainly contributing for significantly higher rate of DCS alarms. These alarms were mainly categorized as frequent alarms, duplicate alarms and chattering alarms. Effective implementation of alarm management philosophy has significantly reduced these alarms and reduced alarm rate from around 700 per hour to 10 per hour.

The paper justifies need for Alarm management philosophy to ensure implementation of efficient DCS alarm system and also provides guideline to achieve it.
A New Approach for CT Interventions in High-Permeability-Contrast Wells of Cupiagua Field, Colombia
Authors: Castaño D. A. , Ruiz N. , Muñoz J. , Zabala R. , Botero O. F. , Mora E. , Nava D. J.
Published: June 2014

Ecopetrol’s – Cupiagua field-, is currently one of the most prolific gas-condensate fields in Colombia. Coiled tubing (CT) interventions have been a constant for more than 10 years, but because of the maturity of the field and the change in the reservoir propertiesmainly the reservoir pressure has fallen below the dewpoint-condensate banking has become a major cause of damage. Moreover, the high permeability contrasts between formations led to unsatisfactory results after the stimulations, such poor placement of the treating fluids in the low permeable intervals and short term results of the treatments. For those reasons, CT interventions with successful results have become a challenge. This paper describes three key CT technologies that have been applied recently in the field. Based on technical analyses and all the particularities of the field, these technologies have overcome the conventional operating restrictions, improving operational efficiency with successful results.
Sacrificial Agent for Reducing Adsorption of Anionic Surfactants
Authors: Shamsijazeyi Hadi , Hirasaki George J. , Verduzco Rafael
Published: June 2014

An important economical factor affecting Enhanced Oil Recovery (EOR) is the adsorption of surfactants on the rocks. Sacrificial agents may be used to reduce the adsorption of surfactants. An alkali (traditionally, sodium carbonate or sodium hydroxide) is often used as sacrificial adsorption agent; however, sodium carbonate is not an effective sacrificial agent in the presence of anhydrite in the rocks due to the reaction between sodium carbonate and sparingly-soluble anhydrite. Therefore, it is essential to develop a sacrificial adsorption agent that can act effectively in the presence of anhydrite.

In this work, sodium polyacrylate is evaluated as a sacrificial agent, and is compared to many other conventional or recently- recommended sacrificial agents, and has shown advantage over all of them for the case of presence of anhydrite. Some experiments have been conducted to demonstrate the ineffectiveness of sodium carbonate as sacrificial agent in the presence of anhydrite. Effect of molecular weight of sodium polyacrylate is tested, and it is found that increase in molecular weight results in decrease in adsorption of surfactant until a certain molecular weight of polyacrylate is reached after which molecular weight has no further effect on reducing adsorption of surfactant. Addition of polyacrylate was shown to reduce adsorption of a selected anionic surfactant on different outcrop minerals, including Carlpool dolomite, industrial calcite, kaolinite, Berea sandstone, and Indiana limestone. To prove the point further, application of polyacrylate was tested with two different anionic surfactants. Adsorption of polyacrylate itself is measured in the presence and absence of surfactant and showed to be independent of the presence of surfactant. The effect of concentration of divalent ions and salinity in the brine on effectiveness of sodium polyacrylate as sacrificial agent has been evaluated on different minerals/rocks. Finally, dynamic adsorption data has been presented in different concentrations of sodium polyacrylate.

All these experiments demonstrate the advantage of using sodium polyacrylate as sacrificial adsorption agent for anionic surfactants even in the presence of anhydrite in the rock.
Solids-Free Fluid Loss Pill for High Temperature Reservoirs
Authors: Gamage Pubudu , Deville Jay P. , Sherman John
Published: June 2014

The leakage of reservoir fluids into a wellbore during perforation, workover, or other completion operations is a substantial concern, especially in high temperature wells where existing fluids utilized to mitigate reservoir fluid influx offer poor performance. To maintain the hydrostatic integrity of the wellbore during these operations, a thermally-stable, solids-free fluid loss pill has been developed.

The pill is composed of synthetic polymers and cross-linkers in monovalent high-density brine. Under ambient pressure and temperature conditions, the pill flows as a viscous liquid and remains fluid for over six months. Upon exposure to elevated temperatures (200°F to 375°F), the pill cross-links to form a robust gel that can act as an appropriately-weighted, low fluid loss pill. This pill can temporarily seal the reservoir, enabling well control during completion operations.

Gelled samples of the fluid loss pill have maintained integrity for up to three weeks under HTHP conditions in laboratory testing with minimal signs of collapse. The gel can be readily destroyed with an oxidative breaker providing a substantial reduction in viscosity. At the end of the completion process, the timing of gel removal is completely controlled by the timing of the breaker addition.

In addition to gel stability tests, formation damage caused by the gel and the fluid loss of the pill were assessed by core flooding experiments using Berea core plugs. Average fluid loss over 3 days at 320 °F was about 50 mL. Restoration of the Berea core permeability after the treatment exceeded 85% of the initial permeability with low lift-off pressures observed. This paper presents full laboratory data on the development of the thermally-stable, solids-free fluid loss pill including gel stability, fluid loss, and breaker testing.
Long-Term Dynamic Flow Testing of Propants
Authors: Kunnath Aven Nevil , Weaver Jim , Tang Tingji
Published: June 2014

The purpose of using proppants in a fracture is to create a hydraulically conductive pathway for reservoir fluids that is open to flow and stays open. Most propped fractures, however, experience a loss of flow capacity with time. Several mechanisms have been identified that contribute to this loss, such as mechanical failure of proppant grains, proppant embedment, fluid residue damage, formation spalling, etc. Recently, fracture diagenesis has been proposed as an additional mechanism that can significantly contribute to the slow loss of fracture conductivity.

Previous attempts to quantify the degree of diagenetic activity have been made under conditions of stress and temperature, but without dynamic fluid flow. This paper presents an automated experimental setup that enables long-term (six months or more), dynamic flow testing using multiple test cells to allow evaluation of multiple proppants simultaneously at reservoir temperature conditions, but without stress applied.

This apparatus was used to determine the rate of diagenetic activity on sand and ceramic proppants with slow, continuously flowing simulated formation water. Permeability loss data for four proppants and six coated proppants subjected to 350°F flowing simulated formation water for six months are presented. Scanning electron microscope (SEM), energy-dispersive X-ray (EDX) spectroscopy, and grain strength data are presented to describe the onset of diagenesis. Dynamic permeability was monitored throughout the test period along with produced fluid ionic content as determined by inductively coupled plasma (ICP). Mass changes of each test proppant were measured.

Results presented in this paper should be helpful to stimulation engineers responsible for selecting proppants for sustained fracture conductivity. It provides detailed description of an automated laboratory method in which proppants can be evaluated for long periods of time with little human interaction.
Impact of Polymer Mechanical Degradation on Shear and Extensional Viscosities: Towards Better Injectivity Forecasts in Polymer Flooding Operations
Authors: Dupas A.. , Hénaut I.. , Rousseau D.. , Poulain P.. , Tabary R.. , Argillier J. -F. , Aubry T..
Published: June 2014

Field data from polymer flooding operations sometimes indicate a better-than-expected polymer injectivity below fracturing pressure. Current interpretations for this unexpected phenomenon are based either on geomechanical considerations (for unconsolidated sand formations) or on polymer mechanical degradation, potentially occurring in the injection facilities and the near wellbore area. In this paper, a new approach of polymer injectivity is suggested. It is based on the study of polymer mechanical degradation with respect to both shear and extensional viscosities.

In the first part of this work, we have investigated the onset of mechanical degradation by submitting semi-dilute solutions of high molecular weight partially hydrolyzed polyacrylamide (HPAM) to extensional laminar flow created by an API capillary system. We have then measured both shear and extensional viscosity of the native and the degraded HPAM solutions. We consider the onset of mechanical degradation to be reached when shear viscosity loss is equal to 10%. At low degradation rate, shear viscosity is unaffected while extensional viscosity decreases up to 30%, whereas, at higher degradation rates, shear viscosity drops by 10% (onset) while extensional viscosity is reduced up to 60%. This means that degraded HPAM with weakly affected shear viscosity can develop much less resistance to extensional flow.

In the second part, we have explored the influence of mechanical degradation on injectivity by determining resistance factors of native and degraded HPAM solutions. Solutions have been injected in reproducible unconsolidated sand packs. At low velocities, resistance factors were similar for both kinds of solutions, as expected from their comparable shear viscosities. However, at high velocities, namely where flow in porous media implies high extensional deformations in the vicinities of the pore throats, apparent rheo-thickening was much less marked for solutions degraded at high extensional rate.

These results allow understanding why polymers which do not seem to be mechanically degraded according to their shear viscosity can show a very good injectivity, thanks to the reduction of extensional resistance in porous media. They could also lead to establish guidelines for designing new polymer pre-treatment methods aimed at improving injectivity while retaining the mobility control ability of polymers.
Sorption Study of ?-ALO(OH) Nanoparticle-Crosslinked Polymeric Scale Inhibitors and Their Improved Squeeze Performance in Porous Media
Authors: Yan C.. , Kan A.T.. T. , Wang W.. , Yan F.. , Wang L.. , Tomson M.B.. B.
Published: June 2014

Polymeric scale inhibitors are widely used in the oil and gas field because of their enhanced thermal stability and better environmental compatibility. However, the squeeze efficiency of such threshold inhibitors, not only polymeric scale inhibitors but also phosphonates, is typically poor in conventional squeeze treatment. In this research, nanoparticle (NP)-crosslinked polymeric scale inhibitors were developed for scale control. Nearly monodispersed boehmite [γ-AlO(OH)] NPs with average size of 2.8 nm were synthesized and used to crosslink sulfonated polycarboxylic acid (SPCA). Crosslinked AlO(OH)-SPCA nanoinhibitors were produced and developed to increase the retention of SPCA in formations by converting liquid-phase polymeric scale inhibitors into a viscous gel. Study of sorption of SPCA onto AlO(OH) NPs under different pHs with and without assistance of Ca2+ was discussed. In addition, study of sorption of various types of scale inhibitors [SPCA; phosphino-polycarboxylic acid (PPCA); and diethylenetriaminepentatakis(methylene phosphonic acid) (DTPMP)] onto AlO(OH) NPs was performed. Squeeze simulation of neat 3% SPCA, AlO(OH) (3%)-SPCA (3%) NPs, and AlO(OH) (3%)-SPCA (3%)-Ca NPs was investigated. The results showed that the addition of Ca2+ ions improves the squeeze performance of SPCA, and the normalized squeeze life (NSL) of such material (8,952 bbl/kg) was improved by a factor greater than 60 compared with that of SPCA alone (152 bbl/kg).
Rock/Fluid Chemistry Impacts on Shale Fracture Behavior
Authors: Aderibigbe Aderonke A. , Lane Robert H.
Published: June 2014

At realistic surfactant concentrations used in fracturing fluid additives, the differences in the average strengths of shale exposed to solutions of these additives are not sufficient to establish a direct correlation between the chemical effect of the surfactants and the mechanical strength of the formation. Prior studies of formations with high quartz content suggest that the adsorption of surfactant on the surface alters formation strength. In this study, using Mancos shale samples, the rock mineralogy, total organic carbon and cation exchange capacity of the Mancos shale samples were determined in order to characterize the shale. Adsorption tests to study the interaction of the shale and aqueous fluid mixture were also carried out using surface tension measurements. The uniaxial compressive strengths and indirect tensile strengths of about 100 rock samples exposed to different fluid environments were measured using unconfined compression and Brazilian tests respectively. Microseismic events, possibly due to microfracture generation or growth, are known to continue for some time as stresses relax after shutdown of hydraulic fracture pumps. Hence, the study of the role of surface chemical effects in compression and tensile fracturing is important in determining whether rock/fluid chemistry can be exploited to improve the growth of conductive microfractures.
Development of a Dual Functional Kinetic Hydrate Inhibitor for a Novel North Sea Wet Gas Application
Authors: Webber Peter , Morales Noah , Conrad Peter , McNamee Kevin , Jones Regan , Vries Gert de , Garming Linda
Published: June 2014

With fields getting more mature and discoveries getting smaller, operators in the North Sea are pushed to reduce development and operating costs. In order to address this challenge, they develop small fields as wet gas subsea satellites and investigate centralizing existing gas processing facilities. Both require wet gas to be transported over increasing distances. This presents an extended challenge for traditional thermodynamic hydrate inhibitor (THI) solutions as increasing subcooling equates to larger volumes being required. The application of low dosage hydrate inhibitors (LDHI) helps to unlock these new smaller fields reducing project expenditure for platform storage, transport, and pumping of hydrate inhibitor while maintain subcooling protection.

A further refinement is to require the application of a kinetic hydrate inhibitor (KHI) with dual functionality. The KHI is to serve as a traditional KHI during steady-state operations while performing as a THI during extended shut-ins and cold-well restarts. This challenge required the development of a step-change polymer technology as a fit for purpose solution.

The minimum performance requirements for the KHI incorporated hydrate forming conditions of 8 °C subcooling and 200 hours of hold time in blind rocking cells.  Besides the high level of subcooling and extended hold time, several secondary chemical properties were essential to success. The expansion of polymer solubility (lower critical solution temperature) in 10-15% NaCl brines at temperatures up to 90 ºC for high temperature injection, polymer package formulation in a traditional thermodynamic inhibitor carrier for chemical deliverability, and extensive compatibility testing with a corrosion inhibitor were identified as key factors and rigorously examined to ensure a suitable inhibitor for the vast application.

This paper describes the qualification process, related lessons learned, and successful first application of this new kinetic hydrate inhibitor offering.
Estimating Scale Deposition through Reservoir History Matching in the Janice Field
Authors: Vazquez Oscar , Young Callum , Demyanov Vasily , Arnold Dan , Fisher Andrew , MacMillan Alasdair , Christie Mike
Published: June 2014

Inorganic scale precipitation and deposition in production wells can be a significant impediment to effective reservoir management. In extreme cases scale can cause the well to be abandoned as a result of reservoir formation damage in the near wellbore area and the narrowing of the production tubing annulus thus preventing fluid flow. The prediction of the time and location of scale formation is therefore essential for scale management. This study is focused on sulphate scales, which form when sulphate rich seawater mixes with formation brines, rich in barium, strontium and calcium, and which are amongst the most difficult types of scale to prevent and remove.

Formation brines in reservoirs with a tendency for sulphate scale deposition can have a very different makeup when compared to seawater, which may be injected for pressure support. Having such different chemistries allows seawater and formation brine to be tracked. In this study, two different types of water are considered, formation brine and injected seawater.

The objective of this work is to predict uncertainty in sulphate scale deposition from multiple history matched reservoir models, by tracking injected seawater in the Janice Field. There are many examples in the literature where conventional reservoir history matching, namely gas rate, oil rate and bottom hole pressure, are used to generate an ensemble of good history matched models, which will determine the uncertainty of a hydrocarbon reservoir production forecast. In this study, the same approach will be adopted, but including produced water chemistry, in particular seawater breakthrough. This approach provides a methodology to predict the uncertainty of the formation brine and the injected seawater mixing zone within the reservoir formation. The methodology provides a Bayesian confidence interval (P10-P50-P90) in time and space for the injected seawater, identifying which wells will be at risk based on seawater breakthrough and in which zones of the reservoir mixing is more likely to occur.
Effective Propagation of HPAM Solutions Through the Tambaredjo Reservoir During a Polymer Flood
Authors: Manichand R. N. , Moe Soe Let K. P. , Gil L. , Quillien B. , Seright R. S.
Published: June 2014

Two new methods were developed for anaerobically sampling polymer solutions from production wells in the Sarah Maria polymer flood pilot project in Suriname. Whereas previous methods indicated severe polymer degradation, the improved methods revealed that the polymer propagated intact over 300 ft through the Tambaredjo formation. This finding substantially reduces concerns about HPAM stability and propagation through low- and moderate-temperature reservoirs. Analysis of produced salinity, polymer concentration, and viscosity indicated that the polymer banks retained low salinity and therefore high viscosity for much of the way through the Sarah Maria polymer flood pilot pattern. A strong shear- thickening rheology was observed for 1000-ppm and 1350-ppm HPAM solutions in porous media, even though the salinity was only 500 ppm TDS. Examination of injectivities revealed that these solutions were injected above the formation parting pressure in the Sarah Maria polymer injection wells. Analysis suggested that the fractures extended only a short distance (~20 ft) from the injection wells and did not jeopardize sweep efficiency. In contrast, the short fractures greatly improved polymer injectivity and reduced concern about polymer mechanical degradation.
Factors Affecting the Stability of Scale Inhibitors Used for Capillary Injection in High Temperature Wells
Authors: Griffin J. Rick , Johnstone James R. , Cotter Terry E. , O'Brien Ashleigh E.
Published: June 2014

In recent years, the percentage of oil production from more challenging environments has increased. In addition to the numerous engineering and logistical difficulties of working at increased depth, temperature and pressure these production zones provide a harsh environment deleterious to the performance of some critical oilfield chemicals. Scale inhibitors are one class of oil field chemicals which are deployed through squeeze treatments into the formation and/or continuous downhole injection for protection of production tubulars. As well depths continue to increase, the exposure time of the injected chemicals also increases. With temperatures in the range of 180-200 °C and pressures exceeding 10,000 psi, the effect of elevated temperature and pressure on scale inhibitor performance is a critical parameter to evaluate using chemical analytical techniques and product performance methods.

Another trend leading to increased thermal exposure is the use of thermal enhanced recovery techniques. Scale inhibitors are exposed to high temperatures in operations such as steam flooding and steam assisted gravity drainage (SAGD).

In this study, a range of chemicals have been evaluated for their short and medium-term thermal stability at 180 and 200 °C. The primary application of this data is for downhole injection and squeeze treatments prior to adsorption. Inhibitor chemical types include sulfonated polycarboxylic acid (SPCA), fluorescent tagged sulfonated polycarboxylic acid (FSPCA), phosphorous tagged sulfonated polycarboxylic acid (PSPCA), sulfonated polyacrylocarboxylic acid (SPAC), polyacrylic acid (PAA), polyvinyl sulfonate (PVS), polyamino polyether methylene phosphonate (PAPEMP), bis(hexamethylene)triamine pentakis(methylene phosphonic acid) (BHTPMP) and diethylenetriamine pentakis(methylene phosphonic acid) (DTPMP). In most cases the sodium or potassium salts of the inhibitors are used.

The chemical effect of temperature on scale inhibitors is measured through molecular weight determination, thermogravimetric analysis (TGA), pH change, and Fourier Transform Infrared (FTIR) analysis. The performance of these inhibitors is measured under static and dynamic conditions for inhibition of barium sulfate scale. These results help to further the knowledge of inhibitor degradation due to thermal effects and indicate the direction for further product development of thermally stable scale inhibitors.
Laboratory Evaluation of H2S Bioscavenging in Produced Water at 60°C
Authors: Harris J. B. , Stepp A. , Pierce T. , Webb R. , Jenneman G. E. , Burger E. D
Published: June 2014

Nitrate can control biogenic souring by lowering sulfate reducing bacteria (SRB) metabolic activity and shifting the microbial community such that nitrate-reducing bacteria (NRB) out-compete SRB for nutrients. Nitrate was applied in a laboratory study using a 20-cc packed bed upflow reactor to determine kinetic rate of H2S removal. The objectives of the testing were to (1) enrich for nitrate-reducing, sulfide-oxidizing microorganisms derived from produced water and (2) determine the kinetic rate of H2S removal at 60˚C in a synthetic medium with an H2S:nitrate molar ratio of 2, and (3) describe the microbial community involved in nitrate-mediated souring control in this system. Sulfide was measured at the face and at the discharge of the column to determine the sulfide oxidation rate. Residence time in the reactor was varied by changing flow rate but a removal rate of nearly 50% H2S was achieved across the column in one hour residence time. This paper provides a description of the microbial community cultivated at high temperature using 16S rRNA to profile the population dynamics resulting from nitrate treatment. Phospholipid fatty acid analysis was also used for taxonomic evaluation and quantifying physiological changes in the biomass due to nitrate treatment.
A Review of Current Techniques in Gamma-Ray And Neutron Log Interpretation
Authors: Stick John C. , Hartline Ralph
Published: June 2014

Introduction

The radioactivity log may present any of several combinations of radioactivity curves depending upon the purpose for which the log is run. The log normally consists of a gamma-ray curve and one or more neutron curves which are selected to provide the specific information desired. Radioactivity logs can provide information useful in exploration for and the development of petroleum reservoirs. They are valuable also in the maintenance of wells by providing information useful to guide completion, repair, recompletion and secondary-recovery operations.

The Gamma-Ray Curve Basis for Geological Significance

The development of the radioactivity log began with the recording of the natural gamma-ray curve. The amplitude of this curve is a measure of the gamma-ray intensity in the borehole. Variations in the amplitude of this curve in a general way follow the concentration of the radio-elements in the formation.

Experience has shown that the great majority of the radio-elements of the sedimentary column are carried by the shales. The gamma-ray curve is thus able to identify the sandstones and the carbonate rocks in which petroleum reservoirs can occur, principally by their low content of shales which carry the radio-elements.

The development of a clean sandstone formation requires, during its deposition, erosional conditions which wash the sand grains free of the fine clay-mineral particles and carry them away to be deposited in another section of the sedimentary basin. This can happen on a grand scale only if erosional and sedimentation conditions are relatively stable over a long period of time. More commonly, the sorting action of the erosional forces is inadequate to fully separate the clay minerals from the sand so that a great majority of sandstones contain clay-mineral fractions.
A New Pressure Testing for Low-Mobility Unconventional Formations: A Synthetic Case Study Based on Field Data
Authors: Hadibeik Hamid , Proett Mark , Chen Dingding , Eyuboglu Sami , Torres-Verdin Carlos , Sepehrnoori Kamy
Published: June 2014

Testing in tight formations and unconventional reservoirs poses significant challenges when determining reservoir pressure. The primary difficulty in testing a low mobility formation is that a conventional pressure transient test cannot be applied because the buildup time required for pressure stability after a typical drawdown is excessively long. To reduce testing time, a new automated pulse test method has been developed.

The new pulse test method consists of a drawdown or injection followed by a short stabilization period. Then depending on the buildup response, a new drawdown or injection is performed followed by a short buildup. This sequence is repeated until the desired buildup stabilization is achieved and then a final extended shut-in period is used for analysis of formation properties such as pressure and mobility. The pressure stabilization time can be further reduced by implementing an adaptive pressure feedback in the system.

This new method uses sequential pressure responses and automated pressure pulses. The analysis of the final pressure yields a measurement in 0.5% range of the initial formation pressure while decreasing the wait time by a factor of 10 for a packer-type formation tester. Furthermore, the pressure measurements are analyzed to obtain reservoir permeability and storage.

The new method was tested on synthetic reservoir models and a field study. These demonstrated that the method permits a rapid appraisal of pressure measurement in comparison with conventional testing. Moreover, the implemented feedback system mitigates the supercharge effect.
Induced Nuclear Reaction Logging
Authors: Hoyer W.A.
Published: June 2014

A pulsed high-energy neturon-induced spectral logging tool has been built and field-tested. The reaction of deuterium on tritium is used to generate pulses of 14-Mev neutrons. By detecting only the prompt gamma rays produced by neutron inelastic reactions in the formation, the presence and relative abundance of carbon, oxygen, calcium, silicon and other important elements may be ascertained from a gamma-ray spectrum. Gamma-ray spectra obtained in a shallow test well and in experimental field use show that it is possible to identify formations and their contained fluids.

Introduction

The penetrating gamma rays from naturally occurring radioactive elements in subsurface formations have been used for a number of years in well logging as a means of characterizing and distinguishing strata. Still another nuclear logging method which has been employed for some years consists of the bombardment of strata with neutrons and the measurement of the number of gamma rays produced by neutron capture reactions involving elements in subsurface strata. Since one of the principal elements entering into capture reactions is hydrogen, the latter procedure essentially results in a hydrogen log, whether the hydrogen be in combined form in either oil or water; thus, the log gives an indirect measure of porosity. These methods, with various refinements, have been developed to such an extent that they have become routine procedures in formation evaluation.

Neither gamma-ray logging nor conventional neutron logging, however, yields sufficient information to permits unequivocal identification of the mineralogic composition of formations, and neither method gives information which may be used for the positive identification of hydrocarbons in strata. Accordingly, a number of efforts have been made in recent years to gain additional information from nuclear logs. Brannon and Osoba have shown that it is possible to identify naturally occurring radioactive elements in subsurface formations by spectral analysis of gamma rays emanating from these elements. Such an identification is of value in the characterization of strata. A simplified form of spectral analysis of gamma radiation resulting from neutron capture reactions between elements in earth materials and bombarding neutrons has been used with some success under favorable conditions to differentiate between petroleum and water.