Cement is a key element for successful drilling and completing of a well. From oil and gas wells to geothermal applications, cement is a major material ensuring zonal isolation. With an increase in global energy needs and an expected uptick in drilling and plugging and abandonment activities, evaluating and understanding cement properties is crucial, since these properties are used in various engineering designs and calculations. The objective of this paper is to present how Nuclear Magnetic Resonance (NMR) can be used to understand the cement hydration process and the development of key properties such as strength and porosity. NMR applications for cement include determination of porosity, water interactions, identification of hydration stages and C-S-H gel development with curing time. Since water is present in all cement slurries, NMR can potentially help to understand microstructural changes in cement during curing. Data from more than 600 cement specimens cured for more than a year are compiled. Standard cement properties such as UCS (unconfined compressive strength) are compared with NMR responses. In this paper, we document cement hydration and porosity changes through NMR measurements in samples with five different recipes. Our study also confirms a strong correlation between NMR response and cement strength.
Kisku, Sayanima (Oil & Natural Gas Corporation Ltd.) | Santhosh Kumar, R. (Oil & Natural Gas Corporation Ltd.) | Dayal, Har sharad (Oil & Natural Gas Corporation Ltd.) | Chadha, Harish Kumar (Oil & Natural Gas Corporation Ltd.) | Srivastava, Anil (Oil & Natural Gas Corporation Ltd.)
Infill drilling is an integral part of brown field management for exploiting un-drained areas with good oil saturation. In a matured field on water-flood, the primary objective is optimized wellbore placement of infill wells in areas with better petro-physical characteristics, bypassing flooded region. It is also important to design a robust completion strategy to safeguard the longevity of these wells by curtailing produced water. This approach assists in dramatic increase in production by isolating water charged sections and thereby restricting rise in water production.
The use of advanced Logging-While-Drilling techniques during horizontal drilling provides an opportunity for effective well planning. Real-time Logging-While-Drilling instruments during directional drilling gives us the opportunity to acquire information pertaining to the reservoir in a single run. Interpretation from the real-time data acquisition boosts the planning during wellbore drilling.
This paper discusses a case study of a field in western offshore, India, which focuses on the applications of geosteering and the use of swell packers for zonal isolation to augment oil production. In this study, two wells have been deliberated where the real-time information has been extracted and included in the decision making process. The bottom-hole assembly used in this case, comprised standard Logging-While-Drilling services such as gamma ray, resistivity, neutron porosity, density and density imaging services and also formation pressure testing.
Since the field under study is a carbonate reservoir that has been on waterflood for the last twenty eight years, chances of early breakthrough of water in the infill wells has posed a high risk in spite of the presence of good bypassed oil saturation. Geosteering has enabled to restrict the horizontal section safely within the desired zone of better oil saturation and geological features, as interpreted from the Logging-While-Drilling data. Further isolation of suspected water bearing zones with swell packers have assisted in healthy well completion by diminishing chances of sharp rise in water cut in the infill wells.
In line Inspection (ILI) Interval are often based on conditions that are assumed constant over long sections of pipeline - perhaps entire pipeline systems. Many pipeline operators are following the fixed ILI Interval based on statuary requirement irrespective of different local corrosion growth conditions prevailing on the particular pipeline system. Scheduling the ILI based on maximum interval defined in statuary requirement may be very unrealistic and pose threats to the integrity of these pipelines. This technical paper discusses the importance of ILI Interval, corrosion growth rate analysis, recent development to determine the ILI Interval, an engineering approach to calculate appropriate ILI-RunInterval, mitigation plan to extend the ILI-RunInterval for particular pipeline system. This technical paper would enhance the awareness among the pipeline operators to appropriately calculate the ILI-Run Interval which would cost beneficial to pipeline operators in long term without any integrity threats.
Viscoelastic surfactants (VES) are essential components in self-diverting acid systems. Their low thermal stability limits their application at elevated temperatures. The industry introduced new VES chemistries with modified hydrophilic functional groups, which enhances their thermal stability. These new chemistries are still challenged by the lack of compatibility with corrosion inhibitors (CI). This work aims to study the nature and the mechanism of the interaction between the VES and the corrosion inhibitors, which affects both the rheological and corrosion inhibition characteristics of the self-diverting acid system.
This study is based on rheology and corrosion inhibition tests, where combinations of VES and corrosion inhibitors are tested and complemented with chemical and microscopic analysis. Negatively charged thiourea and positively charged quaternary ammonium corrosion inhibitors were selected to study their impact on both cationic and zwitterionic VES systems. Each mixture of the corrosion inhibitor and the VES was blended in a 15 and 20 wt% HCl acid mixture, then assessed for its viscosity at different shear rates, CI concentrations, and temperatures up to 280°F in live and spent acid conditions. Each acid solution was assessed using Fourier-Transform-Infra-Red (FTIR) before and after each rheology and corrosion test to track the changes of the mixture functional groups. Each mixture was examined under a polarizing microscope to assess its colloidal nature. The corrosion inhibition effectiveness of selected acid mixtures was evaluated. N-80 steel coupons were immersed statically in the acid mixture for 6 hours at 150°F and 1,000 psi. The corrosion rate was evaluated by using metal coupon weight loss analysis followed by optical microscope examination for the metal surface.
The interaction between the CI and the VES surface charges and molecular geometries dictates both the rheological and the inhibitive properties of the acid mixtures. The use of a small molecular structure anionic CI with a cationic VES, results in a fine monodispersed CI particles in the VES-acid system. The opposite charges between the CI and the VES results in electrostatic attraction forces. Both the fine dispersion and the electrostatic attraction enhances the rheological performance of the mixture and packs the corrosion-inhibiting layer. The addition of a bulk and similarly charged CI with the VES results in a coarse polydispersed CI particles with repulsive nature with the VES. These properties increase the shear-induced structures and lower the packing of the inhibition layer deposited on the metal coupons, which decrease the rheological performance of the acid mixture and increase its corrosion rate. The FTIR analysis shows that there is no chemical reaction between the CIs and the VESs tested.
This work investigates the interactions between the corrosion inhibitors and the viscoelastic surfactants. It explains the impact of the surface charge of both corrosion inhibitors and VES on their rheological and corrosion inhibition characteristics. It adds a selection criterion for compatible VES and corrosion inhibitors.
A new method has been developed to differentiate and quantify the amount of primary amines through a simple chemical process. Colored cyclic adduct compounds are formed by reaction of selective chemicals with primary amine. This adduct formation is preferential to the primary amine, even in the presence of a mixture of secondary and tertiary amines. The adduct shows selective enhanced fluorescence emission at 475-nm wavelength under specific excitation with 420 nm. Due to enhanced fluorescence activity, quantification becomes possible, even below a 1-ppm concentration of specific primary amine. A chemical matrix, formulated with the mixture of different concentrations of primary, secondary and tertiary amines, helps to differentiate and quantify primary amines present in the mixture, even at lower concentrations. This method is validated under synthetic field brine conditions to detect and quantify primary amines towards field applications.
Rodgers, Patrick (Baker Hughes, a GE Company) | Lundy, Brian (Baker Hughes, a GE Company) | Ramachandran, Sunder (Baker Hughes, a GE Company) | Ott, James (Baker Hughes, a GE Company) | Poelker, David (Baker Hughes, a GE Company) | Lee, Dong (Baker Hughes, a GE Company) | Stevens, Corey (Baker Hughes, a GE Company) | Bounds, Christopher (Baker Hughes, a GE Company) | Sullivan, Matthew (Baker Hughes, a GE Company)
Operators producing hydrocarbons from conventional and unconventional wells often encounter interconnected production-related challenges that exacerbate one another. Challenges during production include the corrosion of steel caused by acid gases, as well as the precipitation and accumulation of iron sulfide, calcium carbonate scale, and barium sulfate scale. The accumulation of solids on pipe walls can facilitate under-deposit corrosion and plugging. Each of these issues can lead to failures and costly workovers. To address these issues, current treatment approaches require multiple chemical applications, frequent batch treatments, mechanical intervention, or a combination of approaches. In certain scenarios, these approaches can be impractical, ineffective, and/or uneconomical. The objective of this study was to develop a solution to overcome the aforementioned production challenges simultaneously and continuously with a single chemical application. The design strategy was to formulate chemicals that included a variety of chemistries to inhibit multiple corrosion mechanisms, as well as an iron sulfide dissolver, and a scale inhibitor to inhibit the formation of calcium carbonate and barium sulfate scales. Laboratory tests were conducted to demonstrate that the formulations could function in the aforementioned areas. One formulation was then applied in the field under different production scenarios: oil wells equipped with either a gas lift mechanism or an electrical submersible pump. Data from those situations are presented to demonstrate the field performance of the new formulation. Compared to the benchmark chemical treatment efforts, application of the formulation improved or maintained similar corrosion control, reduced or eliminated the accumulation of iron sulfide solids in the well, and improved scale control in each of the production scenarios. This paper presents a viable option for effectively treating common production challenges simultaneously and with one chemical application, which is particularly useful when it is impractical or uneconomical to employ multiple chemical treatments.
Moore, Joseph (DowDuPont Industrial Biosciences) | Massie-Schuh, Ella (DowDuPont Industrial Biosciences) | Wunch, Kenneth (DowDuPont Industrial Biosciences) | Manna, Kathleen (DowDuPont Industrial Biosciences) | Daly, Rebecca (Colorado State University) | Wilkins, Michael (Colorado State University) | Wrighton, Kelly (Colorado State University)
Hydraulic fracturing presents an ideal breeding ground for microbial proliferation due to the use of large volumes of nutrient-rich, water-based process fluids. Bacteria and/or archaea, when left uncontrolled topside or in the reservoir, can produce hydrogen sulfide, causing biogenic souring of hydrocarbons. In addition, microbial populations emerging from the downhole environment during production can colonize production equipment, leading to biofouling, microbially influenced corrosion (MIC), produced fluid separation issues, and HS&E risks. Mitigating these risks requires effective selection and application of biocides during drilling, completion, and production. To this end, a microbiological audit of a well completion operation with the objective of determining the effectiveness of a tandem chlorine dioxide (ClO2) and glutaraldehyde/quaternary ammonium (glut/quat) microbial control program was carried out. This paper describes the rationale behind selection of sampling points for a comprehensive microbiological field audit and provides the resulting critical analysis of biocide efficacy in the field using molecular assays (qPCR, ATP) and complementary culturing techniques (microtiter MPN and culture vials—commonly termed "bug bottles").
Due to the comprehensive nature of sampling and data collection, it was possible to make much more applicable and relevant observations and recommendations than it would have been using laboratory studies alone. First, multiple sources of microbial contamination were identified topside, including source waters, working tanks, hydration units, and guar. Additionally, critical analysis of biocide efficacy revealed that ClO2 treatment of source water was short-lived and ineffective for operational control, whereas glut/quat treatment of fracturing fluids at the blender was effective both topside and downhole. Analysis of the microbial load at all topside sampling points revealed that complete removal of ClO2 treatment could be offset by as little as a 10% increase in glut/quat dosage at the blender. This is a highly resolved microbiological audit of a hydraulic fracturing opration which offers new, highly relevant perspectives on the effectiveness of some biocide programs for operational control. This overview of biocide efficacies in the field will facilitate recommendations for both immediate and long-term microbial control in fractured shale reservoirs.
Wang, Yefei (Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum East China, Ministry of Education, P. R. China, School of Petroleum Engineering, China University of Petroleum East China) | Yang, Zhen (Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum East China, Ministry of Education, P. R. China, School of Petroleum Engineering, China University of Petroleum East China) | Wang, Renzhuo (Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum East China, Ministry of Education, P. R. China, School of Petroleum Engineering, China University of Petroleum East China) | Chen, Wuhua (Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum East China, Ministry of Education, P. R. China, School of Petroleum Engineering, China University of Petroleum East China) | Ding, Mingchen (Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum East China, Ministry of Education, P. R. China, School of Petroleum Engineering, China University of Petroleum East China) | Zhan, Fengtao (College of Science, China University of Petroleum East China) | Hou, Baofeng (School of Petroleum Engineering, Yangtze University)
A novel indolizine derivative inhibitor for acidization was introduced. It could exhibit effective corrosion inhibition at a much lower concentration without propargyl alcohol and shows economic and environmental advantages. From quinoline, benzyl chloride, and chloroacetic acid, two indolizine derivatives were prepared under certain conditions. These inhibitive indolizine derivatives were both synthesised from benzyl quinoline chloride (BQC), which one of the conventional quaternary ammonium corrosion inhibitors used for acidising. The target compound was purified and instrumental analysis methods including elemental analysis, high-resolution mass spectrometry (HRMS), and NMR were used to characterise the chemical structure. The inhibition performance of the indolizine derivatives in 15 wt.% HCl, 20 wt.% HCl, and mud acid (12%HCl + 3%HF) for N80 steel was investigated by weight loss measurement, electrochemical method (potentiodynamic polarization and EIS), and SEM surface morphology assessment.
When 0.1 wt.% indolizine derivative was added, the inhibition efficiency of N80 steel in 15 wt.% HCl at 90 °C increased to 98.8 % and 99.1 % respectively without the synergistic effect of propargyl alcohol: however, in terms of BQC, even at a dosage of 1.0 wt.%, the inhibition efficiency of N80 steel only reached 83.3 % under the same conditions. The novel derivative could impart an improved corrosion resistance effect. Compared with BQC, there are more active adsorption sites in the derivative and therefore the inhibitor could be better fastened to the steel surface. The firmly adsorbed inhibitors would thereby prevent the metal surface from making contact with H+ ions and finally increase the inhibitory effect. As a high-efficiency corrosion inhibitor, the novel indolizine derivatives may offer a new strategy for corrosion protection in acidising.
Yang, Zhen (College of Petroleum Engineering, China University of Petroleum) | Wang, Yefei (College of Petroleum Engineering, China University of Petroleum) | Wang, Renzhuo (College of Petroleum Engineering, China University of Petroleum) | Chen, Wuhua (College of Petroleum Engineering, China University of Petroleum) | Ding, Mingchen (College of Petroleum Engineering, China University of Petroleum) | Zhan, Fengtao (College of Science, China University of Petroleum) | Hou, Baofeng (School of Petroleum Engineering, Yangtze University)
Propargyl alcohol, at great expense and with high toxicity, is often used as an essential synergistic component of corrosion inhibitors for acidizing; however, in our recent work, a novel indolizine derivative was found to exhibit effective protection performance without the synergism of propargyl alcohol. These indolizine derivatives were easily prepared from quinoline, pyridine, and several halide compounds via 1,3-dipolar cycloaddition reaction. The derivative could prohibit the corrosion of metal at an extremely low concentration and fulfills the requirements of increasingly stringent environmental standards. The inhibition performance of the indolizine derivatives to N80 steel was investigated in 15 wt.% HCl and 20 wt.% HCl by weight loss measurements, potentiodynamic polarization method (Tafel curves), and electrochemical impedance spectroscopy (EIS).
In the absence of propargyl alcohol, when the dosage of indolizine derivatives in 15 wt.% HCl is 0.1 wt.%, the inhibition efficiency of N80 steel increases to approximately 99% at 90 °C. The indolizine derivative shows a superior anti-corrosion performance at a much lower concentration than that of benzyl quinolinium chloride (BQC, a commonly used compound in current acidizing corrosion inhibitors), which serves as the precursor to indolizine derivatives. More importantly, these protective indolizine compounds behave better than the synergistic inhibitor propargyl alcohol. The reinforced active adsorption groups in indolizine derivatives could provide extra adsorption sites and fasten the inhibitive molecule to the steel surface, thus augmenting the protective effect. Here, a new inhibitive indolizine derivative is presented as an acidizing inhibitor that may also offer a low-pollution technique for corrosion prevention.
The 2015 oil price downturn and future uncertainty in the industry have resulted in Malaysia Oil and Gas Regulator PETRONAS (MPM) taking a more proactive role in driving Malaysian Petroleum Arrangement Contractors (PACs) to maximize lifecycle value from their well stock. Key focus areas include streamlining review processes, reducing well cost, maximizing production from active wells and reactivating idle wells, reducing failures from well activities, driving value driven surveillance and promoting low cost well abandonment. This paper will focus on how the objective & value driven approach by PETRONAS MPM have resulted in business performance improvements at the national level through proactive and effective well value maximization throughout field/well lifecycle, from exploration stage down to the decommissioning and abandonment stage.