Weatherford (United Kingdom)

Abstract An onshore oil well in Asia with depleting reservoir pressure and severe liquid loading was identified to be energized for continued production. The solution was needed to furnish the dual purpose of providing gas injection for liquid unloading with the additional feature of a surface controlled dual flow safety valve to isolate both the injection and production conduits. The well was completed with 4-1/2 × 3-1/2 × 2-3/8 in. tubing design producing from 2 reservoir layers and, anticipated an early water cut. The conventional solution is to re-complete the well with GLV. Weatherford proposed a retrofit in-tubing gas lift system with minimal surface modifications and no workover. With the In-tubing gas lift system, the installation could be performed on a Coiled Tubing unit comprising of a smaller crew and reduced Carbon emission compared to a Workover rig. Furthermore, the system does not rely on annular integrity and enables gas injection below the production packer depth. Both injection and production are performed within the tubing bore itself. A comprehensive study of Nodal analysis using simulation software was performed to assess system performance, identify coiled tubing size, and gas injection depth. It was inferred that a gas injection depth of 2800 m would change well deliverability performance and increase oil production. Sensitivity studies on water cut were performed for 10%, 15%, 20%, and 95%, and a gas injection rate of 500 to 2000 MMSCFPD. Optimum gas injection rates were found to be 500 to 1000 MMSCFPD, with 1.25 inch OD coiled tubing exhibiting maximum flow area and minimal pressure drop due to frictional losses. For a high water cut scenario of 95%, a high gas injection rate of 2000 MMSCFPD was anticipated from the simulation. Bottom injection string was run and installed using Hanger and Dual Flow Safety Valve. This safety valve landed across the locked open and communicated existing subsurface safety valve. The top section was run and latched into the polished bore, while also landing the top hanger into a modified spool adaptor on the surface. With this system in the well, coiled tubing acted as the gas injection path and the coiled tubing/tubing annulus provided the production path. Control line pressure release closed the flapper in the dual flow safety valve, stopping fluid movement in both the injection and production flow areas. The simulations and sensitivities performed utilizing the actual well test data enabled the operator to choose the optimum operating parameters and coiled tubing string size to be utilized in the system, and provided the option of deepening the gas injection point to a depth even below the pre-existing side pocket mandrels. The remedial completion system saved the operator from workover costs through a rigless operation with minimal personnel and a reduced carbon footprint. This paper details the implementation of an in-tubing gas lift system in the well facing liquid loading challenges covering the various stages of the project from simulation and analysis of the candidate well to the implementation of the system and the post-installation production outcome. The following aspects of the Inverse Gas Lift system installation will be discussed in this paper: Well Background and Data CollectionSimulation and AnalysisSystem OverviewOperations & System InstallationResults and Conclusion

Compressional and shear formation velocities are key to the prediction of petrophysical properties from seismic attributes. In fast formations shear velocity may be obtained from monopole source, but in slow formations, it is commonly determined from the flexural mode associated with dipole excitation, which is a dispersive borehole-guided mode who’s low frequency and high frequency asymptote to the formation S-velocity, and to the Scholte-velocity, respectively. The shear slowness is commonly computed from well log dipole flexural mode data using Semblance Time Coherence (STC) processing. Dispersion is handled by restricting the waveforms spectral content to the low frequencies that travel close to the formation’s shear velocity. This restricting may not eliminate the need for a residual dispersion correction. Inversion addresses this difficulty by computing shear slowness directly from observed dispersion characteristics. In order to make the inversion efficient the iterative steps which compare observed and forward modeled dispersion curves are replaced with a neural net trained on a large number of pre-modeled curves generated with known formation and borehole properties. Automated mode frequency detection constrains the bandwidth over which dispersion curves are matched. Results from 127,000 modelled and field data points show improved accuracy and precision relative to STC processing.

Journal Article Microstructural Analysis of the Transformation of Organic Matter during Artificial Thermal Maturation of the Upper Cretaceous Boquillas (Eagle Ford) Formation, Texas, USA Get access Wayne K Camp, Wayne K Camp Anadarko Petroleum Corporation, The Woodlands, TX, USA Search for other works by this author on: Oxford Academic Google Scholar Wayne Knowles, Wayne Knowles Weatherford Laboratories, Bideford, Devon, UK Search for other works by this author on: Oxford Academic Google Scholar Kultaransingh Hooghan, Kultaransingh Hooghan Weatherford Laboratories, Houston, TX, USA Search for other works by this author on: Oxford Academic Google Scholar Tim E Ruble Tim E Ruble Weatherford Laboratories, Houston, TX, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 23, Issue S1, 1 July 2017, Pages 2128–2129, https://doi.org/10.1017/S1431927617011308 Published: 04 August 2017

Abstract. We profile trace gas and particulate emissions from near-field airborne measurements of discrete smoke plumes in Brazil during the 2012 biomass burning season. The South American Biomass Burning Analysis (SAMBBA) Project conducted during September and October 2012 sampled across two distinct fire regimes prevalent in the Amazon Basin. Combined measurements from a Compact Time Of Flight Aerosol Mass Spectrometer (C-ToF-AMS) and a Single Particle Soot Photometer (SP2) are reported for the first time in a tropical biomass burning environment. Emissions from a mostly-smouldering rainforest wildfire in Rondonia state and numerous smaller flaming Cerrado fires in Tocantins state are presented. While the Cerrado fires appear to be representative of typical fire conditions in the existing literature, the rainforest wildfire likely represents a more extreme example of biomass burning with a bias towards mostly-smouldering emissions. We determined fire integrated modified combustion efficiencies, emission ratios and emission factors for trace gas and particulate components for these two fire types, alongside aerosol microphysical properties. Seven times more black carbon was emitted from the Cerrado fires per unit of fuel combustion (EFBC of 0.13 ± 0.04 g kg−1) compared to the rainforest fire (EFBC of 0.019 ± 0.006 g kg−1) and more than six times the amount of organic aerosol was emitted from the rainforest fire per unit of fuel combustion (EFOC of 5.00 ± 1.58 g kg−1) compared to the Cerrado fires (EFOC of 0.82 ± 0.26 g kg−1). Particulate phase species emitted from the fires sampled are generally lower than those reported in previous studies and in emission inventories, which is likely a combination of differences in fire combustion efficiency and fuel content, along with different measurement techniques. Previous modelling studies focussed on the biomass burning season in tropical South America have required significant scaling of emissions to reproduce in-situ and satellite aerosol concentrations over the region. Our results do not indicate that emission factors used in inventories are biased low, which could be one potential cause of the reported underestimates in modelling studies. This study supplements and updates trace gas and particulate emission factors for fire type specific biomass burning in Brazil for use in weather and climate models. The study illustrates that initial fire conditions can result in substantial differences in terms of their emitted chemical components, which can potentially perturb the Earth system.

The aim of this article is to examine how strategic talent management (STM) is defined and understood by Chinese small and medium‐sized enterprises (SMEs), and of the talent management and retention strategies Chinese SMEs use in the service sector. The case study of four Chinese service SMEs reveals that managers have different views about talent: according to some, STM means simply having a right candidate in the right job category. The findings also indicate that work environment, career advancement opportunities, and a good compensation package are acknowledged as a best strategy for attracting talent. The SMEs use various recruitment strategies; internship is one of most frequent ones for the recruitment of new talent, which SMEs consider to be a good approach to nurturing new talent. The findings further suggest that Chinese SMEs use similar approaches to those used by firms in developed markets, but Chinese SMEs pay more attention to the compensation package and job roles. Overall, the findings indicate that SMEs take both a universalist and a selective performance–­oriented approach when it comes to talent management. © 2016 Wiley Periodicals, Inc.

Abstract It is estimated that only one third of the remaining worldwide oil and gas reserves are conventional, the remainder being in unconventional reservoirs whose evaluation requires appropriate measurements delivered in a cost-effective way. In the case of shales and other tight reservoirs, the defining characteristics are low matrix porosity and low or ultra-low permeability which requires artificial stimulation to encourage production. The optimum stimulation strategy for a particular reservoir is strongly dependent on the distribution of organic material, and on the mechanical and geometrical properties of the rock, and the associated stress field. It is essential to quantify these to an appropriate level of certainty, and well logs are the primary source of such data. Until recently the options for acquiring appropriate logs in high angle and horizontal wells have been constrained either by the limited available sensors or tool conveyance methods. However, the introduction of memory capable small diameter specialized tools and multiple innovative conveyance options has changed the cost-benefit balance for the better. This paper reviews the current status of open hole log measurements with full spectrum conveyance options, and how they impact the evaluation of these challenging reservoirs.

ABSTRACT Images rendered from measurements made by wireline microresistivity imaging tools include longitudinal gaps whenever the well circumference exceeds the total width of the pad-mounted electrode arrays. The fraction of an image containing null data depends on tool design, and it is commonly approximately 30% for 261 mm (8.5 in.)-bit size wells increasing to approximately 50% in 311 mm (12.25 in.) wells. We use cues from the measured parts to infer information missing from the gaps; a method has been developed that simulates the process by decomposing the measured parts into their morphological components using sparse representations of multiscale multiorientation transforms, then recomposing the full-bore image assuming it to be efficiently represented by the transform’s elemental bases. The approach was evaluated using real data sets with a variety of geologic features, including full-coverage images from small diameter wells artificially obscured to simulate images from larger diameter wells. For borehole images dominated by curvilinear features, reconstructions from artificially obscured images were visually indistinguishable from the original unobscured images for a broad range of coverage loss and for all apparent dip angles below near-vertical, regardless of degree of parallelism (or lack thereof). Successful reconstruction of near-vertical features (including those with complex boundaries such as breakouts) was more dependent on coverage loss, but in these cases, the results were consistent with judgments made by interpreters. Therefore, we found that inpainting provides a consistent starting point for reproducible quantitative geologic analysis, and it is an enabler for automated feature recognition.

Abstract Advances in drilling technology in response to a need for greater evaluation and exploitation of previously marginal resources are leading to increased usage of Controlled and Managed Pressure Drilling systems. Their application on High Pressure High Temperature wells is also increasing in relation to accurate flow and kick detection provision as well as pressure management. The benefits they bring in terms of hazard mitigation, reduced formation damage and improved drilling dynamics are allowing fields with tight operating windows to be drilled with greater safety margins and better economics. A consequence of using closed and pressured systems has been the impact and use of surface evaluation techniques, particularly surface gas logging. Despite provision of real-time information relating to reservoir pressure, fracture gradient and fluid invasion as well as high resolution flow and fluid density variation, until recently there has still been a lack of meaningful surface gas information. This was due to the fact that all surface gas detection systems except for GC tracer currently rely on atmospheric conditions to extract gas from mud in air. By utilising a semi-permeable membrane gas extraction process directly behind the choke manifold, prior to the Mud Gas Separator, the sampling point forms part of the enclosed system. This provides significant benefits in removing any potential surface gas loss. The application and deployment of such a technique is described in this paper. The responsive nature of membrane extraction, along with the repeatability and quantitative nature of the process, lends itself well to comparison with high resolution pressure and flow data generated by the Managed Pressure Drilling system and has the potential to be used to increase drilling efficiencies. The relationship between fluid composition and gas in mud volumes at surface, with derived reservoir pressure and surface parameters is examined in this paper.