Formation of sulphate and carbonate scale is well understood within the hydrocarbon extraction industry with injection of incompatible water such as seawater into reservoir with significant concentration of barium, strontium and calcium. To overcome this challenge chemical inhibition has been utilized for many decades and in the past 15 years elimination/reduction of the sulphate ion source from injection seawater using sulphate reduction membranes has been employed. This paper present laboratory work to qualify a scale inhibitor and field results of its application to prevent scale formation when an operator had to change from low sulphate seawater (LSSW) mixed with produced water (PW) for their water injection source to a blend of LSSW/PW and full sulphate seawater (SW). The increased level of sulphate presented a significant scale risk within the topside process on fluid mixing but more significantly increased the risk of scale formation within the near wellbore region of the injector wells which were under matrix injection rather than fracture flow regime. The qualification of a suitable inhibitor required assessment of the retention of a potentially suitable vinyl sulphonate co polymer scale inhibitors to ensure it had low adsorption and was able to propagate deep into the formation before being adsorbed from the supersaturated brine. Coreflood studies using reservoir core were carried out to assess the scale risk of the LSSW/PW/SW brine, propagation and release characteristic of the short-listed scale inhibitors. The recommendation that followed the laboratory studies was to apply a batch treatment of concentrated scale inhibitor to each injector well to provide a high concentration pad of scale inhibitor that would be transported into the reservoir when the scaling LSSW/PW/SW fluid was injected. Protection was provided by continuous application of the same chemical at minimum inhibitor concentration to prevent scale formation within the topside and the desorption of the batched inhibitor within the near wellbore would prevent scale formation within this critical region. Thirteen injection wells were treated with a pad of 10% vinyl sulphonate co polymer scale inhibitor to a radial distance of 3 ft.
At the 2018 Offshore Achievement Awards, John Fraser, Sparrows Group’s director for health, safety, environment, and quality (HSEQ) and human resources, was presented with the Above and Beyond Award. The Offshore Achievement Awards is the biggest and longest established oil, gas and renewables industry awards for the UK offshore energy sector. The award was presented by Countdown TV presenter Rachel Riley at a black-tie ceremony on 22 March. Fraser initially joined Sparrows Group as a crane operator on the Forties field in 1977 and became the driving force behind the development of key industry processes for the safety and integrity of crane operations, which have benefitted not only Sparrows own employees and operations but also the wider industry. Fraser led the way in developing the Sparrows Offshore Crane Operator Training and Competence Standard in 1990.
Traditional gas-lift technology blossomed between 1929 and 1945, with about 25000 patents being issued during this time
The concept of High Pressure Gas-lift (herein after referred to as HPGL), as discussed in SPE 14347
The case for eliminating failure-prone gas-lift valves is self-evident. However, the case for the second application will be proffered. Conventional gas-lift, while recognized as excellent for producing high volumes of solids- laden fluid from deviated wells, underperforms ESP's in new horizontal oil wells due to frictional losses associated with high tubing flowrates. The case will be made that SPGL combined with reverse flow mitigates the frictional losses associated with high flowrates. Similar to a coil tubing cleanout using high pressure nitrogen, high pressure natural gas can lift large volumes of fluid without the need for gas-lift valves.
Technology and products for HPGL currently exist. Multiple compressor designs will be summarized to show that only one additional stage of compression is needed to support HPGL, with three and four stage designs being capable of performing the task. The recommendation will be made that HPGL compressors be assembled from readily available components, and that multiple pilot tests be made by industry. The importance of maintaining temperatures through the compression process high enough to prevent hydrocarbon condensation will also be explained.
SUMMARY Seismic airguns are not an impulsive source and hence marine seismic data must be designatured before interpretation. A heuristic approach is used to generalize the single airgun model to a small array of closely spaced guns where the bubbles from the different guns coalesce. The simulated signatures are used to designature data from a near-surface survey around a production rig. The results illustrate the importance of deconvolving with the correct source signature and compare favorably to predictionerror filtering. INTRODUCTION The data recorded in a seismic survey is the convolution of the source signature, wave propagation and the reflectivity.
Seemingly unrelated developments in seismic methods are broadband, multi-component sensors, and simultaneous sources. In this paper we explain how these are related.
Different sources have different voices that can be recognized. Multi-component sensors provide information on the direction of the source of incoming waves.
We have developed a method that assigns a probability to the existence of simultaneous source interference indicating the likelihood that at any certain time on any certain trace, interference originated from one source or another. To estimate this probability, we compute two attributes, which we call radiality and source-signature similarity. Radiality is calculated from data with horizontal components such as multi-component land or ocean bottom nodes seismometers or multi-sensor streamers. Similarity can be calculated when different sources have different source signatures or voices. The goal of this work is to use this probability as additional information in processing simultaneous source data.
Presentation Date: Tuesday, September 26, 2017
Start Time: 9:45 AM
Presentation Type: ORAL
ABSTRACT: In this paper, we report on a scoping study that was prompted by operational issues through an Oligocene smectite-rich shale that involved changes in borehole inclination with respect to the bedding. A core characterization workflow is used to specifically probe geomechanical heterogeneity and anisotropy for static and dynamic elastic properties as well as failure strength. Initial petrophysical scanning of the core surface provides a first indication of existing heterogeneity for properties of interest and assists in devising an efficient sampling strategy. Over the three-foot section analyzed, and despite its apparent homogeneity, the core exhibits a two-fold variation in reduced Young’s modulus between softer and stiffer zones, which is tied to slight changes in carbonate content. Confined elastic and mechanical measurements reveal strength anisotropy of the order of 20% and P-wave and S-wave velocity anisotropies of about 20% and 30%, respectively. Moreover, testing shows that the shale is weakest at oblique angle to the bedding due to weak bed parallel surfaces which activate when favorably oriented. These results suggest that anisotropy and heterogeneity both need to be accounted for in borehole stability models involving smectite-rich material.
Accurate wellbore stability prediction in geomechanically unstable formations requires thorough understanding of the drilled rock properties. This includes the ability to predict failure in deviated wells associated with bedding heterogeneity or to better assess the relationship between intrinsic elastic properties and stress/strain boundary conditions for e.g. in situ stress computations and log-based geomechanical forecasting.
This paper presents a geomechanical core analysis workflow that includes petrophysical core scanning for heterogeneity assessment and sample picking, as well as geomechanical testing for anisotropic static/dynamic elastic properties and strength. In particular, the petrophysical scanning includes a mechanical probe called the Impulse Hammer which functions by analyzing the force-time function of a hardened steel sphere mounted on an accelerometer dropped on the surface of the rock. This analysis produces a reduced Young’s modulus at a resolution on the order of the millimeter revealing fine scale heterogeneity. Using the profiles obtained during petrophysical scanning, locations of interest can be chosen for further geomechanical evaluation on plugs.
Abouie, Ali (The University of Texas at Asutin) | Korrani, Aboulghasem Kazemi Nia (The University of Texas at Austin) | Shirdel, Mahdy (The University of Texas at Austin) | Sepehrnoori, Kamy (The University of Texas at Austin)
Scale deposition in surface and subsurface production equipment is one of the common problems during oil production, resulting in equipment corrosion, wellbore plugging, decrease in production rate, and frequent remediations. In this work, a detailed procedure is presented through which a compositional wellbore simulator is developed with the capability of modeling comprehensive geochemical reactions.
The compositional wellbore simulator (UTWELL) is developed by applying different numerical approaches and flow-regime-detection methods to accurately model multiphase flow in the wellbore. In addition, several deposition mechanisms are incorporated for the transportation, entrainment, and deposition of solid particles in the wellbore. Subsequently, a geochemical module, IPhreeqc, is integrated into the wellbore model to handle homogeneous and heterogeneous, reversible and irreversible, and ion-exchange reactions under either local-equilibrium or kinetic conditions. This package provides a robust, flexible, and accurate integrated tool for mechanistic modeling of scale deposition in the wellbore.
Through our integrated simulator, deposition profiles of carbonate and sulfate scales in the wellbore are predicted for several case studies. Significant effects of physiochemical properties (such as pressure, temperature, salinity, and pH value) on the scale deposition in the wellbore are discussed. In addition, comparing simulation results with experimental data reveals that hydrocarbon-phase dissolution has a significant effect on geochemical calculations compared with the temperature/pressure variation effects.
To the best of our knowledge, there is no comprehensive simulator available in the industry through which scale deposition in the wellbore can be predicted accurately. In this paper, scale deposition profile in the wellbore is estimated by including the interaction of the hydrocarbon and aqueous phases and its effect on the aqueous-scale geochemistry (by use of a compositional wellbore simulator); effects of parameters that vary greatly in the wellbore (pressure, temperature, and pH value); and comprehensive geochemistry simulation (provided through coupling of the wellbore simulator with IPhreeqc). The outcome of this study yields a comprehensive tool for scale deposition prediction in the wellbore and will help scale deposition risk-management and mitigation plans.
Waltrich, Paulo J. (Louisiana State University, Pedro Cavalcanti de Souza, Texas A&M University) | Capovilla, Matheus S. (Louisiana State University, Pedro Cavalcanti de Souza, Texas A&M University) | Lee, Woochan (Louisiana State University, Pedro Cavalcanti de Souza, Texas A&M University) | Zulqarnain, Mohammad (Louisiana State University) | Hughes, Richard (Louisiana State University) | Tyagi, Mayank (Louisiana State University) | Williams, Wesley (Louisiana State University) | Kam, Seung (Louisiana State University) | Archer, Alexander (Bureau of Ocean Energy Management) | Singh, Jagdeep (Bureau of Ocean Energy Management) | Nguyen, Hai (Bureau of Ocean Energy Management) | Duhon, John (Bureau of Ocean Energy Management) | Griffith, Craig (Bureau of Ocean Energy Management)
An experimental investigation was carried out to investigate the behavior of gas-liquid flows in a large-diameter pipe with high flow-rates. The objectives are to experimentally evaluate two-phase flows in vertical pipes of large diameter and collect information to verify the accuracy of wellbore flow models applied to Worst-Case Discharge (WCD) calculations.
The flow correlations developed for small diameters, used on Worst-Case-Discharge calculations, show errors of more than 100% compared to the experimental data for large-diameter pipes. However, for low gas-liquid-ratios, the there is a reasonable agreement between experimental data and simulation results for all wellbore flow models tested, with errors lower than 10%. This study uses the experimental data to provide guidance on how to improve these flow correlations and proposes how to use the flow models to obtain improved results on WCD calculations.
Haugen, I. (Statoil) | Døssland, L. (Statoil) | Brankovic, M. (Qinterra Technologies) | Osaland, E. (Qinterra Technologies) | Osugo, L. (Qinterra Technologies) | Grødem, M. (ALTUS Intervention) | Grønnerød, Anders (ALTUS Intervention)
Barium Sulphate (BaSO4) scale is classified as a hard scale and removal is extremely resistant to both chemical and mechanical methods. Coiled-tubing deployed mechanical intervention is effective, but with inherent logistics, footprint and cost implications. Electric-line deployed wellbore cleanout systems have the advantage of being light and easily deployable. In wellbores with inside diameters (ID) of less than 3 in., removal and downhole collection of hard debris has proved to be a particular challenge.
This paper describes a wellbore cleanout operation on powered electrical wireline in the North Sea. The main operational objective was to clear out the wellbore to the top of a suspected malfunctioning Sliding Side Door (SSD), with a drift ID of 2.797 in. Access was required to run a tubing punch to establish communication with the target reservoir and therefore restore well production. The debris severely plugging the wellbore was predominantly BaSO4 scale.
Slickline broaching was initially attempted to remove the obstruction, but could not make sufficient progress. An electric-line deployed wellbore cleanout system, with bottomhole assembly (BHA) outside diameters (OD) of 2.625 in. and 2.75 in. and reservoir chamber OD of 2.5 in. was subsequently deployed, which was effective and consistently able to interact with, and remove to surface, the scale blockage. 168.6 litres of debris was collected by the electric line wellbore cleanout system.
Contributing to the success of the operation was extensive pre-job testing and measurements executed in the laboratory. These simulated downhole completion geometry and expected debris condition and interaction. The pre-job test results fed in to the design of an optimum BHA and were a basis for decision-making during the operation. The resulting system design maximised solids recovery per run, which increased cleanout and collection efficiency. A surface wellsite washout system was used to clean out the collection chambers, which enabled the rapid turnaround of equipment in-between runs.
Cleanout was executed through multiple runs, with the majority returning maximum fill to surface, which ultimately gained access to target depth as efficiently as possible. A multi-finger caliper log run confirmed the removal of the obstruction and a tubing puncher was run to perforate the inner tubing. Production was restored, with an average (over the first three months) oil production rate of 1,290 STB/D (205 Sm3/d), gas rate of 7.2 MMscfd/D (204,321 Sm3/d) and water cut of 69%.
This is the first time that an electric-line deployed wellbore cleanout system with an OD as small as 2.625 in. has delivered high, successive, repeatability in cleaning out hard BaSO4 scale from a completion with an ID as small as 2.797 in.
Scale deposition in surface and subsurface production equipment is one of the common problems during oil production resulting in equipment corrosion, wellbore plugging, decrease in production rate, and frequent remediations. In this work, we present a detailed procedure through which a compositional wellbore simulator is developed with the capability of modeling comprehensive geochemical reactions.
The compositional wellbore simulator (UTWELL) is developed by applying different numerical approaches and flow regimes to accurately monitor multiphase flow in the wellbore. In addition, several deposition mechanisms are incorporated and validated against experimental data to study the transportation, entrainment, and deposition of solid particles in the wellbore. Subsequently, a geochemical module (i.e. IPhreeqc) is integrated into the wellbore model to handle homogenous and heterogeneous, reversible and irreversible, and ion-exchange reactions under either local equilibrium or kinetic conditions. This package provides a robust, flexible, and accurate integrated tool for mechanistic modeling of scale deposition in the wellbore.
Through our integrated simulator, deposition profiles of carbonates and sulfates scales in the wellbore are predicted for several realistic case studies. Significant effects of physiochemical properties (i.e. pressure, temperature, salinity, and
To the best of our knowledge, there is no comprehensive simulator available in the industry through which scale deposition in the wellbore can be predicted accurately. In this work, by including 1) the interaction of the hydrocarbon phases on the aqueous-scale geochemistry (by using a compositional wellbore simulator) 2) effects of parameters that vary greatly in the wellbore (i.e. pressure, temperature, and