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Sour H2S And CO2 Rich Oil And Gas Projects: Lessons Learnt So Far And Have We Figured It All Out?

15 – 17 April 2014

Dubai, UAE | Hilton Dubai Jumeirah Resort

Technical Agenda

Session 1: Drilling Stimulation and Completion Technology

Session Chairs: Mohammad Tahir Khan, Petroleum Development Oman; Richard Singleton, Al Hosn Gas

In this session we will discuss in detail the way to adapt the best practices for sour oil and gas wells during the drilling and completion operation. Also, how to adapt and implement the lesson learnt during the sour project execution phase will be discussed.

In sour wells inhibitors and scavengers being used in the well bore to address the well integrity issues and to protect the tubular from extreme harsh wellbore conditions, the inhibitors and scavenger incompatibilities associated with the mud system could create issues like extreme foaming which effects the operation and disposing off the foam could become an issue. We will discuss how we could avoid extreme foaming and which mud system could provide the best solutions.
This session will also focus on examples of sour field reservoir stimulation; sour field case histories will be included to cover the selection of the stimulation method, the design considerations, and the validation of the treatment.
The questions to be addressed would include:

  • How do we select the right stimulation technique for sour reservoir?
  • What is the best way to design acid frac jobs for tight sour reservoirs, specifically for horizontal wells?
  • How do we stimulate the sour horizontal well section using coiled tubing in tight reservoir in sour environment?

During the entire lifetime of sour oil and gas wells, well intervention plays an important role. This session will review the well intervention, design, and coiled tubing applications.

In well intervention, techniques like re-entry well short radius, coil tubing horizontal drilling, through tubing cement packer, and many others coiled tubing application will be discussed, this is specifically in relation to sour project.

Session 2: HSE Management of Sour Gas Operations and Well Testing

Session Chairs: Falah Al-Azmi, Kuwait Oil Company; Hakan Gurses, Schlumberger

This session will discuss and share the HSE lesson learnt, best practices, new technologies and applications, successful procedures, and implementation of these methods on sour gas operations and well testing in SIMOP’s (simultaneous operations) focusing on Middle East region and with international experience worldwide.

One of the key challenges during the SIMOP’s is; how to communicate and interact within the local community and other operations going on within the field, how to manage the operations while well testing, and what flaring options available for the best gas dispersion of the toxic gas.

Sour gas operations are highly complex and unusual to the day to day business, where everybody should be involved and participated for the success of the project; this can be only achieved if all the parties are working together; starting from the operating company, drilling department, reservoir and production department, HSE department, drilling contractor, and all the other service companies working in the field.

In addition this session will focus on the following topics:

  • Hydrogen sulfide alarm management in production facilities; to discuss various guidelines given under various international standards and its interpretation for implementation of alarm values.
  • HSE case studies of sour oil and gas fields; to share lessons Learnt and best practices for HSE in sour fields.
  • Importance of remote monitoring for safe handling of sour gas operations; to discuss role and importance of available and new technologies for remote monitoring and control of sour gas operations.

Session 3: Material Selection and Operational Adaptations 

Session Chairs: Adrian J. Wiggett, Baker Hughes; Kamal El Bachiri, VAM Drilling Middle East

The search for rich hydrocarbon resources faces new challenges as 'the easy to recover crude' reservoirs are somewhat depleted and the associated drilling/completion techniques are ever changing to meet these needs.

Today´s exploration and development activities challenge the current knowledge to develop new strategies to produce the hydrocarbons at low competitive costs and in the safest way.

This session objective is to provide detail as to how these new challenges can be approached, involving 'state-of-the-art' technology material selections, not only to drill but also to complete wells in harsh environments within a cost effective, uncertain/risky reservoir management environment.

Session 4: Reservoir Characterisation, Evaluation, and Simulation Modelling

Session Chairs: Aggelos Calogirou, Wintershall; Anan Amornprabharwat, PTTEP

A number of data requirements are crucial for materials, equipment, and facilities preparation to handle sour gases. To obtain the development requirements, the nature of formation rock with its properties, origin, and distribution of fluids in the reservoir must be well understood. Reservoir characterisation and simulation modelling will then be established to define the optimum development of sour gas and oil fields, especially with extreme reservoir conditions; high pressure and temperature reservoirs, high concentration of H2S and CO2.

This session will highlight the existing issues in obtaining key data from these highly sour reservoirs, from exploration, appraisal to development phases. Various data acquisitions which are necessary for reservoir characterisation; open hole wireline and LWD logging, compositional/geochemical fluid downhole/surface sampling, coring and wellbore and reservoir imaging, well production testing, production logging (productivity and zonal contributions), and geo-mechanical data.

Additional unique features of reservoir characterisation in sour fields will be addressed to capture the complexity of reservoir rock and fluid behaviour as well as interaction of rock and fluid with H2S and CO2. Utilisation of reservoir simulation models to identify flow behaviours and problems such as sulfide deposition, condensate blockage around the wellbores, reservoir stimulation, miscible gas injection with high miscibility gases; CO2 and H2S, and water and water-gas injection. Recent lessons learnt from various regions will be discussed for further challenges in research and development.

Session 5: Sour Gas Compositional Analysis and Fluid Sampling

Session Chairs: Florian Hollaender, Schlumberger; Raj Deo Tewari, PETRONAS

Fluid behaviour has an important place in the development of fields with significant content of highly corrosive non-hydrocarbon fluids. Accurately determining the type of components present in produced fluids, their concentration, and their distribution across the field is critical in facilities design and operations, from the near wellbore where solids deposition may occur, through the production system where corrosion risks must be properly managed, all the way down to disposal with challenges associated to the handling capacity of acid gas removal units or compatibility of highly sour gas separated gas in the case of re-injection.

Properly characterising fluids start with the capture of representative and useful samples, which can be challenging in extreme sour environments where the proper selection of sampling equipment and procedures is not following usual standards. The understanding of H2S and CO2 distribution, the behaviour phase of reservoir fluids including possible solids and the characterisation of fluid properties throughout the production life are critical to a proper field development planning.
This session will aim first at reviewing current state-of-the-art techniques and technologies for sour fluid sampling, both using downhole open-hole and cased-hole sampling tools following the drilling and early flow sequence of a well but also during production periods for well fluid monitoring purposes both downhole and at surface. The other main topic covered will be that of fluid behaviour modelling. This considers samples from a single reservoir location but also includes the importance of compositional and properties distribution modelling. This session will leverage practical experience from discussion leaders and attendees and will provide participants with good discussion points concerning the importance of proper sampling and the extent to which sampling is required to develop a good understanding of fluid behaviour in sour projects.

Session 6: Sour Gas Storage/Re-Injection and Bi-Products Usage (Sulphur and CO2)

Session Chairs: Gregory R. King, Tengizchevroil; Saleh Al-Mansoori, ADNOC

Sour gas and oil fields are developed by applying existing technologies for separating the H2S and CO2 from sweet gas. As a development option, the inclusion of an acid gas removal plant will lead to the production of sulphur and venting of CO2.  Carbon Capture and Storage (CCS) is widely considered as an opportunity not only for improved pressure maintenance and enhanced oil recovery (EOR), but also for reducing Greenhouse Gas (GHG) emissions through CO2 sequestration. The injection of sour gas or acid gas may, however, cause harm to the reservoir by plugging pore throats and by precipitation of solids leading to a reduction in permeability and injectivity. Incremental benefits by EOR may not be realised due to the bypassing of oil in stratified reservoirs or if permeability reduction is significant.  Later in field life, when the reservoirs are fully depleted, they may be suitable storage locations for acid gas and CO2.  In sour oil and gas fields, H2S and CO2 management based on a gas reinjection scheme is often the most robust technical, economic, and environmental solution for field development.    

Session 7: Knowledge Sharing, Training, and Sour Oil and Gas Guidelines

This session will cover the state of knowledge and technology development; ways to moving forward; what can be done different; how can we improve and increase the awareness of the sour field community inclusive of:                                  

  • Sour gas guidelines (procedures and processes) and standardisation
  • Sour gas skills development and training (equipment and personnel)
  • Knowledge sharing within sour field community