Africa (Sub-Sahara) A drillstem test was performed on the Zafarani-2 well--located about 80 km offshore southern Tanzania. Two separate intervals were tested, and the well flowed at a maximum of 66 MMscf/D of gas. Statoil (65%) is the operator, on behalf of Tanzania Petroleum Development Corporation, with partner ExxonMobil Exploration and Production Tanzania (35%). The FA-1 well--located in 600 m of water in the Foum Assaka license area offshore Morocco--was spudded. The well targets Eagle prospect Lower Cretaceous resources. Target depth is 4000 m. Kosmos Energy (29.9%) is the operator, with partners BP (26.4%),
Africa (Sub-Sahara) Sahara Group discovered hydrocarbons in three wells drilled in Block OPL 274, located onshore in Nigeria's Edo State. Olugei-1 was drilled to a measured depth of 4537 m and encountered five hydrocarbon zones, with 33 m of net pay. Oki-Oziengbe South 4 was drilled to a measured depth of 3816 m and encountered 64.3 m of net pay in 13 hydrocarbon-bearing zones. Oki-Oziengbe South 5 was drilled to a measured depth of 3923 m and encountered 91 m of net pay in 19 reservoirs. Sahara Group (100%) is the operator. Asia Pacific Sino Gas & Energy Holdings (SGE) flowed gas (coalbed methane) from its first horizontal well in the Linxing production sharing contract (PSC) in China's Shanxi province.
Following the Montara (2009) and Macondo (2010) oil spill incidents, the international oil industry has undertaken an unprecedented collective effort to apply the lessons from these and other oil spill incidents to improve the management and technical aspects of oil spill response. Over the last three years the IOGP/IPIECA Joint Industry Project (JIP) on Oil Spill Response has overseen 19 specific projects to enhance knowledge and understanding of good practice across a wide range of related technical disciplines. The legacy of this effort includes a comprehensive library of peer reviewed outputs ranging from scan/ glance technical overview products through the broad suite of 24 Good Practice Guides, and also includes a number of deep study-level technical papers and reports.
The challenge today is to inculcate this vast body of technical guidance into the awareness of decision makers through a coordinated programme of communication and outreach. The overarching aim is to raise levels of knowledge and understanding relating to the tools and techniques of oil spill response amongst opinion formers and decision-makers. In so doing, industry can overcome barriers that currently restrict / prevent access to use all available response tools, based on a scientific assessment of the most appropriate response strategies.
Oil Spill Response Limited (OSRL) is working with industry on initiatives designed to socialise these outputs within a broad range of stakeholders. Key steps on this journey include:
This paper will discuss each of these ongoing initiatives and will highlight the successes that have been achieved and the challenges that remain.
4.While operational response techniques are well established, typically the most problematic and long-lasting aspect of a marine pollution incident is the assessment of environmental harm, environmental rehabilitation programs and continued monitoring of impacts and the success of restoration. Concerns about real or perceived environmental impacts receive intense attention from regulators, media and the public long after the immediate cleanup is complete. Failure to address these concerns can result in serious, long-term reputational damage, along with the potential for large compensation claims that are hard to refute.
Following recent significant offshore spills, there is an increased focus by industry and regulators on marine pollution response. Regulators now consider not only at an operator’s spill contingency plan, but also their ability to implement that plan.
2.In Australia, regulators now require comprehensive operational and scientific monitoring programs to support a spill response and assess the level of damage. This paper draws on our experience developing these programs for offshore oil and gas operators.
3.To be effective, implementation of some aspects of the OSMP must begin almost immediately an incident occurs, when traditionally the focus is on physical containment and clean-up. Pre-impact baseline assessment before oil hits sensitive environments is critical to demonstrating whether the spill has resulted in contamination and the extent of impacts, and a challenge for companies is to identify how they will gather baseline data in a timely and cost-effective way. A credible, robust program of environmental sampling and analysis is also essential to justify the demobilisation of response and remediation activities.
Developing and planning for the rapid implementation of an OSMP is a complex and challenging task.
The OSMP must include study protocols that are flexible enough to account for the specific spill characteristics, in addition to the organisation, staffing (including identification of suitably credible experts to lead scientific programs), HSE plans, initiation and termination criteria, and logistic support requirements.
1.In this paper each of these fundamental components of an Operational and Scientific Monitoring Program (OSMP) are described and discussed in the context of spill contingency planning and with focus on improving spill response outcomes.
Peternell Carballo, Ana Gabriela (Schlumberger) | Dooply, Mohammed I. (Schlumberger Offshore Svcs) | Leveque, Soazig (Schlumberger) | Tovar, Gioconda (Schlumberger Technology Corp.) | Horkowitz, Jack (Schlumberger)
Following the Gulf of Mexico Deepwater drilling moratorium in 2010, the industry focus towards well integrity assurance has significantly increased. Several new and updated regulations and best practices have been published in the last two years, including API Standard 65 - Part 2 and API RP 96. These two industry accepted standards highlighted that determining the hole volume to confirm the cement slurry volume, to fill-up the annulus to the designed top of cement, is one of the many factors impacting cement placement success during well construction process. A new solution for riserless section was developed based on existing Logging While Drilling (LWD) electromagnetic propagation resistivity measurements, which meets the requirement to understand hole volume drilled with water based mud in deepwater environment. Historically, deriving an accurate caliper from LWD electromagnetic propagation resistivity measurements has never been easy due to big uncertainty of mud resistivity (Li et al, 2003). The implementation of a novel simultaneous inversion model and forward modeling database from standard 2-Mhz propagation resistivity, for water-based mud (WBM) and large boreholes, provided the solution to overcome that uncertainty (Whyte et al, 2012). This novel solution was specifically developed to address the needs for the riserless top-hole sections of high cost deepwater wells: from cement volume calculations, identification of borehole degradation through time, and new opportunities for identification of shallow water flows using the full capacity from the inversion process. The extensive validation of this innovative approach with wireline mechanical calipers in numerous hole sections resulted in far better results than initially anticipated (Whyte et al, 2012). The information obtained provided significant insights into the reliability and limitations of the current algorithm. The ability to monitor the borehole size while drilling, as well as analyzing the reaming and trip out passes from recorded data, makes this measurement a valuable source of time-lapse information. The next validation process consisted in the comparison between cement volumes computed using these measurements against identification of cement returns during riserless cementing operations in deepwater wells. The LWD caliper derived from propagation resistivity measurement was analyzed in more than a dozen of wells in Gulf of Mexico. Spefic case studies covering the drilling and cementing operations are presented in this paper.
We present results of monitoring studies on emergent coral reefs and submerged shoals, two potentially sensitive seabed habitats found within range of the modeled hydrocarbon plume from the 2009 Montara uncontrolled release in the Timor Sea.
Divers conducted reef surveys 6 and 16 months after the release was stopped. Hydrocarbons were detected in surface carbonate sediments at very low levels and declined between the two surveys in both frequency of occurrence and concentration. While hydrocarbon degradation precluded source matching, some samples were consistent with a Montara type oil, but there was also evidence for multiple sources of hydrocarbons in the region. Coral and fish communities were in good condition and potential indicators of disturbance in some elements, for example moderate levels of coral bleaching observed in 2010, were related to unusually warm sea surface temperatures rather than distance from the well head platform or plume.
The submerged shoals component targeted a series of nine discrete shoals ~30-150 km from Montara well head platform. The shoals have abrupt bathymetric profiles rising from 100-200 m depths to within 15-36 m of the sea surface. Sufficient light reaches these plateau environments to support benthic habitats for primary producers, including algae, corals and seagrass. Sampling used remotely deployed cameras and grabs.Benthic and fish communities were diverse and shared many species with shallow coral reefs. Hydrocarbon contamination was measured around the base of the shoals. While there was no conclusive evidence of a impact from the spill, spatial patterns in a subset of the fish data showed a reduction in abundance and diversity at shoals closest to the well head. Similarly a marked reduction in seagrass was noted on one shoal closest to the well head platform in the period between surveys, 6-16 months after the release was stopped. These observations may reflect an influence from the hydrocarbon release but could equally be the result of natural spatial patterns and disturbance events in the region.
Overall, the lack of sufficient prior data characterizing the region, especially for the shoals, constrained insights into any effect or otherwise of the spill and reinforces the need for regional scale baseline data. These surveys make a significant contribution and an excellent starting point for baseline characterization of the broader suite of emergent reefs and submerged shoal habitats in the Browse Basin.
The Well Life Cycle Practices Forum (WLCPF) was formed following the UKresponse to the Macondo tragedy in the Gulf of Mexico in April 2010. Inresponse to Macondo, Oil & Gas UK brought together representatives ofoperators, drilling contractors, regulators and trade unions to form the OilSpill Prevention and Response Advisory Group (OSPRAG). In addition todeveloping and building an emergency capping device, assessing and improvingoil spill response capability, and reviewing indemnity and insuranceliabilities, OSPRAG also carried out a review of the UK industry's approach tovarious aspects of well control. OSPRAG published a series of recommendationsin October 2010 which led to the creation of the WLCPF under Oil & Gas UKto help the UK upstream industry implement the recommendations. The WLCPF alsoserves as a forum to discuss pan-industry well-related issues and to interfacewith the UK regulators.
Results, Observations, and Conclusions
The WLCPF has published a series of guidelines to help UK operators comply moreeffectively with regulations and to improve the UK industry's understanding ofwell integrity issues. Six workgroups, with input from over 60 companies andorganisations, have produced guidelines on: BOP issues; relief well planningrequirements; well integrity throughout the well life cycle; competency;behaviours and human factors; well examination and verification.
Significance of Subject Matter
The UK upstream industry has confidence that the UK regulatory environmentdrives the right behaviours to prevent a major well-control incident.Nevertheless, there are areas in which there is scope for improvement. Theguidelines produced by WLCPF, and the WLCPF model itself, could be used byother oil and gas producing provinces to reduce risks in well operations.