As part of the Devil Creek Development Project, Apache successfully used horizontal directional drilling (HDD) with a delayed break out as the installation method for the shoreline crossing of a new gas pipeline at Gnoorea Point, 45 km southwest of Dampier, Western Australia to achieve excellent environmental and social outcomes.
Technical, environmental and community engagement challenges included an HDD reach distance of 1.85 km, a delayed break out technique, hard complex and variable geological strata, the HDD exit point in shallow water (6 m) and surrounded by benthic habitats consisting of corals, seagrass and macroalgae within a Marine Conservation Reserve, stringent regulatory requirements and the onshore drilling location directly adjacent to a heavily used camping area and a public boat ramp with adjacent beach.
To achieve minimal disturbance to the marine environment and social amenity of the surroundings, an extensive and innovative marine monitoring programme was used in combination with an intensive community engagement programme. The techniques used for this project have application to oil and gas activities involving stringent regulatory requirements, sensitive marine environments and proximity to public amenities.
Results, Observations and Conclusions
Mapping of the drilling fluid showed a small area of the seabed that was affected. Some small, unplanned areas of leakage of drilling fluid onto the seabed were also identified and the leaks remediated: these leakages occupied only a very small area of the seabed. Apache were required to demonstrate that HDD activities resulted in no more than 0.5% loss of seagrass, macroalgae and coral based upon losses predicted from mapping, modeling suspended sediment concentrations in the water column and sedimentation rates on the seabed based on drilling fluid discharge rates and applying conservative coral health threshold criteria to discharge model outputs to predict zones of impact to benthic habitats. An extensive marine monitoring programme, sampling before and after HDD, using high definition video camera to capture photoquadrats conclusively demonstrated that losses were significantly less than predicted and permitted.
Drilling operations were a 24 hour activity and located directly adjacent to a popular camp site and boat ramp. Apache engaged with the community before and during the HDD activity and no complaints were received from the users of the area during operations.
Significance of the Subject Matter
Provides an example of industry's ability to operate successfully in sensitive marine environments and close proximity to communities.
In May 2011 Shell announced its commitment to the development of a Floating Liquefied Natural Gas (FLNG) concept by taking the Financial Investment Decision on the Prelude FLNG Project. Prelude is located in Australian offshore waters, approximately 475 km north-northeast of Broome and 825 km west of Darwin, and will be Shell's and possibly the world's first FLNG development. FLNG offers a number of environmental advantages over traditional onshore LNG developments. This paper describes some of these and the associated environmental permitting/approval conditions for the project.
The design team for the Wheatstone offshore platform successfully deployed an ‘Inherently Safe Design' (ISD) approach to engineering the gas processing complex. Through a program of initiatives focused on ISD, a substantial improvement in the safe design of the platform has been delivered.
Major accident events:
The Texas City incident in 2005 initiated the most detailed and far reaching investigation ever undertaken by the US Chemical Safety and Hazard Investigation Board (CSB) at the time. The CSB report included a recommendation that BP form an independent panel to conduct a review of the company's corporate safety culture, safety management systems, and corporate safety oversight at its U.S. refineries. This independent review was conducted and a separate report known as the Baker Report was developed, with the key conclusion being that the process safety culture was deficient.
Major incidents such as the Macondo and Montarra well blow-outs still occur. NOPSA newsletter Issue 86, February 2010 presented data on gas releases, a recognised precursor to major accident events and showed "Design problems at root of most major gas releases??.