OFFSHORE REPORT

DEEPWATER: Loop currents in the Gulf of Mexico have caused operators operational problems for years. The industry has learned to identify them and work around them, but little was know about how they formed. Authors from LSU’s Coastal Marine Institute recently completed an observational study in the eastern GOM where these currents form. They present their findings in this article..

DEEPWATER PRODUCTION: A major oil company and a service company teamed up to overcome production impairment from fines and scale in a deepwater field, using coiled tubing on an intervention vessel. Laboratory testing led to an optimal treatment, while limiting damage to downhole equipment. The authors detail the process, execution and results of the well intervention..

DEEPWATER DRILLING: Exploring offshore Pakistan, Shell engineers faced a common limitation on using foamed cement imposed by rig deck load and space capacity. So, Shell selected DeepCRETE cement slurry and DeepCEM D185, D186, D193 and D175 deepwater additives from Schlumberger to cement a 13 3/8-in. surface string in a 17½-in borehole, taking into account the requirement for 150% excess volume as a safety factor against borehole washouts or losses. Essential to deepwater cementing are formulations that can set up quickly to block gas migration and support the pipe in unstable formations under the cold conditions of the deep sea environment..

OFFSHORE SEISMIC: Deepwater seismic data collection and processing. This case study describes a marine 3D reconnaissance survey, which presented challenges for both data collection and data processing. The challenges stemmed from the deep and complex water bottom, which caused issues with streamer geometry and also major multiple contamination within the seismic data. .

OFFSHORE COMPLETION: Oriented perforating provides benefits. Perforation guns have had the ability to be oriented for decades. The question was, if the stress field of the rock can be determined and perforated in a preferred orientation, would there be benefits from reduced sand production and/or increased production? After many offshore wells were completed with and without oriented perforation, the comparative results strongly suggest the technique results in more production.

 COMPLETION/STIMULATION TECHNOLOGY

In the Middle Bakken formation of North Dakota and Montana, many horizontal laterals are being drilled and completed with new insights gained with every hole. This case study summarizes the lessons learned during well stimulation and operation, explaining the effect of lateral length, wellbore azimuth and stimulation design on well production and well economics. Authors from Hohn Engineering, Nance Petroleum and Pinnacle Technologies present the state-of-the-art in horizontal Bakken completions.

Traditional hydrajetting equipment life has been plagued with rapid failures requiring frequent trips for replacement. The authors describe unique improvements, aside from the mere change of materials or use of customary concepts, that address the cause of jet-nozzle damage, jet-body damage and splashback damage. Detailed studies were performed studying the effects of flow overshot and coriolis effects inside of the tool.

Criteria for fracturing, including fluid selection for specific reservoir conditions, proppant selection, and whether to use water fracs. An overview and concise guide for fracturing that gives practical criteria for selecting the parameters of fracture stimulation, authored by an expert in reservoir engineering.

Fifty-seven high-permeability wells in Mexico’s offshore Cantarell field were acidized with a novel acid diverter based on an Associative Polymer (AP). The low viscosity of the AP diverting system results in ease of mixing, low-friction pressures and eliminated the need for special manifolding or pump requirements. This AP inherently reduces the formation permeability to water with little or no effect on the permeability of hydrocarbons. The field data presented by Pemex and Halliburton shows that the AP outperformed other diverters, such as foams and in-situ crosslinked acid.

 OIL COUNTRY TUBULAR GOODS

After a rigorous development program, a spall-resistant hardbanding process was developed that offers superb drillstem wear resistance and casing-wear protection while reducing friction. These new materials can withstand long and complex drilling programs where extended drilling through casing is required. Through the collaboration of Grant Prideco, the Nano Steel Company, Noble Drilling Ltd. and Nabors Drilling, the process uses nanotechnology and a systematic design approach to manipulate material properties to the desired characteristics..

Casing for mild sour applications. Authors from Valence Operating Company and V&M Star describe the development and application of a 110 KSI pipe grade specifically designed for mild sour service in Valence’s large drilling program in Leon County, Texas. The casing is suitable for wells with the potential to develop a mildly sour environment, but without incurring the significant cost of going to a C110 or T95 product. The new product grade was developed consistent with NACE requirements and to meet all of the requirements of API 5CT/ISO 11960 2004, grade P110. Valence began using the new pipe grade in 2007, resulting significant cost savings.

What’s new in expandable technology? Now in its sixth successful year, World Oil provides a report from all the major, and even some small, expandable service providers. This technology has not seen the usual slow uptake that others have. Service providers and operators have been very busy in developing and using this technology. The report includes all types of expandable technology: casing, patches, screens, etc.

The latest advancements single-diameter wells and monobore liners. This technology has now been achieved with increasing lengths and applications. It could mean a step-change in drilling, by eliminating telescoping casing strings and a workaround for getting through underpressured zones. Each year, technical advances are made to achieving this in a one trip, cost-effective approach. Not only will vertical wells benefit, but it may be the only way to drill some ultra-long extended-reach wells. What the problems are, and how they are being resolved, are discussed. Enventure, Baker Hughes and Weatherford are the principle players in this technology.

 NORTH SEA REGIONAL REPORT

Deloitte Oil and Gas Division, an international consultancy, discusses the most recent North Sea drilling and development activity, as well as governmental policy changes that affect the upstream oil and gas industry.

 REMOTE SENSING

Air-based instrument platform technology test. A field-wide airborne EM survey was conducted with the National Energy Technology Laboratory and Fugro at US Department of Energy facilities. The project located steel-cased wells, tested the effectiveness of cathodic production systems, and determined background atmospheric concentrations of CH₄ and CO₂ (methane and carbon dioxide).