Maxcor® Large-Diameter Rotary Sidewall Coring Technology

Tue, 01/22/2013 - 14:28

Core analysis is an essential part of understanding the geophysical and geochemical characteristics of an oil or gas reservoir. By acquiring and studying rock samples from reservoirs, operators are able to accurately understand the porosity and permeability levels in a well, and have better insight and understanding of the challenges and complications they will face, as well as the strategies they will need to apply to successfully extract the hydrocarbons in place.

Core samples are cylinder shaped rocks taken from the side of drilled oil or gas wells and are usually dissected into multiple samples. In order to successfully acquire oil and gas reservoir core samples, drilling must halt at the top of the subsurface of the reservoir, and the drilling bit must be removed and replaced with a rotary coring bit that is usually composed of diamond, solid metal or tungsten. Unlike the drilling bit, the rotary coring bit has a hollow center called the core barrel, where the core is stored. After the core sample has been acquired, the rotary coring bit is retrieved and the drilling bit installed for drilling to resume. Following recovery of the core sample, it is analyzed in order to understand the porosity and permeability of the rock, but also to uncover the fluid saturation and grain density in order to better understand the conditions of a specific well and the potential productivity levels it may have.

Baker Hughes’ MaxCOR® Large-diameter Rotary Sidewall Coring Technology offers the fastest, most efficient technology for acquiring high-quality 1.5” (3.8 cm) core samples that enable accurate reservoir evaluation and ultimately maximized hydrocarbon recovery. This new technology, which was commercialized in 2011, has a large- diameter rotary sidewall coring tool that can tolerate high-pressure and high-temperature environments, and has the capacity to acquire three times more volume in around the same amount of rig time it takes to deploy standard 1in (2.54cm) rotary sidewall coring tools. Additionally, these larger core samples also give operators the ability to more accurately analyze reservoirs and optimize the hydrocarbon recovery rate of reservoirs since the MaxCOR® sidewall coring service is able to obtain 60 samples in a single run, and operate at up to 25,000 psi and at temperatures of up to 204°C, which are the highest temperature and pressure ratings in the industry according to Baker Hughes. Moreover, this new technology does not only offer more volume in the same amount of rig time, it also offers amore accurate measurement of vital reservoir characteristics such as porosity, permeability and geomechanical properties.

Even though there are multiple options available for core analysis services in the market, according to Baker Hughes MaxCOR® is the only coring technology that has the ability to offer core analyses services after a well has been drilled or is being drilled. Most coring services require the drilling to stop at the top of the subsurface of the reservoir, but this technology has a direct-drive electric motor in place of a traditional hydraulic motor to power the bit, providing maximum power transfer efficiency under all load and borehole temperature conditions, which increases the rotational speed of the bit and radically reduces coring time.

In addition to its applications in conventional oil and gas reservoirs, MaxCOR® Large-diameter Rotary Sidewall Coring Technology also has a proven ability to function in unconventional reservoirs, such as shale plays, and in deepwater wells. In Brazil, Baker Hughes has recovered 94 offshore cores with 100% core recovery efficiency, and in a secondary exploration region, the company claims to have successfully acquired 54 cores with a 30-core tube configuration. Even though these were the first successful large-diameter sidewall core field tests in deepwater, the company is extremely certain of its deepwater capabilities.

“MaxCOR® technology has been used successfully in a number of US shale reservoirs, including the Barnett and the Eagle Ford shale basins,” says Luis Moncada, Vice President of Baker Hughes’ Mexico Geomarket. “This service is invaluable for providing the high-quality core samples operators need to more accurately characterize complex deepwater and shale reservoirs.”