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Drilling and Completion Fluids

When you take a look at the oil industry these days, what is the one thing you hear and read about the most? “Shale plays.” Operators are developing resources, purchasing acreage, and purchasing companies that have acreage in the USA and in countries around the world, now more than ever before.

For long-term economic stability of these projects, they need to be drilled as inexpensively and as fast as possible–basically, they need to be “factory-type wells.” The main fluid-related challenges associated with shale drilling are rate of penetration (ROP), shale stability, torque and drag, and waste management. Many of these wells are being drilled with nonaqueous fluids (NAFs) to meet these challenges, with the only real issue being waste management. However, there are technologies being used that reduce the amount of waste generated with NAFs, such as premium solids-control systems and thermal-desorption methods.

In an effort to eliminate NAF waste-management issues, drilling-fluids companies have developed fit-for-purpose water-based drilling fluids for each of the major shale plays. The shale regions around the world vary in depth, mineralogy, temperature, and other characteristics, and a single fluid formulation does not fit all circumstances. Each fluid is customized to the unique characteristics of a particular shale region. Fluids companies have specific products and chemistries that are designed for a specific type of shale and drilling operation.

As technological advances enable exploitation of shale resources around the world, the challenge will be to find the most-cost-effective solution. As always, the lowest overall well cost may not result from the lowest-cost-per-barrel drilling fluid. One has to take into account ROP, torque and drag, wellbore stability, and waste management when determining the most-cost-effective solution.

There were many good papers written this year, and I have tried to choose a variety of universal topics. Please take time to read them and the papers listed as additional reading.

Read the paper synopses in the November 2011 issue of JPT.

Brent Estes, SPE, is a Drilling Fluids Specialist for Chevron Energy Technology Company supporting worldwide drilling operations. Previously, he was with ExxonMobil and Baroid Drilling Fluids. Estes earned a BS degree in petroleum engineering from Texas A&M University. He has a broad background in all aspects of drilling and completion fluids, including fluids research and development and working as a drilling engineer. Estes has authored several SPE papers and serves on the JPT Editorial Committee.


Quantifying the Invisible: Getting a Handle on Methane’s Climate Impact

Robin Beckwith, Staff Writer JPT/JPT Online

Earlier this year, a Cornell University professor made quite a splash publishing a paper asserting that emissions from shale gas rivaled those from coal. A July 2011 study issued by the Post Carbon Institute underscored this conclusion. Not so, say five separate recent reports–from Carnegie Mellon University, IHS Cambridge Energy Research Associates (CERA), the US National Energy Technology Laboratory (NETL), Argonne Laboratory, and Deutsche Bank Climate Change Advisors (coauthored by individuals from Worldwatch Institute and ICF International). At heart are issues related to measuring and quantifying emissions of an odorless, colorless gas–methane (CH4)–considered the second-most prevalent long-lived greenhouse gas after carbon dioxide (CO2).

Read the full article in the November 2011 JPT.


From Bacteria to Barrels: Microbiology Having an Impact on Oil Fields

The science behind the use of microbes to enhance oil recovery has advanced significantly, but it suffers from old associations.

After decades of trial and error, those working on microbial enhanced oil recovery have identified the “oil-eating” bacteria that laboratory tests suggest can change the properties in an oil reservoir, and know better how to put them to work. The increasing knowledge of the role microbial life plays in oil and gas reservoirs has also led to new approaches for controlling corrosion, managing bacterially-produced hydrogen sulfide, and creating natural gas from coal.

(In this story, “eat” is used to describe the metabolic processes of bacteria. For instance, oil eating is more precisely hydrocarbon oxidizing.)

But the greatest potential payoff and the most debate come from the idea of microbes for enhanced oil recovery (MEOR). “There is a much greater understanding of what microbiology is doing in a reservoir” and how that can be used to produce more oil, said Stuart Page, chief executive officer of Glori Energy, a company that has staked its future of convincing the industry that microbes can be used to recover more oil.

Read the full article from the November 2011 JPT.

Technology Focus: Formation Evaluation

(JPT, August 2011)

Reportedly, companies are struggling to find petrophysicists for their subsurface teams, especially companies exploiting unconventional resources that require a major petrophysical effort to unlock their reserves potential. How has this state of affairs come about? Read more in the August 2011 issue of JPT, including three paper summaries in formation evaluation.

Carbon Capture and Sequestration

[Download the Carbon Capture and Sequestration white paper.]

Briefly stated, carbon capture and sequestration (CCS) will help us to sustain many of the benefits of using hydrocarbons to generate energy as we move into a carbon-constrained world. Even though the CO2 generated by burning hydrocarbons cannot always be captured easily in some cases (as in oil used for transportation), sequestration of CO2 from other sources (such as coal-fired power stations) can help to create, to some degree, the “headroom” needed for the volumes of CO2 that escape capture. Because of the likely continuing competitive (direct) cost of hydrocarbons and in light of the huge investment in infrastructure already made to deliver them, the combination of fossil fuel use with CCS is likely to be emphasized as a strong complement to strategies involving alternative, nonhydrocarbon sources of energy. Moreover, the exploitation of heavy oil, tar sands, oil shales, and liquids derived from coal for transportation fuel is likely to increase, even though these come with a significantly heavier burden of CO2 than that associated with conventional oil and gas. CCS has the potential to mitigate some of this extra CO2 burden.

If we wish to sustain the use of oil, gas, and coal to meet energy demands in a carbon-constrained world and to provide time to move toward alternative energy sources, then it will be necessary to plan for and implement CCS over the coming decades. Subsequently, we should expect a continued need for CCS beyond the end of the century.