Chapter 3 Drilling Fluids

Chapter 3 Drilling Fluids

Author	Zifeng Li
Published	2010
Pages	76

Chapter 3 Drilling Fluids is a 76-page chapter of the petroleum drilling engineering teaching text written by Zifeng Li, professor of petroleum engineering at Yanshan University. It is not a separate book: it is one of thirteen instalments of a single work, each deposited on this wiki under its own title.

The chapter covers drilling fluid — the circulating medium, universally called "mud" in the field, on which every stage of a drilling operation depends.

Drilling fluids

Drilling fluid is pumped down the drill string, out through the nozzles of the bit, and back up the annulus between the string and the borehole wall. Almost nothing in a well can be done without it, and it performs several duties at once:

• Removing cuttings. The returning stream carries rock fragments from the bit face to surface. If it fails, cuttings accumulate and the string sticks.
• Cooling and lubricating the bit and string. A rock bit under load generates heat and friction that would otherwise destroy it.
• Controlling formation pressure. The hydrostatic column of fluid in the hole must exceed the pressure of the formations being penetrated, or those formations will flow into the well — a kick, and if uncontrolled, a blowout. This is the link to well control, the subject of chapter 6.
• Stabilising the borehole wall. The fluid supports the open hole mechanically and, through the filter cake it deposits, chemically — a matter of the fluid's chemistry as much as its weight, since many shales swell and slough when contacted by water.
• Sealing permeable formations so that fluid is not lost into the rock.
• Transmitting hydraulic energy to the bit, which bears directly on rate of penetration and so on the optimisation of drilling parameters.
• Suspending solids when circulation stops, so that weighting material does not settle out during a connection or trip.

The properties engineered to achieve this are density (set by barite or other weighting agents), rheology (the viscosity and gel strength governing carrying capacity and pressure loss), filtration behaviour, and solids content. The principal families are water-based, oil-based and synthetic fluids, with air, mist and foam used where formation pressures allow.

The competing requirements are what make the subject a chapter rather than a paragraph. Fluid heavy enough to hold back formation pressure may fracture a weaker formation lower down and be lost into it; fluid viscous enough to carry cuttings costs pump pressure that would otherwise drive the bit. Drilling-fluid design is the management of those trade-offs.

The parent work

The wiki record of this book was imported from a text file in 2016–2017, and the imported markup carried the Chinese half of the table of contents in a legacy encoding that did not survive. On every one of the thirteen pages it now renders as strings of question marks. The Chinese chapter titles are unrecoverable from the wiki text; the English glosses survive, and the contents of the work are:

• Introduction of drilling engineering
• Chapter 1 — Engineering geology of drilling
• Chapter 2 — Drill tools
• Chapter 3 — Drilling fluids
• Chapter 4 — Optimization of drilling parameters
• Chapter 5 — Design and control of well trajectory
• Chapter 6 — Well control
• Chapter 7 — Well cementing and completion
• Chapter 8 — Other drilling operations

This is the syllabus of a standard university course in drilling engineering, and it proceeds in the order a well is actually drilled: what the rock is, what cuts it, what circulates through it, how fast to push, where to steer, how to keep it from blowing out, how to case and complete it.

Why an engineering textbook appears on this wiki

Zifeng Li is catalogued here for his physics, not his petroleum engineering. He is one of the most persistent critics of special relativity writing in Chinese, arguing in papers such as Special Relativity Arising from a Misunderstanding of Experimental Results on the Constant Speed of Light and Materialistic Views of Space-Time and Mass-Energy that relativity rests on a misreading of experiment and on an idealist conception of space and time that a materialist physics should reject.

His engineering work is nevertheless part of the record, and deliberately so. Li is not an outsider to technical science: he is a doctoral supervisor, a technical editor for SPE Drilling & Completion, and the author of the standard Chinese monograph on rod and pipe string mechanics in oil and gas wells. His dissent from relativity comes from someone whose professional competence in applied mechanics is not in question — which is precisely the kind of case this wiki exists to document, and the reason his teaching texts are catalogued alongside his physics papers.

There is a further connection he himself draws. Li's objection to modern physics is that it has drifted from materialism into abstraction — that space, time, mass and energy are properties of matter in motion rather than free-standing geometrical entities. A working engineer's subject like drilling fluid, where a mistake about a real physical quantity is answered immediately by the well, is the standing contrast he has in mind.

The other chapters on this wiki

• Part 1 of Introduction of Petroleum Drilling Engineering · Part 2 of Introduction of Petroleum Drilling Engineering · Part 3 of Introduction of Petroleum Drilling Engineering
• Chapter 1 Engineering Geology of Drilling
• Part 1 of Chapter 2 Drilling Tools · Part 2 of Chapter 2 Drilling Tools
• Chapter 3 Drilling Fluids (this page)
• Chapter 4 Optimization of Drilling Parameters
• Chapter 5 Design and Control of Well Trajectory
• Chapter 6 Well Control
• Chapter 7 Well Cementing and Completion
• Chapter 8 Other Drilling Operations

See also

• Zifeng Li
• Tubular Mechanics in Oil-Gas Wells and Its Applications
• Category: Book