Sonic log data help determine formation strength

Journal Article · Mon Dec 28 04:00:00 EST 1992 · Oil and Gas Journal; (United States)

OSTI ID:6982863

Stein, N ^[1]

---

1. Sans Co., Boston, MA (United States)

This paper reports that a set of equations helps improve the reliability of using acoustical wave velocity (dynamic) data to obtain quick, acceptable estimates for the Mohr-Coulomb (static) strengths of different types of rock. Good estimates of formation strength from offset well sonic log data can help in the planning of bit programs and well stimulation procedures. Dynamic shear modulus values were calculated from Mohr-Coulomb strength plots for five limestone samples. Care must be exercised in applying this method with log data. The terminal stress decreases as rock strength increases. The true vertical stress should be used in the calculations until the terminal vertical stress is exceeded. If the field-measured stress conditions exceed 6,300 psi for friable sands, 1,500 psi for well-cemented sands, and 500 psi for limestones, then the calculations should be based on the terminal stress values rather than true stress.

• OSTI ID: 6982863
• Journal Information: Oil and Gas Journal; (United States), Journal Name: Oil and Gas Journal; (United States) Vol. 90:52; ISSN OIGJAV; ISSN 0030-1388
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
CALCULATION METHODS
CARBONATE ROCKS
DATA PROCESSING
EQUATIONS
LIMESTONE
OIL WELLS
PROCESSING
ROCKS
SEDIMENTARY ROCKS
SHEAR
SONIC LOGGING
VELOCITY
WAVE PROPAGATION
WELL LOGGING
WELLS