CORING
Conventional coring is acquisition and recovery to surface of a continuous column of reservoir formation material. To the extent possible, core samples are taken in an undamaged, physically unaltered state. The formation material may be solid rock, friable rock, conglomerates, unconsolidated sands, coal, shales, gumbos, or clays. Moreover, the reservoir core material itself will provide the most accurate information available to geologists, engineers, and petrophysicists.
Through coring, Engineers, Geologists and Petrophysicists gain access to reservoir information that can be gathered in no other way. Data on the formation’s lithology, flow characteristics, storage capacity and production potential are just a few of the valuable types of information that can be obtained by a successful coring program. This chapter discusses what coring is and the benefits associated with the process. It also describes how to plan a successful coring project and the BHI coring services that are available. |
A coring program is similar to many engineering projects. It begins with the premise that an investment will reap a reward. It progresses through a phase of exploring alternate sources of information; well tests, logs, previous cores, and cuttings or sidewall cores. This is best done by a team of petrophysical, reservoir, geological, drilling, and production personnel. Hole size, hole angle, temperature, pressure, and rock type will influence the selection of the coring tools. The keys to a successful coring operation are planning and communication. The objective of every coring operation is to gather information that leads to more efficient oil or gas production. |
The main objective of this document is to provide the basis for understanding core analysis and the relationship between core measurements and reservoir simulations. The determination of two-phase properties such as capillary pressure or relative permeability are never simple measurements like porosity or permeability: they must be determined by numerical calculations generally with inverse methods. For many decades, approximate analytical solutions have been used due to the lack of numerical simulators (Hassler-Brunner method for capillary pressure for centrifugation or JBN for relative permeabilities). In most of cases, the analytical calculations lead large errors. |
< back