Process Engineering Term - S

SALES VALUE - The proceeds received for the sale of the mineral.

SALT WATER DISPOSAL WELL - Many wells produce salt water while producing oil. The disposal of this water is a problem to an operator because of pollution. The best solution to the problem is to pump the waste back into a formation that is deep enough not to pollute shallow water sands. Many stripper wells which are no longer commercial are converted for this purpose.

SATURATION - (1) The extent to which the pore space in a formation contains hydrocarbons or connate water. (2) The extent to which gas is dissolved in the liquid hydrocarbons in a formation.

SCOUT TICKETS - A written report of wells drilling in the area. The reports contain all pertinent information - all that can be found out by the enterprising oil scout; operator, location, lease, drilling contractor, depth of well, formations encountered, results of drillstem tests, logs, etc. On tight holes the scout is reduced to surreptitious means to get information. Talks to water hauler, to well-service people who may be talkative or landowner’s brother-in-law. The bird-dogging scout estimates the drillpipe set-backs for approximate depth; he notes the acid trucks or the shooting (perforating) crew; and through his binoculars, he judges the expressions on the operator’s face: happy or disgruntled.

SECONDARY RECOVERY - A broad term encompassing any method of extracting oil from a reservoir after a well or field has exhausted its primary production.

SEDIMENTARY ROCKS - Rock is generally classified in one of three categories: a. Sedimentary; b. Igneous; c. Metamorphic.

SEPARATOR GAS - Natural gas separated out of the oil by a separator at the well.

SERVICE ZONE COMPLETION - The interval in a well bore that has been mechanically prepared for service use, usually water or gas injection to stimulate production from other wells or for water or other waste disposal.

SET CASING - To cement casing in the hole. The cement is pumped downhole to the bottom of the well and is forced up a certain distance into the annular space between casing and the rock wall of the drill hole. It is then allowed to harden, thus sealing off upper formations that may contain water. The small amount of cement in the casing is drilled out in preparation for perforating to permit the oil to enter the casing. The decision to set casing (or pipe) is an indication that the operator believes he has a commercial well.

SETTLED PRODUCTION - The second phase of production in the producing life of a well. (see IP).

SHALE - A very fine-grained sedimentary rock formed by the consolidation and compression of clay, silt, or mud. It has a finely laminated or layered structure. Shale breaks easily into thin parallel layers; a thinly laminated siltstone, mudstone, or claystone. Shale is soft, but sufficiently hard packed (indurated), so as not to disintegrate upon becoming wet. However, some shales absorb water and swell considerable, causing problems in well drilling. Most shales are compacted, and consequently, do not contain commercial quantities of oil and gas.

SHOT HOLE - A small-diameter hole, usually drilled with a portable, truck-mounted drill, for “planting” explosive charges in seismic operations.

SHUT IN - To close the valves at the wellhead so that the well stops flowing or producing; also describes a well on which the valves have been closed.

SHUT-IN PAYMENTS - Payments made for any producible well on the Federal OCS that is temporarily closed down. (See Shut-in zone completion.)

SOUR GAS - Natural gas containing chemical impurities, a notable hydrogen sulfide (H2S) or other sulfur compounds that make it extremely harmful to breathe even small amounts; a gas with disagreeable odor resembling that of rotten eggs.

SQUEEZING A WELL - A technique to seal off with cement a section of the well bore where a leak or incursion of water or gas occurs; forcing to the bottom of the casing and up the annular space between the casing and the wall of the borehole to seal off a formation or plug a leak in the casing; a squeeze job.

STRATIGRAPHIC TEST - A test well drilled to obtain information on the thickness, lithology, porosity, and permeability of the rock layers drilled through or to locate a key bed. Such wells are often drilled to evaluate a potentially productive pay zone.

STRIPPER WELL - The final state in the life of a producing well.

STRUCTURAL TRAP - A fold or break (or both) in the earth's crust which creates an impervious trap for oil and gas. Oil will migrate underground through rock until it is "trapped".

SUCKER ROD - Steel rods that are screwed together to form a “string” that connects the pump inside a well’s tubing downhole to the pumping jack on the surface; pumping rods.

SURFACE PIPE - Pipe which is set with cement through the shallow water sands to avoid polluting the water and keep the sand from caving in while drilling a well.

SUSPENDED WELL - A well on which operations have been discontinued. The usual context is an uncompleted well in which operations ceased during drilling but which has not been plugged and abandoned permanently.

SWAB - A tool which is lowered down the pipe on a wire line. The "swab" is then pulled out of the hole. As it travels up the pipe, rubber elements expand so that the fluid in the pipe is trapped above the swab and pushed to the surface. This operation is necessary when the formation pressure is not high enough to blow the fluids in the pipe to the surface.

SWEET CRUDE - Crude oil containing very little sulfur and having a good odor.

SWEET GAS - Natural gas free of significant amounts of hydrogen sulfide (H2S) when produced.

3-D SEISMIC PROGRAM - Seismic surveys shot from surfaces to map underground stratigraphy; to profile the underlying strata in search of up-dips, down dips, faults, and other promising anomalies.