Glossary

Rat hole

see mouse hole.

Rate of penetration (ROP)

the depth of hole drilled in a specified time; usually given in feet per hour.

Raw natural gas

natural gas containing impurities and unwanted substances such as water, nitrogen, carbon dioxide, hydrogen sulphide gas and helium. Before the gas is marketed, these are removed.

Recompletion

the completion for production of an existing well bore in another formation from that in which the well has been previously completed.

Recoverable reserves

that proportion of the oil and/or gas in a reservoir that can be removed using currently available techniques.

Recovery factor

the ratio of recoverable oil and/or gas reserves to the estimated oil and/or gas reserves in place in the reservoir.

Refinery

a plant used to separate the various components present in crude oil and convert them into usable products or feedstock for other processes.

Relief well

a deviated well drilled into a structure for the purpose of relieving pressure in an adjacent well that has has suffered a blowout

Relinquishment requirement

an agreement whereby oil companies give up their some or all of their licence rights in concessions after a certain period of time. Often a partial relinquishment is made after the initial work programme has been completed.

Rental payment

an annual payment made by an oil company to a State in order to retain rights to a particular concession.

Reserves-to-production ratio

for any given well, field or country. The length of time that reserves would last if production continued at its current rate, at the current level of technology.

Reservoir

a stratum in which oil or gas is present. In a reservoir gas occupies the upper part of the reservoir as it is the lightest, oil the middle section, while water occupies the lower section.

Reservoir pressure

the fluid pressure in an oil or gas reservoir.

Reservoir rock

the porous rock containing interconnected pores or fissures in which oil or gas may be found.

Residual fuel oil

very heavy fuel oils produced from the residue from the fractional distillation process rather than from the distilled fractions.

Return on assets (ROA)

the net profit after tax expressed as a percentage of the total money invested in an enterprise.

Revenue

the gross income from the sale of products produced.

Reverse circulation

pump heavy fluid into the annulus in order to displace lighter fluid from the drillstring. Used in testing and squeeze cementing

Rich gas

gas which is predominantly methane but with a relatively high proportion of other hydrocarbons. Many of these other hydrocarbons would normally be separated out as NGLs.

RIH

run into hole.

Ring fence

a fiscal procedure whereby taxable profits from oil or gas production cannot be offset against other losses made by the company involved.

Riser

see marine riser.

Riser pipeline

a pipe that connects a platform to a sub-sea wellhead or spur line.

Risk capital

equity capital raised to finance a development that has technical, economic and other risks attached to it and thus cannot guarantee a return on investment

RKB

rotary kelly bushing. Depth reference. Well depths often quoted as below RKB.

Rotameter

instrument used to measure the flow rate of a liquid or gas in a pipe.

Rotary drilling

drilling in which the entire drill string and bit are rotated, as opposed to turbine drilling.

Rotary hose

the flexible hose that transfers the drilling mud from the stand pipe to the top of the drill string via a swivel coupling

Rotary RPM

the number of revolutions per minute of the drilling table, i.e. the angular velocity of the drill bit during rotary drilling

Rotary table

see drilling table.

Rotliegendes

formations laid down during the first part of the Permian Period.

Roughneck

one of the assistants to a driller; a labourer who works on the actual derrick floor of an offshore rig or platform.

Round trip

the process which occurs every time a drill bit has to be replaced, whereby the entire drill string is removed from the hole in roughly 90 ft sections and is then returned with a new bit on the end; also described as making a trip

Roustabout

a general labourer in an oil drilling and/or production operation.

Royalty

an interest in an oil and gas lease that gives the owner of the interest the right to receive a portion of the production from the leased acreage (or of the proceeds of the sale thereof), but generally does not require the owner to pay any portion of the costs of drilling or operating the wells on the leased acreage. Royalties may be either landowner's royalties, that are reserved by the owner of the leased acreage at the time the lease is granted, or overriding royalties, which are usually reserved by an owner of the leasehold in connection with a transfer to a subsequent owner