D4102 - Servicing oil and gas wells without rigs, including cementing, oil well decommissioning, pump and water well servicing, acidizing, fracturing, perforating and wireline work.

Operational Details
Cementing involves pumping cement downhole to secure the well casing. After a hole has been drilled, the hole is seldom used again, and therefore must be closed to meet environmental standards. Shot hole cementers place a plug down the hole and fill the hole with cement from the plug to the surface. Abandonment or decommissioning of oil wells involves pumping cement into the well hole in order to secure the casing after cleaning any contaminated oil, gas, or water from the well. The final stage known as cut and cap is when the plugged oil well casing is cut below the surface of the earth. Abandonment or decommissioning only refers to filling up the unused well and does not include the reclamation of the oilfield where the earth is put back to its original state. Tools and equipment used in decommissioning include earth-moving machines, concrete trucks and mechanical cutters. Acidizing is a well stimulation technique that involves pumping acid into a drilled well in order to clean out unwanted materials and debris and improve the productivity of the well. Fracturing is another method of stimulating the well, this includes pumping fluid into the well at a very high pressure which causes the rock to fracture. Oil is then extracted from the rock and pumped to the surface.  Wire line services involve lowering special instruments into a well for testing purposes. A wireline may also be used to pull instruments out of the well or to remove debris from the wellbore.
A wire line truck is equipped with a winch type cylinder that unrolls and rolls up cable onto which instruments or cleaning tools can be attached. A worker drives the wireline truck to the worksite where they assemble or attach the required equipment or recorders to the drill stem or wireline, they then conduct the prescribed procedures and finish by retrieve the equipment from the well.  Perforation refers to a hole being punched in the casing or liner of an oil well to connect it to the reservoir. Perforation is accomplished by lowering a device called a perforating gun to the desired depth in a well and firing them to perforate the casing. Perforating guns use electrical signals from the surface to fire the guns.
Mud logging includes the taking of samples of drill cuttings which are gathered by a mud technician, who might also be a geologist, who analyzes drill bit performance and rate of penetration. Equipment used to confirm the information are chromatographs, total gas analyzers, and ultra-violet boxes, which records UV light and microscopes.

Well testing includes the testing of production levels, downhole pumps and pump jack units. Production testing is performed by compressor equipment that introduces water, nitrogen, or air into the wellbore under pressure and records information on pressure instruments.

SIC Codes
000000345 - Servicing oil and gas wells
000000904 - Shot hole cementing, decommissioning oil wells
000000918 - Pump & water well servicing
000000873 - Acidizing & fracturing
000000872 – Wireline service & perforation