Water-Base Muds

    Drilling Muds A water-base drilling fluid is one that has water as its continuous or liquid phase. The types of drilling fluids are briefly described in the following sections. Freshwater muds are generally lightly treated or untreated muds having a liquid phase of water, containing small concentrations of salt, and having a pH […]


Oil Well Casing

    Types of Casing  Based on the primary function of the casing string, there are five types of casing to be distinguished. Stove or Surface Casing The stovepipe is usually driven to sufficient depth (15–60 ft) to protect loose surface formation and to enable circulation of the drilling fluid. This pipe is sometimes cemented […]


Drilling Fluid Additives

      Each drilling fluid vendor provides a wide array of basic and specialty chemicals to meet the needs of the drilling industry. The general classification of drilling fluid additives below is based on the definitions of the International Association of Drilling Contractors (IADC): Alkalinity or pH control additives are products designed to control […]


Fishing Equipment

Fishing Operations and Equipment A fish is a part of the drill string that separates from the upper remaining portion of the drill string while the drill string is in the well. This can result from the drill string failing mechanically, or from the lower portion of the drill string becoming stuck or otherwise becoming […]

Well Control

Basically, all formations penetrated during drilling are porous and permeable to some degree. Fluids contained in pore spaces are under pressure that is overbalanced by the drilling fluid pressure in the well bore. The borehole pressure is equal to the hydrostatic pressure plus the friction pressure loss in the annulus. If for some reason the […]


Wells – Chemicals

Chemicals Used in Fracturing The identities of chemicals incorporated in fracturing fluids were probably the first thing sensationalized about fracturing. The movie “Gasland” created quite a stir with the statement that a “cocktail” of several hundred toxic chemicals were “potentially” used in fracturing. The grain of truth was that there are many chemicals in additives […]

Drilling Rotating Equipment

Drilling Rotating Equipment

    Rotating system: the figure indicate the comparative sizes of the drill pipe and drill collar. Swivel ♦ The swivel hangs from the drilling hook by means of large bail, or handle. The swivel is not rotate, but allow everything below it to rotate. ♦ Drilling fluid is introduced into the drillstem through a […]


Oil-Base and Synthetic-Base Muds

Drilling Mud Tests The field tests for rheology, mud density, and gel strength are accomplished in the same manner as outlined for water-based drilling mud. The main difference is that rheology is tested at a specific temperature, usually 120◦F or 150◦F. Because oils tend to thin with temperature, heating fluid is required and should be reported on the […]


Testing of Drilling Systems

    To properly control the hole cleaning, suspension, and filtration properties of a drilling fluid, testing of the fluid properties is done on a daily basis. Most tests are conducted at the rig site, and procedures are set forth in the API RPB13B. Testing of water-based fluids and nonaqueous fluids can be similar, but variations of procedures occur […]


Acidizing Concepts

Acid Types Although many acid compounds are available to the oil industry, only the following types have been proven economically effective in oil well stimulation: Inorganic Acids (Strong). · Hydrochloric Acid (HCl). · Hydrofluoric Acid (HCl:HF). Other inorganic acids include Sulphamic, Sulphuric and Nitric acids. Organic Acids (Weak). · Acetic Acid and Glacial Acetic Acid. · […]


Measurement While Drilling MWD

The use of measurement and logging while drilling has matured a great deal in the last 10 years.  The use of these tools that have been developed for the oil and gas industry for use in primarily sedimentary depositional environments must be investigated in light of the goals set for EGS systems.  Let us first […]

directional drilling

Directional Drilling Glossary

The glossary of terms used in directional drilling has been developed by the API Subcommittee on Controlled Deviation Drilling under the jurisdiction of the American Petroleum Institute Production Department’s Executive Committee on Drilling and Production Practice. The most frequently used terms listed below. Angle of inclination (angle of drift). The angle, in degrees, taken at […]

Drilling Bit

Drilling Bits

when talking about oil well drilling, it is important to know How well the drilling bit drills depends on several factors, such as the condition of the drilling bit, the weight applied to it, and the rate at which it is rotated. Also important for a drilling bit performance is the effectiveness of the drilling […]

Drilling Fluids

Drilling Fluid Definitions and General Functions Results of research has shown that penetration rate and its response to weight on bit and rotary speed is highly dependent on the hydraulic horsepower reaching the formation at the bit. Because the drilling fluid flow rate sets the system pressure losses and these pressure losses set the hydraulic […]

Offshore Drilling Rigs

The sequence of operations is as follows when a land well is drilled: –  Prepare location before rig arrives. – Dig cellar. – Install conductor pipe. – Prepare support pad for rig, camp, etc – Build roads, fencing, dig pits. – Sometimes drill water well. – Move rig on to location, rig up and prepare […]

Well Logs

by Ahmed Imad   Well log is a continuous record of measurement made in bore hole respond to variation in some physical properties of rocks through which the bore hole is drilled. Traditionally Logs are display on girded papers shown in figure1. Now a days the log may be taken as films, images, and in digital […]


Completion Techniques

    by Abass Radhi Abbas 1.General Communication between the formation and the wellbore will directly affect the productivity of the well. Factors such as hydrocarbon saturation, porosity, permeability, fluid properties and geometry can be measured or inferred from the measurements but they cannot usually be controlled. By contrast, completion can be controlled and thus […]

oil well

Well Pressure Control

    Basically all formations penetrated during drilling are porous and permeable to some degree. Fluids contained in pore spaces are under pressure that is overbalanced by the drilling fluid pressure in the well bore. The borehole pressure is equal to the hydrostatic pressure plus the friction pressure loss in the annulus. If for some […]

Drilling Pipe

    The major portion of drill string is composed of drill pipe. Drill pipe consists of three components: a tube with a pin tool joint welded to one end and a box tool joint welded to the other.       Before the tool joints are welded to the tube, the tube is upset, or forged, […]