What are typical build rates for horizontal wells?
The Build Up Rates (BUR) for horizontal wells will vary pending on the geological formations encountered while drilling combined with, motor and bit selection, and hole size but generally build rates of 6°/30m to 8°/30m are common.

What is the maximum motor setting that is rotable?
Rotating of Positive Displacement Motors (PDM's) vary with manufacturers and their guidelines. A general rule is to not rotate a setting greater than 1.83° as a risk of failure may occur. Much of this is premised on drilling parameters such as amount of rotation, hole size, weight on bit and the formation.

What kind of doglegs will the tools safely pass through?
Measurement While Drilling (MWD) tools will pass through the doglegs they drill through. The sensor package within the tool is stabilized to withstand rotational and bending stresses within certain tolerances. The tools can move through a 20°/30m dogleg sliding, as rotating through this could cause a malfunction of the components due to the stresses.

What is the minimum angle that is effective when drilling a directional well?
To optimize drilling a directional well, where more time is spent rotating vs. sliding the drill string some basic guidelines can be followed:
- A terminal angle of greater than 12° allows to still utilize gravitational forces (less sliding to maintain angle to target)
-angles less than 30° still allow for conventional wireline logging tools to be used

How important are survey's from nearby existing wells?
When planning wells where existing or nearby wells exist, knowing the distance relative to the proposed well is imperative. Surveys from these wells if available aid in collision avoidance through software creating anti-collision models. Without surveys, a "worst-case scenario" can be generated by theoretically deviating the existing wells towards the proposed well path.

How often are MWD and Gamma Ray tools calibrated?
MWD and Logging While Drilling (LWD) i.e. Gamma Ray equipment are checked and calibrated prior to their assignments. They must fall within specifications set out by manufacturers in order for them to function and work properly. Additional checks are done in the field, prior to running in the hole (roll check) and while running in the hole (shallow check) to assure correct working order and communication with all probes within the string.

What distance are the sensors from the bit?
Sensor distances vary for MWD equipment, as the makeup of the Bottom Hole Assembly (BHA), motors, Non-Magnetic Drill Collars (NMDC), Gamma Ray etc. will somewhat affect placement. Conventional directional equipment distances are in the 11-13m range from the bit, and a finalized distance is given with the known BHA.

Do solar storms or solar flares affect surveys?
Magnetometers that make up part of the sensor package in the MWD tool measures direction (azimuth) downhole. Solar activity along with latitude (Earth's poles) will have a pronounced affect on tool readings. Survey quality needs to be more closely monitored during these instances as when Solar storms originate from the sun's surface they are deflected by the earth's gravitational field producing a geomagnetic storm affecting magnetic declination readings, sometimes as high as 7°. Through the use of magnetic monitoring data sites, this can aid in reducing the affect on survey quality.

What is a datum?
A geodetic datum consists of a reference ellipsoid that is anchored to a certain area of the Earth to best represent that area's surface. This defines the shape and size of the earth and the origin/orientation of the coordinate system used to map the earth.

Is there a difference between NAD27 and NAD83?
Yes, with varying differences depending on the location in question. North American Datum of 1927 (NAD27) is based on the Clarke 1866 ellipsoid that originates at Meades Ranch, Kansas, USA (with the geoidal height assumed zero).
North American Datum of 1983 (NAD83) is based on the GRS80 ellipsoid, with a 'geocentric' origin, best used for North & Central America.

What is the requirement for surveying in the wellbore?
It is good practice to take survey measurements (inclination and azimuth) every 30m (1 single) to identify where you are located in the wellbore. This at times is increased (nearing a landing point, waypoint or existing well) or decreased (drilling vertically to Kick Off Point-KOP). Government regulations will stipulate the frequency of this as well i.e. Alberta-every 150m.

What is the difference between Build Up Rate (BUR) and Dog Leg Severity (DLS)?
BUR takes into account the amount of angle over a prescribed length (30m or 100') between two survey points to achieve a certain angle while Dog Leg Severity (DLS) also takes into account the change in direction (turn) over the same course length. These may impede drilling operations such as tripping or running casing should a wiper trip not be done.