There are two essentially different types of inclination-only tools in current use. The simple MD TOTCO deviation survey tool (single shot) so, called after its manufacturer, and the slightly sophisticated Teledrift style of tool. Totco Ring A Totco ring is not really a drilling sub. We place a small insert inside the drill string between …
Halliburton’s Geopilot RSS rotary steerable system also uses “point the bit” technology. The design concept involves the deflection of a flexible shaft between the drilling bit and the drill string. A high-side reference housing contains a compact and rugged computer-controlled bias unit (eccentric rings) to impart a controlled deflection to this shaft element, allowing for …
Schlumberger provides three types of PowerDrive RSS or rotary steerable systems with different principles of operation, and different generations of tools exist within some of these groups. The division of systems is as follows: In addition to the above rotary steerable systems, a fourth service combines PowerDrive technology with an integrated motor power section. All …
The Baker Hughes AutoTrak RSS (Rotary Steerable) uses a non-rotating sleeve close to the drilling bit. The sleeve utilizes three independent hydraulic and control systems. The hydraulic pistons can push the bit to one side of the hole. And therefore, changing the wellbore’s inclination and/or direction (Figure 1). We can integrate the RSS AutoTrak with …
Formation pore pressure is the pressure exerted by the formation fluids on the walls of the rock pores. The pore pressure supports part of the weight of the overburden stress, while the rock grains take the other part [Rabia, 1985]. Formations are classified based on the magnitude of their pore pressure gradients. In general, two …
The only way to obtain information, before well drilling, on the nature and characteristics of the subsurface, including the pore pressure prediction, is through geophysical prospecting. The seismic reflection method is the most important and extensively used geophysical method for oil prospecting. Although geophysicists and geologists use seismograms mainly for subsurface structural and lithological interpretation, …
Background gas enters the mud circulating system as the formation is drilled by the drilling bit and usually maintains a steady but low level. Additionally, as shales are circulated up the hole, the reduction in pressure explodes the shale particles releasing gas into the drilling mud. These are the most common sources of gas. Pressure …
D is an exponent which, relating drilling penetration rate to weight on bit per unit hole diameter, measures the formation’s ” drillability “. There were several attempts to link the drilling parameters to generate a measure of drillability. The best known was by Jorden and Shirley *, who demonstrated empirically that in homogeneous shale formations, …
Jetting (or badgering) technique is used in directional wells to deviate wellbores in the soft formation. The technique was developed in the mid-1950s and superseded the use of whipstocks as the primary deflection technique. Although jetting or badgering in directional drilling has subsequently been supplanted by downhole motor deflection assemblies (as the primary deflection method), …
With the advent of steerable systems, some directional wells are planned and drilled with complex profile types involving 3-dimensional turns. Generally, this happens mainly in the case of re-drills, where old wells are sidetracked and drilled to entirely new targets. However, these complex well paths are harder to drill, and the old adage that “the …