UNIVERSITATEA “PETROL – GAZE” PLOIEŞTIFACULTATEA INGINERIA PETROLULUI SI GAZELOR

DEPARTAMENTUL FORAJUL SONDELOR

Simularea proceselor de foraj

Coordonator: sef lucr.dr.ing. Ionescu Mihai

Student: POPA ADRIAN DOREL

Specializarea: Forajul Sondelor

Anul: I Masterat

Ploiesti , 2015

Positive Displacement Motor It’s downhole motor used in the oil field to drive the drill bit or other downhole tools during directional drilling or performance drilling applications. As drilling fluid is pumped through the positive displacement motor, it converts the hydraulic power of the fluid into mechanical power to cause the bit to rotate.

It’s downhole motor used in the oil field to drive the drill bit or other downhole tools during directional drilling or performance drilling applications. As drilling fluid is pumped through the positive displacement motor, it converts the hydraulic power of the fluid into mechanical power to cause the bit to rotate.

During directional drilling, this capability is used while drilling in sliding mode, when the drillstring is not rotated from the surface. Positive displacement motors can also be used for performance drilling, straight hole drilling, coring, underreaming, and milling operations. In straight hole drilling, the motor functions as a drilling performance tool to increase the rate of penetration and reduce casing wear by minimizing drillstring rotation.

With high-performance power sections, these mud motors convert hydraulic energy to mechanical energy, which rotates the bit independently of the drillstring. The G2 mud motors results in significant cost savings through:

increasing bit rpm without increasing drillstring rotation speed drilling with less weight on bit reducing drillpipe and casing wear increasing ROP making long runs for extended interval drilling.

In drillstring operations, the mud pump horsepower is consumed as hydraulic horse power inside the drillstring, drillcollars and downhole motor, at bit nozzles and in the annulus.

The determination of the proper jet nozzle size is important because significant increases in penetration rate can be achivied through proper choice of nozzle sizes.

In drillstring operations, the total pump pressure needed is equal to te summation of the frictional pressure losses in the surface equipment, frictional pressure losses in the drillstring and collars, pressure loss in the downhole motor, pressure loss due to the aacelerations of drilling fluid through the jet bit nozzles and the frictional pressure losses in the annulus.

Furthermore to add to the maximization of the bit hydraulic horsepower, the motor horsepower needs to be taken as a separate independent parameter, as the pressure drop across the motor is a strong function of configuration of the motor and the weight on bit applied. The differential pressure across the motor is directly proportional to the weight applied to the bit. The mechanical horsepower (HP) developed by a motor can be calculated from the product of its torque and angular velocity.