Drilling motor with bypass and method

1. A downhole drilling motor comprising:

a motor housing comprising a power housing having an inner bore and an outer surface, a transmission housing having an inner bore and an outer surface, and a bearing housing having an inner bore and an outer surface, wherein the power housing is threadedly connected to the transmission housing and the transmission housing is threadedly connected to the bearing housing;

a power section including a stator elastomer and a rotor at least partially disposed within the inner bore of the power housing, the rotor having an upper end and a lower end, the lower end of the rotor directly coupled to an upper end of a rotor adapter;

a transmission section including a transmission shaft disposed within the inner bore of the transmission housing, the transmission shaft comprising a solid shaft without a central inner bore, the transmission shaft having an upper end and a lower end, the upper end of the transmission shaft directly coupled to a lower end of the rotor adapter;

a bearing section including an upper bearing disposed within the inner bore of the bearing housing; and

a first opening through the transmission housing, the first opening disposed below the stator elastomer and the lower end of the rotor and above the transmission shaft and the bearing section, wherein the first opening extends from the inner bore to the outer surface of the transmission housing to provide a bypass fluid path for a fluid from the inner bore to the outer surface.

2. The downhole drilling motor of claim 1 , further comprising one or more additional openings through the transmission housing, wherein each of the one or more additional openings is disposed below the stator elastomer and the rotor and above the transmission shaft and the bearing section, wherein each of the one or more additional openings extends from the inner bore to the outer surface of the transmission housing to provide the bypass fluid path for the fluid from the inner bore to the outer surface.

3. The downhole drilling motor of claim 2 , wherein a defined bypass fluid flow rate through the bypass fluid path depends on (i) a pressure drop created by a fluid flow through the bearing section and a drill bit of the downhole drilling motor and (ii) a total flow area of the bypass fluid path.

4. The downhole drilling motor of claim 3 , wherein the first opening and the one or more additional openings each has a diameter between 7/32 inches and 28/32 inches.

5. The downhole drilling motor of claim 3 , wherein the first opening and the one or more additional openings each has a nozzle disposed therein through which the bypass fluid path runs.

6. A downhole drilling motor comprising:

a motor housing comprising a power housing having an inner bore and an outer surface, a transmission housing having an inner bore and an outer surface, and a bearing housing having an inner bore and an outer surface, wherein the power housing is threadedly connected to the transmission housing and the transmission housing is threadedly connected to the bearing housing;

a power section including a stator elastomer and a rotor at least partially disposed within the inner bore of the power housing, the rotor having an upper end and a lower end, the lower end of the rotor directly coupled to an upper end of a rotor adapter;

a transmission section including a transmission shaft disposed within the inner bore of the transmission housing, the transmission shaft comprising a solid shaft without a central inner bore, the transmission shaft having an upper end and a lower end, the upper end of the transmission shaft directly coupled to a lower end of the rotor adapter;

a bearing section including an upper bearing partially disposed within the inner bore of the bearing housing;

a first opening through the transmission housing, the first opening disposed below the stator elastomer and the lower end of the rotor and above the transmission shaft and the bearing section, wherein the first opening extends from the inner bore to the outer surface of the transmission housing; and

a first nozzle disposed in the first opening through the transmission housing, the first nozzle configured to provide a bypass fluid path from the inner bore to the outer surface of the transmission housing for a fluid from the inner bore to the outer surface.

7. The downhole drilling motor of claim 6 , further comprising one or more additional openings through the transmission housing and one or more additional nozzles, each of the one or more additional nozzles disposed in one of the one or more additional openings through the transmission housing, wherein each of the one or more additional openings is disposed below the stator elastomer and the rotor and above the transmission shaft and the bearing section, wherein each of the one or more additional openings extends from the inner bore to the outer surface of the transmission housing, and wherein each of the one or more additional nozzles provides the bypass fluid path from the inner bore to the outer surface of the transmission housing.

8. The downhole drilling motor of claim 7 , wherein a defined bypass fluid flow rate through the bypass fluid path depends on (i) a pressure drop created by a fluid flow through the bearing section and a drill bit of the downhole drilling motor and (ii) a total flow area of the bypass fluid path.

9. The downhole drilling motor of claim 8 , wherein the first nozzle and the one or more additional nozzles each has an opening with a diameter between 7/32 inches and 28/32 inches.