Abstract: A method for remotely shutting down a downhole unit of a rotary steering system from ground includes steps of: a: calculating a pressure difference P1 between a front end and a rear end of the drill water hole; b: calculating an extension loss ?P; c: calculating a pressure P2 at the riser after turning on the downlink device; d: calculating an opening area S1 of the throttle valve of the downlink device; and e: adjusting the throttle valve to a calculated opening degree; automatically targeting the function block that needs to be cut off according to a flow change detected downhole, and shutting down the downhole unit. The method can realize self-protection and continuous operation of the entire rotary steering system, reduce frequency of inspection that needs to pull back the drill when the rotary steering system is abnormal, improve drilling efficiency, and reduce costs.

Abstract: A method for remotely shutting down a downhole unit of a rotary steering system from ground includes steps of: a: calculating a pressure difference P1 between a front end and a rear end of the drill water hole; b: calculating an extension loss ?P; c: calculating a pressure P2 at the riser after turning on the downlink device; d: calculating an opening area S1 of the throttle valve of the downlink device; and e: adjusting the throttle valve to a calculated opening degree; automatically targeting the function block that needs to be cut off according to a flow change detected downhole, and shutting down the downhole unit. The method can realize self-protection and continuous operation of the entire rotary steering system, reduce frequency of inspection that needs to pull back the drill when the rotary steering system is abnormal, improve drilling efficiency, and reduce costs.

Abstract: An example method includes combining an interlayer and a carbon fiber fabric, wherein the interlayer comprises a highly oriented milled carbon fiber ply comprising a plurality of out-of-plane carbon fibers. The method further includes winding the interlayer and the carbon fiber fabric around a core to form a composite fiber preform comprising a plurality of layers defining an annulus extending along a central axis. The method further includes densifying the composite fiber preform.

Abstract: An example method includes forming an interlayer on a carbon fiber fabric to form a composite fiber fabric. The interlayer comprises a binder. The method further includes winding the composite fiber fabric around a core to form a composite fiber preform comprising a plurality of layers defining an annulus extending along a central axis. The method further includes densifying the composite fiber preform.

Abstract: A method for controlling well bore pressure based on model prediction control theory and systems theory, includes: detecting a well bottom pressure, a stand pipe pressure, a casing pressure, an injection flow rate and an outlet flow rate during the drilling operation process and determining the presence of overflow or leakage; if there is no overflow or leakage, then fine-adjusting the wellhead casing pressure according to the slight fluctuations of the well bottom pressure, the stand pipe pressure or the casing pressure; if there is overflow or leakage, simulating and calculating the overflow or leakage position and starting time of the overflow or leakage, predicting the variation over a future time period of the well bore pressure in the well drilling process, and utilizing an optimization algorithm to calculate the control parameter under a minimum of an actual well bottom pressure difference during the future period.

Abstract: A method for controlling well bore pressure based on model prediction control theory and systems theory, which belongs to the field of well bore pressure control technique, includes: detecting a well bottom pressure, a stand pipe pressure, a casing pressure, an injection flow rate and an outlet flow rate during construction process, and determining the presence of overflow or leakage; if there is no overflow or leakage, then fine-adjusting the wellhead casing pressure according to the slight fluctuations of the well bottom pressure, the stand pipe pressure or the casing pressure, ensuring that the well bottom pressure, the stand pipe pressure or the casing pressure are at a set value; if there is overflow or leakage, then using a well bore multi-phase flow dynamic model to simulate and calculate the overflow or leakage position and starting time of the overflow or leakage, predicting the variation over a future time period of the well bore pressure in the well drilling process, and utilizing an optimization a