9 results about "Underbalanced drilling" patented technology

A method for underbalanced drilling includes drilling into a subterranean geological formation to form a wellbore therein, injecting a foaming agent into the wellbore during drilling at a wellbore pressure that is below a pore pressure of the subterranean geological formation, and transporting drill cuttings formed by the drilling away from the drilling surface in the foam. The foaming agent forms a foam in the wellbore at a drilling surface at a bottom of the wellbore. The foaming agent is an aqueous solution including an ammonium alcohol ether sulfate surfactant.

The present application relates to the technical field of geothermal well, particularly to a geothermal well underbalanced drilling, system and prediction and installation method, wherein the geothermal well underbalanced drilling comprises a casing; a drill pipe coaxially arranged with the casing, an outer diameter of the drill pipe being smaller than an inner diameter of the casing, and an annulus existing between the drill pipe and the casing; and a gas injection pipe arranged outside the casing and in communication with the annulus, the gas injection pipe being used for injecting variable flow of gas to mix with drilling fluid in the annulus to form gas-liquid two-phase flow. The gas injection pipe is in communication with the annulus of the casing, the mixed density of the liquid in the annulus is changed by injecting gas into the casing, so that the bottom hole pressure is less than the formation pressure, thereby achieving the effect of underbalanced drilling, improving the drilling speed, and preventing a large amount of drilling fluid from leaking into the formation fracture.

A method for underbalanced drilling includes drilling into a subterranean geological formation to form a wellbore therein, injecting a foaming agent into the wellbore during drilling at a wellbore pressure that is below a pore pressure of the subterranean geological formation, and transporting drill cuttings formed by the drilling away from the drilling surface in the foam. The foaming agent forms a foam in the wellbore at a drilling surface at a bottom of the wellbore. The foaming agent is an aqueous solution including an ammonium alcohol ether sulfate surfactant.

A method of underbalanced drilling includes drilling into a subterranean geological formation to form a wellbore and injecting a foaming agent into the wellbore during drilling at a wellbore pressure that is below a pore pressure of the subterranean geological formation. The foaming agent forms a foam in the wellbore at a drilling surface at a bottom of the wellbore and transports drill cuttings formed by the drilling away from the drilling surface in the foam. The foaming agent is an aqueous solution including a gemini amphiphile dicationic surfactant having a linker and a lipophilic tail.

The invention relates to the technical field of geothermal wells, in particular to a geothermal well underbalanced drilling well and system and a prediction and installation method. The drill rod and the casing pipe are coaxially arranged, the outer diameter of the drill rod is smaller than the inner diameter of the casing pipe, and an annulus exists between the drill rod and the casing pipe; and the gas injection pipe is arranged on the outer side of the casing pipe and communicates with the annulus, and the gas injection pipe is used for injecting variable-flow gas to be mixed with the drilling fluid in the annulus to form gas-liquid two-phase flow. The gas injection pipe is communicated with the annulus of the casing pipe, and the mixing density of liquid in the annulus is changed by injecting gas into the casing pipe, so that the well bottom pressure is smaller than the formation pressure, the unbalanced drilling effect is achieved, the drilling speed can be increased, and a large amount of drilling fluid can be prevented from leaking into formation cracks.

This invention discloses a method and apparatus for reducing the bottom-hole circulating temperature of deep shale gas horizontal wells, relating to the field of drilling engineering technology. It addresses the technical problem of unsatisfactory cooling effects when using existing surface cooling methods. The method includes the following steps: Step S1: Obtain the three-pressure profile of the well to be drilled and obtain the underpressure value range; Step S2: Determine the underbalanced drilling process based on the underpressure value range; Step S3: Obtain first relationship information and predict the bottom-hole circulating temperature of the well to be drilled. Based on the bottom-hole circulating temperature, the first relationship information, the three-pressure profile, and the underbalanced drilling process, optimize the drilling fluid density in the drilling process. This invention can effectively reduce the bottom-hole circulating temperature during deep shale gas drilling, ensure stable instrument operation, reduce the number of tripping operations, and guarantee efficient drilling of horizontal wells.

A method of underbalanced drilling includes drilling into a subterranean geological formation to form a wellbore and injecting a foaming agent into the wellbore during drilling at a wellbore pressure that is below a pore pressure of the subterranean geological formation. The foaming agent forms a foam in the wellbore at a drilling surface at a bottom of the wellbore and transports drill cuttings formed by the drilling away from the drilling surface in the foam. The foaming agent is an aqueous solution including a gemini amphiphile dicationic surfactant having a linker and a lipophilic tail.

The present disclosure relates to systems and methods for real-time calculations of a productivity index and a rate-integral productivity index of a well in underbalance drilling. The systems and methods use real-time data received from the well to calculate the productivity index and the rate-integral productivity index of the well. The systems and methods use the productivity index and the rate-integral productivity index to generate visualizations of the well and provide recommendations for the well.

In general, in one aspect, embodiments disclosed herein relate to a method for optimizing underbalanced drilling according to depth of damage. The method includes collecting in situ conditions, well conditions, and formation properties of a subterranean area of interest, calculating changes of in situ stresses induced by a pressure drop inside the wellbore, creating an underbalanced drilling model using the in situ conditions, well conditions, and formation properties, modeling the drilling process, extracting and evaluating plastic mechanical damage from the underbalanced drilling model, adjusting a pre-drilling plan based on the depth of plastic mechanical damage, and finally using the modeled drilling process to drill a well. The in situ stresses include a maximum and minimum confining stress. The underbalanced drilling model includes a mechanical simulation of a first area representing rock surrounding the wellbore, and a second area representing rock inside the wellbore.