Drilling system
AssigneeRocsol Technologies Inc.
InventorsGeir Hareland, Mauricio Jose Farinas Moya, Prasad Baloo Kerkar, Ernesto Rafael Fonseca Ocampos
Life of this patent
Estimating the term…
Abstract
Rock strength is estimated during drilling using a rate of penetration model or a modified mechanical specific energy models. The rock strength estimate can be used in conducting further drilling, for example by a drilling system. Drilling parameters may be altered as a result of determining rock strength, for example to avoid undesirable trending fractures, such as extensive vertical fractures.
Claims19
A method of drilling a well or fracturing a formation drilled by a well, the method comprising the steps of:
- drilling through rock with a drilling system by rotating a drill bit;
- estimating a friction force on the drillstring using a friction model;
- estimating a downhole weight on bit using a surface measurement and the estimated friction force;
- providing a penetration model for calculating the rock mechanical properties and/ or specific energy using rate of penetration of the bit through the rock formations being drilled, the penetration model including a parameter the strength of the rock and known or estimated parameters, the known or estimated parameters including the estimated downhole weight on bit;
- measuring or estimating a value ROP of the rate of penetration of the bit;
- given the known or estimated parameters, determining a value CCS of the parameter representing the strength of the rock required to cause the penetration model to calculate the rate of penetration of the bit to have the measured or estimated value ROP;
- estimating the strength of the rock according to the value CCS;
- and
- setting drilling or fracturing parameters according to the estimated rock strength.
A method of drilling a well or fracturing a formation drilled by a well, the method comprising the steps of:
- drilling through rock with a drilling system by rotating a bit;
- estimating a friction force on the drillstring using a friction model;
- estimating a downhole weight on bit using a surface measurement and the estimated friction force;
- providing a penetration model for calculating the mechanical specific energy of the rock being drilled through, the penetration model including a rate of penetration of the bit, the estimated downhole weight on bit and a hydraulic efficiency of the bit;
- measuring or estimating a value of the rate of penetration of the bit and a value of the hydraulic efficiency of the bit;
- estimating the mechanical specific energy by applying the penetration model to the measured or estimated value of the rate of penetration of the bit, estimated downhole weight on bit, and value of the hydraulic efficiency of the bit;
- and
- setting drilling or fracturing parameters according to the estimated mechanical specific energy.
Dependencies are inferred from the claim text.