Exxon Production Research Company

Eugene A Sikirica

Marco Rasi

Yuh-Hwang Tsao

Mark W Biegler

William E Kline

Michele M Thomas

Albert T Wang

The current invention is a method for modeling the probability of a drill string becoming stuck within a given time frame and a method for applying the model to a well being drilled to reduce the probability of sticking. The model is constructed by performing canonical discriminant analysis on engineering parameters derived from observations taken in historical wells and creating a canonical space with the resulting canonical functions. Posterior probabilities of sticking are then calculated from the historical observations and mapped into the canonical space. To apply the model to a particular well being drilled, the values of the previously derived engineering parameters are calculated from observations in the well being drilled, multiplied by their corresponding canonical coefficients, and summed to obtain a canonical point representation for drilling in that well. This canonical point representation is then mapped into the canonical space to obtain the probability of sticking. The probability of sticking is then compared to probabilities experienced in the past under similar drilling conditions. If the probability of sticking in the well being drilled is found to be higher than average historical probability, it can be reduced by implementing remedial measures that are suggested by simple inspection of the values of the engineering parameters.

Method to combine statistical and engineering techniques for stuck pipe

A method is provided, based on assigned drilling variables, for predicting the area of open region above a bed of cuttings resulting from drilling a high-angle well. The area of the bit used in drilling is compared with the area of the open region and drill pipe to determine a Hole-Cleaning Ratio. Occurrences of sticking of drill pipe or other drilling problems in prior-drilled wells are correlated with Hole Cleaning Ratio in those wells to determine a relationship for predicting risk of drilling problems in wells of interest. Risk factors so determined are used to modify conditions or equipment during drilling or to plan future wells.

Method of controlling cuttings accumulation in high-angle wells

A method for determining a parameter by combination of engineering models and statistical analysis of drilling data in a data base to determine the frequency or probability of sticking of the drill string during drilling of wells at hole-angles from vertical to horizontal. The parameter can be used to decrease the probability of sticking of drill string during drilling a well and to minimize the cost of a well.

Growing community of inventors

Katy, TX, United States of America

Eugene A Sikirica