Specific Drilling Research Articles

Slim Hole Drilling Decreases Carter's Development Costs

Abstract Rising development costs are recognized as one of the major problems facing the oil industry today. To combat this situation, several new concepts designed to improve drilling techniques have been advanced within recent years. Among the ideas proving most effective is slim hole drilling. Carter's slim hole experience has been in both exploration and pool development wells. In addition, slim hole practices have been successfully applied to water injection wells. In comparison with standard operations, both penetration rate and bit life decreased using slim hole methods. No difficulty was encountered in coring, logging and testing in reduced diameter holes. Actual slim hole costs indicated a significant economic advantage over conventional practices. Savings in dry hole costs ranged up to 25 per cent, primarily from reductions in footage and day work rates. Additional savings accrued in producing wells from economy in tubular goods. Slim hole methods may not always be applicable, as consideration should be given to specific drilling problems and objectives. In many cases, however, slim hole drilling provides significant economic advantages over conventional practices. Introduction Increasing development costs are widely recognized as one of the major problems facing the oil industry today. Inflationary effects are firmly evident in all of the principal components of drilling costs, including labor, transportation, steel products and chemicals. Furthermore, deeper drilling is necessitated to offset depletion of shallow reserves. During recent years the concept of slim hole drilling has been experimentally applied within industry to evaluate its significance as a cost reduction measure. In most cases, slim hole results are reported to be proving effective. The purpose of this discussion is to review experience of The Carter Oil Co. in drilling 108 slim holes which have resulted in estimated savings of $162,000 below the cost which would have been incurred with conventional sized holes.