Application of 2,000 Hydraulic Horsepower to Rotary Drilling

Abstract Increases in pump hydraulic horsepower from 500 to over 1,500 have, with adequate bit weights, resulted in penetration rate improvements exceeding 100 per cent in drilling 12–1/4 and 8–5/8-in. holes in south Louisiana. Indications are that further increases in drilling rates may be effected with pump output horsepower increased to 2,000. However, improved methods of generating cuttings are needed to take full advantage of the continuing trend of increasing available mud pump horsepower. For proper power utilization during deep drilling, operating surface pressures of 5,000 psi should accompany development of 2,000 pump horsepower. Drill pipe diameter should not be less than 5 in. Although hydraulic horsepower increases benefit penetration rates with weighted muds as well as with muds of normal weight, loss of returns, more prevalent with heavier muds, may necessitate reduction in circulating rates and horsepower in some instances. Introduction During recent years drilling rates generally have been improved by the combination of increased bit weights and hydraulic horsepower used. Whilehard West Texas drilling, the benefits have been obtained from great increases in bit weight with lesser emphasis on more hydraulic horsepower, as formations become more drillable greater hydraulic horsepower increases are necessary to reap the improvements possible with increased bit weights. Formations penetrated in South Louisiana are predominantly of soft material and can be drilled rapidly. In these formations, bit weights which can be carried are usually limited by the ability of the hydraulic system to keep the bottom of the hole and the bit clean and to remove bit cuttings from the hole. Although in the past, drilling rates with low hydraulic horsepower appeared to be adequate; recent experiments with greatly increased mud pump horsepower have shown that with adequate bit weight, penetration rates increase markedly. To date increases in pump hydraulic horsepower from 500 to values approaching 1,600 have made possible penetration rate improvements exceeding 100 per cent in South Louisiana drilling in normal pressure areas. indications are that further increases in drilling rates may be effected with even greater hydraulic horsepower provided it can be properly utilized. Discussion As this paper is composed of [1] the theoretical application of 2,000 hydraulic horsepower to rotary drilling and [2] the actual field experiences in utilization of 1,500 and smaller hydraulic horsepower, the discussion has been divided in two parts.