Advantages of Flowing Wells through Tubing

It is generally believed that the flowing of wells through tubing instead ofcasing results in the conservation of gas. It is further believed that use oftubing prolongs the flowing life of a well and results in greater ultimaterecovery, provided either that there are no adjacent wells, or that anyadjacent wells are similarly operated. Recent experience in the flowing ofBuckbee zone wells at Santa Fe Springs has not only substantiated both of thesebeliefs but has led to the further conclusion that the use of tubing results ina greater cumulative flowing production, even in a highly competitive fieldlike Santa Fe Springs, where the wells concerned are closely offset by wells ofboth the same and other companies flowing through casing. Further, gas-oilratio has been so reduced that greater ultimate recovery can be expected. In the belief that such would be the case, the majority of the Buckbee zonewells of one company were brought in through tubing, but enough wells wereflowed through casing to form the basis for a comparison. For the purpose ofthis comparison, wells with flow strings 2~-2 or 3-in. dia. are designated astubed wells, while those having flow strings larger than 3-in. dia. aredesignated as untubed wells. Casing used was mostly of 5%-in. dia., theremainder being of 4%-in. dia. There were 15 tubed wells and 8 untubed wellsand they were scattered over the field in such a way that neither group appearsto have any distinct advantage as regards location. Locations of all wellsinvolved in the comparison are shown on Fig. 1. All the Buckbee sand wells ofthe company are included in the average production curves, with the exceptionof eight that were unsatisfactory for reasons other than the method offlowing. Findings 1. Buckbee sand wells flowing through casing larger than 3 in. had an averagemaximum production rate of 4670 bbl. per day, while wells flowed throughstraight tubing or 3-in. casing had an average maximum production of only 3300bbl. per day. (See Fig. 2.)