Improve Primary Cementing by Continuous Monitoring of Circulatable Hole

Abstract

Abstract Previous research has demonstrated that proper hole conditioning is critical to successful cementing operations. However, in the past, there has not been a reliable technique available to the industry to continuously monitor the volume of hole circulating. Liquid calipers (tracers) are difficult to run and cannot be run continuously to know how the well is cleaning and when the well is ready for cementing. This paper discusses a reliable technique to continuously estimate the circulatable hole during hole conditioning. This should provide the operator with a much better tool for improving the success of cement jobs. The method consists of making very sensitive measurements of surface pressure during circulation. A software package was developed to estimate the hole volume circulating from surface pressure, the fluid circulation rate, and fluid properties. The package makes corrections for pressure drop across casing attachments such as float shoes/collars and centralizers. The technique was demonstrated in a research well. Casing was run with attachments to simulate actual field conditions. Static and circulating periods as well as pipe movement were used as data was collected for several days. The effect of static periods, fluid circulation rates, fluid properties, and pipe movement on circulatable hole was clearly observed from these tests. To validate the continuous circulatable hole measurements, dye tracers were used to measure the circulatable hole. These measurements were in good agreement with the real time data from the proposed technique. The proposed technique works in actual wells. It allows continuous estimation of the effect of static periods, fluid circulation rates, pipe movement etc. on circulatable hole. The technique can be used to tell when the well is ready for cementing. The new technique will be very easily applicable to the field. It requires a sensitive pressure transducer at the wellhead, a reliable flowmeter, and properties of the fluid.