Technique of a new drilling fluid - AML used in Saiping-1 horizontal well

To seek a way of developing low pressure and low permeability oil reservoir, Changqing Oil Field and Xi'an Petroleum Institute drilled a horizontal well in co-operation in Ansai Oil Field (North Shaanxi). The deviated depth of the well is 1658.27m. the vertical depth is 1259.19m and the length of the horizontal section is 236.17m. A new low solids, non-dispersed polymer drilling fluid - AML was used in drilling the well. AML consists mainly of three kinds of additives. One is amphionic polymer(A). The second is an inorganic polymer MSF-2(M). The third is lubricants (L). Laboratory and field tests proved that AML drilling fluid is able to overcome the major drilling fluid problems in drilling horizontal wells in Ansai Oil Field, such as hole cleaning, wellbore stability, lubricity and antisticking. The technique of carrying stone cuttings by laminar flow to horizontal well drilling was applied. A compromise was made between the drilling fluid filtration and mud cake's quality. The inhibitive property of the amphionic polymer drilling fluids was improved. The cross-correlation of multi-function additives in the drilling fluid system was further discussed.