Fast Plugging Inhibitive Drilling Fluid Technology for Horizontal Drilling Through Bauxite Rocks
Two wells,the well Long-XX and the well Ning-XX,in Longdong area are recently tested,and the target zone located in the bauxite formation has been found an important alternative resource for the Changqing Oilfield.Significant findings were obtained in exploring the bauxite formation through these two wells.Technical difficulties,such as prevailing of dissolution pores and fractures,borehole wall collapse,mud losses and poor hole cleaning etc.have been encountered in drilling the target bauxite formation.The main factors contributing to borehole wall collapse were found in analyzing and testing the bauxite samples for physical properties,chemical properties,mechanical properties and sensitivity characteristics,and a fast-plugging,inhibitive drilling fluid for safe drilling of the bauxite formation was developed.This drilling fluid has high temperature(170℃)high pressure filter loss of less than 10 mL and percent secondary cuttings recovery of greater than 91%.After soaking the bauxite samples in the drilling fluid and fresh water respectively for 15 days,the compressive strength of the samples tested in the drilling fluid is 81.8%higher than that of the samples tested in the fresh water.This drilling fluid has been tried in drilling the first horizontal Long-4XX well targeted the bauxite reservoir in Changqing,a horizontal section of 700 m was successfully drilled.The daily flowing production rate of this well is 3.53×106 m3,a new record made in developing the upper Paleozoic resources in the Erdos basin in the last 50 more years.This technology has provided a technical support to the development of the similar reservoirs.
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维普
