DUKHAN油田水平井钻井液技术

DUKHAN油田是江苏油田钻井处在卡塔尔承钻的区块，该区块井多为水平井，井深为3000～3200m，水平段长1000～1500m。针对该区块地层易漏、垮塌和造浆性强等特点，在不同的井段采用了不同的钻井液体系。即一开井段用清水／高粘度胶液；二开井段用高密度聚合物膨润土钻井液；三开用低固相聚合物钻井液；四开井段采用无损害无固相聚合物钻井液。现场应用结果表明，该套钻井液体系具有较强的抑制性，能保持较高的动塑比，提高钻井液的携砂和润滑能力，解决了上部地层井漏、垮塌和地层造浆，以及增斜段、水平段的携砂、润滑性问题，保证了DUKHAN油田钻井施工的顺利进行。

Drilling fluid technology for horizontal well drilling in DUKHAN Oilfield

DUKHAN oilfield is a block in Qatar contracted to Jiangsu Oilfield, where many horizontal wells of 3,000 to 3,200 m are drilled, with horizontal sections of 1,000 to 1,500 m. Different drilling fluid systems were selected for different sections, in accordance with the lost circulation, hole sloughing and mud making tendencies of the formation. In the surface 444. 5 mm hole, clear-water/high viscosity gel fluid was used; high density polymer bentonite drilling fluid was used in the 311. 1 mm hole; low solids polymer drilling fluid was used in the 215. 9 mm hole, and solids free polymer drilling fluid without contamination was selected for the 155. 6 mm hole. Field applications showed that this set of drilling fluid system processes such advantages as high inhibition and dynamic to plastic ratio, good cuttings transportation and lubricity, and it can be used to solve the problems of lost circulation, hole collapse and mud making in the upper formation, as well as the poor cuttings transportation and lubricity in the building-up section and horizontal section.