扎纳若尔油田钻井液工艺技术

扎纳若尔油田是CNPC出资控股，与哈萨克斯坦共同组那宾阿克纠宾油气股份公司属下的主力油田。该油田的主要油层为石灰系，深度为2800-3800m左右。该油田的地层情况非常复杂，在钻井施工中经常发生井塌，井漏、卡钴等井下复杂事故，甚至造成井报废，为了提高钻井速度和效率，采用中国的钻井液体系，即一开选用密度为1.05-1.15g/cm^3的两性离子聚合物钻井液；二开用密度为1.05-2.00g/cm^3的两性离子聚磺饱和盐水钻井液体系；三开选用密度为1.14-1.16g/cm^3两性离子矣磺屏蔽暂堵钻井液，该套钻井液体系解决了大段粘土层，泥岩地层造浆，软泥岩塑性流动引起的起钻遇卡，下钻遇阻，划眼等井壁稳定问题；屏蔽暂堵技术提高了油层承压能力，避免了井壁稳定问题；屏蔽暂堵技术提高了油层承压能力，避免了井漏，较好地保护了油气层。该套钻井液体系适应了该区域地层特点，满足了钻井施工要求，油井日产量比过去提高了30%。

Drilling fluid technology in Zananor Oilfield ,Kazakhstan

Zananor Oilfield is a major oilfield developed under one of the overseas projects of CNPC with Kazakhstan. The reservoir of this oilfield is mainly in the Carboniferous system, and its depth is between 2800 -3800 m. Geological condition of this oilfield is very complex, and such downhole troubles as sloughing, lost circulation and sticking frequently take place during drilling, sometimes as severe as well abandonment. Drilling fluid system from China was used, to improve penetration rate and drilling efficiency. In the top 444. 5 mm hole, zwitterionic polymer drilling fluid with weight of 1. 05-1. 15 g/cm3 was used. For the 311. 1 mm hole, saturated polysulfonate brine system of 1.05-2. 0 g/m3 was used, to control mud making problem and for better drilling in the salt bed. Temporary shield plugging agent was added in the 215. 9 mm hole, and mud weight wascontrolled between 1. 14-1. 16 g/cm3 to minimize formation damage. The drilling fluid systems used solve such problems as mud making in thick clay and shale formation, sticking and resistance of pipe during tripping because of the plastic flow of soft mud-stone, and the temporary shield plugging technology enhances the load bearing capacity of the reservoir, thus avoids lost circulation and minimizes the formation damage. By using this set of drilling fluid system, the production rate had increased by 30% in this oilfield.