| Along with the increasingly depleting oil&gas resource, and the enhancement of the oil exploration&development technology, more and more deep and super-deep wells had been designed to be drilled. So, the trend to develop deeper oil and explore extremely high pressure formation, has become the main exploration&development difficulty. The general characteristics of such kind of formation is high temperature and high pressure. Most part of the formation contains crossbedded salt layers, so it is urgent for cementing unit to develop fresh water and salt water high temperature super-high density cement slurry. As the formulation of super-high density cement slurry needs more high density weighting agents but less bonding material, it’s hard to get good stability, thickening time and compressive strength. Therefore, it’s important to research and develop super-high density cement slurry technology to meet both the field density requirement and the properties requirements.This article has made a large quantity of literature investigation in the present research and application of super-high density cement slurry. By selecting optimum solid and liquid materials, the author chose the high density(7.00g/cm3)iron hematite as weighting agent, the silica sand and silica fume and high-temperature-resistant agents as anti-high temperature materials, and the Great system and OMAX system as the needed agents for high temperature super-high density cement slurry study against the present Tarim Basin oil well cementing difficulties, like high temperature, high pressure and the high pressure salt layer contained formation. The author formulated the super-high density cement slurry by adding the weighting agent of high density(7.00g/cm3)hematite and a certain amount of high temperature stabilizer to avoid the hematite settlement. In the salt water super-high density cement slurry, the author added18%industrial salt by weight of water blend.The achievement is two cement slurry systems, one is fresh water super-high density cement slurry, the density of which is2.60g/cm3and2.80g/cm3, the other is the salt water super-high density cement slurry, the density of which is2.80g/cm3,2.90g/cm3and3.00g/cm3. Both the cement slurry systems will meet the BHCT of110-150℃cementing needs. The author has made a whole set of properties tests on a variety of systems at110℃and150℃and all temperature sensitive points. All the results are qualified. |
