Drilling In Salt Paste Layer Of High Pressure Brine Well Control Technology

Salt-gypsum layer in the drilling process, drilling into the salt-gypsum layers of high-pressure brine, when the drilling fluid density is too low, the high pressure salt water will be poured into the wellbore, resulting in the drilling fluid contamination, causing the sidewall collapse, grit sticking, crystallization blockage a series of drilling accident; When the drilling fluid density is too high, will lead to weak formation leakage caused by the underground complex, increased processing difficulty, and even cause serious borehole abandonment. At present, the salt-gypsum layers drilling technology has made great progress, but well control for drilling into the salt-gypsum layers of high-pressure brine is still significant engineering problems, the urgent need to be addressed.This paper around drilling salt-gypsum layers of high-pressure brine well control technology for the following research:1) Analysis the Ta Li mu Oilfield piedmont tectonic of salt-gypsum layers, the distribution law of the high pressure brine and drilling engineering problems, prevent pollution, to prevent the drilling technology of necking; Prevent the overflow of salt water, prevent leakage of high pressure brine drilling technology for a full discussion to determine the reasonable drilling fluid system and the security of the density window。2) High-pressure brine layer of well control risk, selected in accordance with the killing method principles:give priority to pollution prevention; Second, consider the leak loss; consider reasonable to put the spray pressure relief, based on engineering geological environment, a reasonable choice of the method of killing for the address well control issues, put forward a viable drilling into the salt-gypsum layers of high-pressure brine well control technology.3) The crystallization of the high-pressure saturated brine overflow may occur congestion experimental study, using high pressure equipment to be carried out under high pressure sodium chloride, the solubility test, a more reliable dissolution data through the data obtained by fitting the value of the sodium chloride dissolved the relationship between temperature and pressure. On this basis, the analysis in some depth, the dissolution and precipitation of high pressure saturated brine in the process of elimination, and get some useful conclusions for the implementation of reasonable blowout relief kill method provides theoretical support.4) For the open hole weak strata, but difficult to achieve effective sealing, based on a reasonable way of relief, high-pressure saline crystalline blockage, three aspects of well control equipment adaptation research, the formation of operability puts pray pressure relief supporting technology.5) The k7th deep well is a typical case, the well control technology of the salt-gypsum layers of high-pressure brine carried out on-site application analysis, conducted the well control technology for targeted, rationality, practicality discussion and evaluated the safety and economic benefits of well control technology.The main findings are as follows:1) Summarizes the high-pressure salt water there are the above salt, the middle salt and the below salt of the distribution and identified drilling fluid system and the safety of the density window, to prevent salt water overflow, to prevent the loss of salt-gypsum layers of high-pressure brine drilling technology.2) Develop a killing method selection principle:give priority to pollution prevention; second, we consider the leak loss; consider reasonable to put the spray pressure relief. According to the engineering geological environment, put forward a viable drilling into the salt-gypsum layers of high-pressure brine well control technology.3) The first time in the country to carry out high-pressure saturated brine overflow the crystallization congestion experimental study. The study found that high pressure salt water overflow in the circulation flow is not easy to plug the crystallization provides a theoretical support for the implementation of reasonable blowout relief.4) Put forward the innovative of flow pressure relief technology. Basis reasonable pressure relief, the research of high-pressure saline crystalline plug and the research of the improvement well control equipment, the formation of the spray pressure technology on reasonable operability. Which the drill pipe blowout relief equipment, improved A program using a new multi-function kill manifold exchange configuration, has been a patent application.Drill into Salt-gypsum layers of high-pressure brine of well control of the system research, which can effectively resist the well control risks by the salt-gypsum layers of high-pressure brine and have a safety escort of effect in drilling engineering.