Evaluation of Alternative Initial Responses to Kicks Taken during Managed Pressure Drilling

Abstract

An industry-supported research project has completed its evaluation of alternative initial responses to kicks taken during the constant bottom hole pressure (CBHP) method of managed pressure drilling (MPD) operations. The evaluation is the first phase of a study that is intended to provide a basis for comprehensive, reliable well control procedures for MPD operations. The evaluation was based primarily on computer simulations of multiple alternative initial responses to several causes and severities of kicks in different well geometries. Three responses were concluded to have general application: increasing casing pressure until flow out equals flow in, shutting the well in, and using an adaptation of an MPD pump shut down schedule to detect and shut in low rate kicks. A simple shut-in was concluded to be the most generally applicable response because it stops formation flow without requiring any special equipment. However, it also causes an increased risk of exceeding the formation fracture pressure for most situations versus a response that maintains continuous circulation. Increasing casing pressure while maintaining a constant pump rate until flow out equals flow in was concluded to be the most applicable response that avoids the disadvantages of shutting in the well. However, it requires accurate metering of return flow as a basis for determining whether formation flow has stopped. The adaptation of an MPD pump shut down schedule can be used to determine whether questionable kick indications are caused by a kick more conclusively than the other responses. It ends with the well being shut-in. A fourth response, increasing the pump rate, also has important but very limited application. The selection of which response is the most practical is shown to depend on well conditions and the equipment being used. Potential advantages of and constraints on the use of these responses are also explained.

Alternative Shut-In and Pump Start-Up Procedures for Kicks Taken During MPD Operations

“…A non-return valve or float valve is installed in the bottomhole assembly; it allows only downward flow of drilling fluids, which is necessary if the well will be statically underbalanced. There are other optional tools that can complement CBHP operation to improve wellbore pressure management such as coriolis meters (flowmeter), continuous circulating systems (CCS), downhole deployment valves, back pressure pumps, surface multiphase separators, pressure while drilling tools (PWD), and hydraulic flow modeling (Malloy 2008;Rehm 2009;Davoudi 2009). …”

“…However, three initial responses were demonstrated to have a broad application to different kick scenarios: a rapid increase of casing pressure until flow out equals flow in, a simple shut in, and lastly, an adaptation of the MPD pump shut down schedule that allowed confirmation of low rate kicks using a choked flow check. In addition, he concluded that the best initial response depended on well conditions and the equipment that is being used (Davoudi 2009;Davoudi et al 2010).…”

“…Based on the consortium research, Davoudi et al (2010) presented a proposed approach for selecting initial responses during well control events for the CBHP method of MPD. They explained that one of the criteria in selecting the initial kick reaction must be the equipment available on site, specifically whether flow out metering was being used.…”

“…This research has defined two different non circulating responses as preferable among multiple alternative non circulating responses (Davoudi et al 2010). These two responses are described as a simple shut in and as a MPD pump shut down with a "choked flow check."…”

Moving horizon estimation in managed pressure drilling using distributed models

“…Without agusisma@itk.ntnu.no of well control (blowout), loss of assets, and even loss of life. The implication of such undesirable conditions are not only environmental, but it also concerns worker's safety [2]. Therefore, monitoring and control are important issues in oil well drilling.…”