Simulations Comparing Different Initial Responses to Kicks Taken During Managed Pressure Drilling

Abstract

An industry-supported research project to investigate a practical basis for comprehensive well control procedures for managed pressure drilling (MPD) operations is in progress. This paper will describe the results of a simulation-based study comparing alternative initial responses to a range of kick scenarios. The primary responses considered were increasing casing pressure while continuing circulation, increasing the circulating rate without increasing casing pressure, and shutting in the well conventionally. These were investigated using a transient, multi-phase flow simulator. The purpose of the study was to provide a basis for determining the most effective initial response for controlling a kick taken during MPD.The results have helped to identify several important considerations.One important consideration was expected: the ability to minimize casing pressure and therefore the risk of lost returns by continuing to circulate rather than shutting in. There are significant complications if lost returns occur. Loss of returns is difficult to detect in a shut in well if a float is used. With an initial response based on increasing casing pressure until flow out is equal to flow in, it can be difficult to determine whether formation influx has stopped or partial lost returns are offsetting the influx. In cases with narrow margins between pore and fracture pressure, small differences in the drillpipe pressure being held constant during circulation with lost returns can potentially cause results ranging from total lost returns to uncontrolled flow at the surface. The location of the loss zone relative to the kick zone is particularly important in influencing these results. The need for a practical method of identifying lost returns during the initial response is evident, especially when working in a narrow window between formation and fracture pressure gradients. Simulation results are used to exemplify these considerations.A tentative result of this on-going study is that there may be no single best initial response to a kick taken during MPD. The best response may depend on well geometry, kick zone productivity, and likelihood of lost returns.

An Improved Dynamic Well Control Response to a Gas Influx in Managed Pressure Drilling Operations

“…Alternative initial responses to kicks for various well scenarios during managed pressure drilling operations were explored by Das (2007), Das, et al (2008), andDavoudi, et al (2010). For an applied-back-pressure response, reaching Q out = Q in was assumed to stop the influx.…”

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

“…He compared three initial responses by using computer simulation: shutting in the well conventionally, increasing choke pressure while keeping the same pump rate, and increasing pump rate while keeping choke pressure constant. The most important conclusions from Das's research were: a) no single response was identified as the best, b) circulating responses may stop the influx faster than non circulating responses, and c) the increased choke pressure response leads to a lower shoe pressure than SI, thus it reduces the risk of lost returns at the shoe (Das 2007;Das et al 2008).…”

Experimental Validation on a New Valve Core of the Throttle Valve in Managed Pressure Drilling

“…Throttle valve works as a fluid velocity regulator and a wellhead pressure controller in managed pressure drilling (MPD) [1,2]. Valve core is the key component in throttle valve because it is in direct contact with the drilling fluid and can adjust the flow area ( Figure 1).…”