Improved Method for Use of Chelation to Free Stuck Pipe and EnhanceTreatment of Lost Returns (2007)

Improved Method For Use Of Chelation To Free Stuck Pipe And Enhance Treatment Of Lost Returns John K. Montgomery; John K. Montgomery U. of Pennsylvania Search for other works by this author on: This Site Google Scholar Stuart Ronald Keller; Stuart Ronald Keller ExxonMobil Upstream Research Co. Search for other works by this author on: This Site Google Scholar Nancy Krahel; Nancy Krahel ExxonMobil Upstream Research Co. Search for other works by this author on: This Site Google Scholar Marty V. Smith Marty V. Smith ExxonMobil Development Co. Search for other works by this author on: This Site Google Scholar Paper presented at the SPE/IADC Drilling Conference, Amsterdam, The Netherlands, February 2007. Paper Number: SPE-105567-MS https://doi.org/10.2118/105567-MS Published: February 20 2007 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Montgomery, John K., Keller, Stuart Ronald, Krahel, Nancy, and Marty V. Smith. "Improved Method For Use Of Chelation To Free Stuck Pipe And Enhance Treatment Of Lost Returns." Paper presented at the SPE/IADC Drilling Conference, Amsterdam, The Netherlands, February 2007. doi: https://doi.org/10.2118/105567-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE/IADC Drilling Conference and Exhibition Search Advanced Search AbstractThis paper describes how intentionally increasing the permeability of a non-aqueous fluid (NAF) filter cake can enhance treatments to free differentially stuck pipe and recover from lost returns. NAFs are well known for their ability to deposit thin, low-permeability filter cakes that reduce the risk of differential sticking. Yet, differential sticking still occurs and techniques to free the pipe have largely been ineffective. In addition, lost returns in NAF continue to be one of the industry's most difficult and expensive problems to solve.The operator has developed an improved technique to increase the permeability of a NAF filter cake. The technique involves locally soaking the cake using a combination treatment that first conditions the cake and then removes a significant amount of the weighting material. Laboratory experiments have shown the technique can increase cake permeability by more than 850 fold.There are at least two applications for this treatment. In the first, a pill is spotted across pipe segments (e.g., drill collars) believed to be differentially stuck. By increasing the cake permeability, pressure is allowed to penetrate the cake underneath the pipe, allowing it to more easily become free. Dissolving barite also reduces the shear strength of the filter cake, which may also facilitate freeing stuck pipe.A second application is to enhance the performance of high fluid loss lost circulation material (LCM) treatments after NAF has damaged the fracture face permeability. Increased permeability enhances loss of the LCM carrier fluid and development of the immobile mass required to stop the growth of the fracture induced during lost returns. Formation integrity can then be rebuilt using rock mechanics-based techniques.Introduction/BackgroundBarite DissolversBarite dissolvers have long been used in the industry to combat scale in downhole tubulars.1–2 Additionally, barite dissolvers have gained use as a means to treat formation damage from mud invasion since the primary weighting agent for drilling fluids is barite. Barite is extremely insoluble in most acids and typically requires specialized chelation agents to remove. EDTA and DTPA are the most common chelation agents. Similar compounds, variations, mixtures, and new dissolving compounds are also being developed.3–4This paper explores the use of chelation agents for a different application. Rather than remove scale or barite within the formation, the objective is to remove barite that composes the filter cake. Because barite typically comprises a significant volume component of a typical filter cake, anything that removes the barite weighting agent has a tremendous impact on the filter cake properties.Differentially Stuck PipeDifferential pressure sticking (DPS) is a common worldwide drilling problem that results in significant increases in non-productive time and overall well cost.5–6 Additionally, a DPS event may result in abandonment of the current hole and force a sidetrack. To mitigate DPS events, operators often minimize the overbalance (by decreasing mud weight), minimize stationary time, minimize drilled length through low pressure formations, increase drill collar and drill string stabilization, and optimize fluid properties in attempts to minimize the risk of sticking. However, despite the best efforts of operators a DPS event may still occur.A common practice to free differentially stuck pipe is to pump a chemical "spotting" fluid.7 The purpose of the fluid is to dissolve or break down the filter cake so the pipe can be freed. Most service companies provide multiple spotting fluid options. Water-based drilling fluids have engendered numerous spotting fluids that have been used successfully in the field. These spotting fluids are typically composed of NAF. These fluids function by reducing the area of contact and may penetrate the cake and relieve pressure differential. Keywords: drilling fluids and materials, Thickness, differentially, Filter Cake Permeability, drilling fluid chemistry, drilling fluid formulation, pressure differential, differential, filter cake, drilling fluid property Subjects: Drilling Fluids and Materials, Drilling fluid selection and formulation (chemistry, properties) This content is only available via PDF. 2007. SPE/IADC Drilling Conference You can access this article if you purchase or spend a download.