TY - THES

T1 - Cementation optimization of solid expandable liners

AU - Fischer, Philipp

N1 - embargoed until null

PY - 2010

Y1 - 2010

N2 - Solid expandable tubular (SET) are wellbore pipes produced from steel or non-ferrous metals like titanium or aluminum, which show proper mechanical and chemical properties to withstand cold forming operations, in which their diameter is increased, while maintaining conventional pipe geometry and the capability to withstand a certain level of down-hole conditions. The process is performed via an oversized cone, which is forced through the pipe string. Within this procedure the pipe material is predominately deformed in hoop-direction under enormous tensional load. It is deformed over the elastic limit into the plastic region, resulting in a permanent increase in pipe body diameter. As the pipe is subjected to high stress without significant heat contribution the material properties are altered, changing the pipe load capabilities. As the conventional casing program is based on a continuous diameter reduction with each string installed, due to drift considerations, the installation of solid expandable tubular allow a diameter conservation, compared to the previous string up to 100 percent. Based on the technological concept of SET several different application designs have proved to be economically deployable as a tool in well construction. Today’s most common product is the solid expandable liner (SEL). This system consists of a liner string which is expanded down hole and hung in the preliminary base casing string. Although multiple products are available only two basically different design approaches for SEL could be identified. Both design approached covered in this thesis allow cementation of the SEL string, but due to their design characteristics the common practice have to be adapted. Well known practices, parameters and supporting tools, used to achieve good cement job quality, can hardly be applied, due to the changes in design and operational sequence compared to conventional liners. Due to these restrictions a good cementation quality for SEL strings is at least a challenging goal. Analyzing the cementation techniques, developed for the investigated SEL systems as well as the recommendations for SEL cementation, based on literature and field experience, the poor centralization capability was identified as one of the major characteristics which have to be handled. With the appearance of the SET technology as a commercial application, the good centralization technique became obsolete. Due to the low annular clearance while running typical SET strings and the expansion of the pipe it selves, standard centralizers couldn’t be applied. As the leak of centralization is known to be a negatively influence on cementation quality, a low clearance centralizer designs was required, able to join the expansion process without causing any destruction on the casing or constricting the expansion process while maintaining or generating centralization capabilities. Within the last years the first representatives of this new generation of centralizers entered the marked. For both investigated SEL designs, the service providers offer special centralization techniques. To quantify the impact of this new option, a simulation with marked leading software was performed. Therefore the standoff, which represents the degree of centralization, was investigated for both SEL designs with and without centralizers installed, over a range of application parameters. As a result an operation range could be identified, across which the minimum centralization requirements are fulfilled. Furthermore available data of a real world case have been used to investigate the standoff for an individual situation to confirm the initial simulation, which has to be based for simplification reasons on a more generalized point of view, and to optimize the application parameters for the new centralizer techniques

AB - Solid expandable tubular (SET) are wellbore pipes produced from steel or non-ferrous metals like titanium or aluminum, which show proper mechanical and chemical properties to withstand cold forming operations, in which their diameter is increased, while maintaining conventional pipe geometry and the capability to withstand a certain level of down-hole conditions. The process is performed via an oversized cone, which is forced through the pipe string. Within this procedure the pipe material is predominately deformed in hoop-direction under enormous tensional load. It is deformed over the elastic limit into the plastic region, resulting in a permanent increase in pipe body diameter. As the pipe is subjected to high stress without significant heat contribution the material properties are altered, changing the pipe load capabilities. As the conventional casing program is based on a continuous diameter reduction with each string installed, due to drift considerations, the installation of solid expandable tubular allow a diameter conservation, compared to the previous string up to 100 percent. Based on the technological concept of SET several different application designs have proved to be economically deployable as a tool in well construction. Today’s most common product is the solid expandable liner (SEL). This system consists of a liner string which is expanded down hole and hung in the preliminary base casing string. Although multiple products are available only two basically different design approaches for SEL could be identified. Both design approached covered in this thesis allow cementation of the SEL string, but due to their design characteristics the common practice have to be adapted. Well known practices, parameters and supporting tools, used to achieve good cement job quality, can hardly be applied, due to the changes in design and operational sequence compared to conventional liners. Due to these restrictions a good cementation quality for SEL strings is at least a challenging goal. Analyzing the cementation techniques, developed for the investigated SEL systems as well as the recommendations for SEL cementation, based on literature and field experience, the poor centralization capability was identified as one of the major characteristics which have to be handled. With the appearance of the SET technology as a commercial application, the good centralization technique became obsolete. Due to the low annular clearance while running typical SET strings and the expansion of the pipe it selves, standard centralizers couldn’t be applied. As the leak of centralization is known to be a negatively influence on cementation quality, a low clearance centralizer designs was required, able to join the expansion process without causing any destruction on the casing or constricting the expansion process while maintaining or generating centralization capabilities. Within the last years the first representatives of this new generation of centralizers entered the marked. For both investigated SEL designs, the service providers offer special centralization techniques. To quantify the impact of this new option, a simulation with marked leading software was performed. Therefore the standoff, which represents the degree of centralization, was investigated for both SEL designs with and without centralizers installed, over a range of application parameters. As a result an operation range could be identified, across which the minimum centralization requirements are fulfilled. Furthermore available data of a real world case have been used to investigate the standoff for an individual situation to confirm the initial simulation, which has to be based for simplification reasons on a more generalized point of view, and to optimize the application parameters for the new centralizer techniques

KW - Futterrohre

KW - Zementation

KW - Solid Expandables

KW - Casing

KW - Cementation

KW - Solid Expandables

M3 - Master's Thesis

ER -