Remote Well Stimulation Method

Abstract

A method for stimulation of a subsea oil and gas well is provided, comprising the deploying a tree cap on a subsea well using a remotely operated vehicle (ROV), wherein the tree cap includes one or more fluid receptacles; deploying a rigless stimulation tool (RST) in a predetermined location on the sea floor away from the well and other subsea production system infrastructure; deploying at least one flexible well service jumper (WSJ) conduit having a first end connector and a second end connector from a well stimulation vessel (WSV), where the WSJ conduit includes a plurality of attached buoyant members sufficient to enable movement by the ROV under an overhead obstacle, such as a mobile offshore drilling unit (MODU) or platform; operating the ROV to move the first end connector of the WSJ conduit to a first location near the tree cap and temporarily securing the securing the first end connector to the tree frame sufficient to enable flushing of the WSJ conduit with a hydrate inhibitor fluid; connecting the first end of the WSJ conduit to the tree cap; operating the ROV to connect fluid stimulation conduits to the RST to enable a fluidic connection; and delivering a well stimulation fluid via the fluid stimulation conduits through the RST and via the WSJ conduit to the well.

The invention claimed is: 
     
         1 . A method for stimulation of a subsea oil and gas well, comprising:
 (a) deploying a tree cap on a subsea well using a remotely operated vehicle (ROV), wherein the tree cap includes one or more fluid receptacles;   (b) deploying a rigless stimulation tool (RST) in a predetermined location on the sea floor away from the well and other subsea production system infrastructure;   (c) deploying at least one flexible well service jumper (WSJ) conduit having a first end connector and a second end connector from a well stimulation vessel (WSV), where the WSJ conduit includes a plurality of attached buoyant members sufficient to enable movement by the ROV under an overhead obstacle, such as a mobile offshore drilling unit (MODU) or platform;   (d) operating the ROV to move the first end connector of the WSJ conduit to a first location near the tree cap and temporarily securing the securing the first end connector to the tree frame sufficient to enable flushing of the WSJ conduit with a hydrate inhibitor fluid;   (e) operating a crane on the WSV to lower the WSJ conduit along a predetermined route away from the tree cap toward the RST;   (f) operating the ROV to connect the second end connector of the WSJ conduit to the RST to enable a fluidic connection;   (g) operating the ROV having an onboard supply of the hydrate inhibitor fluid and delivering the fluid through the WSJ conduit to displace water within the WSJ conduit;   (h) connecting the first end of the WSJ conduit to the tree cap;   (i) positioning the WSV in a safe overboarding zone (SOZ);   (j) while the WSV is positioned in a SOZ, deploying one or more fluid stimulation conduits from the WSV, wherein each of the fluid stimulation conduits has a first end connector and a second end connector, and wherein the first end connector is fluidically connected to a coiled tubing line on the WSV;   (k) operating the ROV to connect the second end connectors of the fluid stimulation conduits to the RST to enable a fluidic connection; and   
     
     
       ( 1 ) delivering a well stimulation fluid via the fluid stimulation conduits through the RST and via the WSJ conduit to the well. 
     
     
         2 . The method of  claim 1 , wherein the RST is mounted on a mudmat or suction pile. 
     
     
         3 . The method of  claim 1 , wherein during deployment of the WSJ conduit between the well and the RST by the ROV, the WSJ conduit is supported by one or more buoyant members. 
     
     
         4 . The method of  claim 1 , wherein the fluid stimulation conduits are connected to the coiled tubing lines via passive breakaway, such as mid line weak link (MLWL), connectors. 
     
     
         5 . The method of  claim 1 , wherein each of the coiled tubing lines include clump weights, and wherein the fluid stimulation conduits are lowered to a position where the clump weights are about 50-100 feet above the sea floor. 
     
     
         6 . The method of  claim 1 , wherein the fluid stimulation conduits are deployed via a pendant cable from the WSV, and wherein the pendant cable is disconnected when the fluid stimulation conduits are in a substantially vertical orientation. 
     
     
         7 . The method of  claim 1 , wherein the fluid stimulation conduits are deployed via a crane positioned on the WSV, and wherein the crane is disconnected when the fluid stimulation conduits are in a substantially vertical orientation. 
     
     
         8 . The method of  claim 1 , wherein the WSJ conduit is supported by a plurality of buoyant members as required to avoid contact with or relieve weight on other subsea assets. 
     
     
         9 . The method of  claim 1 , wherein the ROV is operated to position and install the WSJ conduit under the MODU or platform. 
     
     
         10 . The method of  claim 1 , wherein multiple WSJ conduits are connected between the tree cap and the RST.