Downhole shut-in device for pressure variation testing in gas lift wells

Abstract

The device is based on the principle of downhole shut-in of oil producing wells that do not flow to surface self-powered but require the injection of gas to lighten the fluid column and thus enable the well to produce. This downhole shut-in device comprises a check valve, an anchoring system, a seal system; an untethering system, a shock absorber and a sleeve for the protection of pressure and temperature memory probes. The objective of the downhole shut-in device is to obtain characteristic information of the fluid-rock system from variations in the pressures recorded in order to obtain the dynamic characterization of the reservoir.

1 . A downhole shut-in device for testing pressure variation in gas lift wells, characterized in that it comprises a check valve for pressure retaining with variable opening, which allows the flow path of the reservoir, an anchoring system, which allows to install the device into the production tubing, a sealing system which has the function of sealing the well, an anchorage system, which is composed of four lower jaws and three upper ones; an untethering system, which allows to retrieve the device, a shock absorber, which serves to dissipate the energy generated by shock and vibration in the body of the device during all stages of the operation and a jacket for memory probes, to avoid loss of information due to operating conditions in which the reservoir may be, even preventing damage to probe circuitry. 
     
     
         2 . A downhole shut-in device for testing pressure variation in gas lift wells, according to  claim 1 , wherein the check valve allows reservoir flow only from bottom to top of the closure equipment. 
     
     
         3 . A downhole shut-in device for testing pressure variation in gas lift wells, according to  claim 1 , wherein the check valve has a homogeneous fluid inlet and outlet according to the fluid composition, flow rate and downhole pressure when the well is flowing, and at the top it has the fishing neck, which is designed to work with a JDC pulling tool. 
     
     
         4 . A downhole shut-in device for testing pressure variation in gas lift wells, according to  claim 1 , wherein the anchorage bidirectional system comprises four lower jaws and three upper ones, which allow the device to be placed on any free area of the production tubing. 
     
     
         5 . A downhole shut-in device for testing pressure variation in gas lift wells, according to  claim 1 , wherein the sealing mechanism comprises three high temperature resistant seals and ensures the tightness to prevent the well flow pass otherwise than within the device in its operation. 
     
     
         6 . A downhole shut-in device for testing pressure variation in gas lift wells, according to  claim 1 , wherein the shock absorber can dissipate the energy generated by shock and vibration in the device body during all phases of operation. 
     
     
         7 . A downhole shut-in device for testing pressure variation in gas lift wells, according to  claim 1 , wherein the probe jacket protects memory probes from any impact occurred during the course of the operation of the device.