Search

The even steam injection string for horizontal well can realize even steaming in long horizontal section of horizontal well for thermal production heavy oil and improve steam injection quality. However, compared with the often used Ø73 mm tubing, the conventional even steam injection string is larger in outside diameter, so there are a number ofvariable diameter on the whole string and hence the string is hard to retrieve; in addition, the steam distribution valve is directly opposite the screen tube, so there exists the risk of screen washout while stream injection. For this reason, an easy-to-retrieve, anti-sand burial even steam injection string for horizontal well is developed, which is composed of ball-like safety release joint, small diameter lateral steam distribution valve and small diameter check valve, etc. The steam comes out of distribution valve on side orifices, so avoiding the risk of screen washout; the outside diameter of the whole string is small without obvious diameter varieties, which reduces the risk of being unable to retrieve the string due to sand burial. The string is equipped with safe connections, so when the string is buried, the release can be realized to retrieve the upper tubing and then the lower tubing shall be fished. This technology enjoys a favorable prospect and promotional value in heavy oil horizontal wells with severe sand production and screen completion. [ABSTRACT FROM AUTHOR]

Aiming at problems encountered in using plug sealing technological string K344 such as "flag erecting & sausage stuffing" serious accidents, plugging agent being easy flow back, and existed bayonet-tube packer being poor pressure resistant and difficult drilling and removing, a research on safe sealing technological string with bayonet-tube has carried out. The newly safe plugging string is composed of novel bayonet-tube drillable bridge plug, setting tool, bayonet tube and centralizer. After ash injection, the bayonet tube could be rapidly pulled out and then the injection channel could be shut down to prevent the plugging agent flow back, which could avoid most of the accidents. The special sealing method of bayonet-tube tools and specific design of drilling and grinding tools with drillable bridge plugs greatly enhance the pressure resistant index and drillability of packers. Field application of this technological string has showed good effect and obviously increased the safety of sealing construction. [ABSTRACT FROM AUTHOR]

In this work, a T 2 -T 1 switchable superparamagnetic iron oxide nanoprobe with a pH/H 2 O 2 dual response was obtained using a microemulsion method. This novel method for the controllable assembly of small iron clusters followed by their independent modification was reported, which could not be prepared by common synthetic methods. The size of the assembled nanoprobe was uniform and controllable, with a stable T 2 magnetic resonance imaging (MRI) signal under a single condition. When the nanoprobe was exposed to the tumor environment, the higher H + and H 2 O 2 concentrations at the tumor site could dissociate the nanoprobe and redisperse into small iron clusters. When this occurred, the T 2 MRI signal was converted into a T 1 MRI signal, achieving specific detection of tumors by a pH/H 2 O 2 dual-response T 2 -T 1 MRI.

Ultrasmall superparamagnetic iron oxide nanoparticles (USPIONs) are a novel T1 contrast agent with good biocompatibility and switchable imaging signal that have not been widely applied for magnetic resonance imaging (MRI) because it is difficult to induce their relatively close ideal agglomeration. Here, by combining the microemulsion method with the biomineralization principle, a pH-responsive T2-T1 switchable MRI nanoprobe was constructed via the microemulsion-confined biomineralization of PEGylated USPIONs (PEG-USPIONs). The size of the formed CaCO 3 -coated PEG-USPION conjugates (PEG-USPIONs@CaCO 3 nanoprobe) was uniform and controllable, and the preparation method was simple. The PEG-USPIONs inside the nanoconjugates agglomerate more tightly, and the T1-MRI signal of the nanoprobe is converted to the T2-MRI signal. When exposed to the acidic environment of the tumor tissue or internal organelles, the CaCO 3 -coating of the nanoprobes is dissolved, and free PEG-USPIONs are released, thus realizing the T1-weighted imaging of the tumors. The suitability of the PEG-USPIONs@CaCO 3 nanoprobe for tumor MRI detection was successfully demonstrated using a mouse model bearing a subcutaneous 4T1 xenograft.

Here, we have developed a novel photoactivatable red chemiluminescent AIEgen probe (ACL), based on the combination of the red-emission AIEgen fluorophore (TPEDC) that shows excellent singlet oxygen ( 1 O 2 )-generation ability and the precursor of Schaap's dioxetane (the linker connected to adamantane is the C═C bond) that can be modified to target various analytes, for in vitro and in vivo measurement of hydrazine. Prior to applying for sensing detection, the C═C bond connected to adamantane in ACL was first converted into dioxetane by irradiation to form the activated chemiluminescent AIEgen probe (ACLD). Then, the self-immolative reaction was triggered upon the deprotection of the acylated phenolic hydroxyl group in ACLD in the presence of hydrazine, resulting in the release of the high energy held in the 1,2-dioxetanes, and then, the chemiexcitation was triggered, thereby producing red chemiluminescence through the intramolecular chemiluminescence resonance energy transfer from Schaap's dioxetane to TPEDC. This chemiluminescent AIEgen probe was evaluated in a clean buffer environment as well as using living cells and mouse models.