Synthesis and Molecular Dynamics Simulation of Amphiphilic Low Molecular Weight Polymer Viscosity Reducer for Heavy Oil Cold Recovery

In order to reduce the viscosity of heavy oil, the performance of emulsifying viscosity reducers is limited. In this study, a new kind of amphiphilic low molecular weight viscosity reducer was prepared by emulsion copolymerization of acrylamide (AM), acrylic acid (AA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and Butene benzene (PB). The synthesis feasibility and viscosity reduction mechanism of viscosity reducer in heavy oil were explored using Materials Studio software from the perspective of molecular dynamics. The results of the molecular dynamics simulation revealed that the addition of viscosity reducer into heavy oil varied the potential energy, non-potential energy, density and hydrogen bond distribution of heavy oil. Benefiting from its structure, the benzene ring in PB was well embedded in the interlayer structure of asphaltene, contributing to weaken the network structure of the heavy oil. Moreover, the two strong polar groups (COO− and SO3−) of AA and AMPS, which constituted the branched chains of the viscosity reducer’s molecular structure, gradually disassembled the network structure from the ‘inward’ to the ‘outward’ of the heavy oil network structure, thereby driving heavy oil viscosity reduction (as clarified by molecular dynamics). Owing to its temperature resistance, this kind of new amphiphilic low molecular copolymer could be an effective viscosity reducer for heavy oil cold recovery at elevated temperatures.

Intermolecular hydrogen bond ruptured by graphite with different lamellar number

Intermolecular hydrogen bonds are formed through the electrostatic attraction between the hydrogen nucleus on a strong polar bond and high electronegative atom with an unshared pair of electrons and a partial negative charge. It affects the physical and chemical properties of substances. Based on this, we presented a physical method to modulate intermolecular hydrogen bonds for not changing the physical–chemical properties of materials. The graphite and graphene are added into the glycerol, respectively, by being used as a viscosity reducer in this paper. The samples are characterized by Raman and 1H-nuclear magnetic resonance. Results show that intermolecular hydrogen bonds are adjusted by graphite or graphene. The rheology of glycerol is reduced to varying degrees. Transmission electron microscopes and computer simulation show that the spatial limiting action of graphite or graphene is the main cause of breaking the intermolecular hydrogen bond network structure. We hope this work reveals the potential interplay between nanomaterials and hydroxyl liquids, which will contribute to the field of solid–liquid coupling lubrication.

Synthesis of Alkyl Aliphatic Hydrazine and Application in Crude Oil as Flow Improvers

In this paper, alkyl aliphatic hydrazine, which is different from traditional polymer fluidity improver, was synthesized from aliphatic hydrazine and cetane bromide, and evaluated as a pour point and viscosity-reducer depressant for crude oil. The evaluation results showed that alkyl aliphatic hydrazone fully reduced the pour point and viscosity of crude oil with the increase of crude oil fluidity. The viscosity reduction rate of crude oil in Jinghe oilfield was 79.6%, and the pour point was reduced by about 11.3 °C. The viscosity reduction rate of crude oil in Xinjiang Oilfield was 74.7%, and the pour point was reduced by 8.0 °C. The long alkyl chain is beneficial to the eutectic of wax in crude oil, and the polar group inhibits the crystal growth, resulting in the decrease of pour point and viscosity. The waste oil is fully recycled into oilfield chemicals.

A Strategic Approach for Producing a PCP Well with High Flowline Pressures in a Restricted System

A progressive cavity pump (PCP) well (S-648) remotely located in Heritage's offshore field was unable to produce since October 2018 due to high flowline pressures. This paper describes the approach that was taken to produce the well and initiatives undertaken to resolve challenges. Analysis of the fluid properties was conducted for input into a multiphase flow simulation software. The software was utilized to determine flowline restriction and a solution to reducing flowline pressures by viscosity reduction and flowline replacement. Since subsea flowline replacement is a costly and time-consuming exercise, a laboratory viscosity evaluation was done utilizing a chemical viscosity reducer. The results were inputted into the software to determine the percentage reduction in flowline pressure for producing the well. The chemical solution was applied despite multiple challenges. Infrastructure on the location was a challenge with no pneumatic or 110V electrical supply to operate the chemical injection pump, limited space on the well deck for a chemical tank and no access to refill the chemical tank. Initiatives were taken to resolve these challenges and commission the injection. Upon commissioning of the chemical injection system, the flowline pressure reduced by approximately 70% and the well was able to restart and sustain production until this day. The initial chemical injection rate was optimized downwards for reducing the operating costs for the well without increase in the flowline pressure. Testing facilities were not available for this well at start up to quantify production, however pump functionality checks were being done to assure that fluid was moving through the system. The pump is capable of a flowrate of 200 barrels per day. Assuming 80% pump efficiency, the initial estimate of production gain from this initiative was approximately 70 barrels of oil per day. When testing facilities became available in February 2020, the well tested production was 172 barrels of oil per day. This approach can be utilized to start up and produce wells with high flowline pressures in an offshore environment within a short timeframe, where restrictions are present and modifying/replacing flowlines is not possible or cost effective.