Our Team

Kristoforus Jimmy Yans
Managing Partner

Jimmy obtained his law degree from University of Indonesia. Jimmy has served several multinational companies during his initial three years working period It gave him a lot of experience to handle compliance matter, foreign direct investment and licenses. In 2010, he started his professional career in a prominent law firm specializing in oil & gas industry. During his professional career, he experience in drafting contract and legal opinion regarding specific legal issues encountered by client, performing legal due diligence to support client with legal data analysis for conducting corporate action, representing client in a contract negotiation, dispute resolution both non-litigation and litigation before Indonesia national court or arbitration.

Throughout his career, he has advises Indonesian oil and gas state owned enterprise, regional owned enterprises, special task force for upstream oil and gas business activities Republic of Indonesia (SKK Migas), both domestic and foreign PSCs contractors, oil and gas service companies, cooperation operation (KSO) partner companies, startup companies, and also individual which encounter legal matter such as land matter, property, etc. By his experiences and competency, he is an expert in drafting agreements which related to engineering procurement construction (EPC) project, drilling and drilling support service, unitization of oil and gas fields, cooperation oil and gas operation in Pertamina working area, gas sales and transportation. He has also obtained certificate as PSC tender committee member issued by SKKMigas.

His professional experiences are among others:

  1. Assist Indonesian authorities in preparing draft of laws and regulations particularly in oil and gas industry;
  2. Assist PSCs contractor in tender process in compliance with SKK Migas working guidelines;
  3. Providing legal opinion to Indonesian PSCs contractor concerning variety legal issues related to Indonesian oil and gas industry e.g. implementation of PSC, EPC dispute, Participating Interest Acquisition, and other implementation of Indonesian law and regulation;
  4. Perform legal due diligence prior the participating interest (PI) acquisition and other corporate action;
  5. Advising regional owned enterprise concerning its cooperation with investor/financier in regard with 10% Indonesian participant; 
  6. Preparing, reviewing and negotiating contracts for Indonesian oil and gas state owned enterprises and other PSCs contractors, such as Oil and Gas Production Sharing Contracts, Joint Operating Agreements, Unitization and Unit Operating Agreements, Facility Sharing Agreements, Farm in Agreements, Engineering Procurement Construction Installation Agreements, Seismic/ drilling/ vessel/ fixed wing agreements, Principle of Agreement for the field development of Liquid Natural Gas, Operational Cooperation Agreement (KSO), Technical Assistance Contract, Enhanced Production Cooperation Agreement, Old Wells Work-over Contracts, Gas Sale Agreements, Partnership Agreements, and other contracts;
  7. Providing legal services to several investment funds of some major investment companies in terms of its dissolution and liquidation.

Adhesa Pramudya Abiyanto

Senior Associate

Adhesa graduated from Faculty of Law of Atma Jaya Catholic University in 2010, and obtained his Master Degree from Faculty of Law of Gadjah Mada University in 2017 both focusing on Economic & Business Law. Adhesa had honed his experience in providing legal services since 2010 from working in several prominent law firms. Adhesa had experienced in handling clients from various background, such as state owned companies, PSC contractors, oil & gas service companies, shipping companies, plantation companies, general mining companies and individuals, and he involved in many projects in oil & gas industry and dispute settlement.

In dispute resolution and litigation, Adhesa had represent clients in court and arbitration tribunal for various disputes such as EPCI contract, Technical Assistance Contract (TAC), Refinery Lease agreement, Construction, Coal Agency Agreement, Industrial Relation, Pre-emptive right, minority shareholder and many others. He also involved as defense attorney on various corruption case. Adhesa held Advocate License from PERADI.

Margaretta Mellisa

Senior Associate

Mellisa obtained her Bachelor of Law degree focusing on business law from the University of Indonesia. Mellisa joined at JTAsyer in 2017, before joined at JTAsyer she worked at several well-known media company such as, Ochannel TV, Skymedia Network, and MTV Indonesia , and she had experienced in handling media and advertising industries projects.

During her working period, she experienced in assisting client to obtain several permits with Indonesia regulatory bodies such as Ministry of Health, Indonesia Investment Coordinating Board, Ministry of Law and Human Right, Ministry of Industry, regional government and several other relevant government institutions. She has also experienced in reviewing agreement within the area of entertainment law, power purchase, oil and gas, vessel charter, coal sales, and involving in a dispute resolution both before commercial arbitration and also Indonesia national court. With her experiences worked in media and advertising industry, Mellisa also providing opinion and research regarding media and advertising agreement. Mellisa held Advocate License from PERADI.

Mohammad Fahruli 

Senior Associate

Fahruli obtained his Bachelor of Law from Universitas Kristen Indonesia, majoring in Criminal Law. Fahrul joined at JTAsyer in 2022, prior joining JTAsyer Law Firm, He worked at several boutique law firm, and He had experiences involved in litigation and dispute resolution, employment, investment and general corporate matters. Fahruli is a member of Indonesian Advocates Association (Perhimpunan Advokat Indonesia – PERADI).

Erneylla Edwina Pritha 


Pritha obtained her Bachelor of law from Atma Jaya Catholic University in 2017, and later joined in JTAsyer at the same year. Pritha experienced in the areas of Corporate Commercial/Mergers & Acquisitions, Oil and Gas, Electricity, and also involved in represent companies or individuals in dispute resolution such as asset ownership dispute, asset proxy dispute and industrial relation dispute.

    Meliana Manurung 

Junior Associate

Meliana joined at JTAsyer in 2021. At JTAsyer, Meliana handles general corporate matters and she also involved in many oil and gas industry projects such as drafting agreement. Meliana obtained her Bachelor of Law from Atma Jaya Catholic University of Indonesia in 2020, focusing on International Law. During college, Meliana active in student’s organization and participating at the 13th Indonesian Round of The International Humanitarian Law Moot Court Competition and got 2nd Best Memorial.

 Mas Insan Kamil 

Junior Associate

Insan Kamil graduated from the Faculty of Law, Universitas Gadjah Mada in early 2023. During his studies, he developed an interest in environmental and energy matters. Insan Kamil joined JTAsyer Law Firm in mid 2023. During his time in JTAsyer Law Firm, he is assisting other Associates in litigation and general corporate matters relating to energy, electricity, oil & gas disputes.