SHAREHOLDER AGREEMENT, dated as of October 23, 1999 (this "Agreement"), by and among Compagnie
Generale de Geophysique, a French societe anonyme ("Parent"),Sercel Acquisition Corp., a Nevada corporation
("Purchaser"), and Tech-Sym Corporation, a Nevada corporation (the "Stockholder").
A. The Stockholder is the beneficial owner of 7,995,000 shares (the "Shares") of common stock, $.01 par value
per share (the "Common Stock"), of the Company.
B. Parent, Purchaser and Geoscience Corporation, a Nevada corporation (the "Company"), have entered into an
Agreement and Plan of Merger, dated as of the date hereof (as amended from time to time, the "Merger
Agreement"), which provides, among other things, that, upon the terms and subject to the conditions therein,
Purchaser will commence a cash tender offer to purchase at a price equal to $6.71 per share all the Common
Stock and thereafter provides that Purchaser will merge (the "Merger") with and into the Company and each
issued and outstanding share of Common Stock will be converted into the right to receive $6.71 in cash.
C. As a condition to the willingness of Parent and Purchaser to enter into the Merger Agreement, Parent and
Purchaser have requested that the Stockholder agree, and in order to induce Parent and Purchaser to enter into
the Merger Agreement, the Stockholder has agreed, to enter into this Agreement.
NOW, THEREFORE, in consideration of the foregoing premises and the representations, warranties, covenants
and agreements set forth herein, the parties hereto hereby agree as follows:
Section 1.1. Certain Definitions. Capitalized terms used but not otherwise defined herein have the meanings
ascribed to such terms in the Merger Agreement.
Section 1.2 Representations and Warranties of the Stockholder. The Stockholder represents and warrants to
and Purchaser, as of the date hereof and as of the Offer Completion Date, as follows:
(a) The Stockholder is the beneficial owner (as